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Global Changes and Sierra Nevada Forests of the Future: Managing in the Face of Uncertainty
... These objectives are often achieved using mechanical thinning and prescribed burning treatments (Agee & Skinner, 2005;Hessburg et al., 2015Hessburg et al., , 2021Jain et al., 2012;Prichard et al., 2021) and by leveraging the beneficial work of wildfires (Chamberlain, Bartl-Geller, et al., 2024;Churchill et al., 2022;Huffman et al., 2020). With disturbance regimes and vegetation dynamics continuing to shift with climate change (McDowell et al., 2020;Schoennagel et al., 2017;Weed et al., 2013), ongoing evaluation of treatment effectiveness will be a critical component of adaptive management programs in dry forest ecosystems in decades to come Larson et al., 2013;Millar et al., 2007). ...
... We demonstrate how the use of SAR models can ensure that underrepresented yet potentially important treatment categories can still be evaluated, while producing robust statistical outputs. These evaluations of less common treatment types could support increased experimentation and learning by managers Larson et al., 2013;Millar et al., 2007). F I G U R E 5 Drivers of burn severity and treatment effectiveness for the Schneider Springs Fire, Washington, USA. ...
... Wildfires are increasing in size and severity across many forested ecosystems of western North America (Cova et al., 2023;Parks et al., 2023;Singleton et al., 2019), prompting managers to implement treatments to mitigate fire risk and improve forest resilience (Hessburg et al., 2015Prichard et al., 2021). Studies that evaluate how treatments influence burn severity are common in the literature; however, continued monitoring of treatment effectiveness is essential, especially as climate change continues to have novel impacts on fire weather, fuel dynamics, and associated fire behavior and severity (Millar et al., 2007). Under futures marked by increasing novelty and uncertainty, our framework can provide critical decision-support criteria that may promote more strategic management actions aimed at reducing wildfire risk and fostering resilience across dry forest ecosystems of western North America. ...
Interruption of frequent burning in dry forests across western North America and the continued impacts of anthropogenic climate change have resulted in increases in fire size and severity compared to historical fire regimes. Recent legislation, funding, and planning have emphasized increased implementation of mechanical thinning and prescribed burning treatments to decrease the risk of undesirable ecological and social outcomes due to fire. As wildfires and treatments continue to interact, managers require consistent approaches to evaluate treatment effectiveness at moderating burn severity. In this study, we present a repeatable, remote sensing–based, analytical framework for conducting fire‐scale assessments of treatment effectiveness that informs local management while also supporting cross‐fire comparisons. We demonstrate this framework on the 2021 Bootleg Fire in Oregon and the 2021 Schneider Springs Fire in Washington. Our framework used (1) machine learning to identify key bioclimatic, topographic, and fire weather drivers of burn severity in each fire, (2) standardized workflows to statistically sample untreated control units, and (3) spatial regression modeling to evaluate the effects of treatment type and time since treatment on burn severity. The application of our framework showed that, in both fires, recent prescribed burning treatments were the most effective at reducing burn severity relative to untreated controls. In contrast, thinning‐only treatments only produced low/moderate‐severity effects under the more moderate fire weather conditions in the Schneider Springs Fire. Our framework offers a robust approach for evaluating treatment effects on burn severity at the scale of individual fires, which can be scaled up to assess treatment effectiveness across multiple fires. As climate change brings increased uncertainty to dry forest ecosystems of western North America, our framework can support more strategic management actions to reduce wildfire risk and foster resilience.
... C'est avec ce mode de gestion qu'émergent les notions de résistance, résilience et réponse de l'écosystème aux effets du changement climatique. D'après Millar et al. (2007), la résistance désigne la capacité d'un écosystème à résister à l'influence du changement climatique ou à éviter les effets nuisibles du changement. Les pratiques visant à créer de la résistance cherchent à améliorer les défenses des forêts contre les effets directs et indirects des changements environnementaux. ...
... Résilience : capacité d'un écosystème à retourner à un état désiré après une perturbation (Millar et al., 2007). Une forêt est résiliente si elle peut s'adapter à des changements graduels puis recouvrer un état antérieur après la perturbation, que ce soit naturellement ou grâce à la gestion (Thorne et al., 2017). ...
... Transition : capacité d'un écosystème à s'adapter à l'accumulation des changements environnementaux (Millar et al., 2007). ...
Un habitat forestier est un ensemble indissociable avec une faune, une végétation, et un compartiment stationnel (climat, sol…). Avec les impacts déjà visibles du changement climatique, une réflexion globale sur la préservation et la gestion des habitats forestiers est urgente : les cortèges floristiques évoluent, certaines essences dépérissent, d’autres risquent de voir leur aire de répartition se modifier... En France, les outils dont disposent les forestiers pour évaluer ces risques concernent principalement les essences de production, sans vision intégrative de la vulnérabilité des écosystèmes. L’intégration du changement climatique dans la préservation et la gestion des habitats forestiers nécessite de développer un cadre méthodologique cohérent et reproductible permettant de quantifier leur vulnérabilité. De quelle façon les habitats sont déjà et seront exposés à ces changements ? Les habitats sont-ils sensibles aux changements climatiques (contraction ou déplacement de la niche écologique favorable, dépérissements
d’essences, sensibilité de la flore des sous-bois…) ? Les habitats peuvent-ils s’adapter au changement climatique (seuls ou via des sylvicultures adaptatives) ?
Conscient des enjeux, le CNPF-IDF a développé ces dernières années une méthode
reproductible d’évaluation de la vulnérabilité climatique des habitats forestiers.
L’objectif est, d’une part, de produire un diagnostic de vulnérabilité propre à chaque
habitat selon une échelle d’étude donnée (territoire, parcelle), et d’autre part, d’éclairer les décideurs et les gestionnaires sur la manière d’adapter leurs modes de gestion des habitats forestiers en contexte de changement climatique.
Ce guide méthodologique a pour but de faciliter l’appropriation de cette méthode par les acteurs forestiers. Il fournit dans un premier temps les fondements méthodologiques du diagnostic de vulnérabilité. Des exemples concrets sont ensuite présentés afin d’illustrer le fonctionnement de la méthode et son application à divers habitats. Ainsi, ce guide contribue à promouvoir l’intégration des enjeux liés au changement climatique dans la gestion des écosystèmes forestiers et à encourager la transition vers une gestion plus proactive, qui anticipe et atténue les effets des dérèglements climatiques.
... This is exemplified by the rapid pace of climate change, which could exceed the natural migration rate of some species, leading to maladaptation and ecological and economic losses (Aitken et al., 2008;Mckenney et al., 2011;Price et al., 2013;Etterson et al., 2020;Prasad et al., 2020;Bisbing et al., 2021). One adaptation strategy increasingly discussed is Forest Assisted Migration (FAM), usually as a mechanism to accelerate natural species or genotype migration to compensate for anticipated ecological, economic, and cultural losses (Millar et al., 2007;Pedlar et al., 2012;Williams and Dumroese, 2013;Nagel et al., 2017;Palik et al., 2022). The emerging consensus is that as forest vulnerability to climate change increases, FAM will likely become an increasingly important strategy in forest conservation and management. ...
... There is a growing need to manage for climate-driven range shifts (Bonebrake et al., 2018). Novel strategies and frameworks aimed to conserve ecosystem integrity under climate change, including FAM, are being increasingly researched and implemented (Millar et al., 2007;Pedlar et al., 2012;Nagel et al., 2017;Palik et al., 2022;Royo et al., 2023). Challenges implementing FAM include identifying optimal seed sources and estimating seed-transfer guidelines when relevant genetic information is unavailable. ...
Introduction: Global climate change and associated stressors threaten forest ecosystems due to the rapid pace of climate change, which could exceed the natural migration rate of some tree species. In response, there is growing interest to research and implement forest assisted migration (FAM). Here, we used a species-independent indicator based on climate analogy, according to the sigma (dis)similarity (σd) index, to match planting sites across the eastern US with (future) climatically-compatible seedlots (CCS).
Methods: We developed CCS for a grid composed of 1 × 1° of latitude and longitude. CCS were based on future climate analogs with ≤2σd analogy to ensure CCS were representative of future climate change. CCS were located for three time periods, 2030's, 2050's, and 2090's and three emissions scenarios (SSP2-4.5, SSP3-7.0, and SSP5-8.5) from the Coupled Model Intercomparison Project phase 6 database, using 12 climate variables.
Results: CCS were identified for the majority of 1 × 1° grids based on the SSP3-7.0 scenario. Approximately 28% of 1 × 1° grid's 2090's projections included future climate novelty. The 2030's, 2050's, and 2090's CCS were located on average 222, 358, and 662 km or 1, 2, and 3 eastern seed zones away from the 1 × 1° grids, respectively. CCS were also located further south-southwest (188–197°). In addition, the average forest cover of CCS was approximately 2%, 5%, and 10% less than that of the 1 × 1° grids.
Discussion: Our development and synthesis of CCS emphasized four key results: (i) average distances to 2030's and 2050's CCS were similar to seed-transfer guidelines for some tree species, but 2090's CCS exceeded current recommendations; (ii) south-southwesterly locations of CCS aligned with tree species habitat distribution dynamics; (iii) future climate novelty potentially challenges the conceptual basis of FAM if tree species are not adapted to climate change; and (iv) variation in forest cover among CCS presents potential opportunities and challenges due the presence or absence of forestland to source seed. Ultimately, our goal was to locate and synthesize CCS that could enable FAM decision support.
... Despite extensive research on maple biology, gaps remain in understanding their biogeographical distribution and ecological adaptations (Millar et al 2007, Foster et al 2018. This review synthesizes existing literature on maple species' distribution patterns, soil preferences, climate requirements, and adaptive strategies. ...
... Sustainable forest management practices, including habitat protection, restoration efforts, and climate-resilient silvicultural practices, are essential for preserving maple ecosystems and their ecological and economic benefits in the face of ongoing environmental challenges. Collaboration among scientists, policymakers, and land managers is vital for integrating scientific knowledge into decision-making processes and ensuring the long-term sustainability and resilience of maple forests (Millar et al 2007, Foster et al 2018. ...
Maple trees, iconic symbols of Canada's temperate forests, epitomize a profound evolutionary heritage, intricate biogeographical distribution, and remarkable ecological adaptations. This comprehensive review synthesizes existing research on maple trees, exploring their evolutionary origins, historical migration patterns, soil preferences, climate requirements, and adaptive strategies. Through an interdisciplinary approach, we examine the interplay of geological phenomena, environmental dynamics, and human influences that shape the distribution and diversity of maple species worldwide. Insights gleaned from this review enhance our understanding of maple trees' ecological significance and inform conservation efforts to preserve their habitats and genetic diversity amidst global environmental changes.
... Global climate change is expected to affect forested ecosystems worldwide, with impacts to community structure, composition, and ecosystem function (Dale et al., 2001). Consequently, these challenges have given rise to forest management strategies that emphasize ecological maintenance and restoration , climate change adaptation (Millar et al., 2007;Bowditch et al., 2020), and greenhouse gas mitigation (i.e., natural climate solutions; (Griscom et al., 2017). Understanding how to implement these strategies, along with associated barriers and opportunities, will be important for moving towards operational implementation of climate-smart and adaptive management strategies in the face of global change (Nagel et al., 2017;Verkerk et al., 2020). ...
... Although many respondents reported to have had experience implementing strategies related to maintaining historical conditions (e.g., reforestation of native species, maintenance of ecosystem function, rehabilitation of degraded sites), fewer anticipate future projects solely focused on these objectives. This trend is supported by other results in our study that illustrate the population of forest managers sampled here underemphasize strategies aimed at resisting the effects of global change (e.g., planting to maintain historical/existing conditions), rather, they exhibit a preference for planting strategies related to promoting adaptation, resilience, or ecological transition (e.g., to diversify current conditions, to change forest conditions to align with future climate, to change forest conditions to adapt to disturbances, and to store more carbon and greenhouse gasses; (Millar et al., 2007;Palik et al., 2022). ...
Threats to the future function of forested ecosystems and stability of ecosystem service provisioning due to global change have motivated climate-adaptive forest management strategies that include various forms of tree planting termed "adaptation plantings". Despite the emergence of these strategies, less is known as to how foresters and other natural resource managers perceive or are engaged with adaptation plantings like forest assisted migration (FAM). This knowledge gap is most pronounced in regions like New England and the North Central US (hereafter, the Northeastern US) where tree planting is less common but expected to be an important forest management tool for adaptation. To address this, we surveyed 33 natural resource managers in this region actively engaged in climate change adaptation (i.e., early adopters of the practice) to assess how tree planting for adaptation is currently being pursued against the perceived barriers, opportunities, and potential future engagement with the strategy. Survey respondents overwhelmingly (93.5%) forecast increases in the future use of adaptation plantings in their work in the region, attributed to increased awareness, acceptance, and interest in the practice. Respondents expressed notable interest in strategies related to diversification and most types of FAM (e.g., assisted population expansion and assisted range expansion), but hesitancy to engage with more contentious planting types like afforestation or FAM linked to the long-distance translocation of exotic species (e.g., assisted species migration). Although examples of local enrichment plantings (i.e., non-FAM) proliferate, nineteen of the top twenty most common tree genera planted contain at least one example of FAM in the study region. The most notable barriers reported were themed as 1) biotic and abiotic, 2) information and material, and 3) policy, social, and economic factors. While most respondents report difficulty obtaining adequate planting material from nurseries (i.e., seedlings), over 80% placed orders shortly before planting (< 1 year) which likely generates difficulty in sourcing seedlings suited for a specific site and future range of environmental conditions. Although this study is limited by focusing on subset of natural resource managers who are early adopters of climate change adaptation within the region, valuable inferences into the barriers and trends are possible from this population serving on the front lines of forest adaptation. Together, these results from early adopters suggest a potentially growing need for allocating resources that engage forest stewards in adaptation planning and serve to refine policy, financing, and management practices to support this adaptation strategy in this region and beyond.
... When managing for ecological resilience, the aim is to maintain or restore key functions, as opposed to emergent properties of ecosystems (i.e., biodiversity measured as species richness) (Bone et al., 2016;Millar et al., 2007). One challenge that arises when managing for functional resilience is the potential contradiction with biodiversity conservation objectives, since functioning could supposedly be maintained by a few dominant species (e.g., Grime, 1997;Schwartz et al., 2000) or even non-native species (Leuzinger & Rewald, 2021). ...
... However, to meet conservation objectives, there must be recognition of both the role social systems play in the resilience of ecological systems and how social systems change with a nonstationary climate and continued human development (Adger, 2000;Mauer, 2020). Rivers are experiencing significant changes in the 21st century due to shifting climates, societies, and economies introducing uncertainty that impedes conservation decision-making while also increasing its urgency (Jones et al., 2016;Millar et al., 2007;Morelli et al., 2016;Polasky et al., 2011). The challenge is that a changing climate and societal structure influence the diversity and underlying objectives of actors, which may be economic but also culturally derived (Hoelting, 2022). ...
The United Nations' Convention on Biological Diversity set forth the 30 × 30 target, an agenda for countries to protect at least 30% of their terrestrial, inland water, and coastal and marine areas by 2030. With <6 years to reach that goal, riverine conservation professionals are faced with the difficult decision of prioritizing which rivers or river segments should be conserved (protected and/or restored). While incorporating resilience into conservation planning is essential for enhancing, restoring, and maintaining the vital riverine ecosystem services (ES) most threatened by climate change and other environmental and human stresses, this paradigm is at odds with traditional conservation approaches that are either opportunistic or reactionary, where only unique and highly visible ecosystems have been prioritized. Barriers to implementing resilience‐based riverine conservation planning include: (1) difficulties in conceptualizing and quantifying resilience; (2) insufficient consideration of the social components of riverine systems; (3) the inapplicability of terrestrial‐only conservation models to aquatic systems; and (4) the traditional ad hoc and opportunistic approach to conservation. To overcome these barriers, we propose a resilience‐based riverine conservation framework that includes: (1) assessing riverine resilience using indicator frameworks; (2) considering rivers as dynamically coupled social–ecological systems; (3) explicitly incorporating terrestrial–aquatic network connectivity into conservation decision‐making; and (4) strategic systems planning using a novel resilience–conservation matrix as a tool. This framework has the potential to transform conservation practices around the globe to more effectively protect river systems and enhance their resilience to climate change and human development.
This article is categorized under: Water and Life > Conservation, Management, and Awareness
Science of Water > Water and Environmental Change
Human Water > Water Governance
... For Q3, we combine the NSO HSH map (Q1) with climate-based projections of forest vegetation zones and estimates of severe wildfire likelihood. Finally, and consistent with the climate adaptation literature (e.g., Lynch et al., 2021;Millar et al., 2007), we distill the information gleaned through our process to map our study area into four ecologically-anchored categories that can guide where to manage for NSO HSH and where to focus on restoring open canopy, fire resistant forest (Fig. 1). Taken together, our approach can help managers estimate sustainable levels of NSO HSH habitat and identify locations with the greatest probability of current and future persistence in increasingly dynamic landscapes. ...
... Our approach of examining habitat through an ecological and management lens (Figs. 1,8,9) aligns well with the climate adaptation literature (Gaines et al., 2012;Hobbs et al., 2014, Lynch et al., 2021Millar et al., 2007), identifying those locations where change can be resisted or facilitated/directed, and where resilience can be fostered through active management. However, which adaptation strategy is chosen by land managers will vary over space and through time. ...
Keywords: Wildfire, Climate change, Late-successional forest, Adaptive management, Digital aerial photogrammetry (DAP), LiDAR.
A B S T R A C T Maintaining dense forest habitats for the threatened northern spotted owl (NSO) has proven challenging in seasonally dry, fire-dependent landscapes where low-density conditions were historically dominant and are generally more climate-and disturbance-resilient. To better inform the dual, sometimes-conflicting objectives of species conservation and forest resilience, we developed an approach to evaluate NSO habitat sustainability by: (1) quantifying the structure of high suitability habitat (HSH) associated with NSO using two remotely sensed platforms, (2) estimating current and historical HSH abundance, and (3) identifying HSH locations more likely to persist given current and future forest-zone climate projections and increasing risk of severe wildfire. Tall, closed-canopy conditions effectively comprised the key structural features of HSH, providing a means to map habitat through time. Both historical amounts and contemporary spatial patterns of HSH and other forest and non-forest conditions around occupied NSO sites indicated that HSH and forest resilience goals can be congruent at multiple scales. Independent lines of evidence suggest HSH historically composed ~18-24% of the dry and moist mixed-conifer landscape-considerably lower levels than current management goals in many areas. Projected shifts in climate and severe-fire likelihood suggest substantial spatial and temporal shifts where HSH will be sustainable into the future-mainly in currently moist as well as some cold forest types. These findings can inform the potential convergence and trade-offs of species conservation and disturbance resilience goals across local and regional landscapes, based on the inherent capacity of the landscape to support both goals under projected shifts in climate and wildfire.
... The combination of climate change and a range of anthropogenic stressors, including land use change, pollution, and introduction of nonnative species (e.g., Bates et al., 2017;Christensen et al., 2006;Jenny et al., 2020), is resulting in ecological transformation, defined by Crausbay et al. (2022, p. 72) as "the dramatic and irreversible shift in multiple ecological characteristics of an ecosystem, the basis of which is a high degree of turnover in ecological communities." Inherent in the challenge of ecological transformation is the "nonstationarity" of future climate conditions (Milly et al., 2008), which often creates disparities between emerging ecological realities and ecological objectives that were set based on historical baselines (Biggs et al., 2018;Millar et al., 2007;Schuurman et al., 2022;West et al., 2009). As Crausbay et al. (2022, p. 71) point out, "the rates and magnitudes of modern global change challenge the viability of longstanding management philosophies, cultures, and mandates built on the assumption that the climate of the future-and therefore what is ecologically possible in a given place-will reflect the past (e.g., US Forest Service's 2012 Forest Planning Rule, US Fish and Wildlife Service policies on habitat management in wildlife refuges)." ...
... In Figure 4, as citizen and stakeholder attitudes evolve in response to changing ecological conditions, we expect that accept and direct strategies will become more viable, with direct strategies being at an early disadvantage given the widespread distrust at present of meddling with nature (Hagerman & Satterfield, 2014;Sjoberg, 2000). Conversely, resist strategies may become a less preferred option (and thus less publicly feasible) as resist strategies become more ecologically challenging or expensive (Millar et al., 2007;St-Laurent et al., 2018). We greatly expanded the range of uncertainty of resist strategies to encompass the possibility of emerging public support for direct strategies that involve higher levels of intervention in ecosystem process and function. ...
Ecological transformations are occurring as a result of climate change, challenging traditional approaches to land management decision‐making. The resist–accept–direct (RAD) framework helps managers consider how to respond to this challenge. We examined how the feasibility of the choices to resist, accept, and direct shifts in complex and dynamic ways through time. We considered 4 distinct types of social feasibility: regulatory, financial, public, and organizational. Our commentary is grounded in literature review and the examples that exist but necessarily has speculative elements because empirical evidence on this newly emerging management strategy is scarce. We expect that resist strategies will become less feasible over time as managers encounter situations where resisting is ecologically, by regulation, financially, or publicly not feasible. Similarly, we expect that as regulatory frameworks increasingly permit their use, if costs decrease, and if the public accepts them, managers will increasingly view accept and direct strategies as more viable options than they do at present. Exploring multiple types of feasibility over time allows consideration of both social and ecological trajectories of change in tandem. Our theorizing suggested that deepening the time horizon of decision‐making allows one to think carefully about when one should adopt different approaches and how to combine them over time.
... This information enables efficient prioritization and resource allocation by identifying areas where management activities can increase the adaptive capacity of ecosystems and minimize adverse impacts. Incorporating climate change in the R&R framework can identify areas where important changes in climate are expected and can allow managers to evaluate all options for responding to transitioning ecological conditions, for example, directing ecosystems to new conditions (Millar et al., 2007;Schuurman et al., 2022;Snyder et al., 2018). ...
In water‐limited dryland ecosystems of the Western United States, climate change is intensifying the impacts of heat, drought, and wildfire. Disturbances often lead to increased abundance of invasive species, in part, because dryland restoration and rehabilitation are inhibited by limited moisture and infrequent plant recruitment events. Information on ecological resilience to disturbance (recovery potential) and resistance to invasive species can aid in addressing these challenges by informing long‐term restoration and conservation planning. Here, we quantified the impacts of projected future climate on ecological resilience and invasion resistance (R&R) in the sagebrush region using novel algorithms based on ecologically relevant and climate‐sensitive predictors of climate and ecological drought. We used a process‐based ecohydrological model to project these predictor variables and resulting R&R indicators for two future climate scenarios and 20 climate models. Results suggested widespread future R&R decreases (24%–34% of the 1.16 million km² study area) that are generally consistent among climate models. Variables related to rising temperatures were most strongly linked to decreases in R&R indicators. New continuous R&R indices quantified responses to climate change; particularly useful for areas without projected change in the R&R category but where R&R still may decrease, for example, some of the areas with a historically low R&R category. Additionally, we found that areas currently characterized as having high sagebrush ecological integrity had the largest areal percentage with expected declines in R&R in the future, suggesting continuing declines in sagebrush ecosystems. One limitation of these R&R projections was relatively novel future climatic conditions in particularly hot and dry areas that were underrepresented in the training data. Including more data from these areas in future updates could further improve the reliability of the projections. Overall, these projected future declines in R&R highlight a growing challenge for natural resource managers in the region, and the resulting spatially explicit datasets provide information that can improve long‐term risk assessments, prioritizations, and climate adaptation efforts.
... Future climate change (i.e., global warming and increased summer dryness) is expected to generally reduce forest productivity and increase rates of tree mortality (Allen et al. 2010). Climate change's potential impact on forest resources poses a huge challenge for sustainable management (Millar et al. 2007). To address these climate challenges, it is important to develop climate-smart technologies and management approaches (Shephard et al. 2022), especially in urban areas (Swanson et al. 2016). ...
... Changing climate conditions and disturbance regimes are likely to catalyze changes in species distributions by altering the survival of mature trees and limiting tree regeneration (Dobrowski et al., 2015;Coop et al., 2020;Stevens-Rumann et al., 2022). Combined with additional biotic pressures, such as chronic browsing by introduced herbivores (Leopold et al., 1947;Nuñez et al., 2010,), these novel interacting disturbances compromise an ecosystem's adaptive capacity (i.e., the ability to adjust composition, structure, and function in response to external forces) (Millar et al., 2007;Nagel et al., 2017). Understanding and anticipating species' responses to these pressures offers insight into how managers can sustain forest ecosystems. ...
Changes in forest structure and shifts in tree species composition have occurred globally due to climate change and altered disturbance regimes. With climate trending toward warmer and drier conditions, these altered forest communities may reorganize in diverse and unpredictable ways. This is especially true in mountain environments where a range of vegetation types and abiotic conditions coexist. In this study, we used long-term permanent plot data from a site spanning broad environmental gradients to assess regeneration and mortality patterns in populations of aspen (Populus tremuloides). The study site, located on the San Francisco Peaks, Ari-zona, USA, is near the hot, dry edge of the species' range and has experienced compounding pressure from extreme drought, chronic ungulate browsing, and wildfire in the past two decades. Over a 20-year study period, spanning one of the most prolonged drought periods in at least 1200 years, aspen overstory mortality averaged 42 % and was most common in smaller, younger trees and at lower elevations. Aspen regeneration density increased 13 % and was found in a greater proportion of study sites. However, we observed a noticeable lack of stems in the tallest regeneration size class (>200 cm) and the smaller tree size class (2.5-15 cm in diameter), potentially indicating a demographic bottleneck whereby few trees are recruiting into the overstory. Likewise, prolific aspen suckering occurred after a 2001 wildfire, although regeneration density eventually decreased to pre-fire levels, with <1 % of individuals reaching heights >200 cm. Aspen regeneration densities showed the greatest increases in cool, wet sites and beneath open forest canopies. Disturbances function as catalysts for aspen regeneration, but persistence of aspen stands depends on recruitment of stems into overstory size classes, a process that is limited, particularly on lower and more exposed sites.
... These changes increase the uncertainty of the fate of ecosystems, which makes the decision-making process more challenging overall (Polasky et al., 2011). To address these challenges, a growing literature has proposed a focus of management goals on ecological resiliency, that is, the ability of the system to respond to disturbance (Chapin et al., 2010;Millar et al., 2007;Spears et al., 2015). Achieving this goal of managing for ecological resiliency relies on an understanding of the ecological drivers of this resiliency (Scheffer & Carpenter, 2003). ...
Human‐caused global change produces biotic and abiotic conditions that increase the uncertainty and risk of failure of restoration efforts. A focus of managing for resiliency, that is, the ability of the system to respond to disturbance, has the potential to reduce this uncertainty and risk. However, identifying what drives resiliency might depend on how one measures it. An example of a system where identifying how the drivers of different aspects of resiliency can inform restoration under climate change is the northern coast of California, where kelp experienced a decline in coverage of over 95% due to the combination of an intense marine heat wave and the functional extinction of the primary predator of the kelp‐grazing purple sea urchin, the sunflower sea star. Although restoration efforts focused on urchin removal and kelp reintroduction in this system are ongoing, the question of how to increase the resiliency of this system to future marine heat waves remains open. In this paper, we introduce a dynamical model that describes a tritrophic food chain of kelp, purple urchins, and a purple urchin predator such as the sunflower sea star. We run a global sensitivity analysis of three different resiliency metrics (recovery likelihood, recovery rate, and resistance to disturbance) of the kelp forest to identify their ecological drivers. We find that each metric depends the most on a unique set of drivers: Recovery likelihood depends the most on live and drift kelp production, recovery rate depends the most on urchin production and feedbacks that determine urchin grazing on live kelp, and resistance depends the most on feedbacks that determine predator consumption of urchins. Therefore, an understanding of the potential role of predator reintroduction or recovery in kelp systems relies on a comprehensive approach to measuring resiliency.
... While substitution might provide temporary relief or alternatives for certain natural resources, it cannot be the sole strategy for addressing environmental challenges. Effective protection strategies must consider the limits of substitutability by focusing on conserving irreplaceable natural assets and enhancing the resilience of ecosystems (Carroll & Ray, 2021;Millar et al., 2007). This dual approach helps maintain the balance between utilizing and conserving natural resources, aiming for a sustainable future where human and natural capital coexist harmoniously. ...
The innovation ecosystems in economies dependent on natural resources use these assets as fundamental capital to promote development and economic growth. Ensuring the lasting sustainability of these economies represents a difficult challenge, especially in a context of limited and irreplaceable natural capital. This study explores indicators of natural capital protection (environmental quality, reduction of greenhouse gas emissions, protection of biodiversity and ecosystems, and cultural and social values) in Sub-Saharan Africa (SSA), the Middle East, and North Africa (MENA), two regions dependent on natural resources. A new panel quantile estimation technique is applied to panel data covering 59 countries from 2019 to 2023. The results indicate that, in SSA economies, lower levels of these indicators contribute positively to higher levels of natural capital protection. In the MENA economies, only higher levels of environmental quality and cultural and social values contribute positively to higher levels of natural capital protection. The critical implications arising from this study emphasize the urgent need to implement strategies aimed at safeguarding natural capital in economies heavily dependent on it. These strategies include resilient urban development, investment in climate resilient infrastructure, The strategies include resilient urban development, investment in climate-resilient infrastructure, recognition and valorization of environmental services, attention to modern renewable energy technologies, environmental education, greater consideration of the balance between environmental sustainability and human well-being by governments, and recognition of the impacts of globalization on environmental sustainability and human development. The uniqueness of this study lies in its pioneering approach to the pressing issues of protecting natural capital in natural resource-dependent economies. It is a pioneer in analyzing several countries in two regions regarding synergies between protecting natural capital and its indicators in economies dependent on natural resources.
... can contribute to more informed decision-making and policy formulation regarding carbon sequestration, ecosystem health, and climate resilience (Anderegg et al., 2020;COP15-Copenhagen, 2009;Millar et al., 2007). ...
Polar‐orbiting satellites have significantly improved our understanding of the terrestrial carbon cycle, yet they are not designed to observe sub‐daily dynamics that can provide unique insight into carbon cycle processes. Geostationary satellites offer remote sensing capabilities at temporal resolutions of 5‐min, or even less. This study explores the use of geostationary satellite data acquired by the Geostationary Operational Environmental Satellite—R Series (GOES‐R) to estimate terrestrial gross primary productivity (GPP) and ecosystem respiration (RECO) using machine learning. We collected and processed data from 126 AmeriFlux eddy covariance towers in the Contiguous United States synchronized with imagery from the GOES‐R Advanced Baseline Imager (ABI) from 2017 to 2022 to develop ML models and assess their performance. Tree‐based ensemble regressions showed promising performance for predicting GPP (R² of 0.70 ± 0.11 and RMSE of 4.04 ± 1.65 μmol m⁻² s⁻¹) and RECO (R² of 0.77 ± 0.10 and RMSE of 0.90 ± 0.49 μmol m⁻² s⁻¹) on a half‐hourly time step using GOES‐R surface products and top‐of‐atmosphere observations. Our findings align with global efforts to utilize geostationary satellites to improve carbon flux estimation and provide insight into how to estimate terrestrial carbon dioxide fluxes in near‐real time.
... Furthermore, accurate tree species mapping and biodiversity assessment contribute to our understanding of ecosystem processes, such as carbon sequestration, nutrient cycling, and habitat suitability for various species (Fahey et al., 2018;Liang et al., 2016;Paquette & Messier, 2011). This knowledge is crucial for developing sustainable forest management practices and mitigating the impacts of environmental changes (Brockerhoff et al., 2017;Lindner et al., 2010;Millar et al., 2007). Moreover, these techniques can aid in monitoring the dynamics of soil moisture and its relationship with climate patterns in semi-arid regions , further enhancing our understanding of ecosystem resilience and vulnerability. ...
Forests play a crucial role in maintaining ecological balance and biodiversity, making the accurate mapping of
tree species and assessment of biodiversity indices essential for informed management decisions. This study
introduces an innovative methodology that integrates EnMAP (Environmental Mapping and Analysis Program)
hyperspectral data with Sentinel-2 multitemporal data to classify tree species in the biodiverse landscapes of
Kampinos National Park and its surrounding regions in Poland.
We extract essential vegetation indices such as NDVI, NDMI, SAVI, and EVI from Sentinel-2 data to assess
forest health and dynamics. The Sentinel-2 data is upscaled from 10 m to 30 m to align with EnMAP’s spatial
resolution, followed by precise co-registration of the images using QGIS. Utilizing a rich dataset from the Na�tional Forest Inventory, we extract spectral signatures of nine distinct tree species from both data sources. We
employ five machine learning algorithms—Support Vector Machines (SVM), Random Forest (RF), CatBoost
(CAT), Gradient Boosting Classifier (GBC), and XGBoost (XGB)—to enhance classification accuracy.
Through iterative experimentation with data reduction techniques and algorithm tuning, we achieve optimal
performance across needle-leaved and broad-leaved species. The resulting tree species maps are validated
through quantitative accuracy assessments against mixed-species polygons from the National Forest Inventory
and ground truthing in the Kampinos National Park. Achieving an overall accuracy of 85% to 93%, our study
demonstrates the efficacy of this integrated approach in tree species mapping. Furthermore, the tree species maps
serve as a foundation for deriving key biodiversity indices—species richness, Shannon-Wiener Diversity Index,
Simpson’s Diversity Index, and a composite Biodiversity Index—providing insights into spatial biodiversity
patterns and informing targeted conservation strategies. This study exemplifies the potential of combining
advanced remote sensing techniques with field validation to enhance our understanding of forest ecosystems and
guide sustainable management practices.
... Consequently, some of the forests on the Refuge are currently characterized by young, structurally simple forests. Forests characterized by simple canopy structure and low plant species diversity are less likely to support high levels of overall biodiversity when exposed to climate change effects such as drought, wildfire, insects, and diseases when compared to older, more complex, diverse forests (Halofsky et al. 2018;Millar et al. 2007). ...
The primary objective of this assessment is to highlight the observed and potential climatic and ecosystem changes resulting from the effects of climate change. The assessment covers four focal habitats that comprise the majority of Willapa National Wildlife Refuge (Willapa NWR, Refuge) acreage, including forest (Sitka spruce zone and old-growth forests), estuarine (intertidal flat and salt marsh), streams and rivers, and coastal (coastal dune and shore pine forest).
Willapa National Wildlife Refuge is located on Willapa Bay along the southern Washington coastline in the Pacific Northwest (PNW). The Willapa Hills border the Refuge to the east and are part of the Coast Range, which continues south, across the Columbia River, and north, as the Olympic Mountains.
... Numerous processes, tools, and concepts are emerging to support adaptation governance, including a group of frameworks that highlight different options in the face of change. This includes the Resist-Accept-Direct (RAD) framework Lynch et al. 2022), the Resistance-Resilience-Transformation framework (Peterson St-Laurent et al. 2021), and Resistance-Resilience-Response framework (Millar et al. 2007). These frameworks have slight variations; however, for the purposes of this paper, we will refer to all as "RAD frameworks". ...
Globally, water governance struggles to reconcile increased demands on water resources with climate change–induced reductions in supply, making climate adaptation in water governance a pressing concern. The Resist-Accept-Direct (RAD) framework has emerged as a climate adaptation tool designed to help make adaptation decisions. However, there is limited understanding of social and political factors, which are critical in driving RAD decisions. This paper explores how communities are employing RAD to make climate adaptation decisions, using a case study of the Goulburn-Murray Resilience Strategy (the Strategy); a community-led strategy that uses a version of the RAD framework to build regional resilience in the Goulburn-Murray Irrigation District (GMID) in Australia’s Murray-Darling Basin (MDB). The Strategy focuses on building socio-economic, rather than ecological, resilience, making this research a valuable contribution to RAD literature. To apply the RAD framework to socio-economic adaptation, we adapted the framework to include IPCC language around incremental, transformational, planned, and autonomous adaptation. With the GMID considered a leader of resilience thinking in Australia, the Strategy may help decision-makers address water overallocation and contested governance in the MDB, and provide lessons for water governance globally. Data analysed from 20 semi-structured interviews with people involved with the Strategy revealed two main findings: (1) Communities and governments prioritise different actions under the RAD framework. Governments, particularly at the state level, preference incremental planned adaptation to maintain the status quo (resist), over incremental autonomous adaptation to changing conditions (accept), and transformational planned adaptation at various scales (direct). (2) Community and government actors perceive that factors driving governments’ preference for incremental-resist adaptation include electoral short-termism, linear planning, and conservative government culture.
... However, FAM turns out to be an interesting strategy for provoking reflections from different institutional and informal authorities. As it is a controversial strategy, it works as an invitation to debate human action, as well as the management of uncertainty (Lidskog and Löfmarck, 2015;Millar et al., 2007). ...
Forest Assisted Migration (FAM) emerges as a promising strategy of adaptation to climate change (CC) in the forestry sector. This method integrates various sources of knowledge to identify optimal locations for future tree species establishment through human intervention. As climate change presents numerous challenges to Quebec’s forests, including shifts in suitable habitats for tree species, the FAM recommends a proactive approach to adapt to these changes. Recognizing the importance of addressing risks and following international resolutions, such as the Paris Agreement on Climate Change (COP21) and Convention on Biological Diversity (CBD), social perception becomes a critical consideration in the decision-making process regarding FAM. To investigate this issue, we conducted semi-structured interviews with 18 key stakeholders in Quebec, including officials from the Ministry of Natural Resources and Forestry, employees of private forestry technical companies, forestry researchers, private forest owners, non-governmental organizations (NGO) members, and other forest stakeholders. We analyzed the data collected in this phase through thematic discrimination, focusing on (i) acceptability (ii) risk perception (iii) feasibility, and (iv) purpose. Then, we compared the discourses with data from other publications addressing the social aspects of FAM. To develop this reflection, we found it important to use a conceptual framework that encompasses the articulation among some concepts of intervention through FAM vs. non-intervention, public trust in government authorities, risk perception and scientific knowledge. The interviews revealed a general inclination among stakeholders to support FAM, dependent upon cautious implementation with pilot projects and studies serving as references for future large-scale applications. Concerns raised by stakeholders included seed production, adequate experimental monitoring, and careful species selection. While some stakeholders were more knowledgeable about current FAM research, others emphasized the importance of economic viability, public participation in decision-making, and transparency in forestry processes. We identified communication and public involvement as fundamental aspects for advancing the perspective of FAM implementation in Quebec; it is crucial to recognize the presence of humans in FAM target areas and their potential contributions to implementation. Moving forward, forest authorities responsible for FAM should prioritize stakeholder engagement at all levels to ensure a socially inclusive strategy of adaptation that respects a wide range of considerations.
... implement climate change adaptation strategies, such as assisted migration (Champagne et al. 2021;Royo et al. 2023). In addition to rehabilitating highly altered stands, these investments could facilitate transition and foster stand resilience and adaptability in a context of uncertain future conditions driven by climate change (Millar et al. 2007;Messier et al. 2019). ...
Repeated diameter-limit cutting in mixedwood forests often leads to altered stand composition, quality, and regeneration, hence decreasing productivity and value over time. We studied the evolution of stand characteristics after diameter-limit cutting on a 15-year period, beginning from 11 to 43 years after cutting. We used 415 sample plots (200 m²) and three criteria: (i) ≥9.0 m²/ha overstory (trees ≥9.1 cm dbh [diameter at breast height, 1.3 m above ground]) acceptable growing stock (AGS, i.e. basal area of vigorous trees with sawlog potential), (ii) ≥3.0 m²/ha pole timber AGS (9.1 cm-23.0 cm dbh) and (iii) ≥60% sapling (dbh 1.1-9.0 cm) stocking of desired species. Stand initial quality was determined in function of overstory AGS at the beginning of the monitoring period: good quality (AGS≥9.0 m²/ha), impoverished (7.0≤AGS< 9.0 m²/ha), degraded (AGS <7.0 m²/ha). After 15 years, 47% of stands satisfied at least two criteria, but most stands (65%) had insufficient sapling regeneration. Stands in good quality and impoverished categories had sufficient basal area and AGS to support a new partial cutting cycle, contrary to stands in the degraded category. A conceptual model based on these three criteria is presented to guide silvicultural rehabilitation of uneven-aged mixedwood stands altered by past cutting practices.
... A resilient landscape will be a mosaic of stands of different ages and structures (Millar, Stephenson, and Stephens 2007). Landscape diversity can be restored by appropriately combining natural regeneration, direct seeding, and planting. ...
... Modifications in pest dynamics and their impacts could cumulate with climate-induced change in other natural disturbances (e.g., wildfires) to put further pressure on forest ecosystems and the forest sector (Boulanger & Pascual Puigdevall, 2021). As we navigate these uncertain times, a proactive and integrated approach in forest management and ecological research will be crucial to mitigate the compounded effects of climate change and preserve the integrity and sustainability of forest ecosystems (Millar et al., 2007). ...
Climate change is redefining the dynamics of forest ecosystems globally, particularly through its impact on forest pest populations such as the spruce budworm (SBW, Choristoneura fumiferana [Clem.]), a major defoliator in North American boreal forests. This study investigates the shifts in the population dynamics of spruce budworm across its range in response to recent climate change. We used a process-based, temperature-dependent ecophysiological model combined with the ERA5 reanalysis to assess changes in SBW phenology, reproduction rate, winter survival and population growth rates from 1950 to 2022 across North America. Our findings demonstrate a pronounced northward expansion of suitable climate conditions for SBW, accompanied by earlier phenological events and increased reproduction rates in northern regions. Conversely, the southern parts of its range are experiencing increased winter mortality due to warmer temperatures. This study highlights the significant impact of elevated temperatures, particularly during critical developmental windows such as spring and summer, which are pivotal for spruce budworm survival and reproduction. Additionally, our results reveal that the observed shifts in pest dynamics are more strongly driven by climate change than by changes in landscape composition and structure. We estimated that suitable growth rates have shifted northward by over 68 km on average, but this shift reached more than 200 km in the easternmost portions of its range. Climate-induced shift in suitable conditions for SBW underscores the need for adaptive forest management strategies that consider the rapid ecological changes and the potential for increased forest vulnerability due to climatic and biotic stressors. This study provides vital insights that can inform adaptive management ensuring the sustainability of forest ecosystems in the face of ongoing climate change.
... The figure was generated using R version 4.2.1 100 . Trees, with their substantial role in ecological processes and resource supply, represent a fundamental component of forest ecosystems that require effective management strategies in the context of climate change 120,121 . Shifts in latitudinal distribution of key forest-forming tree species in the Northern Hemisphere 1,122,123 may result in significant range changes or even the gradual loss of entire ecosystems reliant on specific tree species 124 . ...
Climate change significantly impacts the distribution of woody plants, indirectly influencing the dynamics of entire ecosystems. Understanding species' varied responses to the environment and their reliance on biotic interactions is crucial for predicting the global changes' impact on woodland biodiversity. Our study focusses on Dicranum viride, a moss of conservation priority, and its dependence on specific phorophytes (host trees). Using species distribution modelling (SDM) techniques, we initially modelled its distribution using climate-only variables. As a novel approach, we also modelled the distribution of the main phorophyte species and incorporated them into D. viride SDM alongside climate data. Finally, we analysed the overlap of climatic and geographic niches between the epiphyte and the phorophytes. Inclusion of biotic interactions significantly improved model performance, with phorophyte availability emerging as the primary predictor. This underscores the significance of epiphyte-phorophyte interactions, supported by substantial niche overlap. Predictions indicate a potential decline in the suitability of most of the current areas for D. viride, with noticeable shifts towards the northern regions of Europe. Our study underscores the importance of incorporating biotic interactions into SDMs, especially for dependent organisms. Understanding such connections is essential to implement successful conservation strategies and adapt forest management practices to environmental changes.
... Tree regeneration is a key component of forest resilience, which is commonly defined as the degree of perturbation a system can withstand and still return to its previous state as opposed to shifting to a new state (Holling, 1973;Millar et al., 2007). Successful tree regeneration and recruitment in temperate forests are threatened by widespread and varied challenges include climate change, altered disturbance regimes, over-browsing, pests, and pathogens . ...
Tree regeneration shapes forest carbon dynamics by determining long‐term forest composition and structure, which suggests that threats to natural regeneration may diminish the capacity of forests to replace live tree carbon transferred to the atmosphere or other pools through tree mortality. Yet, the potential implications of tree regeneration patterns for future carbon dynamics have been sparsely studied. We used forest inventory plots to investigate whether the composition of existing tree regeneration is consistent with aboveground carbon stock loss, replacement, or gain for forests across the northeastern and midwestern USA, leveraging a recently developed method to predict the likelihood of sapling recruitment from seedling abundance tallied within six seedling height classes. A comparison of carbon stock predictions from tree and seedling composition suggested that 29% of plots were poised to lose carbon based on seedling composition, 55% were poised for replacement of carbon stocks (<5 Mg ha⁻¹ difference) and 16% were poised to gain carbon. Forests predicted to lose carbon tended to be on steeper slopes, at lower latitudes, and in rolling upland environments. Although plots predicted to gain and lose carbon had similar stand ages, carbon loss plots had greater current carbon stocks. Synthesis and applications. Our results demonstrate the utility of considering tree regeneration through the lens of carbon replacement to develop effective management strategies to secure long‐term carbon storage and resilience in the context of global change. Forests poised to lose C due to climate change and other stressors could be prioritized for regeneration strategies that enhance long‐term carbon resilience and stewardship.
... Multiple strategies can lead to forests that are better adapted to climate that is increasingly deviating from historical conditions. Various adaptation frameworks have been proposed (e.g., Lynch et al. 2021;Millar et al. 2007;Nagel et al. 2017;Schuurman et al. 2022) which generally describe three types of active strategies: 1) making forest ecosystems more resistant to climate change and climate-induced disturbances, 2) making forest ecosystems more resilient, and 3) transitioning forest ecosystems from historical conditions into ecosystems better suited for the climate of the future. Specific forest practices for adapting to climate change will vary based on the region, forest type, objectives, and social-ecological context . ...
Climate-smart forestry is an increasingly important topic in forest policy and for practices. However, what does and does not constitute climate-smart forestry is subject of debate. At stake are billions of dollars of investment aimed at encouraging climate-smart forestry practices in the United States. As a leading voice for ecologically, economically, and socially responsible forestry, The Forest Stewards Guild (FSG) has produced a position statement based on the organization's vision, mission, and principles to guide conversations around climate-smart forestry for all interested stakeholders. This forest perspective presents and expands on the findings of the FSG position on climate-smart forestry. There are three common aspects in the multiple co-existing definitions of climate-smart forestry: 1) adapting forests to expected future climate conditions, 2) mitigating climate change by leveraging carbon sequestration and storage functions of forests, and 3) improving social outcomes. There are potential trade-offs with other benefits forests provide if climate-smart forestry is pursued without holistic consideration of forest ecosystems. We suggest that such trade-offs can be minimized if the goals of climate-smart forestry projects are communicated transparently, system boundaries are made as comprehensive as possible, potential trade-offs are assessed along with climate benefits, climate-smart practices are tailored to the social-ecological contexts, and uncertainty is recognized.
... Management options are needed to help increase juvenile survival under the harsher conditions of the Anthropocene, both for naturally recruited juveniles as well as planted ones. In addition to traditional forest management practices of selective thinning, contouring, mulching, pest, and wildfire control (Millar et al., 2007;Millar and Stephenson, 2015;Andrews et al., 2020), recent advances in nanoscience and nanotechnology may provide an additional set of useful tools for forest managers to reduce the risk of tree mortality during extreme drought and heat waves (Field et al., 2020). Nanochitosan is a biopolymer plant elicitor derived by the deacetylation of chitin-a commercially produced byproduct acquired by upcycling waste from the seafood industry. ...
Mortality of tree species around the globe is increasingly driven by hotter drought and heat waves. Tree juveniles are at risk, as well as adults, and this will have a negative effect on forest dynamics and structure under climate change. Novel management options are urgently needed to reduce this mortality and positively affect forest dynamics and structure. Potential drought-ameliorating soil amendments such as nanochitosan – a biopolymer upcycled from byproducts of the seafood industry – may provide an additional set of useful tools for reducing juvenile mortality during hotter droughts. Nanochitosan promotes water and nutrient absorption in plants but has not been tested in the context of drought and heat stress. We evaluated factors affecting mortality risk and rate for dryland Pinus edulis juveniles (2–3 years old) in a growth chamber using a factorial experiment that included ambient and +4°C warmer base temperatures, with and without a 10 day +8°C heat wave, and with and without a nanochitosan soil amendment. The nanochitosan treatment reduced the relative risk of mortality, emphasizing a protective function of this soil amendment, reducing the relative risk of mortality by 37%. Importantly, the protective effects of nanochitosan soil amendment in delaying tree mortality under hotter drought and heat waves provides a new, potentially positive management treatment for tree juveniles trying to survive in the climate of the Anthropocene.
... Wildfires and climate change are reshaping forests, and the management decisions made immediately postfire may have lasting effects on ecosystem reorganization (Keeley et al., 2005;Stevens et al., 2021). Changes in climate and disturbance regimes are leading to postfire communities that diverge strongly from their prefire composition, for example, type conversions from forest to nonforest ecosystems (Coop et al., 2020;Davis et al., 2019;Enright et al., 2015;Johnstone et al., 2016;Nemens et al., 2022) or invasions of non-native species (Alba et al., 2015;Applestein & Germino, 2022;Hunter et al., 2006;Keeley, 2006;Shinneman & Baker, 2009), and more information is needed to inform management to resist, accept, or direct ecosystem change (Millar et al., 2007;Schuurman et al., 2022). ...
Wildfires and climate change increasingly are transforming vegetation composition and structure, and postfire management may have long‐lasting effects on ecosystem reorganization. Postfire aerial seeding treatments are commonly used to reduce runoff and soil erosion, but little is known about how seeding treatments affect native vegetation recovery over long periods of time, particularly in type‐converted forests that have been dramatically transformed by the effects of repeated, high‐severity fire. In this study, we analyze and report on a rare long‐term (23‐year) dataset that documents vegetation dynamics following a 1996 post‐fire aerial seeding treatment and a subsequent 2011 high‐severity reburn in a dry conifer landscape of northern New Mexico, USA. Repeated surveys between 1997 and 2019 of 49 permanent transects were analyzed for differences in vegetation cover, richness, and diversity between seeded and unseeded areas, and to characterize the development of seeded and unseeded vegetation communities through time and across gradients of burn severity, elevation, and soil‐available water capacity. Seeded plots showed no significant difference in bare ground cover during the initial years postfire relative to unseeded plots. Postfire seeding led to a clear and sustained divergence in herbaceous community composition. Seeded plots had a much higher cover of non‐native graminoids, primarily Bromus inermis, a likely contaminant in the seed mix. High‐severity reburning of all plots in 2011 reduced native graminoid cover by half at seeded plots compared with both prefire levels and with plots that were unseeded following the initial 1996 fire. In addition, higher fire severity was associated with increased non‐native graminoid cover and reduced native graminoid cover. This study documents fire‐driven ecosystem transformation from conifer forest into a shrub‐and‐grass‐dominated system, reinforced by aerial seeding of grasses and high‐severity reburning. This unique long‐term dataset illustrates that post‐fire seeding carries significant risks of unwanted non‐native species invasions that persist through subsequent fires—thus alternative postfire management actions merit consideration to better support native ecosystem resilience given emergent climate change and increasing disturbance. This study also highlights the importance of long‐term monitoring of postfire vegetation dynamics, as short‐term assessments miss key elements of complex ecosystem responses to fire and postfire management actions.
... 5 Kombinace výše uvedených přístupů, příp. další (Millar et al. 2007;Bolte et al. 2009). ...
The review article deals with the silvicultural and phytosanitary risks, which may influence the use of oak and walnut species in the Czech Republic in the climate change. The study covers 12 species: eight oak species native to Central and South-Eastern Europe along with the North-American northern red oak, eastern black walnut, Persian walnut, and hybrids of the two walnut species. Future risks associated with cultivation of northern red oak and eastern black walnut were found to be most serious. On the contrary, Turkey oak and Hungarian should be considered a species suitable for most drought-exposed sites. Growing of the studied species in new areas and sites should follow adjusted silvicultural designs. These could include creation of mixed stands managed with due care of individual trees. The coppice with standards, coppice, and even transformation towards agroforestry systems may be suitable systems for the studied species.
... Once again, dynamic land management schemes are needed to embrace these complexities (Rhodes et al., 2022). For instance, regulations may be needed now to ensure that a site remains suitable in the future, either through habitat protection or restoration actions (Bullock et al., 2022;Millar et al., 2007). ...
Current rates of climate change and gloomy climate projections confront managers and conservation planners with the need to integrate climate change into already complex decision‐making processes. Predicting and prioritizing climatically stable areas and the areas likely to facilitate adaptive species’ range adjustments are important stages in maximizing conservation outcomes and rationalizing future land management. I determined, for the most threatened European terrestrial mammal species, the spatial adaptive trajectories (SATs) of highest expected persistence up to 2080. I devised simple spatial network indices for evaluation of species in those SATs: total persistence; proportion of SATs that offer in situ adaptation (i.e., stable refugia); number of SATs converging in a site; and relationship between SAT convergence and persistence and protected areas, the Natura 2000 and Emerald networks, and areas of low human disturbance. I compared the performance of high‐persistence SATs with a scenario in which each species remained in the areas with the best climatic conditions in the baseline period. The 1000 most persistence SATs for each of the 39 species covered one fifth of Europe. The areas with the largest adaptive potential (i.e., high persistence, stability, and SAT convergence) did not always overlap for all the species. Predominantly, these regions were located in southwestern Europe, Central Europe, and Scandinavia, with some occurrences in Eastern Europe. For most species, persistence in the most climatically suitable areas during the baseline period was lower than within SATs, underscoring their reliance on adaptive movements. Importantly, conservation areas (particularly protected areas) covered only minor fractions of species persistence among SATs, and hubs of spatial climate adaptation (i.e., areas of high SAT convergence) were seriously underrepresented in most conservation areas. These results highlight the need to perform analyses on spatial species’ dynamics under climate change.
... Climate change adaptation strategies should be part of the risk management component in sustainable forest management plans (Spittlehouse and Stewart 2003). It is believed that attempting to maintain ecosystems sustainably by managing forests using past management strategies will not be enough and therefore new approaches to forest management are required (Linder 2000, Millar et al. 2007, Lindner et al. 2014, Seidl et al. 2017. ...
Forests play a key role in mitigating climate change as they are one of the major sinks for carbon. The idea of how to use these important resources more efficiently and effectively has led to the emergence of a new trend in forestry in recent years, Climate Smart Forestry (CSF). CSF aims to reduce greenhouse gas emissions and seeks to fortify forests against potential climate change consequences in the future while increasing production and incomes sustainably from forests. The purpose of this study was to determine the measures, indicators, and criteria that promote CSF in T??rkiye. Following this, the strengths and weaknesses of Türkiye’s forestry legislation and practices were analyzed using the nine criteria derived from academic literature on CSF. Thus, the degree to which Turkish forestry practices and legislation are consistent with the CSF and its reflections were assessed.
Zusammenfassung: Unterstützte Wanderung (Assisted Migration) ist ein Konzept, das ursprünglich aus dem Naturschutz stammt, und bei dem vom Klimawandel bedrohte Arten in Regionen gebracht werden, an deren Klima sie besser angepasst sind. Von selbst würden diese Arten aber diese entfernten Regionen mit günstigerem Klima nicht erreichen können. Die nordamerikanische Forstwirtschaft hat sich die Unterstützte Wanderung zu eigen gemacht, um in Klimaregionen, die sich stark verändern, frühzeitig Baumarten einzubringen, die im neuen Klima heimisch sein werden. Die Methode ist die gleiche, der Blickwinkel aber ein anderer. Auch in Europa gibt es in südlichen Regionen Baumarten, die für das kommende Klima in Mitteleuropa geeignet sind und durch Unter-stützte Wanderung eingebracht werden können (z.B. Esskastanie, Zerreiche, Flaumeiche, Hopfenbuche, Schwarzkiefer u.a.). Lokale, angepasste Herkünfte (Provenienzen) von europaweit vertretenen Arten weisen ebenfalls entsprechend unterschiedliche Anpassung an Hitze und Trockenheit auf, die im Genotyp festgeschrieben sind. Mit einer unterstützten Wanderung der Gene (Assisted Gene Flow) wird der Genpool der heimischen Populationen mit Genen aus besser klimaangepassten Populationen angereichert. Der Unterstützte Genfluss wird von einer Introgression in den Genbestand der Ausgangspopulation gefolgt, die die weitere genetische Anpassung in den folgenden Baumgenerationen forciert.
Climate change has significantly impacted the wildfire regimes in lodgepole pine forests, resulting in prolonged fire seasons and altered fire behaviour. In North America, fire patterns have shifted towards more frequent and severe wildfires after a century of fire suppression. In response, silviculture practices in fire-prone areas should aim to restore diverse forest structures that are resistant or resilient to wildfires. In Western Canada, where forestry is a key industry, interest in seeking silvicultural solutions for promoting forest resilience to wildfires has increased following the devastating wildfire seasons between 2017 and 2023. Irregular shelterwood, a silvicultural system with a relatively short history of implementation in British Columbia, has been deployed in ecologically sensitive areas to promote structural heterogeneity and meet management goals for biodiversity and wildlife values. Although the impacts of irregular shelterwood on wildlife habitat and abundance have been well studied, the interaction between wildfire and the stand structure created by irregular shelterwood remains poorly understood. To understand the effectiveness of the irregular shelterwood in building wildfire resilience, we present a study of a lodgepole pine stand that was treated with irregular shelterwood and partially burned in a wildfire in 2017. This study collected ground fuel, canopy fuel, and tree data from four stand types (irregular shelterwood treated-burnt, treated-unburnt, untreated-burnt, and untreated-unburnt) and analyzed the difference in char height and fire-induced mortality between burnt and unburnt conditions, with irregular shelterwood treatment being a variable. The results demonstrated reduced wildfire effect in the irregular shelterwood stand in this region of British Columbia. This observation was made at a stage where the openings have not been colonized by regeneration. This case study provides valuable insights into the effectiveness of irregular shelterwood in mitigating wildfire risk, and proposes a potential silviculture solution to promote forest resilience to wildfire.
To address impacts of climate change and other stressors on stream ecosystems, managers must prioritize resources and locations for conservation actions to facilitate effective cross-boundary solutions. Through a science management partnership, we co-produced a spatially explicit landscape assessment framework for cold-water fish habitat and riparian corridors in three large watersheds of the southwestern United States. Using literature review and stakeholder workshops, we developed indicators of vulnerability and built spatial datasets depicting areas of low to high vulnerability based on exposure, sensitivity, and adaptive capacity for each resource. We found that, in general, vulnerability was greater for cold-water fish habitat than for riparian corridors. The Little Colorado River and San Juan River watersheds had the highest percentages of subwatersheds with high vulnerability of cold-water fish habitat. Conversely, the Upper Rio Grande watershed had the highest percentage with high vulnerability of riparian corridors. Assessments like ours facilitate the management of water resources at the scale of watersheds or river basins and incorporate physical characteristics, land-use history, current management practices, and status of imperiled species into actionable management plans.
Climate change can exacerbate pest population growth, posing significant threats to ecosystem functions and services, social development, and food security. Risk assessment is a valuable tool for effective pest management that identifies potential pest expansion and ecosystem dispersal patterns. We applied a habitat suitability model coupled with priority protection planning software to determine key monitoring areas (KMA) for tree insect pest risks under climate change and used forest ecoregions and nature reserves to assess the ecological risk of insect pest invasion. Finally, we collated the prevention and control measures for reducing future pest invasions. The KMA for tree insect pests in our current and future climate is mainly concentrated in eastern and southern China. However, with climate change, the KMA gradually expands from southeastern to northeastern China. In the current and future climate scenarios, ecoregions requiring high monitoring levels were restricted to the eastern and southern coastal areas of China, and nature reserves requiring the highest monitoring levels were mainly distributed in southeastern China. Tree insect pest invasion assessment using ecoregions and nature reserves identified that future climates increase the risk of pest invasions in forest ecoregions and nature reserves, especially in northeastern China. The increased risk and severity of tree insect pest invasions require implementing monitoring and preventative measures in these areas. We effectively assessed the pest invasion risks using forest ecoregions and nature reserves under climate change. Our assessments suggest that monitoring and early prevention should focus on southeastern and northeastern China.
Across the world, experiments have shown us the possibility of reversing ecological damage by employing restoration strategies to counter biodiversity loss and ecosystem degradation. The discipline of ecological restoration encompasses efforts aimed at enabling the restoration of the structure and function of ecosystems, thereby facilitating the provision of goods and services ensuing from the ecosystems. Ecological restoration has emerged as a critical strategy for addressing the pressing global challenges of climate change, land degradation, and the loss of vital ecosystem services. This comprehensive approach aims to revive the health, integrity, and sustainability of degraded ecosystems, ultimately enhancing their resilience to the impacts of a changing climate. This branch draws upon the foundations of ecological theory, and applies an interdisciplinary approach. The disciplines of earth sciences, life sciences and social sciences are employed to achieve ecological goals that benefit society.
Abstract
Regional planning for protection and use of lands and waters to conserve biodiversity and other values is a relatively young discipline. Methods for selecting conservation areas at regional scales have advanced in recent decades. Stress introduced by a changing climate further exacerbates this already complex and challenging process. New methods will be required to adapt as ecosystems change. Ecoregional planning steps are reviewed, and potential alternatives are identified for adapting to climate change. Iterative planning steps commonly include defining the planning region,selecting focal features, mapping feature distributions, assessing current conditions, establishing representation objectives, designing regional scenarios, identifying conservation strategies, and measuring success of regional plans. Since decisions that are implemented today will be revisited into the future, an iterative approach of increasing frequency is required.
Forests are one of the world’s most valuable resources. They are particularly prone to the specific effects of changing climate, such as increasing temperature, changing precipitation patterns, frequency and intensity of extreme weather, and shifting climatic zones. Forest ecosystems rely on various natural mechanisms to adapt, such as genetic variations among species, phenotypic plasticity, seed dispersal, species migration, etc. The genetic variation allows individual trees to possess adaptive traits, which could be advantageous in response to changing climatic conditions. Trees adjust their physical and physiological traits, acknowledging environmental signs. Tree species have developed methods to disperse seeds across large distances. This enables them to colonize new locations that may give better habitat circumstances when the environment changes. Owing to the rapid change in the climatic conditions within a few decades, there exists a sudden shift within the native range of some species as they have shifted towards the higher altitude or latitude where they get suitable conditions to thrive. Some forest ecosystems also have evolved in the presence of periodic wildfires. Certain tree species have developed adaptations, viz., fire-resistant bark or the requirement for periodic fires to release seeds and stimulate regeneration. Forest ecosystems exhibit resilience by employing a blend of innate adaptation mechanisms to address shifts in their surroundings. Ecosystem resilience refers to a system’s ability to withstand disruptions, adjust to evolving circumstances, and restore its functions and structure following disturbances while retaining its integrity. It is crucial to emphasize that anthropogenic disturbances, including deforestation, habitat fragmentation, and climate disruption, can interrupt these natural adaptation mechanisms and pose significant challenges to forest ecosystems. Conservation efforts, sustainable management of forests, and measures to mitigate environmental change are essential to support and enhance these natural adaptation mechanisms in forests.
You can find the full paper here:
https://authors.elsevier.com/a/1jmN81L%7EGwcMv4
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Highlights
• This study addresses whether the radial growth of Oriental beech responds better to drought than that of the European beech.
• We analyzed radial growth between 1920 and 2018 of 138 European and 122 Oriental beeches growing in eight different locations.
• The current knowledge base is not sufficient for a well-informed decision whether Oriental beech would be suitable for "assisted gene flow”.
• Based on our study, no substantial gain in drought tolerance of European beech forests through the introduction of Oriental beech can be suggested.
Accurate evaluation of forest biomass distribution and its long-term change over wide areas is required for effective forest carbon management and prediction of landscape-scale forest dynamics. We evaluated a landscape-scale (225 km²) decadal forest carbon budget at a 1 ha spatial resolution in a cool-temperate forest, by repeating airborne laser observations 10 years apart and partitioning net forest biomass change (FBC) into growth and mortality. Using >10 000 samples, we revealed that naturally regenerated forests have large spatial heterogeneity in net biomass change, and 3/4 of the photosynthetically acquired carbon stock moved to necromass even without anthropogenic disturbances. Actual carbon residence time as living tree biomass was estimated by dividing biomass by growth or mortality rates. The residence time was 107 and 106 years, respectively with large spatial variation among stands (48 and 42 years, respectively, as the difference between 25 and 75 percentile), although studied forest stands have small variation in the forest functional type in a landscape-scale. The best predictors of subsequent decadal biomass changes were two forest structural factors, mean canopy height and canopy height variation in addition to one environmental factor, elevation. Considering the long lifetime of trees, these structural factors may be an indicator of forest soundness rather than a cause of forest growth or mortality. However, in any cases, these structural factors can be powerful predictors of subsequent FBC.
In the summer of 2023, unprecedented amounts of smoke from Canadian wildfires descended upon the north eastern United States. As a result, millions of people in this fire-infrequent region were exposed to extremely hazardous air quality and grew more aware of wildland fire issues they had previously been largely insulated from. Before this event fades from memory, and before forecasted increases in fire activity reach the region and others like it across the globe, an opportunity exists to broadly reconsider fire management within currently fire- infrequent regions. We review related science and conclude that climate change driven increases in fire activity are predicted for many fire-infrequent regions where fire-sensitive structures and species compositions have been recently promoted by strong adherence to passive “asbestos forest” management paradigms (i.e., approaches over-minimizing fire’s historical influence). Without intervention, shifts towards drought- and fire- sensitive trees will continue ahead of forecasted increases in fire activity – risking future degradation of regional forests and associated ecosystem services. However, prescribed fire and mechanical surrogates – and research refining effective application – could enhance fire resilience by restoring disturbance-dependent biodiversity.
Unfortunately, positive feedback between asbestos paradigms and ecological change in the absence of fire continue to limit the use of such tools and related research. The 2023 smoke event in the northeastern U.S. provides an opportunity to galvanize global stakeholder support for researching and applying disturbance-integrated land management. These perspectives will be key to enhancing forest resiliency across similar regions where fire activity is currently rare but predicted to increase in the future.
Forest assisted migration, the human-mediated movement of tree populations or species, is an adaptive silvicultural tool that could help forest transition to future climate while maintaining their productivity and ecosystem services. However, we need additional knowledge about the physiology of translocated seedlings to select the most appropriate species, provenances (i.e., seed sources) and silvicultural treatments surrounding this adaptive strategy. We used the first experimental site of the DREAM Network to assess early ecophysiology of local and translocated seedlings of eight species ( Prunus serotina , Quercus rubra , Acer saccharum , Picea glauca , Picea rubens , Pinus strobus , Pinus resinosa and Thuja occidentalis ). Seedlings were planted in a mixed plantation design in patch clearcut and in regular shelterwood system. For each species, seedlings were produced from three geographical provenances representing current climate (2018), mid-century and end-century climates (predicted for 2050 and 2080), based on climate analogues. Shelterwood partial cover proved useful during the establishment (e.g., to protect seedlings from late frost) with limited impacts on physiological performance. When planted in patch clearcut, Prunus serotina , Quercus rubra and Acer saccharum from mid-century and end-century climate analogues experienced lower water stress, suggesting a better drought tolerance than those from local provenances. Overall, insights from this ecophysiological monitoring indicated that translocated southern seedlings perform as well as or better than local provenances, suggesting that they can acclimate to their new destination site.
Forests and grasslands play an important role in water and air purification, in prevention of soil erosion, and in provision of habitat to wildlife. Internet of Things has a tremendous potential to play a vital role in the forest ecosystem management and stability. The conservation of species and habitats, timber production, prevention of forest soil degradation, and forest fire prediction, mitigation, and control can be attained through forest management using Internet of Things. The use and adoption of IoT in forest ecosystem management is challenging due to many factors. Vast geographical areas and limited resources in terms of budget and equipment are some of the limiting factors. In digital forestry, IoT deployment offers effective operations, control, and forecasts for soil erosion, fires, and undesirable depositions. In this chapter, IoT sensing and communication applications are presented for digital forestry systems. Different IoT systems for digital forest monitoring applications are also discussed.
The rate of climate change advancement and its predicted impact are valid reasons for intense discourse on thetopic of choosing the most suitable silvicultural and adaptation measures for the longevity and sustainability of forest com-munities. Changes in growth conditions of plants can be expected in both vertical (altitudinal) and horizontal (geographi-cal) directions. The anticipated occurrence rate of these changes should, according to climate models, be higher than thenatural adaptability rate of longevous tree species. This study focuses on the possibility of utilising regional geographicalunits of the Czech Republic (Central Europe) – Natural Forest Areas (NFAs) – for introducing the principles of assistedforest migration to national silviculture policies in order to find solutions for the predicted climate change scenarios.The primary objectives are (i) to review the history of the NFA concept, (ii) to discuss the perspectives of NFAs withregard to climate change, and (iii) to propose possible solutions for further development in comparison with alternativeapproaches to horizontal classification of the Czech Republic. This study is the first of its kind that provides a complete tex-tual and graphic overview of the NFAs' history from 1959 to 2018, highlighting the purpose of NFAs as both frameworksfor the maintenance of the genetic potential of forest tree species' populations and frameworks for long-term strategicmanagement planning. Further development of the concept is discussed in connection with the main principles of assistedforest migration and the possibility of employing geospatial modellation analyses for a more precise definition of current NFA borders. An assessment of the areas' potential is also debated, mainly with an emphasis on the zonality of forest sites.
Norway spruce (Picea abies L.) forests are experiencing severe dieback due to drought and related bark beetle infestations. These disturbances are amplified by poor tree vitality, which is linked to acidification in soils and exacerbated by atmospheric deposition. However, the large-scale deployment of rock dust as a soil-restoring amendment is hampered by uncertainties about its benefits in the long term. This study reassessed an experiment that was set up in 1987 in Vorarlberg, Austria, and sampled again in 2021. It comprises three 3 ha-large twin plots (topsoil pHCaCl2 = 3.0, eCEC = 5–10 cmolc/kg) consisting of Norway spruce-dominated selection system stands. The soil amendments consisted of a mixture of basalt and diabase rock dust, complemented with bentonite and lime at a total dose of 4.7 Mg/ha, the equivalent acid neutralising capacity is about 2.5–3.3 Mg CaCO3/ha. The topsoil pH increased in 1991 after application by about 0.3 units but became untraceable in 2021. In contrast, the 2021 samples confirmed treatment effects on a significant and large rise in forest floor eCEC (+9 cmolc/kg) and in topsoil base saturation (+15 %-point). Tree vitality and growth were evaluated for Norway spruce (63 trees) and silver fir (Abies alba) (17 trees) through foliar nutrient concentrations, defoliation, radial growth and Laser Ablation - Inductively Coupled Plasma - Mass Spectrometry (LA-ICP-MS). Overall, foliar and tree ring concentrations of P, Ca and Mg increased in plots amended with rock dust. The tree radial growth responded to the treatment from 1989 onwards, with differences in annual Basal Area Increments (BAI) peaking about 20 years after applications. Growth improvement was markedly larger for trees with an age below 150 years. Remarkably, the amended spruce trees with limited N-deficiency (needle N > 10 mg/g) had a factor 1.3 larger BAI in 2010 than control trees. In contrast, N-deficient trees, mostly located at higher altitudes with lower current N deposition (needle N < 10 mg/g), did only marginally respond to the rock dust. Herb layer plant species richness increased in 2021 with the addition of rock dust, with 13 additional species compared to the 24 found in the control. Biodiversity indices showed that a marginal change occurred both in richness and evenness. The Ellenberg R increased slightly in the most acidic site but without loss of the typical species for oligotrophic spruce forests. In conclusion, it is possible to increase vitality and growth via rock dust amendments, provided that N-deficiency or tree age are not growth-limiting factors.
An extensive ground survey of the white pine species in Sequoia and Kings Canyon National Parks was performed on foot from 1995-1999. The white pine distribution, including sugar pine (Pinus lambertiana), whitebark pine (Pinus albicaulis), foxtail pine (Pinus balfouriana), limber pine (Pinus flexilis), and western white pine Pinus monitcola) was modeled using existing (1995) data in the form of vegetation type maps and an aerially stratified random sampling scheme was devised for the installation and evaluation of 151 permanent monitoring plots. Three additional plots were installed in areas of particular interest. Observed white pine distribution was mapped in selected areas in conjunction with the plot establishment. Within each plot, an average of 48 white pines greater than one meter tall were measured and mapped for long-term monitoring, and evaluated for white pine blister rust (Cronartium ribicola) infection. Data from these plots provides a rough estimate of the incidence and severity of effect of blister rust upon the populations of these species within the park boundaries. The average incidence of rust infection was 6.6% for all plots in the random sampling scheme; rust was found only in plots containing sugar pine (21.1% average incidence) and western white pine (2.7% average incidence). Incidence and severity of rust were related to associated Ribes species, elevation, and topographic position. Rust was found to be more often associated with Ribes nevadense and Ribes roezlii than other Ribes species, rarely found above 8800 feet in elevation, and most often found in valley bottoms. In certain areas, sugar pines and western white pines have been significantly affected by bole infections in smaller trees, which often results in mortality. The populations of foxtail, whitebark, and limber pines within these parks appear to remain virtually unaffected by blister rust.
Alternative fire hazard reduction techniques are needed for managing fuel profiles in forest ecosystems located within the so-called wildland-urban interface. The present study includes experimental fuel manipulations initiated along the Rocky Mountain National Park interface with residential areas in Colorado, USA. Three thinning/slash disposal treatments were applied on two lodgepole pine (Pinus contorta) stands: thinning with whole-tree removal; thinning with stem removal - lopping and scattering; and thinning with stem removal - hand piling and burning. Results indicate that treatments reduced surface fire behavior parameters, bringing them down and closer to Limits of direct attack methods. Crown fire potential was decreased not only because of canopy removal, but also as a result of potential reduction in heat generated by surface fuels. Projected fire behavior for the thinning-without-slash-removal scenario indicates the possibility of serious control problems with major fire runs and crown fires given an outbreak.
Owens Valley, California, was markedly different during the Wisconsin glacial stage from what it is today. Alpine glaciers bounded the Sierra Nevada, and pluvial Owens Lake reached highstands and overflowed its natural basin. We analyzed three layers from two packrat middens, dated to ca 23,000-14,500 yr BP, obtained from Haystack Mountain (1155 m) only 10 m above and < 100 m from the highstand strandline of pluvial Owens Lake. During this period vegetation near Owens Lake reflects the influence of the Tioga glacial advance and retreat on lake levels, and microclimatic effects on shoreline vegetation. Between ca 23,000 and 17,500 yr BP a Utah juniper (Juniperus osteosperma) and single-needle pinyon pine (Pinus monophyllla) woodland existed at the site. In the layers dated to ca 17,500 and 16,000 yr BP, macrofossils document the presence of Rocky Mountain juniper (Juniperus scopulorum), a species that no longer occurs in California. It is suggested that meltwater from the retreating glacial ice inundated the Owens River Lake chain causing pluvial Owens Lake to reach its highstand. This caused an increase in effective moisture, due to high groundwater, allowing the mesophytic Rocky Mountain juniper to exist at the site.
The environmental and biotic history of the late Quaternary represents a critical junction between ecology, global change studies, and pre-Quaternary paleobiology. Late Quaternary records indicate the modes and mechanisms of environmental variation and biotic responses at time-scales of 101-104 years. Climatic changes of the late Quaternary have occurred continuously across a wide range of temporal scales, with the magnitude of change generally increasing with time span. Responses of terrestrial plant populations have ranged from tolerance in situ to moderate shifts in habitat to migration and/or extinction, depending on magnitudes and rates of environmental change. Species assemblages have been disaggregated and recombined, forming a changing array of vegetation patterns on the landscape. These patterns of change are characteristic of terrestrial plants and animals but may not be representative of all other life-forms or habitats. Complexity of response, particularly extent of species recombination, depends in part on the nature of the underlying environmental gradients and how they change through time. Environmental gradients in certain habitats may change in relatively simple fashion, allowing long-term persistence of species associations and spatial patterns. Consideration of late Quaternary climatic changes indicates that both the rate and magnitude of climatic changes anticipated for the coming century are unprecedented, presenting unique challenges to the biota of the planet.
Aim This study appraises historical fire regimes for Californian mixed-conifer forests of the Sierra San Pedro Mártir (SSPM). The SSPM represents the last remaining mixed-conifer forest along the Pacific coast still subject to uncontrolled, periodic ground fire.
Location The SSPM is a north–south trending fault bound range, centred on 31°N latitude, 100 km SE of Ensenada, Baja California.
Methods We surveyed forests for composition, population structure, and historical dynamics both spatially and temporally over the past 65 years using repeat aerial photographs and ground sampling. Fire perimeter history was reconstructed based on time-series aerial photographs dating from 1942 to 1991 and interpretable back to 1925. A total of 256 1-ha sites randomly selected from aerial photographs were examined along a chronosequence for density and cover of canopy trees, density of snags and downed logs, and cover of non-conifer trees and shrubs. Twenty-four stands were sampled on-the-ground by a point-centred quarter method which yielded data on tree density, basal area, frequency, importance value, and shrub and herb cover.
Results Forests experience moderately intense understory fires that range in size to 6400 ha, as well as numerous smaller, low intensity burns with low cumulative spatial extent. SSPM forests average 25–45% cover and 65–145 trees per ha. Sapling densities were two to three times that of overstory trees. Size-age distributions of trees ≥ 4 cm dbh indicate multi-age stands with steady-state dynamics. Stands are similar to Californian mixed conifer forests prior to the imposition of fire suppression policy. Livestock grazing does not appear to be suppressing conifer regeneration.
Main conclusions Our spatially-based reconstruction shows the open forest structure in SSPM to be a product of infrequent, intense surface fires with fire rotation periods of 52 years, rather than frequent, low intensity fires at intervals of 4–20 years proposed from California fire-scar dendrochronology (FSD) studies. Ground fires in SSPM were intense enough to kill pole-size trees and a significant number of overstory trees. We attribute long fire intervals to the gradual build-up of subcontinuous shrub cover, conifer recruitment and litter accumulation. Differences from photo interpretation and FSD estimates are due to assumptions made with respect to site-based (point) sampling of fire, and nonfractal fire intensities along fire size frequency distributions. Fire return intervals determined by FSD give undue importance to local burns which collectively use up little fuel, cover little area, and have little demographic impact on forests.
Ecological restoration is the process of reestablishing the structure and func- tion of native ecosystems and developing mutually beneficial human-wildland interactions that are compatible with the evolutionary history of those systems. Restoration is based on an ecosystem's reference conditions (or natural range of variability); the difference between reference conditions and contemporary conditions is used to assess the need for restorative treatments and to evaluate their success. Since ecosystems are highly complex and dynamic, it is not possible to describe comprehensively all possible attributes of ref- erence conditions. Instead, ecosystem characteristics with essential roles in the evolutionary environment are chosen for detailed study. Key characteristics of structure, function, and disturbance—especially fire regimes in ponderosa pine ecosystems—are quantified as far as possible through dendroecological and paleoecological studies, historical evidence, and comparison to undisrupted sites. Ecological restoration treatments are designed to reverse recent, human-caused ecological degradation. Testing of restoration treatments at four sites in northern Arizona, USA, has shown promise, but the diverse context of management goals and constraints for Southwestern forest ecosystems means that appropriate applica- tions of restoration techniques will probably differ in various settings.
Tree-ring records spanning the past seven centuries from the central and southern Rocky Mountains were studied using wavelet analysis to examine multidecadal (>30-70 yr) patterns of drought variation. Fifteen tree-ring series were grouped into five regional composite chronologies based on shared low-frequency behavior. Strong multidecadal phasing of moisture variation was present in all regions during the late 16th century megadrought. Oscillatory modes in the 30-70 yr domain persisted until the mid-19th century in two regions, and wet-dry cycles were apparently synchronous at some sites until the 1950s drought. The 16th/17th century pattern of severe multidecadal drought followed by decades of wet conditions resembles the 1950s drought and post-1976 wet period. The 16th century megadrought, which may have resulted from coupling of a decadal (similar to20-30 yr) Pacific cool phase with a multidecadal warm phase in the North Atlantic, marked a substantial reorganization of climate in the Rocky Mountain region.
Forest insects and pathogens are the most pervasive and important agents of disturbance in North American forests, affecting an area almost 50 times larger than fire and with an economic impact nearly five times as great. The same attributes that result in an insect herbivore being termed a "pest" predispose it to disruption by climate change, particularly global warming. Although many pest species have co-evolved relationships with forest hosts that may or may not be harmful over the long term, the effects on these relationships may have disastrous consequences. We consider both the data and models necessary to evaluate the impacts of climate change, as well as the assessments that have been made to date. The results indicate that all aspects of insect outbreak behavior will intensify as the climate warms. This reinforces the need for more detailed monitoring and evaluations as climatic events unfold. Luckily, we are well placed to make rapid progress, using software tools, databases, and the models that are already available.
Improved understanding of tree growth responses to climate is needed to model and predict forest ecosystem responses to current and future climatic variability. We used dendroecological methods to study the effects of climatic variability on radial growth of a subalpine conifer, mountain hemlock (Tsuga mertensiana). Tree-ring chronologies were developed for 31 sites, spanning the latitudinal and elevational ranges of mountain hemlock in the Pacific Northwest. Factor analysis was used to identify common patterns of inter- annual growth variability among the chronologies, and correlation and regression analyses were used to identify climatic factors associated with that variability. Factor analysis identified three common growth patterns, representing groups of sites with different climate-growth relationships. At high-elevation and midrange sites in Wash- ington and northern Oregon, growth was negatively correlated with spring snowpack depth, and positively correlated with growth-year summer temperature and the winter Pacific Decadal Oscillation index (PDO). In southern Oregon, growth was negatively correlated with spring snowpack depth and previous summer temperature, and positively correlated with previous summer precipitation. At the low-elevation sites, growth was mostly insen- sitive to annual climatic variability but displayed sensitivity to decadal variability in the PDO opposite to that found at high-elevation sites. Mountain hemlock growth appears to be limited by late snowmelt, short growing sea- sons, and cool summer temperatures throughout much of its range in the Pacific Northwest. Earlier snowmelt, higher summer temperatures, and lower summer precipitation in southern Oregon produce conditions under which growth is limited by summer temperature and/or soil water availability. Increasing atmospheric CO2 concentrations could produce warmer temperatures and reduced snowpack depths in the next century. Such changes would likely increase mountain hemlock growth and productivity throughout much of its range in Washington and northern Oregon. Increased summer drought stress and reduced productivity would be likely, how- ever, in mountain hemlock forests of southern Oregon and near the species lower elevation
Climate in the North Pacific and North American sectors has experienced interdecadal shifts during the twentieth century. A network of recently developed tree-ring chronologies for Southern and Baja California extends the instrumental record and reveals decadal-scale variability back to 1661. The Pacific decadal oscillation (PDO) is closely matched by the dominant mode of tree-ring variability that provides a preliminary view of multiannual climate fluctuations spanning the past four centuries. The reconstructed PDO index features a prominent bidecadal oscillation, whose amplitude weakened in the late l700s to mid-1800s. A comparison with proxy records of ENSO suggests that the greatest decadal-scale oscillations in Pacific climate between 1706 and 1977 occurred around 1750, 1905, and 1947.
Evidence gleaned from the instrumental record of climate data identifies a robust, recurring pattern of ocean–atmosphere climate variability centered over the midlatitude North Pacific basin. Over the past century, the amplitude of this climate pattern has varied irregularly at interannual-to-interdecadal timescales. There is evidence of reversals in the prevailing polarity of the oscillation occurring around 1925, 1947, and 1977; the last two reversals correspond to dramatic shifts in salmon production regimes in the North Pacific Ocean. This climate pattern also affects coastal sea and continental surface air temperatures, as well as streamflow in major west coast river systems, from Alaska to California.
Ecological responses to climatic variability in the Southwest include regionally synchronized fires, insect outbreaks, and pulses in tree demography (births and deaths). Multicentury, tree-ring reconstructions of drought, disturbance history, and tree demography reveal climatic effects across scales, from annual to decadal, and from local (�102 km2) to mesoscale (104–106 km2). Climate–disturbance relations are more variable and complex than previously assumed. During the past three centuries, mesoscale outbreaks of the western spruce budworm (Choristoneura occidentalis) were associated with wet, not dry episodes, contrary to conventional wisdom. Regional fires occur during extreme droughts but, in some ecosystems, antecedent wet conditions play a secondary role by regulating accumulation of fuels. Interdecadal changes in fire–climate associations parallel other evidence for shifts in the frequency or amplitude of the Southern Oscillation (SO) during the past three centuries. High interannual, fire–climate correlations (r � 0.7 to 0.9) during specific decades (i.e., circa 1740–80 and 1830– 60) reflect periods of high amplitude in the SO and rapid switching from extreme wet to dry years in the Southwest, thereby entraining fire occurrence across the region. Weak correlations from 1780 to 1830 correspond with a decrease in SO frequency or amplitude inferred from independent tree-ring width, ice core, and coral isotope reconstructions.
The main objective of this project was to reconstruct past fire history in different giant sequoia groves distributed along a north·south transect from Yosemite National Park southward to Mountain Home State Forest. We planned to develop millennia-length fire-scar chronologies
for different sequoia mixed-conifer groves and to compare the fire histories (fire frequency, size, intensity, and season) within and among these groves. Earlier fire-scar studies in the Redwood Mountain Grove by Kilgore and Taylor (1979) demonstrated that pre-settlement (pre·1875) surface fires were relatively frequent with two to three year mean fire intervals within watersheds of about 800 to 1000 ha., and five to nine year mean fire intervals in smaller sites of 3 to 16 ha. These fire-scar chronologies, based upon specimens from pines, fir, and incense cedar, were used to estimate fire frequency variations within two watersheds back to about A.D. 1700, although a few samples had scars extending back into the late 1400s. Our goal has been to spatially expand and temporally extend the knowledge base of fire history to other sequoia mixed-conifer groves in the Sierra Nevada by sampling ancient fire-scarred sequoias.
Natural scientists are being encouraged by environmental and developmental agencies to define and operationalize the concept of sustainability in a “scientific” manner. Such an approach is fraught with dangers because values, opinions, and social influences are an inextricable part of science, especially applied science. Natural scientists’ attempts to define sustainability, particularly to decide what should be sustained, cannot therefore be value-neutral. They simply end up shifting value judgments to different levels by choosing either a single obvious objective, an arbitrary range of objectives, or an arbitrary method of aggregating different preferences. This lack of self-reflectiveness on the part of scientists has important consequences for the direction of research and its political implications. Natural scientists should heed lessons from earlier cases of scientists’ involvement in policy and redefine the terms of reference before shouldering their social burden. The dilemma of pursuing objective science in a value-loaded and socially charged discourse can be resolved by properly understanding the role of analysis and by pursuing a socially grounded pluralistic approach to problem definition and research methodology.
Question: What are the shape, abundance, size, and structural characteristics of sapling patches in an old-growth Pinus jeffreyi-mixed conifer forest with a relatively intact disturbance regime? Location: Sierra San Pedro Martir, Baja California, Mexico. Methods: Regeneration was quantified by sampling sapling patches on seven 1200 m permanently marked line transects. For all patches intersected, tree size, species, age, and patch canopy cover were recorded. Patch structural characteristics were statistically compared to data from unbiased forest inventory plots. The minimum regeneration patch was defined as three saplings in a 49-m2 area. Results: We sampled 54 sapling regeneration patches. Patch size varied from 6.6 to 674.8 m2. A small portion of the forest was in patches (patch fraction = 3.8%, patch abundance = 8.5 per ha). The majority of the patches were small; 64.8% were less than the mean patch area of 100.1 m2. Patches were shaped as a rhombus. For all forest characteristics, mean values inside patches were significantly different than those from the unbiased forest inventory plots. Conclusions: These forests have a fine-grained pattern of regeneration patches. Our largest patch size of 674.8 m2 is the smallest reported in Pinus jeffreyi, P. ponderosa, and mixed conifer forests; other studies have probably had more difficulty delineating regeneration patches because of forest ingrowth from fire exclusion. Frequent fire, irregular seed crops, and seed dispersal by small mammals and birds could create this regeneration patch regime. High variation in nutrient availability after fire could also contribute to increased stand patchiness. Nomenclature: Hickman (1993) for vascular plants; Kays & Wilson (2002) for mammals. Abbreviation: Pj-mc = Pinus jeffreyi-mixed conifer; SSPM = Sierra San Pedro Martir.
Compares the simulations of three biogeography models (BIOME2, Dynamic Global Phytogeography Model (DOLY), and Mapped Atmosphere-Plant Soil System (MAPSS)) and the biogeochemistry models (BIOME-BGC (BioGeochemistry Cycles), CENTURY, and Terrestrial Ecosystem Model (TEM)) for the coterminous United States under contemporary conditions of atmospheric CO2 and climate. Also compares the simulations of these models under doubled CO2 and a range of climate scenarios. -from Authors
The basin and range topography creates a situation where montane vegetation is discontinuous and separated into habitat islands of various sizes. Packrat Neotoma midden coverage is heavily skewed toward the late Wisconsinan and Late Holocene. The full glacial flora of the basin was impoverished and the shift from a Late Wisconsinan to modern vegetation occurred at different sites. Inferred midden vegetation assemblages from the Great Basin-Mojave Desert reflect a full glacial climate with temperatures 7-8°C below modern levels and a mean annual precipitation greater by 30-40% over today's values. -S.J.Yates
We reconstructed a 3500-yr history of fluctuations in treeline elevation and tree abundance in the southern Sierra Nevada. Treeline elevation was higher than at present throughout most of the last 3500 yr. Declines in the abundance of live trees and treeline elevation occurred twice during the last 1000 yr: from 950 to 550 yr BP and from 450 to 50 yr BP. The earlier decline coincided with a period of warm temperatures (relative to present) in which at least two severe, multidecadal droughts occurred. This decline was apparently triggered by an increase in the rate of adult mortality in treeline forests. The more recent decline occurred during a period of low temperatures lasting for up to 400 yr and was apparently caused by a sustained failure of regeneration in combination with an increased rate of adult mortality. The apparent past importance of precipitation in controlling the position and structure of the treeline ecotone suggests that climatic controls over treeline may be more complex than previously thought. In the Sierra Nevada, responses of high-elevation forests to future warming may depend strongly on water supply.
The presettlement state of a giant sequoia-mixed conifer forest community in the Redwood Creek watershed, Kings Canyon National Park, is reconstructed using in backward projection in time of plant aggregations. The most conspicuous change in the forest community from the presettlement condition (@?1890) was a general increase in the area of aggregations dominated by polesize trees and mature trees, and a corresponding decrease in the area of aggregations dominated by sapling- and seedling-size trees. Aggregations dominated by white fir had both the greatest decline in area for sapling and seedling aggregations and the greatest increase in area for large mature, mature, and pole aggregations of any species in the watershed. The area of aggregations dominated by shrubs also declined, with manzanita aggregations showing the largest loss in area for any shrub species. Hardwoods were also a far more important part of the presettlement forest community than they are today.
Significant climate anomalies have characterized the last 1000 yr in the Sierra Nevada, California, USA. Two warm, dry periods of 150- and 200-yr duration occurred during AD 900-1350, which were followed by anomalously cold climates, known as the Little Ice Age, that lasted from AD 1400 to 1900. Climate in the last century has been significantly warmer. Regional biotic and physical response to these climatic periods occurred. Climate variability presents challenges when interpreting historical variability, including the need to accommodate climate effects when comparing current ecosystems to historical conditions, especially if comparisons are done to evaluate causes (e.g., human impacts) of differences, or to develop models for restoration of current ecosystems. Many historical studies focus on "presettlement" periods, which usually fall within the Little Ice Age. Thus, it should be assumed that ecosystems inferred for these historical periods responded to different climates than those at present, and management implications should be adjusted accordingly. The warmer centuries before the Little Ice Age may be a more appropriate analogue to the present, although no historic period is likely to be better as a model than an understanding of what conditions would be at present without intervention. Understanding the climate context of historical reconstruction studies, and adjusting implications to the present, should strengthen the value of historical variability research to management.
Two recent studies using tree aggregations to analyze forest age-structure stability and past forest structure are flawed. A better understanding of aggregation dynamics is needed before aggregation analysis is used in forest management.
Correlative approaches to understanding the climatic controls of vegetation distribution have exhibited at least two important weaknesses: they have been conceptually divorced across spatial scales, and their climatic parameters have not necessarily represented aspects of climate of broad physiological importance to plants. Using examples from the literature and from the Sierra Nevada of California, I argue that two water balance parameters—actual evapotranspiration (AET) and deficit (D)—are biologically meaningful, are well correlated with the distribution of vegetation types, and exhibit these qualities over several orders of magnitude of spatial scale (continental to local). I reach four additional conclusions. (1) Some pairs of climatic parameters presently in use are functionally similar to AET and D; however, AET and D may be easier to interpret biologically. (2) Several well-known climatic parameters are biologically less meaningful or less important than AET and D, and consequently are poorer correlates of the distribution of vegetation types. Of particular interest, AET is a much better correlate of the distributions of coniferous and deciduous forests than minimum temperature. (3) The effects of evaporative demand and water availability on a site's water balance are intrinsically different. For example, the ‘dry’ experienced by plants on sunward slopes (high evaporative demand) is not comparable to the ‘dry’ experienced by plants on soils with low water-holding capacities (low water availability), and these differences are reflected in vegetation patterns. (4) Many traditional topographic moisture scalars—those that additively combine measures related to evaporative demand and water availability—are not necessarily meaningful for describing site conditions as sensed by plants; the same holds for measured soil moisture. However, using AET and D in place of moisture scalars and measured soil moisture can solve these problems.
To most early ecologists, the ‘natural’ ecosystem was the community that would be reached after a long period without large-scale disturbance (fire, windstrom, etc.). More recently, it has been realized that in most areas some type of large-scale disturbance is indigenous, and must be included in any realistic definition of ‘naturalness’. In some areas an equilibrium may exist in which patchy disturbance is balanced by regrowth, but in others equilibrium may be impossible because (1) individual disturbances are too large or infrequent; (2) ephemeral events have long-lasting disruptive effects; and/or (3) climate changes interrupt any movement toward equilibrium that does occur. Examples of non-equilibrium ecosystems include the African savannas, the Big Woods of Minnesota, the lodgepole pine forests of Yellowstone National Park, and possibly the old-growth Douglas-fir forests of the Pacific Northwest.Where an equilibrium does not exist, defining the ‘natural’ vegetation becomes much more challenging, because the vegetation in any given area would not be stable over long periods of time even without man's influence. In many areas it may be unrealistic to try to define the natural vegetation for a site; one must recognize that there are often several communities that could be the ‘natural’ vegetation for any given site at any given time.
One hundred years of fire suppression in a mixed-conifer forest which evolved with frequent natural fires has shifted successional patterns, increased the density of small trees, produced an unnatural accumulation of ground fuels. Analysis of species composition, vegetation structure and age distribution in each of four forest types within the mixed-conifer zone of Sequoia and Kings Canyon National Parks, California, has documented a substantial increase in young, shade tolerant white fir in each type. The original dominant species have decreased in relative abundance in most cases. The sequioa type has been most affected by the fire suppression policy. Giant sequioa show poor reproduction in the absence of fire. The sequoia type also exhibits the greatest accumulation of ground fuels. The ponderosa pine, white fir and mixed forest types also show successional changes as well as significant accumulations of flammable ground fuels following a century of fire exclusion. The management implications of these findings are discussed.
Fire history and forest structural characteristics of adjacent Jeffrey pine (Pinus jeffreyi) and upper montane forests was investigated in the eastern Sierra Nevada at the University of California Valentine Natural Reserve. Jeffrey pine forests had lower canopy cover, higher amounts of fine fuels, and higher shrub cover when compared to upper montane forest that were dominated by red fir (Abies magnifica). Fire dates were determined using standard dendrochronolgy techniques from fire-scarred Jeffrey pine, lodgepole pine (Pinus contorta var. murrayana), red fir, and western white pine (Pinus monticola) trees, snags, stumps, and downed logs. Fires were recorded from 1745 to 1889 and mean fire return intervals were 9 and 24.7 years for the Jeffrey pine and upper montane forest types, respectively. The median fire return interval was 9.0 years for Jeffrey pine and 24.0 years for upper montane forests. Significant differences were found in mean fire intervals and fire history distributions between the two similarly sized fire history plots even though they were only separated by approximately 100 m. This study suggests that fire regimes can vary over very fine spatial scales. Differences in fire regimes are likely due to differences in fuel beds and fire behavior.
STUDIES from sites around the world1-5 have provided evidence for anomalous climate conditions persisting for several hundred years before about AD 1300. Early workers emphasized the temperature increase that marked this period in the British Isles, coining the terms 'Mediaeval Warm Epoch' and 'Little Climatic Optimum', but many sites seem to have experienced equally important hydrological changes. Here I present a study of relict tree stumps rooted in present-day lakes, marshes and streams, which suggests that California's Sierra Nevada experienced extremely severe drought conditions for more than two centuries before ad ~ 1112 and for more than 140 years before ad ~ 1350. During these periods, runoff from the Sierra was significantly lower than during any of the persistent droughts that have occurred in the region over the past 140 years. I also present similar evidence from Patagonia of drought conditions coinciding with at least the first of these dry periods in California. I suggest that the droughts may have been caused by reorientation of the mid-latitude storm tracks, owing to a general contraction of the circumpolar vortices and/or a change in the position of the vortex waves. If this reorientation was caused by mediaeval warming, future natural or anthropogenically induced warming may cause a recurrence of the extreme drought conditions.
While current projections of future climate change associated with increases in atmospheric greenhouse gases have a high degree of uncertainty, the potential effects of climate change on forests are of increasing concern. A number of studies based on forest simulation models predict substantial alteration of forest composition, forest dieback, or even loss of forest cover in response to increased temperatures associated with increasing atmospheric carbon dioxide concentrations. However, the structure of these computer models may cause them to overemphasize the role of climate in controlling tree growth and mortality. Model functions that represent the influence of climate on tree growth are based on the geographic range limits of a species, predicting maximal growth in the center of the range and zero growth (100 % mortality) at the range limits and beyond. This modeling approach ignores the fact that the geographic range of a species reflects the influence of both climate and other environmental factors, including competition with other tree species, soil characteristics, barriers to dispersal, and distributions of pests and pathogens. These climate-response functions in forest simulation models implicitly assume that tree species occur in all environments where it!s possible for them to survive (their fundamental niche or potential habitat) and that these potential habitats are entirely defined by climate. Hence, any alteration of climate must result in a fairly rapid decline of species near their range limits and rapid alteration of forest composition and structure. The climate-response functions that lead to these unrealistic conclusions have no basis in plant physiology or actual measurements of tree
The earth experiences climate change whether from human-meditated atmospheric effects or as a response to natural drivers. High mountain ecosystems are both sensitive to climate variability and prone to be early indicators of effects that will ripple through distant ecosystems. To better anticipate effects of climate change, and to promote effective mitigation and adaptation, we must accurately measure and understand responses of mountain biota. The Global Observation Research Initiative in Alpine Environments (GLORIA), headquartered in Vienna, Austria, is an international monitoring program focused on responses of high-elevation