Susan C. Cook-Patton

• Senior Forest Restoration Scientist at The Nature Conservancy

Reforestation is a prominent climate change mitigation strategy, but available global maps of reforestation potential are widely criticized and highly variable, which limits their ability to provide robust estimates of both the locations and total area of opportunity. Here we develop global maps that address common critiques, build on a review of 8...

Addressing global environmental conservation problems requires rapidly translating natural and conservation social science evidence to policy‐relevant information. Yet, exponential increases in scientific production combined with disciplinary differences in reporting research make interdisciplinary evidence syntheses especially challenging. Ongoing...

Pathways to achieving net zero carbon emissions commonly involve deploying reforestation, afforestation, and bioenergy crops across millions of hectares of land. It is often assumed that by helping to mitigate climate change, these strategies indirectly benefit biodiversity. Here, we modeled the climate and habitat requirements of 14,234 vertebrate...

Many trees depend on animals for seed dispersal, and human activities that disrupt seed dispersal by animals may impact forest regeneration and carbon storage. Yet whether expected negative impacts are observable across regrowing forests remains untested. We modeled seed dispersal disruption and its relationship to aboveground carbon accumulation o...

Natural climate solutions (NCS) play a critical role in climate change mitigation. NCS can generate win–win co-benefits for biodiversity and human well-being, but they can also involve trade-offs (co-impacts). However, the massive evidence base on NCS co-benefits and possible trade-offs is poorly understood. We employ large language models to asses...

Forest regeneration is a crucial strategy for mitigating and adapting to global warming. Yet its precise impact on local climate remains uncertain, a factor that complicates decision-making when it comes to prioritizing investments. Here, we developed global maps illustrating how natural forest regeneration influences key local climate drivers—land...

Societal Impact Statement Human interactions with forests have shaped Earth's climate for millennia and will continue to do so as we target net‐zero emission goals. Accurately characterizing these climate impacts requires making reliable forest carbon data available for forest monitoring and planning. Here, we develop a semi‐automated process for s...

Forests play a crucial role in regulating the global climate. Yet, forests also influence the local climate conditions through biophysical processes that directly impact human wellbeing. With growing policy emphasis on these climate adaptation effects, we review the scale dependent impacts of forests on climate conditions and their implications for...

Forest restoration is gaining momentum as a natural climate solution to provide carbon dioxide removal while also addressing the biodiversity crisis. Globally, three primary restoration strategies—natural regeneration, assisted natural regeneration, and active restoration—have been adopted. However, inconsistent monitoring of forest dynamics mean l...

Mitigating climate change cost-effectively requires identifying least-cost-per-ton GHG abatement methods. Here, we estimate and map GHG abatement cost (US$ per tCO2) for two common reforestation methods: natural regeneration and plantations. We do so by producing and integrating new maps of implementation costs and opportunity costs of reforestatio...

Meeting global climate commitments and avoiding severe global warming requires drastic reductions in emissions and large-scale removals of atmospheric carbon dioxide1. Forest regrowth offers scalable and cost-effective carbon removal,2,3 but rates vary substantially by location and age of forest stand4,5. Here we generate pixel level (~1-km2) Chapm...

Excessive heat is a major and growing risk for urban residents. Here, we estimate the inequality in summertime heat-related mortality, morbidity, and electricity consumption across 5723 US municipalities and other places, housing 180 million people during the 2020 census. On average, trees in majority non-Hispanic white neighborhoods cool the air b...

Restoring tree cover changes albedo, which is the fraction of sunlight reflected from the Earth’s surface. In most locations, these changes in albedo offset or even negate the carbon removal benefits with the latter leading to global warming. Previous efforts to quantify the global climate mitigation benefit of restoring tree cover have not account...

Natural climate solutions can mitigate climate change in the near-term, during a climate-critical window. Yet, persistent misunderstandings about what constitutes a natural climate solution generate unnecessary confusion and controversy, thereby delaying critical mitigation action. Based on a review of scientific literature and best practices, we d...

Although decades of research suggest that higher species richness improves ecosystem functioning and stability, planted forests are predominantly monocultures. To determine whether diversification of plantations would enhance aboveground carbon storage, we systematically reviewed over 11,360 publications, and acquired data from a global network of...

Silvopasture—integrating trees, forage, and grazing livestock on the same piece of land—is increasingly popular, given its potential to store carbon (C) and improve farmers’ livelihoods. We examined the C and economic implications of adding different silvopastoral systems to existing pastures in historically forested areas of the eastern United Sta...

The expansion of agroforestry could provide substantial climate change mitigation (up to 0.31 Pg C yr−1), comparable to other prominent natural climate solutions such as reforestation. Yet, climate-focused agroforestry efforts grapple with ambiguity about which agroforestry actions provide mitigation, uncertainty about the magnitude of that mitigat...

Restoring tree cover is a prominent natural climate solution 1–3 , but can decrease albedo and lead to global warming in some places 4–10 . Existing assessments of the mitigation potential from restoring tree cover 2,3,11,12 poorly account for albedo due to a lack of spatial data. Here we produce a global 500-m map that incorporates albedo and maxi...

Tree plantings have the potential to increase species diversity and sequester carbon, yet planting failure and early mortality pose significant barriers to their success. Biodiversity‐ecosystem function theory suggests that diverse tree plantings could improve survival outcomes through either the portfolio or facilitation effect, yet there remain f...

Excessive heat is a major and growing risk for urban residents. Urban trees can significantly reduce summer peak temperatures, thus reducing heat-related mortality, morbidity, as well as cooling energy demand. However, urban tree canopy is inequitably distributed in US cities, which has been shown to contribute to higher summer temperatures in peop...

Purpose of the Review Improved forest management is a promising avenue for climate change mitigation. However, we lack synthetic understanding of how different management actions impact aboveground carbon stocks, particularly at scales relevant for designing and implementing forest-based climate solutions. Here, we quantitatively assess and review...

Restoring tree cover in tropical countries has the potential to benefit millions of smallholders through improvements in income and environmental services. However, despite their dominant landholding shares in many countries, smallholders' role in restoration has not been addressed in prior global or pan-tropical restoration studies. We fill this l...

Surface gold mining severely degrades landscapes, causing deforestation, soil erosion and displacement, and toxic contamination. The prevalence of both large‐scale and artisanal, small‐scale surface gold mining in the tropics has risen over recent decades. Restoration strategies developed for less‐severe forms of degradation may not sufficiently ad...

Restoring forest cover is a key action for mitigating climate change. Although monoculture plantations dominate existing commitments to restore forest cover, we lack a synthetic view of how carbon accumulates in these systems. Here, we assemble a global database of 4756 field-plot measurements from monoculture plantations across all forested contin...

There is growing interest in agroforestry as a climate solution, given its potential to store additional carbon in agricultural landscapes, while also enhancing livelihoods and biodiversity. However, substantial uncertainty remains around how much carbon can be captured, and how that varies by location and by practice. One of the central challenges...

Recently, agroforestry (AF) has received growing recognition as a promising natural climate solution (NCS) – an improved land-use practice that helps mitigate climate change. As a first approximation, it is clear that the addition of woody biomass on agricultural lands will provide additional carbon sequestration and storage. However, our review of...

Significance Despite increased interest in land-based carbon storage as a climate solution, there are physical limits on how much additional carbon can be incorporated into terrestrial ecosystems. To effectively determine where and how to act, jurisdictions need robust data illustrating the magnitude and distribution of opportunities to increase ca...

Reforestation in the tropics is highlighted as an important intervention to mitigate climate change globally because of its potential for high CO2 removal rates, ranging from 4.5 to 40.7 t CO2e ha⁻¹ yr⁻¹ during the first 20 years of tree growth. Reforestation is critical to meeting emissions’ targets of the Paris Climate Agreement, as well as achie...

Agroforestry systems have the potential to sequester carbon and offer numerous benefits to rural communities, but their capacity to offer valuable cooling services has not been quantified on continental scales. Here, we find that trees in pasturelands (“silvopasture”) across Latin America and Africa can offer substantial cooling benefits. These coo...

Natural forest is declining globally as the area of planted forest increases. Planted forests are often monocultures, despite results suggesting that higher species richness improves ecosystem functioning and stability. To test if this is generally the case, we performed a meta-analysis of available results. We assessed aboveground carbon stocks in...

Avoiding catastrophic climate change requires rapid decarbonization and improved ecosystem stewardship at a planetary scale. The carbon released through the burning of fossil fuels would take millennia to regenerate on Earth. Though the timeframe of carbon recovery for ecosystems such as peatlands, mangroves and old-growth forests is shorter (centu...

For monitoring and reporting forest carbon stocks and fluxes, many countries in the tropics and subtropics rely on default values of forest aboveground biomass (AGB) from the Intergovernmental Panel on Climate Change (IPCC) Guidelines for National Greenhouse Gas (GHG) Inventories. Default IPCC forest AGB values originated from 2006, and are relativ...

Limited time and resources remain to constrain the climate crisis. Natural climate solutions represent promising options to protect, manage and restore natural lands for additional climate mitigation, but they differ in (1) the magnitude and (2) immediacy of mitigation potential, as well as (3) cost-effectiveness and (4) the co-benefits they offer....

Tree planting is both a promising and controversial solution to climate change and biodiversity loss. However, this controversy is largely theoretical because we lack detailed information of how tree planting is proceeding on-the-ground. Here, we compiled a pantropical dataset of 174 tree planting organizations to determine the type of organization...

Agroforestry, or the intentional integration of trees on crop or pastureland, is a sustainable land use system that provides ecosystem services including climate change mitigation and private benefits for smallholders. While existing reviews of agroforestry adoption focus on government policy, there is increasing interest from, and opportunities fo...

Alongside the steep reductions needed in fossil fuel emissions, natural climate solutions (NCS) represent readily deployable options that can contribute to Canada’s goals for emission reductions. We estimate the mitigation potential of 24 NCS related to the protection, management, and restoration of natural systems that can also deliver numerous co...

Forests are major components of the global carbon (C) cycle and thereby strongly influence atmospheric carbon dioxide (CO2) and climate. However, efforts to incorporate forests into climate models and CO2 accounting frameworks have been constrained by a lack of accessible, global-scale synthesis on how C cycling varies across forest types and stand...

Restoration of forest cover can curtail the climate crisis and provide many co-benefits, or waste limited resources. To use restoration of forest cover to its highest potential, global dynamic monitoring is needed that combines existing restoration projects with control plots and remote-sensing technologies.

Large-scale global reforestation goals have been proposed to help mitigate climate change and provide other ecosystem services. To explore reforestation potential in the United States, we used GIS analyses, surveys of nursery managers and foresters, and literature synthesis to assess the opportunities and challenges associated with meeting proposed...

Article Lower cost and more feasible options to restore forest cover in the contiguous United States for climate mitigation Graphical Abstract Highlights d Restoring forest cover in the US can be a cost-effective climate solution d New forest across 51.6 Mha could capture 314 MtCO 2 year À1 d We provide critical information to guide decisions about...

To constrain global warming, we must strongly curtail greenhouse gas emissions and capture excess atmospheric carbon dioxide1,2. Regrowing natural forests is a prominent strategy for capturing additional carbon³, but accurate assessments of its potential are limited by uncertainty and variability in carbon accumulation rates2,3. To assess why and w...

While improved management of agricultural landscapes is promoted as a promising natural climate solution, available estimates of the mitigation potential are based on coarse assessments of both agricultural extent and aboveground carbon density. Here we combine 30 meter resolution global maps of aboveground woody carbon, tree cover, and cropland ex...

The role of tree diversity in restored forests and its impact on key ecological processes like growth and resistance to herbivory has become increasingly important. We analyzed height growth and white‐tailed deer Odocoileus virginianus browsing damage to saplings of 16 broadleaved tree species in a large‐scale (13 ha) reforestation experiment in Ma...

Mitigating climate change requires clean energy and the removal of atmospheric carbon. Building soil carbon is an appealing way to increase carbon sinks and reduce emissions owing to the associated benefits to agriculture. However, the practical implementation of soil carbon climate strategies lags behind the potential, partly because we lack clari...

Avoiding catastrophic climate change requires rapid decarbonization and improved ecosystem stewardship. To achieve the latter, ecosystems should be prioritized by responsiveness to direct, localized action and the magnitude and recoverability of their carbon stores. Here, we show that a range of ecosystems contain ‘irrecoverable carbon’ that is vul...

Tree plantations and forest restoration are leading strategies for enhancing terrestrial carbon (C) sequestration and mitigating climate change. While it is well established that species-rich natural forests offer superior C sequestering benefits relative to short-rotation commercial monoculture plantations, differences in rates of C capture and st...

Better land stewardship is needed to achieve the Paris Agreement's temperature goal, particularly in the tropics, where greenhouse gas emissions from the destruction of ecosystems are largest, and where the potential for additional land carbon storage is greatest. As countries enhance their nationally determined contributions (NDCs) to the Paris Ag...

As countries advance in greenhouse gas (GHG) accounting for climate change mitigation, consistent estimates of aboveground net biomass change (∆AGB) are needed. Countries with limited forest monitoring capabilities in the tropics and subtropics rely on IPCC 2006 default ∆AGB rates, which are values per ecological zone, per continent. Similarly, res...

Achieving the 1.5–2.0 °C temperature targets of the Paris climate agreement requires not only reducing emissions of greenhouse gases (GHGs) but also increasing removals of GHGs from the atmosphere [1,2]. Reforestation is a potentially large-scale method for removing CO2 and storing it in the biomass and soils of ecosystems [3,4,5,6,7,8], yet its co...

We respond to concerns raised by Baldocchi and Penuelas who question the potential for ecosystems to provide carbon sinks and storage, and conclude that we should focus on decarbonizing our energy systems. While we agree with many of their concerns, we arrive at a different conclusion: we need strong action to advance both clean energy solutions an...

Limiting climate warming to <2°C requires increased mitigation efforts, including land stewardship, whose potential in the United States is poorly understood. We quantified the potential of natural climate solutions (NCS)—21 conservation, restoration, and improved land management interventions on natural and agricultural lands—to increase carbon st...

Genotypic diversity in plant populations is known to enhance plant performance and ecosystem function. Nonetheless, the effect of genotypic diversity has rarely been examined across a population's lifecycle despite the expectation that changing conditions, such as population density, will alter the benefits of diversity. We simultaneously manipulat...

Biological control agents may have unintended effects on native biota, particularly species that are closely related to the target invader. Here, we explored how Chrysolina quadrigemina , a beetle introduced to control the invasive weed Hypericum perforatum , impacts native H. punctatum in Tompkins County, New York, USA. Using a suite of complement...

Natural Survey Data

Sun/shade Experiment Data

Transect Experiment Data

The science of conservation has faced unprecedented challenges in terms of environmental damage and rapid global change in its 40-year history, and environmental problems are only increasing as greater demands are placed on limited natural resources. Conservation science has been adapting to keep pace with these changes. Here, we highlight contempo...

Experimentation in grasslands and other ecosystems suggest that diverse plant communities grow more vigorously than simple communities, support a more robust animal community, and better resist stressors like disease, herbivory, and invasion. Despite the potential advantages of plant diversity on green roofs, many green roof communities consist of...

Climate change is dramatically altering the distribution and abundance of many species. An examination of traits may elucidate why some species respond more strongly to climate change than others, particularly when ecophysiological thresholds set range limits. Mangrove forests are expanding polewards. Although multiple environmental factors influen...

Predictions of climate-related shifts in species ranges have largely been based on correlative models. Due to limitations of these models, there is a need for more integration of experimental approaches when studying impacts of climate change on species distributions. Here we used controlled experiments to identify physiological thresholds that con...

Plant diversity can affect ecological processes such as competition and herbivory, and these ecological processes can act as drivers of evolutionary change. However, surprisingly little is known about how ecological variation in plant diversity can alter selective regimes on members of the community. Here, we examine how plant diversity at two diff...

Specialist herbivores are thought to often enhance or maintain plant diversity within ecosystems, because they prevent their host species from becoming competitively dominant. In contrast, specialist herbivores are not generally expected to have negative impacts on non-hosts. However, we describe a cascade of indirect interactions whereby a special...

Although exotic plants comprise a substantial portion of floristic biodiversity, their contributions to community and ecosystem processes are not well understood. We manipulated plant species richness in old-field communities to compare the impacts of native vs. exotic species on plant biomass, seed production, and arthropod community structure. Pl...

The effects of herbivores and diversity on plant communities have been studied separately but rarely in combination. We conducted two concurrent experiments over 3 years to examine how tree seedling diversity, density and herbivory affected forest regeneration. One experiment factorially manipulated plant diversity (one versus 15 species) and the p...

The legacy of ancient human practices can affect the diversity and structure of modern ecosys-tems. Here, we examined how prehistoric refuse dumps (''middens'') impacted soil chemistry and plant community composition in forests along the Chesa-peake Bay by collecting vegetational and soil nutrient data. The centuries-to millennia-old shell middens...

Specialist herbivores are often thought to benefit the larger plant community, because they prevent their host species from becoming competitively dominant. In contrast, specialist enemies are not generally expected to have negative impacts on non-hosts. However, we describe a cascade of indirect interactions whereby a specialist sooty mold ( Scori...

Specialist herbivores are often thought to benefit the larger plant community, because they prevent their host species from becoming competitively dominant. In contrast, specialist enemies are not generally expected to have negative impacts on non-hosts. However, we describe a cascade of indirect interactions whereby a specialist sooty mold ( Scori...

Background/Question/Methods Mangroves are tropical and subtropical tree species that have recently begun moving into temperate zones. Mangrove distributions are thought to be limited by freezing temperatures, suggesting that poleward migrations result from either a warming climate or selection for cold-tolerant individuals at the edge of the rang...

Background/Question/Methods Decades of experimentation show that loss of biodiversity can negatively impact ecosystems. While most of these experiments occurred in grassland systems and/or manipulated a single trophic level, the majority of terrestrial producer diversity resides in forests and exists in trophically complex environments. Here we c...

Biodiversity is quantified via richness (e.g., the number of species), evenness (the relative abundance distribution of those species), or proportional diversity (a combination of richness and evenness, such as the Shannon index, H'). While empirical studies show no consistent relationship between these aspects of biodiversity within communities, t...

Biodiversity loss is proceeding at an unprecedented rate, yet we lack a thorough understanding of the consequences of losing diversity at different scales. While species diversity is known to impact community and ecosystem processes, genotypic diversity is assumed to have relatively smaller effects. Nonetheless, a few recent studies suggest that ge...

Background: Weedy non-native species have long been predicted to be more phenotypically plastic than native species. Question: Are weedy non-native species more plastic than natives? Organisms: Fourteen perennial plant species: Acer platanoides, Acer saccharum, Bromus inermis, Bromus latiglumis, Celastrus orbiculatus, Celastrus scandens, Elymus rep...