Hans Pretzsch's research while affiliated with Technische Universität München and other places

Publications (405)

Article
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Quercus robur/Quercus petraea and Pinus sylvestris are widely distributed and economically important tree species in Europe co-occurring on mesotrophic, xeric and mesic sites. Increasing dry conditions may reduce their growth, but growth reductions may be modified by mixture, competition and site conditions. The annual diameter growth in monospecif...
Article
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Against the backdrop of global change, the intensity, duration, and frequency of droughts are projected to increase and threaten forest ecosystems worldwide. Tree responses to drought are complex and likely to vary among species, drought characteristics, and site conditions. Here, we examined the drought response patterns of three major temperate t...
Article
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Laser scanning has revolutionized the ability to quantify single-tree morphologies and stand structural variables. In this study, we address the issue of occlusion when scanning a spruce (Picea abies (L.) H.Karst.) and beech (Fagus sylvatica L.) forest with a mobile laser scanner by making use of a unique study site setup. We scanned forest stands...
Article
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Mangroves continue to be threatened across their range by a mix of anthropogenic and climate change-related stress. Climate change-induced salinity is likely to alter the structure and functions of highly productive mangrove systems. However, we still lack a comprehensive understanding of how rising salinity affects forest structure and functions b...
Article
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Traditionally, due to its light ecology, oak is regenerated on clear cuts or areas here the crown coverage is heavily reduced. Thus, the regeneration phase is relatively short. Recently, selective long-term regeneration phases avoiding large gaps in the canopy but fostering mixed-species stands have been advocated as being more in keeping with clos...
Article
Eruptive population dynamics of forest insect species regularly attract the interest of ecologists but also often evoke debates among stakeholders concerning impacts that outbreaks or pest control activities have on forest communities including insectivorous birds. Lymantria dispar is the most serious native defoliator in mixed oak-broadleaf forest...
Preprint
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Mangroves continue to be threatened across their range by a mix of anthropogenic and climate change-related stress. Climate change-induced salinity is likely to alter the structure and functions of highly productive mangrove systems. However, we still lack a comprehensive understanding of how rising salinity affects forest structure and functions b...
Article
Increasing species diversity is considered a promising strategy to mitigate the negative impacts of global change on forests. However, the interactions between regional climate conditions and species-mixing effects on climate-growth relationships and drought resistance remain poorly documented. In this study, we investigated the patterns of species...
Article
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Heterogeneity of structure can increase mechanical stability, stress resistance and resilience, biodiversity and many other functions and services of forest stands. That is why many silvicultural measures aim at enhancing structural diversity. However, the effectiveness and potential of structuring may depend on the site conditions. Here, we reveal...
Article
The structure and dynamics of Central Europe’s forests are increasingly characterized by canopy gaps which either result from disturbances or from planned silvicultural actions. It remains, however, unclear, whether the neighborhood to a gap has effects on tree growth which cannot be sufficiently covered by existing standard models so far. In order...
Article
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After drought events, tree recovery depends on sufficient carbon (C) allocation to the sink organs. The present study aimed to elucidate dynamics of tree‐level C sink activity and allocation of recent photoassimilates (Cnew) and stored C in c. 70‐year‐old Norway spruce (Picea abies) trees during a four week period after drought release. We conducte...
Article
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Abstract Climate change is increasing the severity and frequency of droughts around the globe, leading to tree mortality that reduces production and provision of other ecosystem services. Recent studies show that growth of mixed stands may be more resilient to drought than pure stands. The two most economically‐important and widely‐distributed tree...
Article
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The latitudinal diversity gradient (LDG) is one of the most recognized global patterns of species richness exhibited across a wide range of taxa. Numerous hypotheses have been proposed in the past two centuries to explain LDG, but rigorous tests of the drivers of LDGs have been limited by a lack of high-quality global species richness data. Here we...
Article
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How drought affects tree and stand growth is an old question, but is getting unprecedented relevance in view of climate change. Stress effects related to drought have been mostly studied at the individual tree level, mostly investigating dominant trees and using their responses as indicator for the impact at the stand level. However, findings at tr...
Article
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The increasing disturbances in monocultures around the world are testimony to their instability under global change. Many studies have claimed that temporal stability of productivity increases with species richness, although the ecological fundaments have mainly been investigated through diversity experiments. To adequately manage forest ecosystems...
Article
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Rare domestic tree species are increasingly being viewed as promising alternatives and additions to current main tree species in forests facing climate change. For a feasible management of these rare species, it is, however, necessary to know their growth patterns and space requirements. This information has been lacking in management and science u...
Article
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Key message Structural characteristics of tree crowns obtained by TLidar scanning can be used for estimating the course of the stem diameter growth in the past. Abstract To improve human well-being through sustainable management of ecosystems, particular attention is given to the structures, functions, and services of forest trees and stands. T...
Article
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Thinning experiments were primarily established for analysing how treatment variants determine the amount and quality of wood production. Given climate change, they may also explain how silvicultural treatment determined drought resistance. Especially for tree species cultivated in regions beyond their natural range, silvicultural treatment may hel...
Article
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The conversion to climate-stable, resilient and productive forests has resulted in an increasing share of mixed stands. Different growth conditions and silvicultural treatments lead to an increased scatter in strength compared to what is expected from monoculture experience. The study (i) quantified the magnitude of variation in strength of Europea...
Conference Paper
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El inventario forestal por métodos de masa con tecnología LiDAR está implantado operativamente en España. Una de sus principales limitaciones es el coste de adquisición de datos, que supone largos periodos entre campañas de captura, lo que, unido a la obsolescencia del mismo ante perturbaciones naturales o artificiales, especialmente en ecosistemas...
Article
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Future climate predictions for the Mediterranean area include prolonged droughts and an increase in the frequency of extreme events. Silvicultural modification of stand density can buffer the response of tree growth to changes in climate by enhancing soil water availability. We analyzed the stem growth dynamics of Pinus halepensis, including the da...
Article
Full-text available
Heterogeneity of structure can increase mechanical stability, stress resistance and resilience, biodiversity and many other functions and services of forest stands. That is why many silvicultural measures aim at enhancing structural diversity. However, the effectiveness and potential of structuring may depend on the site conditions. Here, we reveal...
Article
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While the impacts of forest management options on carbon (C) storage are well documented, the way they affect C distribution among ecosystem components remains poorly investigated. Yet, partitioning of total forest C stocks, particularly between aboveground woody biomass and the soil, greatly impacts the stability of C stocks against disturbances i...
Article
High planting densities in coniferous stands usually lead to advantageous wood properties with high yields for strength graded timber in sawmills. In timber design, however, the focus is on mechanical wood properties, as structural engineers rely on the characteristic values for strength, stiffness and wood density defined for the strength classes....
Article
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Crown shapes of common European urban tree species differ from tree species to tree species and are modified by the age of a tree and its local environment. A tree’s crown shape has a great influence on the crown volume and thus on the ecosystem service provision of a tree such as the shade area or the shade density. We used the data of 3852 tree i...
Article
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Wood production is one of the most important ecosystem service that forests provide to society. However, under changing climatic onditions, this appears to be subject to increasing uncertainties. In the present study we analyzed how long-term productivity of oak (Quercus petraea [Matt.] Liebl. and Quercus robur L.) stands has developed, how oak beh...
Article
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Urbanization and climate change are two inevitable megatrends of this century. Knowledge about the growth responses of urban trees to climate is of utmost importance towards future management of green infrastructure with the aim of a sustainable provision of the environmental ecosystem services. Using tree-ring records, this study analyzed growth r...
Article
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Key message TLS scans of three surveys before, during and after gypsy moth gradation, allowed high-resolution tracking of defoliation and subsequent inter-annual growth losses on an individual tree level. Abstract Foliation strongly determines all tree growth processes but can be reduced by various stress factors. Insect defoliation starts at vari...
Article
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NASAs Global Ecosystem Dynamics Investigation (GEDI) is collecting space-borne full waveform lidar data with a primary science goal of producing accurate estimates of forest aboveground biomass density (AGBD). This paper presents the development of the models used to create GEDIs footprint-level (~25 m) AGBD (GEDI04_A) product, including a descript...
Article
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Due to high productivity and past management approaches, the forests of Central Europe are heavily dominated by conifers, even on sites where they do not occur naturally at all. One prominent example is Norway spruce (Picea abies H. Karst.), a species considered particularly vulnerable to severe droughts, especially outside of its ecological niche...
Article
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Forest tree growth is primarily explained, modelled, and predicted depending on current age or size, environmental conditions, and competitive status in the stand. The accumulated size is commonly used as a proxy for a tree's past development. However, recent studies suggest that antecedent conditions may impact present growth by epigenetic, transc...
Article
That tree species mixing may strongly affect tree structure and tree growth is so far hardly considered in tree and stand models. Hence, for a better understanding and design of mixed species stands, the inter-specific facilitation and competition needs better representation in individual tree models. Here, we show for the five most common tree spe...
Article
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Significance Tree diversity is fundamental for forest ecosystem stability and services. However, because of limited available data, estimates of tree diversity at large geographic domains still rely heavily on published lists of species descriptions that are geographically uneven in coverage. These limitations have precluded efforts to generate a g...
Article
Forest composed of Picea abies L., Abies alba Mill. and Fagus sylvatica L. cover a large area in the European mountain regions and have a high ecological and socio-economic importance as they supply many ecosystems services. Because of climate change, these forests are exposed to warming, and this effect increases with elevation, which may impact t...
Article
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Green infrastructure (GI) has emerged as a feasible strategy for promoting adaptive capacities of cities to climate change by alleviating urban heat island (UHI) and thus heat stress for humans. However, GI can also intensify the winter cold stress. To understand the extent of UHI within a city as well as the link between outdoor thermal stress bot...
Chapter
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Mountain forests in Europe have to face recently speeding-up phenomena related to climate change, reflected not only by the increases in the mean global temperature but also by frequent extreme events, that can cause a lot of various damages threatening forest stability. The crucial task of management is to adapt forests to environmental uncertaint...
Article
Tree species mixtures can overyield monospecific stands and provide many other advantageous regulating and provisioning ecosystem services. So far, the effect of mixing on growth were mostly described at the individual tree level or cumulatively at the stand level. How overyielding emerges from the mixing pattern, how it is modulated by the current...
Article
is collecting spaceborne full waveform lidar data with a primary science goal of producing accurate estimates of forest aboveground biomass density (AGBD). This paper presents the development of the models used to create GEDI's footprint-level (~25 m) AGBD (GEDI04_A) product, including a description of the datasets used and the procedure for final...
Poster
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Strategien zur Klimawandelanpassung im urbanen Raum erfordern die vermehrte Verwendung von Vegetation zur Verminderung von Hitzebelastungen und für den Regenwasserrückhalt nach Starkregenereignissen. In den bayerischen Ballungsräumen steht das Grün aber aufgrund des Bevölkerungswachstums durch bauliche Nachverdichtung bzw. hochverdichtete Bauweisen...
Article
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In the field of assessing forest ecosystem service provision and biodiversity, there seems to be a gap between an existing large body of valuable expert knowledge and its application. We propose fuzzy logic evaluation systems as a contribution to closing that gap. With this method-focused pilot study, we explored the potential of fuzzy logic for as...
Article
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Die Trauben- und die Stieleiche sind zwei heimische Baumarten, die aufgrund ihrer breiten ökologischen Amplituden und vergleichsweise hohen Trockenheitstoleranz im Klimawandel eine wichtige Rolle im Waldumbau spielen können. Wie sich ihr Höhenwachstum entlang eines klimatischen Gradienten und bei unterschiedlicher Bestandesstruktur verhält, wurde i...
Chapter
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Models to predict the effects of different silvicultural treatments on future forest development are the best available tools to demonstrate and test possible climate-smart pathways of mountain forestry. This chapter reviews the state of the art in modelling approaches to predict the future growth of European mountain forests under changing environ...
Article
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Global forests are the main component of the land carbon sink, which acts as a partial buffer to CO2 emissions into the atmosphere. Dynamic vegetation models offer an approach to projecting the development of forest carbon sink capacity in a future climate. Forest management capabilities are important to include in dynamic vegetation models to acco...
Chapter
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Pedunculate and sessile oak are widely distributed across Europe due to their large ecological amplitude. Thus, there is a rich silvicultural experience with oak in different European countries. With the help of a survey in 18 countries, an overview of the respective silvicultural objectives and approaches could be established. The dominant product...
Chapter
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In the evaluation, the productivity of monospecific and mixed oak stands and individual trees growing on long-term experimental plots was analyzed on the basis of stand structural characteristics. According to the results, stand productivity is up to 22% higher in mixed stands than in monospecific stands. The increase is mainly determined by beech...
Article
Many recent studies address that diversification of tree species and stand structure can increase the level and stability of growth and other forest functions and services to mitigate natural and human disturbances. Most studies so far focussed on the diversification of tree species mixing and stand structure. The potential of intra-specific geneti...
Article
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Forest management faces growing uncertainty concerning environmental conditions and demand for ecosystem services. To help forest managers consider uncertainty, we applied a robust and multi-criteria approach to select the optimal composition of a forest enterprise from 12 stand types. In our simulation, the forest enterprise strives for either fin...
Chapter
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Natural forest management methods are increasingly becoming the focus of silvicultural regeneration procedures. Classical oak regeneration techniques are mostly carried out on large areas. Long-term and small-scaled regeneration are hardly applied. Also due to competition from mixed tree species. On long-term experiments in the Steigerwald, Spessar...
Chapter
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In 28 of 30 Bavarian strict forest reserves (SFR) with oak investigated, a build-up of stocks has been discernible since the beginning of the surveys since over 40 years. The basal area proportion of oak (Quercus sp.) decreased by an average of 0.02% per year in oak forest communities and by 0.12% per year in beech forest communities. The mortality...
Article
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Compared with far-developed measures and methods for mono-specific forest stands, the silvicultural prescriptions for mixed-species stands are at their early beginning. However, they are essential for the well-conceived establishment, design, and control of mixed-species stands, currently promoted in many countries worldwide. Here, we review the st...
Article
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Quantifying tree defoliation by insects over large areas is a major challenge in forest management, but it is essential in ecosystem assessments of disturbance and resistance against herbivory. However, the trajectory from leaf‐flush to insect defoliation to refoliation in broadleaf trees is highly variable. Its tracking requires high temporal‐ and...
Article
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Currently, silvicultural prescriptions such as thinning monospecific stands from above and transitioning from monospecific to mixed-species stands are scrutinised regarding their ability to reduce stress and damage. That the quantity and quality of the trees harvested by intermediate and final cuts will vary depending on the chosen prescription is...
Article
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Knowledge of the maximum forest stand density and the self-thinning process is important for understanding, modelling and scheduling thinnings in silviculture. The upper trajectories of stem number, N, vs mean diameter, dq or mean tree volume vs stem number are often used for quantifying maximum stand density. The long debate about how site conditi...
Article
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Research Highlights: We make use of long term observation data from a selection forest in Bavaria. Despite the changing environmental conditions, stand level productivity remains constant over time. Maintaining species and structural diversity by forest management can contribute to resilient forest ecosystems. Background and Objectives: Forests in...
Article
Urban trees are important, green features of cities. However, knowledge of the size development of frequently planted tree species, which is the basis for modeling environmental benefits of urban trees, is mostly limited. Within this study, allometric relationships for tree structures like tree height, crown parameters, and leaf area were developed...
Article
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Research Highlights: The spatial distribution of trees results from several ecological processes that can be difficult to measure. We applied a point process modelling approach that uses the diameter and species of neighbouring trees to represent inter-tree interactions through repulsive and attractive processes. Thinning treatments slightly influe...
Article
Due to climate change, the occurrence of drought events with essential effects on trees will arise. The impact of severe drought stress on trees’ vitality with regard to growth has often been analysed using traditional, easy-to-measure variables, such as diameter at breast height (d1.3). Another commonly used tree-vitality indicator is crown transp...
Article
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This study combined an empirically based simulation with an analysis of the trade-off between structural heterogeneity and stand productivity depending on time, spatial scale, and silvicultural management, whereas volume growth and tree species diversity have been examined in detail, the role of forest structure and its interdependencies with stand...
Article
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Recently, many studies worldwide tapped tree ring pattern for detection of growth events and trends caused by weather extremes and climate change. As long-term experiments with permanent survey of all trees are rare, growth trend analyses are mostly based on retrospective measurements of growth via increment coring or stem analyses of the remaining...
Article
Urban greenspaces showed the potential to lessen the urban heat island effect. However, a detailed understanding on the mechanisms of different components of greenspaces such as grass surfaces, trees or a combination of grey and green infrastructure on reducing heat loads at local and city scale and different weather conditions is still limited. We...
Article
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Key message Prediction of tree growth based on size or mass as proposed by the Metabolic Scaling Theory is an over-simplification and can be significantly improved by consideration of stem and crown morphology. Tree growth and metabolic scaling theory, as well as corresponding growth equations, use tree volume or mass as predictors for growth. Howe...
Article
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The growth of forest trees under given environmental conditions is assumed to depend mainly on their age, stem and crown size, and competitive position in the stand. The current stem and crown size are commonly recognized as adequate proxy markers for the tree's ecological memory of the past. In contrast, tree ring structure, crown whorl morphology...
Article
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Over recent decades, climate change has been particularly severe in the Mediterranean basin, where the intensity and frequency of drought events have had a significant effect on tree growth and mortality. In this context, differences in structural and physiological strategies between tree species could help to mitigate the damage inflicted by clima...
Article
In central Europe forests, the share of European beech (Fagus sylvatica L.) trees has been increased in the last decades. Machine strength grading of hardwood is challenging due to a lack of knowledge about strength predictors. However, high strength classes are needed for the utilization as glued and cross laminated timber. We used the information...
Article
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The Kroof experiment: realization and efficacy of a recurrent drought experiment plus recovery in a beech/spruce forest. Ecosphere 12(3): Abstract. Forest ecosystems play a central role in global water and carbon cycles, yet the impact of global climate change, in particular drought, on trees and forests is poorly understood. Therefore, there is an...