I´m particularly interested in Forest Biodiversity and Forest Ecology and Maintaining ecological Functions and Managing Biodiversity under Global change conditions Address: Büsgenweg 1a, D-37077 Göttingen
Anthropogenic impacts such as global warming, land-use change and nitrogen deposition are affecti... more Anthropogenic impacts such as global warming, land-use change and nitrogen deposition are affecting plant communities worldwide, and particularly alpine communities have been undergoing significant changes in recent years. We therefore analysed changes in the alpine calcareous grassland vegetation (Carex sempervirens and Carex firma communities) in the Berchtesgaden National Park over the last 30 years. We used data from permanent plots to produce a "floristic time series" from the 1980s to the present. We analysed the changes in the composition and species richness and tried to link these to autogenic or allogenic processes, with special focus on anthropogenic nitrogen deposition as a potential major cause. We found clear floristic changes over the study period, with an increase in average species richness of more than 10 species per plot in both communities. The Carex firma communities also showed a significant decrease in the average indicator values for continentality,...
Im Ebersberger Forst, dem größten geschlossenen Waldkomplex der südlichen Münchner Schotter- eben... more Im Ebersberger Forst, dem größten geschlossenen Waldkomplex der südlichen Münchner Schotter- ebene, wurden die Effekte des Waldumbaus auf den Humuszustand sowie die Artenzusammensetzung und Diversität der Waldbodenvegetation untersucht. Dabei wurden drei Bewirtschaftungssysteme (Fichtenreinbestandswirtschaft "Z" vs. Umbau von Fichtenreinbeständen in Fichten-Buchen-Misch- bestände mit geringem "L" bzw. hohem Laubholzanteil "H") miteinander verglichen. Auf den insge- samt 54 Probeflächen (18 je System) fanden nach standardisierten Methoden Aufnahmen zum Humus (Humusform sowie Auflagemächtigkeit) sowie zur Bodenvegetation (Gefäßpflanzen, Moose) statt. Dabei zeigte sich, dass mit zunehmendem Buchenanteil der Anteil "ungünstiger" Humusformen (rohhumusartiger Moder, Moder) zurückgeht, während bei den "günstigen" Humusformen (mullartiger Moder, F-Mull) eine Zunahme zu verzeichnen ist. Mit diesen Veränderungen geht auch eine signifikant nied...
The southern slope of the, basaltic “Bauersberg” in the montane belt of the “Lange Rhön” is analy... more The southern slope of the, basaltic “Bauersberg” in the montane belt of the “Lange Rhön” is analysed for its flora and vegetation, especially on extensive rocky places with extreme conditions for plant life. These show a typical pattern of vegetation distribution, even in comparison with other regions. Because of the isolation in the landscape of open rocky places, they both offer a refuge for glacial relicts and pose a genetic requirement for the evolution of endemic organisms. Communities of epilithic lichens grow most ly on the rocks in the centre of the rubble slope of the “Bauersberg”. Each rock shows a typical pattern of lichen communities: the L ecideetum lithophilae grows on horizontal surfaces, the L ecanoretum sord idae on vertical surfaces and the L ecideetum lu cidae on the undersides, protected from rainfall. Communities of epilithic mosses grow mostly in more humid, shaded margins. Their vegetation pattern is related to the different conditions along the slope: In the...
Concerted efforts are required to achieve the essential UN Sustainable Development Goals (SDGs) o... more Concerted efforts are required to achieve the essential UN Sustainable Development Goals (SDGs) of the 2030 Agenda. This concept paper is focused on the development of a new Master of Forestry (MF) degree program at our University of Applied Sciences (UAS). With this move, we want to outline how capacity building and valuable synergy effects can be obtained from close cooperation in teaching and research, in order to educate our scientifically trained and practice-oriented forestry students in applying new management responses to natural disturbance impacts and sustainable use of terrestrial natural resources for forest resource-dependent communities. Specifically, we show how the emergent issues of global warming and the associated increased vulnerability of temperate deciduous forests can be tackled. Actions to overcome knowledge transfer barriers will provide sound solutions for SDG 4 (quality education), SDG 5 (gender equality), SDG 7 (affordable and clean energy), SDG 12 (respo...
The map of "Regional natural forest composition by main tree species" (WALENTOWSKI et a... more The map of "Regional natural forest composition by main tree species" (WALENTOWSKI et al. 2001) depicts Bavaria as a region largely predominated by the European beech (Fagus sylvatica). Analyses of climatope, hygrotope and trophotope of fir-dominated regional natural units make evident that the reasons for the preponderance of the European silver fir (Abies alba) are edaphic. In terms of regeneration vigour, growth and yield the fir particularly dominates in habitats with a combination of humus cover, acid-oligotrophic topsoils and clayey or waterlogged subsoils, where the beech usually exhibits stunted and malformed growth forms. This ecological preference has the effect that Bavarian Abies alba-forests are restricted to small patches within a matrix of potential natural vegetation formed by mixed deciduous-coniferous mountain forests. Within European Natura 2000 areas Abies-forests should be recorded carefully as special habitats. Their transitional character between tem...
Climate change challenges important native timber species in Central Europe. The introduction of ... more Climate change challenges important native timber species in Central Europe. The introduction of non-native tree species originating from warmer climates is one option to make Central European forests compatible to global warming. This, however, requires an assessment of the species’ growth requirements, and of its impact on biodiversity in its native ranges. Silver lime (Tilia tomentosa), a moderately drought-tolerant, thermophilous tree species of South-eastern Europe is considered suitable for the future. Along three elevational transects in western Romania, we assessed the impact of changing climate and local site conditions on the abundance of this tree species and contrasted plant species diversity and composition of lime-dominated forests with mesophytic oak and beech forests. Local site conditions and disturbance histories shaped the distribution pattern of silver lime. When dominant, it reduced plant species diversity within stands due to its dense canopy. For shade-toleran...
Global warming and increasing drought severity are exposing temperate forests to increasing stres... more Global warming and increasing drought severity are exposing temperate forests to increasing stress, challenging silvicultural decision making. Growth analyses in marginal tree populations at drought-induced range limits may provide valuable information on tree species' adaptive potentials and species-specific climate turning points. We studied the climate sensitivity and resilience to drought of radial growth, and long-term growth trends of mesic and rear-edge populations of Fagus sylvatica in comparison to three oak species (Quercus petraea, Q. frainetto, Q. cerris) and Tilia tomentosa in natural ecotones from mesic beech to xeric oak forests along three elevation transects in western Romania. Radial growth of all species was positively influenced by summer precipitation and low drought intensity, and negatively by high summer temperatures. The basal area increment (BAI) of F. sylvatica and T. tomentosa has declined in the last 10-20 years with warming and a deterioration of the summer water balance, while the three Quercus species maintained stable growth rates, though at lower BAI levels, suggesting a negative relationship between mean BAI and drought resistance among the five species. Growth reductions during three severe drought events (2000, 2003, 2012) were stronger, and growth resilience lower, in F. sylvatica and T. tomentosa than in the Quercus species, pointing at a thermal limit of beech at June-August temperatures of 20-21 • C. As the climate of the studied ecotones is similar to the predicted climate at colline/ submontane elevation in Central Europe in about 50 years, a decline in beech growth and vitality is likely also in drought-affected regions in the distribution centre with future warming. Our results demonstrate that choosing stress-tolerant Q. petraea (as well as Q. frainetto and Q. cerris) instead of more productive timber species is a relatively safe option for Central European forestry in a warmer climate.
Key message Climate-warming related replacement of beech by oak forests in the course of natural ... more Key message Climate-warming related replacement of beech by oak forests in the course of natural forest succession or silvicultural decisions may considerably reduce ecosystem carbon storage of central European woodlands. Context Climate warming may change the carbon (C) storage in forest biomass and soil through future shifts in tree species composition. With a projected warming by 2–3 K over the twenty-first century, silvicultural adaptation measures and natural succession might lead to the replacement of European beech forests by thermophilic oak forests in drought- and heat-affected regions of central and south-eastern Europe, but the consequences for ecosystem C storage of this species shift are not clear. Aims To quantify the change in C storage in biomass and soil with a shift from beech (Fagus sylvatica) to oak forest (Quercus petraea, Q. frainetto, Q. cerris), we measured the aboveground biomass (AGC) and soil C pools (SOC). Methods AGC pools and SOC stocks to − 100 cm dept...
Die Geobotanik beschäftigt sich mit den Veränderungen der Vegetation auf regionaler und globaler ... more Die Geobotanik beschäftigt sich mit den Veränderungen der Vegetation auf regionaler und globaler Ebene und auf historischen bis geologischen Zeithorizonten. Im Folgenden soll der Versuch unternommen werden, die Artenvielfalt Mitteleuropas, mit Fokus auf Pflanzen, in einen geografischen Rahmen zu stellen, um daraus für den Artenschutz in der Gegenwart zu lernen. Integrativer Naturschutz, in dem Schutzbestrebungen des Naturschutzes mit Interessen wirtschaftlicher Nutzung verbunden werden, ist die vielleicht wichtigste Möglichkeit, Artenvielfalt auf großer Fläche zu erhalten
European beech (Fagus sylvatica) is a drought-sensitive species that likely will retreat from its... more European beech (Fagus sylvatica) is a drought-sensitive species that likely will retreat from its xeric distribution edges in the course of climate warming. Physiological measurements indicate that the species may not only be sensitive to soil water deficits, but also to high temperatures and elevated atmospheric vapor pressure deficits (vpd). Through microclimatological measurements in the stand interior across near-natural beech forest–oak forest ecotones, we searched for microclimatic tipping points in the contact zone with the aim to define the thermic and hydrometeorological limits of beech more precisely. In three transects in the foothills of the Romanian western Carpathians, we measured in mid-summer 2019 air temperature, relative air humidity, and vpd at 2 m height in the stand interior across the ecotone from pure oak to pure beech forests, and compared the readings to the microclimate in forest gaps. Mean daytime temperature (T) and vpd were by 2 K and 2 hPa, respectively...
Abstract Deadwood is a fundamental forest habitat component and highly important for biodiversity... more Abstract Deadwood is a fundamental forest habitat component and highly important for biodiversity conservation. Its availability, composition, size, categories and distribution depend on various structural and environmental factors (e.g., forest age, management, tree mortality, climate, decomposition). We analysed deadwood patterns along altitudinal gradients of managed (three) and unmanaged (one) deciduous forests in Western Romania. A total of 153 plots (119 managed, 34 unmanaged) of four pre-classified forest types dominated by Fagus sylvatica, Quercus petraea, Quercus frainetto with Quercus cerris, and Tilia tomentosa were evaluated, the former two both in managed and unmanaged stands. The managed forest types displayed an average deadwood volume of 47 m3 ha−1 with lying deadwood accounting for over 70%. About 40% of deadwood objects occurred in the early to intermediate decomposition stage. Deadwood volumes in unmanaged forest types exceeded those of managed forests two- to threefold although the deadwood amounts observed in managed forests were similar to low-intervention or recently abandoned forests, lying within critical threshold values considered important for the long-term preservation of biodiversity. Linear-mixed-effects models confirmed the positive impact of non-management and the negative effect of annual mean temperature on deadwood volume. Prediction models suggested that management and annual mean temperature showed additive effects, indicating that a combination of environmental and structural parameters determines the amount of deadwood in the studied forest types. As climatic variables strongly influence tree species composition and thus forest type, management involving deadwood retention or accumulation should consider forest-type specific characteristics and thresholds.
Anthropogenic impacts such as global warming, land-use change and nitrogen deposition are affecti... more Anthropogenic impacts such as global warming, land-use change and nitrogen deposition are affecting plant communities worldwide, and particularly alpine communities have been undergoing significant changes in recent years. We therefore analysed changes in the alpine calcareous grassland vegetation (Carex sempervirens and Carex firma communities) in the Berchtesgaden National Park over the last 30 years. We used data from permanent plots to produce a "floristic time series" from the 1980s to the present. We analysed the changes in the composition and species richness and tried to link these to autogenic or allogenic processes, with special focus on anthropogenic nitrogen deposition as a potential major cause. We found clear floristic changes over the study period, with an increase in average species richness of more than 10 species per plot in both communities. The Carex firma communities also showed a significant decrease in the average indicator values for continentality,...
Im Ebersberger Forst, dem größten geschlossenen Waldkomplex der südlichen Münchner Schotter- eben... more Im Ebersberger Forst, dem größten geschlossenen Waldkomplex der südlichen Münchner Schotter- ebene, wurden die Effekte des Waldumbaus auf den Humuszustand sowie die Artenzusammensetzung und Diversität der Waldbodenvegetation untersucht. Dabei wurden drei Bewirtschaftungssysteme (Fichtenreinbestandswirtschaft "Z" vs. Umbau von Fichtenreinbeständen in Fichten-Buchen-Misch- bestände mit geringem "L" bzw. hohem Laubholzanteil "H") miteinander verglichen. Auf den insge- samt 54 Probeflächen (18 je System) fanden nach standardisierten Methoden Aufnahmen zum Humus (Humusform sowie Auflagemächtigkeit) sowie zur Bodenvegetation (Gefäßpflanzen, Moose) statt. Dabei zeigte sich, dass mit zunehmendem Buchenanteil der Anteil "ungünstiger" Humusformen (rohhumusartiger Moder, Moder) zurückgeht, während bei den "günstigen" Humusformen (mullartiger Moder, F-Mull) eine Zunahme zu verzeichnen ist. Mit diesen Veränderungen geht auch eine signifikant nied...
The southern slope of the, basaltic “Bauersberg” in the montane belt of the “Lange Rhön” is analy... more The southern slope of the, basaltic “Bauersberg” in the montane belt of the “Lange Rhön” is analysed for its flora and vegetation, especially on extensive rocky places with extreme conditions for plant life. These show a typical pattern of vegetation distribution, even in comparison with other regions. Because of the isolation in the landscape of open rocky places, they both offer a refuge for glacial relicts and pose a genetic requirement for the evolution of endemic organisms. Communities of epilithic lichens grow most ly on the rocks in the centre of the rubble slope of the “Bauersberg”. Each rock shows a typical pattern of lichen communities: the L ecideetum lithophilae grows on horizontal surfaces, the L ecanoretum sord idae on vertical surfaces and the L ecideetum lu cidae on the undersides, protected from rainfall. Communities of epilithic mosses grow mostly in more humid, shaded margins. Their vegetation pattern is related to the different conditions along the slope: In the...
Concerted efforts are required to achieve the essential UN Sustainable Development Goals (SDGs) o... more Concerted efforts are required to achieve the essential UN Sustainable Development Goals (SDGs) of the 2030 Agenda. This concept paper is focused on the development of a new Master of Forestry (MF) degree program at our University of Applied Sciences (UAS). With this move, we want to outline how capacity building and valuable synergy effects can be obtained from close cooperation in teaching and research, in order to educate our scientifically trained and practice-oriented forestry students in applying new management responses to natural disturbance impacts and sustainable use of terrestrial natural resources for forest resource-dependent communities. Specifically, we show how the emergent issues of global warming and the associated increased vulnerability of temperate deciduous forests can be tackled. Actions to overcome knowledge transfer barriers will provide sound solutions for SDG 4 (quality education), SDG 5 (gender equality), SDG 7 (affordable and clean energy), SDG 12 (respo...
The map of "Regional natural forest composition by main tree species" (WALENTOWSKI et a... more The map of "Regional natural forest composition by main tree species" (WALENTOWSKI et al. 2001) depicts Bavaria as a region largely predominated by the European beech (Fagus sylvatica). Analyses of climatope, hygrotope and trophotope of fir-dominated regional natural units make evident that the reasons for the preponderance of the European silver fir (Abies alba) are edaphic. In terms of regeneration vigour, growth and yield the fir particularly dominates in habitats with a combination of humus cover, acid-oligotrophic topsoils and clayey or waterlogged subsoils, where the beech usually exhibits stunted and malformed growth forms. This ecological preference has the effect that Bavarian Abies alba-forests are restricted to small patches within a matrix of potential natural vegetation formed by mixed deciduous-coniferous mountain forests. Within European Natura 2000 areas Abies-forests should be recorded carefully as special habitats. Their transitional character between tem...
Climate change challenges important native timber species in Central Europe. The introduction of ... more Climate change challenges important native timber species in Central Europe. The introduction of non-native tree species originating from warmer climates is one option to make Central European forests compatible to global warming. This, however, requires an assessment of the species’ growth requirements, and of its impact on biodiversity in its native ranges. Silver lime (Tilia tomentosa), a moderately drought-tolerant, thermophilous tree species of South-eastern Europe is considered suitable for the future. Along three elevational transects in western Romania, we assessed the impact of changing climate and local site conditions on the abundance of this tree species and contrasted plant species diversity and composition of lime-dominated forests with mesophytic oak and beech forests. Local site conditions and disturbance histories shaped the distribution pattern of silver lime. When dominant, it reduced plant species diversity within stands due to its dense canopy. For shade-toleran...
Global warming and increasing drought severity are exposing temperate forests to increasing stres... more Global warming and increasing drought severity are exposing temperate forests to increasing stress, challenging silvicultural decision making. Growth analyses in marginal tree populations at drought-induced range limits may provide valuable information on tree species' adaptive potentials and species-specific climate turning points. We studied the climate sensitivity and resilience to drought of radial growth, and long-term growth trends of mesic and rear-edge populations of Fagus sylvatica in comparison to three oak species (Quercus petraea, Q. frainetto, Q. cerris) and Tilia tomentosa in natural ecotones from mesic beech to xeric oak forests along three elevation transects in western Romania. Radial growth of all species was positively influenced by summer precipitation and low drought intensity, and negatively by high summer temperatures. The basal area increment (BAI) of F. sylvatica and T. tomentosa has declined in the last 10-20 years with warming and a deterioration of the summer water balance, while the three Quercus species maintained stable growth rates, though at lower BAI levels, suggesting a negative relationship between mean BAI and drought resistance among the five species. Growth reductions during three severe drought events (2000, 2003, 2012) were stronger, and growth resilience lower, in F. sylvatica and T. tomentosa than in the Quercus species, pointing at a thermal limit of beech at June-August temperatures of 20-21 • C. As the climate of the studied ecotones is similar to the predicted climate at colline/ submontane elevation in Central Europe in about 50 years, a decline in beech growth and vitality is likely also in drought-affected regions in the distribution centre with future warming. Our results demonstrate that choosing stress-tolerant Q. petraea (as well as Q. frainetto and Q. cerris) instead of more productive timber species is a relatively safe option for Central European forestry in a warmer climate.
Key message Climate-warming related replacement of beech by oak forests in the course of natural ... more Key message Climate-warming related replacement of beech by oak forests in the course of natural forest succession or silvicultural decisions may considerably reduce ecosystem carbon storage of central European woodlands. Context Climate warming may change the carbon (C) storage in forest biomass and soil through future shifts in tree species composition. With a projected warming by 2–3 K over the twenty-first century, silvicultural adaptation measures and natural succession might lead to the replacement of European beech forests by thermophilic oak forests in drought- and heat-affected regions of central and south-eastern Europe, but the consequences for ecosystem C storage of this species shift are not clear. Aims To quantify the change in C storage in biomass and soil with a shift from beech (Fagus sylvatica) to oak forest (Quercus petraea, Q. frainetto, Q. cerris), we measured the aboveground biomass (AGC) and soil C pools (SOC). Methods AGC pools and SOC stocks to − 100 cm dept...
Die Geobotanik beschäftigt sich mit den Veränderungen der Vegetation auf regionaler und globaler ... more Die Geobotanik beschäftigt sich mit den Veränderungen der Vegetation auf regionaler und globaler Ebene und auf historischen bis geologischen Zeithorizonten. Im Folgenden soll der Versuch unternommen werden, die Artenvielfalt Mitteleuropas, mit Fokus auf Pflanzen, in einen geografischen Rahmen zu stellen, um daraus für den Artenschutz in der Gegenwart zu lernen. Integrativer Naturschutz, in dem Schutzbestrebungen des Naturschutzes mit Interessen wirtschaftlicher Nutzung verbunden werden, ist die vielleicht wichtigste Möglichkeit, Artenvielfalt auf großer Fläche zu erhalten
European beech (Fagus sylvatica) is a drought-sensitive species that likely will retreat from its... more European beech (Fagus sylvatica) is a drought-sensitive species that likely will retreat from its xeric distribution edges in the course of climate warming. Physiological measurements indicate that the species may not only be sensitive to soil water deficits, but also to high temperatures and elevated atmospheric vapor pressure deficits (vpd). Through microclimatological measurements in the stand interior across near-natural beech forest–oak forest ecotones, we searched for microclimatic tipping points in the contact zone with the aim to define the thermic and hydrometeorological limits of beech more precisely. In three transects in the foothills of the Romanian western Carpathians, we measured in mid-summer 2019 air temperature, relative air humidity, and vpd at 2 m height in the stand interior across the ecotone from pure oak to pure beech forests, and compared the readings to the microclimate in forest gaps. Mean daytime temperature (T) and vpd were by 2 K and 2 hPa, respectively...
Abstract Deadwood is a fundamental forest habitat component and highly important for biodiversity... more Abstract Deadwood is a fundamental forest habitat component and highly important for biodiversity conservation. Its availability, composition, size, categories and distribution depend on various structural and environmental factors (e.g., forest age, management, tree mortality, climate, decomposition). We analysed deadwood patterns along altitudinal gradients of managed (three) and unmanaged (one) deciduous forests in Western Romania. A total of 153 plots (119 managed, 34 unmanaged) of four pre-classified forest types dominated by Fagus sylvatica, Quercus petraea, Quercus frainetto with Quercus cerris, and Tilia tomentosa were evaluated, the former two both in managed and unmanaged stands. The managed forest types displayed an average deadwood volume of 47 m3 ha−1 with lying deadwood accounting for over 70%. About 40% of deadwood objects occurred in the early to intermediate decomposition stage. Deadwood volumes in unmanaged forest types exceeded those of managed forests two- to threefold although the deadwood amounts observed in managed forests were similar to low-intervention or recently abandoned forests, lying within critical threshold values considered important for the long-term preservation of biodiversity. Linear-mixed-effects models confirmed the positive impact of non-management and the negative effect of annual mean temperature on deadwood volume. Prediction models suggested that management and annual mean temperature showed additive effects, indicating that a combination of environmental and structural parameters determines the amount of deadwood in the studied forest types. As climatic variables strongly influence tree species composition and thus forest type, management involving deadwood retention or accumulation should consider forest-type specific characteristics and thresholds.
Rüther, C. and Walentowski, H., 2008. Tree species composition and historic changes of the Central European oak/beech region. In: Floren, A. and Schmidl, J. (eds): Canopy arthropod research in Europe, pp. 61-88, bioform entomology, Nuremberg., 2008
After the ending of the final glaciations, tree species re-immigrated to Central Europe from thei... more After the ending of the final glaciations, tree species re-immigrated to Central Europe from their southern refuges. Fagus sylvatica (beech) was the last principal tree species to arrive at the northernmost areas of the Central European region, viz. northwestern Germany, Denmark and southern Sweden. Due to their high competitive ability, F. sylvatica plays a predominant role in Central European Fagion-forest communities, whose native ranges are lowlands and low mountain ranges. Depending on local soil and climatic conditions, other tree genera are included such as Quercus (oak), Picea (spruce) and Abies (¿ r) (both Pinaceae). Indeed, only under exceptional environmental conditions is the competitive ability of F. sylvatica limited in such a manner that other tree species may predominate. Even rare occurrences of one associated tree species within beech forests may assure a long habitat tradition for specialised biocoenoses. Since the Neolithic period, human activities interfered with the forest-covered regions of Central Europe. The forests were changed sig-ni¿ cantly by multiple historical uses and management techniques. Anthropogenic transformation of the forests was driven by wood pasture, pollarding techniques, litter utilisation, coppicing, coppicing with standards and high-forest systems (selective and clear-cutting). These had crucial effects on tree species composition as well as the stand climate of the forests. They changed the spatial and temporal structures of the stands as well as the cycling of soil matter. Another effect of human activities was drastic reduction of forest cover. The unwitting transition of tree species composition finished in the Middle Ages. Since then, human interference has concentrated on targeted timber selection. These alterations make clear that structural components and site conditions of commercial forests deviate considerably from those of the original natural forests. Modern management methods have to consider biodiversity and the degree of naturalness with regard to the tradition of old-growth trees, natural tree species combination and natural ground layer vegetation. Important standards for a sustainable forestry combined with conservation of biodiversity are heterogeneity, complexity and scale.
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