Ulrich Kohnle

Ulrich Kohnle
Forstliche Versuchs- und Forschungsanstalt Baden-Württemberg · Department of Forest Growth

Prof.Dr.

About

138
Publications
26,246
Reads
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2,808
Citations
Citations since 2016
36 Research Items
1567 Citations
2016201720182019202020212022050100150200
2016201720182019202020212022050100150200
2016201720182019202020212022050100150200
2016201720182019202020212022050100150200
Additional affiliations
September 2001 - present
Forstliche Versuchs- und Forschungsanstalt Baden-Württemberg
Position
  • Head of Department
April 1982 - January 1992
University of Freiburg
Position
  • Researcher

Publications

Publications (138)
Article
Highlights: • Spatial variation in site index and temperature is larger than temporal variation. • Coefficients of space-for-time substitution model differ from individual models. • Prediction bias of state-space model is smaller than for space-for-time substitution. • Climate warming lowers site index for high and rises for low productivity class...
Article
Beech (Fagus sylvatica L.) is one of the most important broadleaved tree species in central Europe. The natural distribution area is mainly in central and southern Europe, from the Pyrenees in northern Spain, through the French Massif Central, the Alps, German low mountain ranges, the Carpathians to the Crimean peninsula on the Black Sea in Eastern...
Article
The maximum size-density relationship describes site carrying capacity, i.e., the maximum number of trees of a given size that can be stocked per unit area (self-thinning line). We analysed whether the self-thinning lines of Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.) have remained unchanged over time in South Germa...
Article
Full-text available
Extreme droughts are expected to increase in frequency and severity in many regions of the world, threatening multiple ecosystem services provided by forests. Effective strategies to adapt forests to such droughts require comprehensive information on the effects and importance of the factors influencing forest resistance and resilience. We used a u...
Article
Full-text available
Key message This study showed that regeneration success (presence of oaks ≥ 150 cm in total height) in artificial canopy openings of a mature mixed sessile oak stand was mainly driven by initial oak seedling density. ContextSmall-scale harvesting methods as practiced in close-to-nature forestry may disadvantage the regeneration of more light-demand...
Article
Full-text available
The primary aim of using treeshelters is offering protection for young trees against browsing and fraying. However treeshelters also significantly modify growth of protected trees. Even though there are many investigations on the behavior of broadleaved tree species in treeshelters, conifer species and particularly Douglas-fir [Pseudotsuga menziesi...
Article
Full-text available
In this review, the unique features and facts of long-term experiments are presented. Long-term experimental plots provide information of forest stand dynamics which cannot be derived from forest inventories or small temporary plots. Most comprise unthinned plots which represent the site specific maximum stand density as an unambiguous reference. B...
Article
The timely establishment of natural regeneration of the preferred species after the death or removal of mature trees is essential in continuous-cover forestry. In the context of the gradual shift from even-aged and monospecific to uneven-aged and/or mixed forest stands, the limited availability of statistical models to predict seedling establishmen...
Article
Die in Nordamerika beheimatete Douglasie bildet sehr hochwertiges Kernholz, das vielseitig eingesetzt werden kann. Insbesondere für den Einsatz im Außenbereich wird die Qualität dieses Holzes auch in Europa geschätzt, woraus Bestrebungen entstanden, diese Baumart auf ihre Eignung zur Anpflanzung vor allem in Mitteleuropa zu prüfen. In den frühen 1...
Article
Future increases in temperature and changes in precipitation patterns may negatively affect the growth performance of economically important tree species such as Norway spruce, which in the past have often been established and managed in monocultures. Structural diversity has been advocated as a silvicultural approach to increase resistance and res...
Article
Full-text available
The coniferous forest tree Douglas-fir (Pseudotsuga menziesii) is native to the pacific North America, and is increasingly planted in temperate regions worldwide. Nitrogen (N) metabolism is of great importance for growth, resistance and resilience of trees. In the present study, foliar N metabolism of adult trees of three coastal and one interior p...
Data
Nitrogen (N) pools and compounds in needles of adult Douglas-fir trees of four provenances grown on two field sites in south-western Germany (Wiesloch and Schluchsee). Data are plotted over experimental and environmental factors identified as significant predictors (for details of the statistical analysis see Material and methods; data are plotted...
Data
Correlation between needle total nitrogen (N) pools in needles of adult Douglas-fir trees of four provenances with tree height. Trees were grown on two field sites in south-western Germany. (PDF)
Data
Amino acids and ammonia content (μmol g-1 DW) in previous year needles of the four provenances (AR, CR, RI and LA) in May and July 2010 (5/10 and 7/10) and 2011 (5/11 and 7/11) at two sites (Wiesloch and Schluchsee). (PDF)
Data
Provenance-related patterns of nitrogen partitioning in previous year needles of the four Douglas-fir provenances sampled in 2010 (AR, Salmon Arm; CR, Conrad Creek; LA, Cameron Lake; RI, Santiam River). Clustering was revealed by score plots of partial least squares–discriminant analyses. (PDF)
Data
Results of sequential regression of N compounds in needles of adult Douglas-fir trees of four provenances on soil water availability and site effects independent from soil water availability. (PDF)
Data
Variable Importance in Projection (VIP) scores of component 1 from PLS_DA shown the importance of factors determining the site related (W, Wiesloch; S, Schluchsee) nitrogen partitioning patterns in 2010 (A) and 2011 (B). (PDF)
Data
Variable Importance in Projection (VIP) scores of component 1 from PLS_DA shown the importance determining the seasons related nitrogen partitioning patterns in May (5/10) and July (7/10) 2010 (A, B) and 2011(May, 5/11 and July, 7/11) (C, D) at Wiesloch (W) and Schluchsee (S) respectively. (PDF)
Data
Provenance-related patterns of nitrogen partitioning in previous year needles of the four Douglas-fir provenances sampled in 2011 (AR, Salmon Arm; CR, Conrad Creek; LA, Cameron Lake; RI, Santiam River). Clustering was revealed by score plots of partial least squares–discriminant analyses. (PDF)
Data
Correlation between needle total N pools in needles of adult Douglas-fir trees of four provenances grown on field site ‘Schluchsee’ in south-western Germany with net photosynthetic assimilation rate (A) measured on the same trees in July 2010 and 2011. (PDF)
Article
Full-text available
Bark wounds by damage during harvesting are a serious problem in forestry due to fungi infection and wood deterioration. This paper presents results of an investigation about the influence of the wounds on the internal structure of such injured stems. In an experiment, bark wounds were artificially created at the stem base of Norway spruce [Picea a...
Conference Paper
Full-text available
Bereits entwickelte Bonitätsmodelle für Fichte wurden testweise auf dendrometrische Daten der Bundeswaldinventur und von langfristigen Versuchsflächen angewendet und Abweichungen zwischen Modellvorhersagen und realen Daten evaluiert.
Article
The annual growth of the Finnish forests has doubled in less than a century but the reasons for the increase have been a subject of much debate. Site index aggregates the mid- to long-term impacts of variable edaphic and climatic factors on site productivity and is an important characteristic with regard to the ongoing environmental changes. We qua...
Article
Due to their expected higher resilience following disturbances and adaptive potential to new climatic conditions, interest in uneven-aged mixed forests has increased in recent years. It is, however, unclear how to best quantify their site-specific growth potential, particularly at a time when there is a pressing need to consider the effects of a ch...
Article
Full-text available
Data from eight experimental sites of young and high-density Norway spruce (Picea abies (L.) H. Karst.) natural regeneration stands in Southwest Germany were analyzed. The treatments (pre-commercial thinnings) ranged from systematic reduction (< 3,000 remaining stems per ha) to a no-treatment control, complemented by an intermediate selective thinn...
Article
Accurate and reliable predictions of the future development of forest site productivity are crucial forthe effective management of forest stands. Static models which simply extrapolate productivity intothe future are inappropriate under conditions of environmental change since they lack a close linkbetween fundamental environmental drivers and fore...
Article
Full-text available
Douglas-fir (Pseudotsuga menziesii) is a conifer tree native to western North America. In central Europe, it shows superior growth performance and is considered a suitable substitute for tree species impaired in vitality due to climate change. Maintenance and improvement of growth performance in a changing environment is a main challenge for forest...
Article
Full-text available
This is an overview of the results from previously published climate modeling studies reporting on projected aspects of future storminess over the North Atlantic European region (NAER) in the period 2020-2190. Changes in storminess are summarized for seven subregions in the study area and rated by a categorical evaluation scheme that takes into acc...
Preprint
Douglas-fir ( Pseudotsuga menziesii ) is a conifer tree native to western North America. In central Europe, it shows superior growth performance and is considered a suitable substitute for tree species impaired in vitality due to climate change. Maintenance and improvement of growth performance in a changing environment is a main challenge for fore...
Article
Full-text available
In an experiment with beech (Fagus sylvatica L), two types of bark lesions were created artificially in 2006 at the same time on each tree to simulate an "extraction wound" (surface area 442 cm2; 34 cm in height, 13 cm in width) at the stem base, and a "felling wound" (442 cm2; 68 cm in height, 6,5 cm in width) at five meters height. In 2009, the t...
Article
Full-text available
Key message We provided a precise quantitative analysis of the factors at the origin of bark damage during harvesting operations and developed a model able to predict them accurately. The major factors were the distance of trees to skid trails, the intensity of removals, the harvesting system as well as the interactions between the distance of tree...
Article
Full-text available
Documented information on the growth dynamics and related silvicultural manipulation of naturally regenerat ed Douglas-fir beneath a canopy shelter is scarce. We hypothesized that long regeneration phases creating dense cohorts of Douglas-fir advanced regeneration beneath a closed canopy of mature trees have a negative impact on the formation of a...
Article
Full-text available
The objective of the study is to introduce a simultaneous approach to extracting growth trends from diameter increment series by combining tree- and stand-level information in the framework of mixed-effects modeling. The model results are compared with those of the sequential modeling approach according to Yue et al. (2011). Comprehensive data from...
Article
Full-text available
Für die Extraktion umweltbedingter Zuwachstrends aus Daten langfristiger Versuchsflächen wurden vor kurzem zwei neue Methoden entwickelt. Verwendet werden dabei entweder Jahrringserien von Probebäumen (jährlich aufgelöste Messdaten, Durchmesserzuwachstrends auf Baumebene (Yue et al., 2011) bzw. Messreihen periodischer Wiederholungsaufnahmen (mehrjä...
Article
Full-text available
Due to the fact that forest ecosystems can potentially mitigate the impact of climate change, the carbon balance of managed forests has caught the attention of a large scientific community. Some authors conclude that extending rotation lengths would actually favour the climate change mitigation effect since more carbon would be stored in the biomas...
Article
Full-text available
„Pflanzenklumpen“ (Clusterpflanzungen) werden bereits seit Längerem als Alternativen zur konventionellen Vollkultur in Reihenpflanzung erprobt. Mit der Trupppflanzung steht offensichtlich ein sehr flexibles, vorteilhaftes Verfahren zur Begründung von Eichenmischbeständen zur Verfügung. Über die Anzahl an Trupps je Hektar können anfängliche finanzie...
Article
Full-text available
Historically, the sweet chestnut tree [Castanea sativa Mill.] has been known as a tree species that is rich in biomass production and frequently used in coppice forests. The following investigation was conducted to explore the possibility of producing valuable timber from this species. The basis were measurements on 42 temporary plots with sweet ch...
Article
Full-text available
This paper presents the results of the analyses of branch and stem characteristics of five Douglas-fir provenances (Figure 1, Table 1). This provenance trial covers trees from three different sites under a wide range of relevant environmental factors (Table 2). The plots of the international Douglas-fir provenance trial in Baden-Württemberg were es...
Article
Full-text available
Recently, two new methods have been developed to extract environmentally driven growth trends from data provided by long-term experiments. The methods draw either on year ring series of sample trees cut during the experiments (annually resolved growth data, tree-level diameter increment trend; (YUE et al., 2011) or on series of periodic re-measurem...
Data
Full-text available
The study developed a conceptual framework for partitioning the components of diameter increment to potentially detect the influence of environmental changes. This process consisted of two steps. First, a multiplicative decomposition diameter increment model was introduced to evaluate the influence of ageing, site quality, competition status, and t...
Article
Full-text available
In this paper the potential of using computer tomography imagery was evaluated as data source for forest-based research. The aim of this study is the validation of data resulting from the high-resolution computer tomography (CT). The estimates of height analysis, branch, and bark characteristics from computer tomography images were compared with tr...
Article
Interactions between plant species can be dynamic, changing spatially and temporally with variability in climatic, soil and stand conditions. We examined how inter- and intra-specific interactions between Abies alba Mill. and Picea abies (L.) Karst. varied with climate, site quality and stand density in the Black Forest of south-western Germany, us...
Article
Full-text available
Der Wachstumssimulator W+ wurde für die Simulation der Baum- und Bestandesentwicklung konzipiert und ist als Instrument für die Entscheidungsunterstützung bei der Bestandesbehandlung gedacht. Derzeit ist er für Fichten-, Douglasien- und Buchen-Reinbestände parametrisiert. Die Parametrisierung basiert auf Daten von Behandlungsversuchen der Forstlich...
Article
Full-text available
Nester-oder Trupppflanzungen bei Eiche – was ist besser? Eichennester-und Eichentrupppflanzungen (auch Clusterpflanzungen) werden seit den 1980er bzw. 1990er Jahren als ökologische und ökonomische Alternativen zur traditionellen Reihenpflanzung insbesondere nach Sturmwurf vermehrt für die Bestandesbegründung genutzt. In einer auf Erhebungen aus ein...
Article
Full-text available
Context Since storm damage has a large impact on forest management in Central Europe, we investigated the main storm risk factors for two important conifer species, Douglas-fir (Pseudotsuga menziesii [Mirbel] Franco) and Norway spruce (Picea abies [L.] Karst.). Aims We compared general storm damage levels of Douglas-fir and Norway spruce, the latte...
Article
Full-text available
The mixture of beech (Fagus sylvatica L.) and oak (sessile oak, Quercus petraea (Matt.) Liebl., and pedunculate oak, Q. robur L.) is of considerable importance in Europe and will probably become even more important under climate change. Therefore, the performance of oak and beech in mixture was compared with the species’ growth in pure stands. Data...
Article
Full-text available
In Zeiten des Klimawandels werden Mischbestände zur Risikominimierung empfohlen. Doch wie soll die Mischung in die Bestände kommen? Eine international angelegte Studie führte nun einen Vergleich zwischen den „Pflanzen-Klumpen“,auch Clusterpflanzungen genannt, und der konventionellen Vollkultur in Reihen pflanzung durch. Dabei wurden Wachstum und Qu...
Article
The paper reviews theoretical considerations and empirical facts on the productivity of mixed species forest stands versus pure stands. The theoretical part first draws attention on the combined effect of facilitation and competition and the net result for both individual and mean tree growth in pure and mixed forest stands (Figs. 1-3). By species...
Article
Full-text available
The growth simulator W + has been conceived for the simulation of the tree and stand development and is intended as a decision supporting tool for stand management. Currently, it is parametrised for European beech, Norway spruce, and Douglas fir. Parametrisation was performed with data from growth experiment plots of the Forest Research Station of...
Article
Full-text available
During timber harvest trees of the residual stand may suffer damages through bark lesions. This may happen associated either with felling or transportation processes. Although qualitative information on the causal factors is available, quantitative interdependences between the major factors and the resulting degree of damage are largely unknown so...