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Introduction
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September 2001 - present
April 1982 - January 1992
Publications
Publications (140)
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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)
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)
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)
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)
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)
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)
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)
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)
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...
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.
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
Ipsenol, Ipsdienol, and £-myrcenol are male specific compounds of Ips schmutzenhoferi. Overall 46 compounds could be identified from males and females. The diversity of oxygenated terpenes is particularly high in males.
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...
„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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
Cluster planting of oaks (Quercus robur and Quercus petraea) was introduced to central Europe in the 1980s and 1990s as an economic and ecological alternative to the traditional and costly row planting for re-afforestation of wind-thrown and clear-cut areas. Clusters comprising 20–30 seedlings are either ‘nests’ (nest planting) with very dense spac...
Long regeneration periods, which result in two-layered or multilayered forest stands, are an important element of the close-to-nature forest management paradigm in central Europe. Such extended regeneration periods, however, may lead to undesirable development of advance regeneration, specifically in species such as Douglas-fir (Pseudotsuga menzies...
For Central Europe, regional climate models predict increases in temperature and frequency drought events. Therefore, growth and productivity of forest trees will depend on the tolerance or adaptability to extreme events. The objective of our study was to examine physiological reactions of different Douglas-fir provenances to contrasting environmen...
In order to compare Norway spruce (Picea abies) and silver fir (Abies alba) with respect to susceptibility to wound colonizing fungi, wood stains and rots, experimental cortical lesions were created in situ on mature trees. The study was performed with 40 Norway spruce and 39 silver fir. Two years after the infliction of the lesions the experiment...
Growth and value production of Douglas-fir under varying stand densities
The investigation is focused on the effects of initial tree number and thinning on growth and value performance of Douglas-fir stands. Data base is a coordinated Douglas-fir spacing experiment in South Germany, started 40 years ago and comprising variants of tree numbers with...
Provenance-specific variation in bark thickness in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) is important for accurate volume calculations and might carry ecological implications as well. To investigate variation, diameter at breast height (dbh) and double bark thickness (dbt) were measured in 10 experiments in southwestern Germany (16 Ame...
In the search of timber species being tolerant towards summer droughts, which are expected to be more frequent in future, Douglas-fir is often discussed as a potential alternative for spruce in Central Europe. To assess physiological and growth reactions of Douglas-fir provenances towards climate- and weather-related environmental conditions we too...
Bark damages caused by logging activities occur at unacceptably high levels in forests of southwest Germany (28% of the trees). Furthermore, the level has increased in the last two decades. Spruce and beech as the major tree species are shown to display the highest level of bark damages (both 28%). Although foresters obviously tend to favour cuttin...
A method was developed to extract environmentally driven growth trends from data of periodically repeated measurements of experimental stands. The method was applied to 470 long-term Norway spruce (Picea abies [L.] Karst.) experiment stands located in southwest Germany. The detection of trends in stand basal area increment was based on a composite...
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...
For scientists and forest managers it is not always clear to which geographical areas and natural ranges statistical growth models may be applied, or whether developed models can be transferred to new regions. We therefore compiled a procedure for model testing and adaptation based on other studies in this context. This procedure consists of three...
Data on storm damage attributed to the two high-impact winter storms 'Wiebke' (28 February 1990) and 'Lothar' (26 December 1999) were used for GIS-based estimation and mapping (in a 50 × 50 m resolution grid) of the winter storm damage probability (P(DAM)) for the forests of the German federal state of Baden-Wuerttemberg (Southwest Germany). The P(...
