Forest Research Institute of Baden Wuerttemberg

Freiburg, Germany

Forest Research Institute of Baden Wuerttemberg

Freiburg, Germany
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Enderle R.,Forest Research Institute of Baden Wuerttemberg | Busskamp J.,Forest Research Institute of Baden Wuerttemberg | Busskamp J.,Northwest German Forest Research Station | Metzler B.,Forest Research Institute of Baden Wuerttemberg
Baltic Forestry | Year: 2017

Ash dieback, caused by the ascomycete Hymenoscyphus fraxineus, is a tree disease, which currently devastates European ash populations. Only a very small fraction of ash individuals exhibits a high degree of quantitative genetic resistance and is likely to survive the disease. We investigated the growth performance of differentially diseased saplings in order to assess the impact of ash dieback on individual competitiveness in dense natural ash regeneration. The research took place on three sites in southwestern Germany. From summer 2013 to winter 2014/2015, 20.4% of the monitored ash saplings died. In general, shorter trees were more severely diseased. There were no differences in shoot length between healthy or moderately infected trees, whereas shoot length was significantly reduced in trees with more than 50% of symptomatic shoots (p ≤ 0.006). These highly impacted trees significantly lost tree height to the disease, whereas only marginal height reduction could be detected for lesser affected trees. Our results indicate that trees resistant enough to maintain at least 50% of their crowns are generally able to survive competition in dense regeneration. Thus, promotion of natural ash regeneration could be an effective measure complementary to breeding for resistance to preserve ash as a tree species in the forests. © Lithuanian Research Centre for Agriculture and Forestry.

Hanewinkel M.,Swiss Federal Institute of forest | Hanewinkel M.,Albert Ludwigs University of Freiburg | Cullmann D.A.,Forest Research Institute of Baden Wuerttemberg | Schelhaas M.-J.,Wageningen University | And 2 more authors.
Nature Climate Change | Year: 2013

European forests, covering more than 2 million km2 or 32% of the land surface1, are to a large extent intensively managed and support an important timber industry. Climate change is expected to strongly affect tree species distribution within these forests2,3. Climate and land use are undergoing rapid changes at present4, with initial range shifts already visible5. However, discussions on the consequences of biome shifts have concentrated on ecological issues6. Here we show that forecasted changes in temperature and precipitation may have severe economic consequences. On the basis of our model results, the expected value of European forest land will decrease owing to the decline of economically valuable species in the absence of effective countermeasures. We found that by 2100 - depending on the interest rate and climate scenario applied - this loss varies between 14 and 50% (mean: 28% for an interest rate of 2%) of the present value of forest land in Europe, excluding Russia, and may total several hundred billion Euros. Our model shows that - depending on different realizations of three climate scenarios - by 2100, between 21 and 60% (mean: 34%) of European forest lands will be suitable only for a Mediterranean oak forest type with low economic returns for forest owners and the timber industry and reduced carbon sequestration. Copyright © 2013 Macmillan Publishers Limited.

Hein S.,University of Applied Forest science | Hein S.,Forest Research Institute of Baden Wuerttemberg | Weiskittel A.R.,University of Maine, United States
European Journal of Forest Research | Year: 2010

Models of binary outcomes are commonly used in forestry, but the predictions errors of these types of models are difficult to present effectively. In addition, most studies generally use a fixed value of 0.5 as the separation between events and non-events. The use of cutpoint analysis has been widely utilized in the health sciences and other fields, while it is relatively uncommon in the forestry literature. Cutpoint analysis involves locating the optimal value that minimizes prediction errors associated with binary outcomes. This case study illustrates the use of cutpoint analysis to improve a dynamic model of individual branch mortality. In this study, the use of cutpoint analysis increased the model specificity (prediction of events) from 77.8% (standard cutpoint of 0.5) to 90.3% (optimal cutpoint of 0.672). At the same time, the sensitivity of the model decreased only slightly and the false positive rate (non-event predicted as an event) was greatly decreased from 22.2 to 9.7%. In addition, the use of receiver operating characteristics (ROC) curves was an effective approach for evaluating prediction errors of models of binary outcomes. Cutpoint analysis is a simple yet effective method for improving predictions of binary outcomes and should be used more regularly, particularly when modelling the binary outcome of rare events such as mortality. © 2010 Springer-Verlag.

Hanewinkel M.,Swiss Federal Institute of forest | Cullmann D.A.,Forest Research Institute of Baden Wuerttemberg | Michiels H.-G.,Forest Research Institute of Baden Wuerttemberg | Kandler G.,Forest Research Institute of Baden Wuerttemberg
Journal of Environmental Management | Year: 2014

The paper deals with the management problem how to decide on tree species suitability under changing environmental conditions. It presents an algorithm that classifies the output of a range shift model for major tree species in Europe into multiple classes that can be linked to qualities characterizing the ecological niche of the species. The classes: i) Core distribution area, ii) Extended distribution area, iii) Occasional occurrence area, and iv) No occurrence area are first theoretically developed and then statistically described. The classes are interpreted from an ecological point of view using criteria like population structure, competitive strength, site spectrum and vulnerability to biotic hazards. The functioning of the algorithm is demonstrated using the example of a generalized linear model that was fitted to a pan-European dataset of presence/absence of major tree species with downscaled climate data from a General Circulation Model (GCM). Applications of the algorithm to tree species suitability classification on a European and regional level are shown. The thresholds that are used by the algorithm are precision-based and include Cohen's Kappa. A validation of the algorithm using an independent dataset of the German National Forest Inventory shows good accordance of the statistically derived classes with ecological traits for Norway spruce, while the differentiation especially between core and extended distribution for European beech that is in the centre of its natural range in this area is less accurate. We hypothesize that for species in the core of their range regional factors like forest history superimpose climatic factors. Problems of uncertainty issued from potentially applying a multitude of modelling approaches and/or climate realizations within the range shift model are discussed and a way to deal with the uncertainty by revealing the underlying attitude towards risk of the decision maker is proposed. © 2014 Elsevier Ltd.

Hanewinkel M.,Forest Research Institute of Baden Wuerttemberg | Peltola H.,University of Eastern Finland | Soares P.,University of Lisbon | Gonzalez-Olabarria J.R.,Center Tecnologic Forestal Of Catalonia
Forest Systems | Year: 2010

The aim of this paper is to discuss the different recently developed empirical and mechanistic modelling approaches for assessing the risk of wind and fire damage to forests. Additionally the work will explore possible ways to integrate these approaches, including feedback mechanisms, into growth and yield models and decision support tools used in forestry. The integration of mechanistic and empirical storm risk models, as well as an empirical/mechanistic fire risk model into growth simulators is demonstrated and future challenges and options for risk modelling and for creating complex decision support tools, including growth simulators, meteorological components and risk modules, are discussed.

Enderle R.,Forest Research Institute of Baden Wuerttemberg | Nakou A.,Forest Research Institute of Baden Wuerttemberg | Thomas K.,Research Institute for Forest Ecology and Forestry | Metzler B.,Forest Research Institute of Baden Wuerttemberg
Annals of Forest Science | Year: 2015

Context: It might be possible to establish a new generation of Fraxinus excelsior which is insusceptible towards ash dieback (agent: Hymenoscyphus pseudoalbidus) by efficient breeding. However, a considerable number of highly tolerant individuals which have the ability to pass on this trait to their progeny are needed.Aims: The aim of this study was to identify the potential of provenances from southwestern Germany as a source of future selection for resistance or resistance breeding.Methods: In July 2012 and 2013, ash dieback severity was scored by assessing the crown defoliation and the portion of epicormic shoots in the crowns in clonal seed orchards with a total of 1,726 ash trees in southwestern Germany.Results: Ash dieback severity differed strongly between the orchards and the clones. Broad-sense heritability ranged from 0.18 to 0.55 for crown defoliation and from 0.48 to 0.58 for the portion of epicormic shoots between the orchards. Clones from nearby populations did not show differences in general levels of susceptibility.Conclusion: The study highlights that there is high genetic variation in susceptibility and considerable genetic potential for resistance breeding in provenances from southwestern Germany. © 2014, INRA and Springer-Verlag France.

Wagenhoff E.,Forest Research Institute of Baden Wuerttemberg | Blum R.,Forest Research Institute of Baden Wuerttemberg | Delb H.,Forest Research Institute of Baden Wuerttemberg
Journal of Forest Science | Year: 2014

Cockchafers are among the most dreaded insect pests in many European countries, causing economic losses in agriculture, horticulture and forestry. In forests of south-western Germany, populations of the forest cockchafer (Melolontha hippocastani) and also the field cockchafer (M. melolontha) have been increasing during the past three decades and, therefore, monitoring of these populations has been intensified. In the present field study, data on adult emergence from the soil, male swarming flights and female oogenesis, collected at three infestation sites by visual inspection, with soil eclectors and with light traps in early spring 2009-2011, are presented and discussed in the context of the current knowledge of cockchafer biology. Furthermore, three air temperature sum models for the prediction of the onset of the swarming flight period in spring, published in the early/mid 20th century, were validated in view of their applicability in forestry practice.

Wagenhoff E.,Forest Research Institute of Baden Wuerttemberg | Blum R.,Forest Research Institute of Baden Wuerttemberg | Delb H.,Forest Research Institute of Baden Wuerttemberg
Phytoparasitica | Year: 2016

Sublethal effects of NeemAzal®-T/S (1 % azadirachtin A) on female cockchafers were studied in two experiments with caged beetles. The beetles were collected in early spring whilst leaving the soil after hibernation. At that time, they had not fed before and they were virgin. The beetles were kept singly in plastic boxes and provided with treated leaves at different stages of egg maturation. The amount of food consumed and the progression of body weight were recorded daily, whereas the state of oogenesis was surveyed at defined intervals. It was shown that food consumption, body weight development and egg maturation were affected by the uptake of azadirachtin-treated plant material compared to beetles from control groups. In no-choice experiments, azadirachtin-treated leaves were accepted readily and feeding was reduced by 60–70 % compared to females fed with untreated foliage. Recovery by feeding on untreated leaves after the uptake of contaminated foliage was either not evident or at a very low level. Moreover, egg maturation was interrupted when females were fed with azadirachtin-treated leaves during the process of oogenesis. If egg maturation was accomplished at the time of first uptake of azadirachtin-treated plant material, caged females were able to lay as many eggs as females from the control group, the egg hatching rate was not affected, and there were no signs of morphological malformations in the freshly hatched L1-larvae. © 2016, Springer Science+Business Media Dordrecht.

Braunisch V.,Forest Research Institute of Baden Wuerttemberg | Suchant R.,University of Bern
Ecography | Year: 2010

Systematic species surveys over large areas are mostly not affordable, constraining conservation planners to make best use of incomplete data. Spatially explicit species distribution models (SDM) may be useful to detect and compensate for incomplete information. SDMs can either be based on standardized, systematic sampling in a restricted subarea, or - as a cost-effective alternative - on data haphazardly collated by "volunteer-based monitoring schemes" (VMS), area-wide but inherently biased and of heterogeneous spatial precision. Using data on capercaillie Tetrao urogallus, we evaluated the capacity of SDMs generated from incomplete survey data to localise unknown areas inhabited by the species and to predict relative local observation density. Addressing the trade-off between data precision, sample size and spatial extent of the sampling area, we compared three different sampling strategies: VMS-data collected throughout the whole study area (7000 km 2) using either 1) exact locations or 2) locations aggregated to grid cells of the size of an average individual home range, and 3) systematic transect counts conducted within a small subarea (23.8 km 2). For each strategy, we compared two sample sizes and two modelling methods (ENFA and Maxent), which were evaluated using cross-validation and independent data. Models based on VMS-data (strategies 1 and 2) performed equally well in predicting relative observation density and in localizing "unknown" occurrences. They always outperformed strategy 3-models, irrespective of sample size and modelling method, partly because the VMS-data provided the more comprehensive clues for setting the discrimination-threshold for predicting presence or absence. Accounting for potential errors due to extrapolation (e.g. projections outside the environmental domain or potentially biasing variables) reduced, but did not fully compensate for the observed discrepancies. As they cover a broader range of species-habitat relations, the area-wide data achieved a better model quality with less a-priori knowledge. Furthermore, in a highly mobile species like capercaillie a sampling resolution corresponding to an individuals' home range can lead to equally good predictions as the use of exact locations. Consequently, when a trade-off between the sampling effort and the spatial extent of the sampling area is necessary, less precise data unsystematically collected over a large representative region are preferable to systematically sampled data from a restricted region. © 2010 The Authors.

Arlettaz R.,University of Bern | Arlettaz R.,Institute of Ecology and Evolution | Arlettaz R.,Swiss Ornithological Institute | Schaub M.,Swiss Ornithological Institute | And 7 more authors.
BioScience | Year: 2010

There is a vigorous debate about the capacity of conservation biology, as a scientific discipline, to effectively contribute to actions that preserve and restore biodiversity. Various factors may be responsible for the current great divide that exists between conservation research and action. Part of the problem may be a lack of involvement by conservation scientists in actually conducting or helping implement concrete conservation actions, yet scientists' involvement can be decisive for successful implementation, as illustrated here by the rapid recovery of an endangered hoopoe population in the Swiss Alps after researchers decided to implement the corrective measures they were proposing themselves. We argue that a conceptual paradigm shift should take place in the academic conservation discipline toward more commitment on the part of researchers to turn conservation science into conservation action. Practical implementation should be regarded as an integrated part of scientific conservation activity, as it actually constitutes the ultimate assessment of the effectiveness of the recommended conservation guidelines, and should be rewarded as such. © 2010 by American Institute of Biological Sciences. All rights reserved.

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