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Chakraborty D.,University of Natural Resources and Life Sciences, Vienna | Wang T.,University of British Columbia | Andre K.,Central Institute for Meteorology und Geodynamics | Konnert M.,Bavarian Office for Forest Seeding and Planting | And 3 more authors.

Identifying populations within tree species potentially adapted to future climatic conditions is an important requirement for reforestation and assisted migration programmes. Such populations can be identified either by empirical response functions based on correlations of quantitative traits with climate variables or by climate envelope models that compare the climate of seed sources and potential growing areas. In the present study, we analyzed the intraspecific variation in climate growth response of Douglas-fir planted within the non-analogous climate conditions of Central and continental Europe. With data from 50 common garden trials, we developed Universal Response Functions (URF) for tree height and mean basal area and compared the growth performance of the selected best performing populations with that of populations identified through a climate envelope approach. Climate variables of the trial location were found to be stronger predictors of growth performance than climate variables of the population origin. Although the precipitation regime of the population sources varied strongly none of the precipitation related climate variables of population origin was found to be significant within the models. Overall, the URFs explained more than 88% of variation in growth performance. Populations identified by the URF models originate from western Cascades and coastal areas of Washington and Oregon and show significantly higher growth performance than populations identified by the climate envelope approach under both current and climate change scenarios. The URFs predict decreasing growth performance at low and middle elevations of the case study area, but increasing growth performance on high elevation sites. Our analysis suggests that population recommendations based on empirical approaches should be preferred and population selections by climate envelope models without considering climatic constrains of growth performance should be carefully appraised before transferring populations to planting locations with novel or dissimilar climate. Copyright: © 2015 Chakraborty et al. Source

Thiel D.,University of Bayreuth | Kreyling J.,University of Bayreuth | Backhaus S.,University of Bayreuth | Beierkuhnlein C.,University of Bayreuth | And 6 more authors.
European Journal of Forest Research

Climate extremes are expected to increase in frequency and magnitude as a consequence of global warming, threatening the functioning, services and goods of forest ecosystems. Across Europe, the ecologically and economically important tree species Fagus sylvatica is expected to suffer particularly under such conditions. The regional introduction of provenances from drier and warmer climates is one option to adapt beech forest ecosystems to these adverse effects of climate change. Marginal populations from the drought-prone southern and north-eastern edges of the species' distribution come into focus in search of suitable candidates for Central European deciduous forests. Here, we test three marginal provenances (Spain, Bulgaria and Poland) and three provenances from the centre of the distribution range (Germany) for their response to drought in two different soil types (sand, loam) in a full factorial common garden experiment in Landau, Germany. Drought impacted all growth parameters negatively (leaf damage?22 % (percentage points), height-40 % and diameter increment-41 %), and the sandy substrate exacerbated this effect. However, provenances differed in their response to drought and soil type. Evidence for a local adaptation to summer drought was detected, especially in terms of mortality rates. The Bulgarian and Spanish provenance showed a stable performance under drought conditions (BG-27 %in diameter increment; ES-32 %), compared to the Polish (-48 %) or the most sensitiveGerman provenances (-57 %), yet for Bulgaria on a low level of total increment. This may indicate a trade-off between drought tolerance and growth.Therefore, a sole focus on drought-resistant marginal provenances seems to not be conducive, as they might be less adapted to other climatic factors, e.g. frost, as well. However, intermixed with local Central European provenances, these may act as functional insurance in future drought-prone forest stands. © Springer-Verlag Berlin Heidelberg 2013. Source

Fussi B.,Bavarian Office for Forest Seeding and Planting | Konnert M.,Bavarian Office for Forest Seeding and Planting
Silvae Genetica

European common ash is an important component of mixed forest ecosystems in Bavaria and is considered a valuable tree species under climate change. The first aim of the present study was to assess the genetic diversity within and between ash populations in Bavaria in comparison with neighboring regions. Because ash stands have been heavily attacked by ash shoot disease in the last few years, the second aim of the study was to detect genetic differences between susceptible and less susceptible trees (trees with defoliation up to 30%) within populations. Altogether 41 populations were investigated using nuclear and chloroplast microsatellites. The results showed high genetic variation within and high genetic differentiation between ash populations. Higher chloroplast microsatellite variation was detected instead populations from south-eastern Bavaria compared to other regions. The comparison of susceptible and less susceptible groups of individuals within each population revealed medium to high genetic differences in some cases. For the observed heterozygosity, higher values were found for the group of less susceptible trees compared to the group of all trees or to the group of susceptible trees within populations. This could be a first indication that individuals with a higher heterozygosity might be able to withstand ash dieback in a better way compared to homozygotic individuals. Within the group of less susceptible trees a relatively wide genetic base exists whereupon a future breeding programme can be built. Thus it is of utmost importance for the species to maintain less affected trees in order to keep the genetic potential for future adaptation processes within ash populations, seed production and regeneration. Source

Fussi B.,Bavarian Office for Forest Seeding and Planting | Dounavi A.,Forest Research Institute of Baden Wurttemberg | Konnert M.,Bavarian Office for Forest Seeding and Planting
Annals of Forest Research

Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] is an economically valuable non-native tree species in Germany and is considered very promising in view of global climate change. Therefore, the genetic characterization of Douglas-fir populations and seed stands in Germany is essential. We studied coastal and interior Douglas-fir varieties, both present in Germany, by using eleven isoenzyme and four microsatellite loci. By analyzing eight reference populations of known origin we were able to identify the two varieties on the population level using Bayesian and distance based methods. Seven populations present in Bavaria were then successfully assigned to one of the two varieties. Within varieties we found stronger grouping within the interior variety than within the coastal one. Despite lower differences within coastal Douglas-fir we have first indications for the origin of two populations. For two Bavarian populations, natural regeneration was included and genetic data revealed no significant genetic difference between adults and offspring. The parentage analysis for one of the studied stands revealed that a large proportion of adults took part in the reproduction, but some trees were more successful than others in transferring their genes to the next generation. Our study was able to improve variety identification of Douglas-fir using isoenzyme markers and nuclear microsatellites and study reproductive patterns, both are important issues for the management of Douglas-fir stands in Bavaria. Source

Thiel D.,University of Bayreuth | Nagy L.,University of Bayreuth | Beierkuhnlein C.,University of Bayreuth | Huber G.,Bavarian Office for Forest Seeding and Planting | And 3 more authors.
Forest Ecology and Management

Climate extremes are expected to increase in frequency and magnitude as a consequence of global warming, threatening the functioning, services and goods of forest ecosystems.The introduction of species from drier and warmer climates is one option that is discussed to adapt forest ecosystems to these adverse effects of climate change. The (sub)-mediterranean Pinus nigra is a potential candidate for such assisted migration, especially for dry sites in Central Europe. The high genetic diversity within this species and thus the potential differences in adaptive capacity, however, makes it necessary to assess the response of P. nigra provenances to climatic extremes and identify suitable populations or ecotypes which are better adapted to projected future climates than indigenous species.Here, we tested juvenile plants of 6 provenances of P. nigra for their response to different climate change scenarios (42-days drought and warming by 1.6. K) in a full-factorial common-garden experiment in Bayreuth, Germany. In the second year only the warming treatment was imposed. Height, shoot quantity, mortality and needle phenology were determined for the two consecutive years.Provenances differed in absolute growth (from 6.0 to 7.4 in 2009 and from 4.4 to 5.9. cm in 2010) and survival rates (from 78.6% to 97.6%), but not in terms of shoot quantity and, surprisingly, sensitivity to drought and warming. The drought treatment showed a delayed impact on height growth, as a significant growth reduction was detected for the second year (-2.6. cm), but not for the first year, when the actual treatment took place. Drought decreases survival rates by 20.6%. The drought treatment had no effect on needle phenology.Warming did not impact growth performance (height, shoot quantity). However, warming in combination with the drought treatment decreased the survival rate (-13%). Plants exposed to the warming treatment showed an earlier onset of needle development (-10.6. days).Our results imply that no significant local adaptation of growth and survival to drought and warming occurs in P. nigra. Performance and growth response in face of warming and drought cannot be predicted by the climate at the places of origin. We therefore recommend that an introduction of P. nigra to regions outside its natural distribution range should not aim at introducing a single best-adapted provenance but at establishing populations with a high genetic diversity, e.g. by promoting natural regeneration in native stands or by intermixing with different genotypes in order to maintain a high adaptive capacity to climate change. © 2012 Elsevier B.V. Source

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