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Isik K.,Akdeniz University | Kleinschmit J.,Lower Saxony Forest Research Institute | Steiner W.,Northwest German Forest Research Institute
Forest Science | Year: 2010

Heights of rooted cuttings from 40 clones of Norway spruce (Picea abies [L.] Karst) were measured at ages 3, 5, 8, 10, 13, and 17 from rooting at seven test environments in northern Germany. To determine the optimal age for juvenile selection for height, age-related changes in variance components, clone-mean heritability, and age-age correlations were estimated. Partitions of variance components were essentially constant after age 8. Clone-mean heritabilities were highest at age 3 (0.94) and were essentially stable after age 5. Age-age correlations were generally high between similar ages but declined as the difference between pairs of measurement ages increased. Genetic correlations were greater than corresponding phenotypic correlations but were similar in value. Trait-trait correlations between height and diameter (rG 0.83) and height and volume (G 0.90) at age 17 were also high. Simple linear regressions of genetic and phenotypic age-age correlations on LAR (natural log of the ratio of younger age to older age) were significant (R2 ≥ 0.76). Predicted efficiencies of selection suggested that for a rotation age of 60 years, the optimum selection age would be as early as 13 years. Furthermore, gains per year would be increased by about 1 1/2 times if selections were made at about age 15 rather than age 60.

Cornille A.,French National Center for Scientific Research | Cornille A.,University Paris - Sud | Cornille A.,Agro ParisTech | Giraud T.,French National Center for Scientific Research | And 14 more authors.
Molecular Ecology | Year: 2013

Understanding the way in which the climatic oscillations of the Quaternary Period have shaped the distribution and genetic structure of extant tree species provides insight into the processes driving species diversification, distribution and survival. Deciphering the genetic consequences of past climatic change is also critical for the conservation and sustainable management of forest and tree genetic resources, a timely endeavour as the Earth heads into a period of fast climate change. We used a combination of genetic data and ecological niche models to investigate the historical patterns of biogeographic range expansion of a wild fruit tree, the European crabapple (Malus sylvestris), a wild contributor to the domesticated apple. Both climatic predictions for the last glacial maximum and analyses of microsatellite variation indicated that M. sylvestris experienced range contraction and fragmentation. Bayesian clustering analyses revealed a clear pattern of genetic structure, with one genetic cluster spanning a large area in Western Europe and two other genetic clusters with a more limited distribution range in Eastern Europe, one around the Carpathian Mountains and the other restricted to the Balkan Peninsula. Approximate Bayesian computation appeared to be a powerful technique for inferring the history of these clusters, supporting a scenario of simultaneous differentiation of three separate glacial refugia. Admixture between these three populations was found in their suture zones. A weak isolation by distance pattern was detected within each population, indicating a high extent of historical gene flow for the European crabapple. © 2013 Blackwell Publishing Ltd.

Daume S.,University of Gottingen | Daume S.,University of Stockholm | Albert M.,Northwest German Forest Research Institute | von Gadow K.,University of Gottingen | von Gadow K.,Stellenbosch University
Forest Ecology and Management | Year: 2014

Forest monitoring captures human impacts and other biotic and abiotic influences on forests and is a pre-requisite for the sustainable use and protection of forest ecosystems. Forest inventories for example are a key tool to plan sustainable harvesting, whereas Forest Observational Studies provide the empirical basis for an improved understanding and long-term evaluation of forest ecosystem dynamics. To that end detailed data is collected at stand level, often integrated in larger forest observational networks, which feeds into forest ecosystem models. Forests exist however in a constantly changing societal context and the direct or indirect impact of human activity has become a crucial driver on all types of ecosystems. The Millenium Ecosystem Assessment underlines the linkage between social and ecological systems, highlighting the centrality of ecosystem services to human well-being and the requirement for ecosystem monitoring in the anthropocene to provide a holistic view of ecosystems as social-ecological systems. Framing information about the social context of a forest ecosystem, gaining the expertise and providing resources to collect this type of information is usually outside the scope of data collection for forest inventories and monitoring. Studies in other domains faced a similar challenge and turned to data mining informal online information sources to supplement traditional monitoring and data collection strategies. This paper explores how forest monitoring approaches especially Forest Observational Studies with their long-term and large-scale focus may be complemented by social media mining. We outline (a) how social media mining methods from other domains could be applied to forest monitoring, (b) discuss identification of stakeholders, events and demands on forest ecosystems as examples of social contextual information that could be obtained via this route and (c) explain how this information could be automatically mined from social media, online news and other similar online information sources. The proposed approach is discussed on the basis of examples from a broad set of other domains. © 2013 Elsevier B.V.

Talkner U.,University of Gottingen | Talkner U.,Northwest German Forest Research Institute | Kramer I.,University of Gottingen | Kramer I.,Leibniz Institute for Baltic Sea Research | And 2 more authors.
Plant and Soil | Year: 2010

Atmospheric deposition is an important nutrient input to forests. The chemical composition of the rainfall is altered by the forest canopy due to interception and canopy exchange. Bulk deposition and stand deposition (throughfall plus stemflow) of Na+, Cl-, K+, Ca2+, Mg2+, PO43-, SO42-, H+, Mn2+, Al3+, Fe2+, NH4+, NO3-and Norg were measured in nine deciduous forest plots with different tree species diversity in central Germany. Interception deposition and canopy exchange rates were calculated with a canopy budget model. The investigated forest plots were pure beech (Fagus sylvatica L.) plots, three-species plots (Fagus sylvatica, Tilia cordata Mill. or T. platyphyllos Scop. and Fraxinus excelsior L.) and five-species plots (Fagus sylvatica, T. cordata or T. platyphyllos, Fraxinus excelsior, Acer platanoides L., A. pseudoplatanus L. or A. campestre L. and Carpinus betulus L.). The interception deposition of all ions was highest in pure beech plots and was negatively related to the Shannon index. The stand deposition of K+, Ca2+, Mg2+ and PO43- was higher in mixed species plots than in pure beech plots due to higher canopy leaching rates in the mixed species plots. The acid input to the canopy and to the soil was higher in pure beech plots than in mixed species plots. The high canopy leaching rates of Mn2+ in pure beech plots indicated differences in soil properties between the plot types. Indeed, pH, effective cation exchange capacity and base saturation were lower in pure beech plots. This may have contributed to the lower leaching rates of K+, Ca2+ and Mg2+ compared to the mixed species plots. However, foliar analyses indicated differences in the ion status among the tree species, which may additionally have influenced canopy exchange. In conclusion, the nutrient input to the soil resulting from deposition and canopy leaching was higher in mixed species plots than in pure beech plots, whereas the acid input was highest in pure beech plots. © 2010 The Author(s).

Bittner S.,Helmholtz Center for Environmental Research | Talkner U.,University of Gottingen | Talkner U.,Northwest German Forest Research Institute | Kramer I.,University of Gottingen | And 4 more authors.
Agricultural and Forest Meteorology | Year: 2010

This modeling study used recent observations at a temperate broad-leaved forest in Central Germany to calculate water balances of a Fagus sylvatica monoculture and mixed stands of F. sylvatica, Tilia spp., Acer spp., Carpinus betulus, Fraxinus excelsior and Quercus robur. To simulate soil water flow the modeling framework Expert-N was applied which combines models that describe the physiological and hydrological processes of the plant-soil system including models of evapotranspiration (Penman-Monteith equation), interception (revised Gash model) and soil water flow (Richards equation). Measurements of rainfall partitioning, volumetric soil water content, evapotranspiration and tree transpiration provided reliable data for the parameterization and the calibration of the model for three stands of different diversity levels. They allowed to include species specific physiological (transpiration rates, response to dry soil water conditions) and structural (leaf area dynamics) characteristics. During the 3-year long observation period 2005-2007 the mean yearly precipitation was 652. mm, the simulated mean yearly interception loss of the three observed forest stands was between 219 and 272. mm, the transpiration accounted for 197-225. mm, the forest floor evaporation for 96-104. mm, the drainage for 16-60. mm and the runoff for 13-50. mm. The calculations of the water balance were sensitive to the species composition of the forest and showed differences of rainfall interception and root water uptake between the stands. The applied stand-level model was able to simulate the water dynamics of the monospecific and mixed forest stands. It was shown that differences in drought tolerance of tree species can have a strong impact on the simulated soil water extraction during periods when available soil water is low. © 2010 Elsevier B.V.

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