@article{CaronDeFrenneBrunetetal.2014,
  author    = {Caron, Maria Mercedes and De Frenne, P. and Brunet, J. and Chabrerie, Olivier and Cousins, S. A. O. and De Backer, L. and Diekmann, M. and Graae, B. J. and Heinken, Thilo and Kolb, A. and Naaf, T. and Plue, J. and Selvi, F. and Strimbeck, G. R. and Wulf, Monika and Verheyen, Kris},
  title     = {Latitudinal variation in seeds characteristics of Acer platanoides and A. pseudoplatanus},
  series = {Plant ecology : an international journal},
  volume    = {215},
  journal   = {Plant ecology : an international journal},
  number    = {8},
  publisher = {Springer},
  address   = {Dordrecht},
  issn      = {1385-0237},
  doi       = {10.1007/s11258-014-0343-x},
  pages     = {911 -- 925},
  year      = {2014},
  abstract  = {Climate change will likely affect population dynamics of numerous plant species by modifying several aspects of the life cycle. Because plant regeneration from seeds may be particularly vulnerable, here we assess the possible effects of climate change on seed characteristics and present an integrated analysis of seven seed traits (nutrient concentrations, samara mass, seed mass, wing length, seed viability, germination percentage, and seedling biomass) of Acer platanoides and A. pseudoplatanus seeds collected along a wide latitudinal gradient from Italy to Norway. Seed traits were analyzed in relation to the environmental conditions experienced by the mother trees along the latitudinal gradient. We found that seed traits of A. platanoides were more influenced by the climatic conditions than those of A. pseudoplatanus. Additionally, seed viability, germination percentage, and seedling biomass of A. platanoides were strongly related to the seed mass and nutrient concentration. While A. platanoides seeds were more influenced by the environmental conditions (generally negatively affected by rising temperatures), compared to A. pseudoplatanus, A. platanoides still showed higher germination percentage and seedling biomass than A. pseudoplatanus. Thus, further research on subsequent life-history stages of both species is needed. The variation in seed quality observed along the climatic gradient highlights the importance of studying the possible impact of climate change on seed production and species demography.},
  language  = {en}
}
@article{LeuschnerWulfBaeuchleretal.2014,
  author    = {Leuschner, Christoph and Wulf, Monika and Baeuchler, Patricia and Hertel, Dietrich},
  title     = {Forest continuity as a key determinant of soil carbon and nutrient storage in beech forests on sandy soils in Northern Germany},
  series = {Ecosystems},
  volume    = {17},
  journal   = {Ecosystems},
  number    = {3},
  publisher = {Springer},
  address   = {New York},
  issn      = {1432-9840},
  doi       = {10.1007/s10021-013-9738-0},
  pages     = {497 -- 511},
  year      = {2014},
  abstract  = {Forest (or tree) age has been identified as an important determinant of the carbon (C) storage potential of forest soils. A large part of Central Europe's current forested area was affected by land use change with long periods of cultivation in past centuries suggesting that the organic C stocks in the soil (SOC) under recent forest may partly be legacies of the past and that stand age effects have to be distinguished from forest continuity effects (that is, the time since re-afforestation). We examined the influence of mean tree age and forest continuity on the SOC pool and the stores of total N and available P, Ca, Mg, and K in the soil (mineral soil and organic layer) across a sample of 14 beech (Fagus sylvatica) forests on sandy soil with variable tree age (23-189 years) and forest continuity (50-year-old afforestation to ancient ('permanent') forest, that is, > 230 years of proven continuity). Ancient beech forests (> 230 years of continuity) stored on average 47 and 44\% more organic C and total N in the soil than recent beech afforestation (50-128 years of continuity). Contrary to expectation, we found large and significant C and N pool differences between the forest categories in the mineral soil but not in the organic layer indicating that decade- or century-long cultivation has reduced the subsoil C and nutrient stores while the organic layer element pools have approached a new equilibrium after only 50-128 years. PCA and correlation analyses suggest that forest continuity cannot be ignored when trying to understand the variation in soil C stocks between different stands. Forest clearing, subsequent cultivation, and eventual re-afforestation with beech resulted in similar relative stock reductions of C and N and, thus, no change in soil C/N ratio. We conclude that the continuity of forest cover, which may or may not be related to tree age, is a key determinant of the soil C and nutrient stores of beech forests in the old cultural landscape of Central Europe.},
  language  = {en}
}