Nitrogen balance in forest soils: nutritional limitation of plants under climate change stresses.
Forest ecosystems with low soil nitrogen (N) availability are characterized by direct competition for this growth-limiting resource between several players, i.e. various components of vegetation, such as old-growth trees, natural regeneration and understorey species, mycorrhizal fungi, free-living fungi and bacteria. With the increase in frequency and intensity of extreme climate events predicted in current climate change scenarios, also competition for N between plants and/or soil microorganisms will be affected. In this review, we summarize the present understanding of ecosystem N cycling in N-limited forests and its interaction with extreme climate events, such as heat, drought and flooding. More specifically, the impacts of environmental stresses on microbial release and consumption of bioavailable N, N uptake and competition between plants, as well as plant and microbial uptake are presented. Furthermore, the consequences of drying-wetting cycles on N cycling are discussed. Additionally, we highlight the current methodological difficulties that limit present understanding of N cycling in forest ecosystems and the need for interdisciplinary studies.
Chair of Tree Physiology, Institute of Forest Botany and Tree Physiology, University of Freiburg, Freiburg, Germany.
H
H
Rennenberg
M
M
Dannenmann
A
A
Gessler
J
J
Kreuzwieser
J
J
Simon
H
H
Papen
D057231:Climate Change; D009584:Nitrogen / Q000737:chemistry / Q000378:metabolism*; D063245:Plant Development; D010944:Plants / Q000378:metabolism*; D012987:Soil / Q000032:analysis*; D013312:Stress, Physiological; D014197:Trees
D012987:Soil; D009584:Nitrogen