Summary
Published in International Journal of Plant & Soil Science 2(2): 155-189. https://doi.org/10.9734/IJPSS/2013/4233
Nitrogen is considered the most important element in plant nutrition and growth. However its role and availability for boreal forest conifers is still debated. Boreal conifers have adapted strategies to cope with the reduced availability of N. ECM fungi, associated with boreal conifer roots, increase soil exploration and N nutrition, especially where organic N predominates. Conifers usually take up ammonium at levels comparable to simple organic N, which probably grows in importance as organic matter accumulates with stand age, while estimates of nitrate uptake are generally lower. Conifers, especially slow growing species, may rely on internal N cycling to sustain the development of new tissues in spring. N increases photosynthesis and leaf area and thus increases growth and wood formation, leading to wider radial rings mostly because of increased earlywood production. N-depositions and disturbances (e.g. fire and harvest) may alter the soil Ncycle and affect boreal forest growth. N depositions are considered responsible for the increase in boreal forest growth during the last century. Intensive harvest and high Ndepositions may shift limitation from N to another element (e.g. P, K, and B). Climate change should affect the N cycle through complex mechanisms, including changes in the fire return interval, direct effects of warmer soils on N mineralization and stimulating plant growth modifying the balance between N stored in soils and in the living and dead (e.g. wood) biomass. Future research should try to improve our understanding of the possible outcomes of changes in disturbance regimes, N-depositions and climate, including the role of N fixation by mosses, canopy N uptake and the responses of conifers in relation to changes in microbial (symbiotic and not) communities.
Sector(s):
Forests
Categorie(s):
Scientific Article
Theme(s):
Ecosystems and Environment, Forest Ecology, Forestry Research, Forests
Departmental author(s):
Author(s)
LUPI, Carlo, Hubert MORIN, Annie DESLAURIERS, Sergio ROSSI and Daniel HOULE
Year of publication :
2013
Format :
PDF available upon request
How to get the publication :
Keywords :
Nitrogen, sol forestier, changement climatique, forêt boréale, cycle de l'azote, écologie forestière, écosystèmes et environnement, article scientifique de recherche forestière, ecosystems and environment, forest ecology, forest soils, nitrogen, climatic change, boreal forest, nitrogen cycling
