Influence of tree species on carbon and nitrogen transformation patterns in forest floor profiles
Résumé
Background Among forest management practices, forest tree species substitution influences biogeochemical cycles and soil interactions rapidly (decades) and significantly. Methods We studied the impact of tree species on forest floor properties in 27-year-old monospecific stands of oak, beech, spruce and Douglas-fir, grown in common garden. Results In spite of similar litterfall C-inputs (1.3-1.8 Mg ha(-1) yr(-1)), C-stocks strongly differed between coniferous (16-21 Mg ha(-1)) and broadleaved (7-9 Mg ha(-1)) forest floors. The large C-mineralization under oak (196 C-mu g C-total-g(-1) d(-1)) relatively to other stands (125-147 C-mu g C-total-g(-1) d(-1)) and the large dissolved organic carbon release under broadleaved forest floors may explain this difference. Spruce forest floor exhibited the lowest net nitrification and the largest contribution of organic anions to the anionic charge of aqueous leachate (62.5 % +/- 1.7). Conversely, Douglas-fir forest floor exhibited the largest relative nitrification and the largest contribution of nitrate to the anionic charge (70.8 % +/- 0.7). Conclusion We conclude that tree species induce a specific signature in term of proton donors at the forest floor level (organic vs nitric acid), which involves potential impacts on pedogenetic processes in the mineral horizon beneath.
Auteurs, date et publication :
Auteurs Florence Trum , Hugues Titeux , Jacques Ranger , Bruno Delvaux
Publication : Annals of Forest Science
Date : 2011
Volume : 68
Issue : 4
Pages : 837-847