Canadian Forest Service Publications

Site influences on net ecosystem productivity in managed Abies balsamea stands. 2007. Bourque, C.P-A.; Lehnert, S.; Xing, Z.; Meng, F.-R.; Swift, D.E. Pages 25-31 in Chinese National Committee for the International Geosphere-Biosphere Programme, compiler. Proceedings, International Conference on Regional Carbon Budgets, August 16-18, 2006, Beijing, China. Natural Resources Canada, Canadian Forest Service, Atlantic Forestry Centre, Fredericton, N.B.

Year: 2007

Issued by: Atlantic Forestry Centre

Catalog ID: 26911

Language: English

Availability: Order paper copy (free)

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This paper investigates site influences on net ecosystem productivity (NEP) in 15 managed balsam fir stands in SW New Brunswick, Canada. Flux towers in 2 of the 15 stands provide a short-term measurement of NEP and site micrometeorology for the June 29-November 30, 2004 period. Site conditions between Charlie Lake (CL01) and Nashwaak Lake (NWL) flux sites for the 2004 period reveal few differences. The greatest differences occur in soil temperature and soil water content (SWC), with CL01 being the warmer and wetter of the two sites. These differences, particularly in SWC are hypothesized to be responsible for the 29% increase in NEP at CL01 for the 2004 period. Slope position (SP, an index of potential soil wetness, indicates because of physiographic position NWL has dryer soils. Stem analysis of 42 trees from the two sites show that over the lifetime of the stands, mean annual increment at CL01 was 4.8 compared with 4.5 m3 ha-1 yr-1 for the NWL. Relating SI to SP revealed that Si co-varies with SP in a parabolic fashion. Excessively wet or dry soils are shown to have reduced site productivity, while soils and intermediate SWC promote improved stand growth.