PARENT SESSION
Poster Session 32: Biogeochemistry
Thursday, August 11, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Nitrogen and Phosphorus Dynamics of Foliage, Litter and Oi Horizon on Landslide Disturbed Forests of the White Mountain National Forest, NH, USA.
Bryant, David*,1, Aber, John2, Innes, James3, Wandland, Kristen4, Zarin, Daniel5, 1 School of Life Sciences, Tempe, AZ, USA2 University of New Hampshire, Durham, NH, USA3 USDA Forest Service - PSW Research Station, Davis, CA4 ENSR International, Raliegh, NC, USA5 School of Forest Resources & Conservation, Gainesville, FL, USA
ABSTRACT- Foliar nutrient ratios have been shown to be an accurate indicator of relative nutrient limitations in forest ecosystems. We present evidence of potential phosphorus limitation on forest stands disturbed by landslides during the 20th Century. Nutrient content was measured in fresh foliage and litterfall of five tree species on four sites at 2 elevations in the White Mountain National Forest, NH, USA. A two-year litterbag experiment followed mass and nutrient dynamics of 4 of these species on the same sites. Nutrient content of the Oi horizon was measured on three of the four sites. Stand weighted mean foliar N:P ratios varied from 10 (indicating N limitation) to 30 (indicating P limitation). Litter fall N:P increased in direct relation to, that of foliage N:P (Litter N:P = foliar N:P x 1.38 − 5.24, R2 = 0.9764). The proportion of foliar P remaining in litter of each species was significantly correlated with the foliar concentration of N (% foliar P in litter = (% foliar N x 27.534 − 15.099, R2 = 0.5212) but not P. Release of N and P from litterbags was strongly correlated to the initial content of each nutrient regardless of species. The ratio of N:P in the Oi horizon on three of the four sites declined in strong correlation with the foliar N:P of each sites (Oi horizon N:P = Foliar N:P x 0.4461 + 7.9535 R2 = 0.9072). These findings suggest that ecosystem P is conserved relative to N in sites with the highest foliar N:P ratios.
Key words: Nutrient Limitation, Forest disturbance, Nutrient Stoichiometry, White Mountain National Forest