PARENT SESSION
Poster Session 2: Forest Ecology
Monday, August 8, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Mass and nutrient dynamics of coarse and fine woody debris in a chronosequence of northern hardwood forest stands.
Acker, Marty1, Arthur, Mary1, 1 Universityof Kentucky, Lexington, KY
ABSTRACT- As part of a larger study examining the availability of calcium through stand age in a northern hardwood forest, we analyzed the role of woody debris in nutrient distribution. Woody debris may play an important role in the redistribution of nutrients from the canopy to the soil surface during forest development, particularly during the shift in species dominance from pin cherry in young stands to beech, maple, and birch in more mature stands. To test the hypothesis that nutrient pools in woody debris fluctuate with stand age and species composition, woody debris was measured in a chronosequence of 15 northern hardwood forest stands in the White Mountains, New Hampshire. Stands ranged from 12 to 128 years since clearcut. We used line-intersect sampling based on the USDA Forest Inventory Analysis to measure fine woody debris (FWD; ≥3.0cm and <7.5cm diameter) and coarse woody debris (CWD; ≥7.5cm diameter). Our results show that woody debris accumulates at a steady rate in young stands, followed by fluctuations in the woody debris pool as stands mature. This shift coincides with the overstory transition from pin cherry to northern hardwood species. In general, these observations corroborate woody debris dynamics previously reported. Fine woody debris more strongly influenced total woody debris pools in young stands than in mature stands. During the woody debris accumulation phase, FWD is dominated by pin cherry because many pin cherry boles are in this smaller size class and branch production and mortality appears to be high for this species. The species composition of CWD is more varied. The nutrient status of woody debris varies as a function of species, size class, and decay class; combinations of these characteristics determine the distribution of nutrients in the woody debris pool through stand development. In particular, high calcium concentrations in pin cherry and the rapid disappearance of pin cherry from the total woody debris pool has important implications for the soil nutrient status in these developing forests.
Key words: Woody Debris, Chronosequence, Northern hardwood forest