Monday, November 13, 2006

What Controls Calcium Budgets in Northern Hardwood Forests: Species Composition or Parent Material?.

Ruth Yanai1, Steven Hamburg2, Joel D. Blum3, Mary Arthur4, Marty Acker5, Farrah Fatemi1, and Matthew Vadeboncoeur6. (1) SUNY-ESF, 350 Illick Hall, Forestry Dr, Syracuse, NY 13210, (2) PO Box 1943 135 Angell St., Brown University, Brown University, Center for Environmental Studies, Providence, RI 02912-1943, (3) Univ of Michigan, 2534 CC Little, Ann Arbor, MI 48109, (4) TP Cooper Building, University of Kentucky, University of Kentucky, Department of Forestry, Lexington, KY 40546-0073, (5) Forestry Dept, TP Cooper Bldg, Univ of Kentucky, Lexington, KY 40546-0073, (6) Brown Univ, Center for Env Studies, PO Box 1943, 135 Angell St, Providence, RI 02912-1943

We earlier presented calcium cycling budgets in northern hardwood stands of different ages in the White Mountains of New Hampshire, which indicated that young stands were accumulating Ca in the forest floor as well as the vegetation, and that litter was more Ca-rich in young (<30 yr old) than in older sites. Chronosequence studies are difficult to interpret, if based on small numbers of stands. Our study of 13 sites showed that differences in species composition were related to differences in Ca concentration in litterfall but also to differences in parent material. We characterized woody debris , across the chronosequence, and found lower biomass and nutrient pools in younger than older stands, except that very young (<20 yr old) stands had residual debris from the harvested stand. We also studied biomass pools (vegetation, woody debris and the forest floor) in triplicate stands of three ages (14-19 yr, 26-29 yr, and > 100 yr) all located within the Bartlett Experimental Forest, New Hampshire. Vegetation was the most important biomass pool, increasing, of course, with stand age; the Ca concentrations in wood changed with stand age for some species (increasing for beech, red maple, and yellow birch, but decreasing for pin cherry). We also characterized Ca pools in the mineral soil, but these were more related to differences in the parent material than to the successional status of the vegetation.