PROCEEDINGS: Index of Abstracts

INCREASING SOIL TEMPERATURE IN A NORTHERN HARDWOOD FOREST: EFFECTS ON ELEMENTAL DYNAMICS AND PRIMARY PRODUCTIVITY

Patrick J. McHale-1, Myron J. Mitchell1, Dudley J. Raynal1 and Francis P. Bowles-2

1-State University of New York, College of Environmental Science and Forestry, Dept. of Environmental Forest Biology, One Forestry Drive, Syracuse, NY 13210. 2-Research Designs, Box 26, Woods Hole, MA 02543.

To investigate the effects of elevated soil temperatures on a forest ecosystem, heating cables were buried at a depth of 5 cm within the forest floor of a northern hardwood forest at the Huntington Wildlife Forest (Adirondack Mountains, New York). Temperature was elevated 2.5, 5.0 and 7.5°C above ambient, during May - September in both 1993 and 1994. Various aspects of forest ecosystem dynamics were studied, including soil solution chemistry (lysimeters at 15 and 50 cm depths), trace gas flux (closed box technique), decomposition of maple and American beech litter, and tree seed germination. A preliminary experiment showed that there was less effect on soil solution chemistry when cables were buried at 5 versus 15 cm depths. The soil warming plots experienced negligible disturbance effects associated with installation of heating cables. Nitrate concentrations were elevated in the highest temperature treatment. Carbon dioxide flux was positively correlated with soil temperature, as was the decomposition rate for American beech litter. In heated plots, germination of Pinus strobus (white pine) was positively correlated with soil temperature.