Dendroclimatological analysis of Eastern Hemlock (Tsuga canadensis L.) in Southeastern Ohio, USA. (Plant Ecology 02:00 PM, Saturday, April 5, 2003 Brewer/Frost Science 142 Dr. Cadance A. Lowell-Presiding).

Weaver, Scott A. ; McCarthy, Brian C.

3:45

Dendroclimatological techniques were applied to eastern hemlock growing in Hocking County, OH to determine the relationship between radial growth and climate. Increment cores were obtained from trees sampled on sandstone ledges (N = 10) and forest interiors (N = 14) to evaluate the effect of site quality on climate signals. Increment cores were obtained, prepared, and cross-dated using standard protocols, from which a master ring-width chronology spanning 201 years (1800-2000) was developed. Monthly climatic variables (temperature, precipitation, and Palmer Drought Severity Index) were obtained for the current and previous growing seasons (1895-2000). The master ring width chronology and each of the two subset chronologies were significantly (P < 0.05) correlated with growing season drought severity and precipitation. Temperature was generally uncorrelated with growth. While the mean ([+ or -] SE) annual growth of forest trees (1.92 mm [+ or -] 0.05) compared to ledge trees (1.39 [+ or -] 0.03) was significantly different (Z = 8.6, P < 0.001), both were significantly (P < 0.05) correlated with drought severity from June of the previous year to September of the current year. The ledge trees showed a greater degree of correlation with the months prior to the current growing season (previous November to current March), while the forest trees showed a stronger correlation with the current growing season (April through September). Differences in soil depth, competition, and transpiration are the most likely explanation for the observed response patterns.

SCOTT A. WEAVER [email protected], BRIAN C. MCCARTHY [email protected], DEPT OF ENVIRONMENTAL AND PLANT BIOLOGY, OHIO UNIVERSITY, ATHENS OH 45701