PARENT SESSION
OOS 5: Restoration Effects of Fire and Thinning Treatments on Mixed-Conifer Ecosystems.
Organized by: M North and J Innes
Monday, August 2, 8:00 AM to 11:30 AM, Meeting Room E 148.

Species specific growth patterns and El Nino reconstruction using tree-rings in the southern Sierra Nevada.

Hurteau, Matthew^*,1, Zald, Harold^*,2, North, Malcolm^*,3, ¹ University of California, Davis, Davis, CA² U.S.D.A. Forest Service, Corvalis, OR³ U.S.D.A. Forest Service, Davis, CA

ABSTRACT- Annual weather patterns vary significantly between the northern and southern Sierra Nevada and there are few long-term records south of Yosemite National Park. To develop a better climate history for the southern Sierra Nevada and investigate which mixed conifer species is most highly correlated with temperature and precipitation, we collected 571 cross-sections from stumps in a 2000-2001 thinning treatment at the Teakettle Experimental Forest, 80 km east of Fresno. The cross-sections or cookies were collected from the five dominant mixed conifer species, Abies concolor, A. magnifica, Calocedrus decurrens, Pinus lambertiana, and Pinus jeffreyi, dating back as far as 1616. Annual growth was measured for each cross section using standard dendrochronological techniques. We used multivariate techniques to determine which suite of climate attributes provides the best explanatory power for each of the five species growth patterns. Each of the five species showed a significant response to mean annual temperature and annual precipitation. In addition, we used time series forecasting to tease apart the relationship between ring width and El Nino events. This relationship allowed us to reconstruct the El Nino record for the region. Abies magnifica, Pinus lambertiana and Pinus jeffreyi had the greatest annual growth response to wet El Nino events. We will cross-validate our reconstruction against existing multi-proxy El Nino reconstructions.

Key words: sierra nevada, el nino