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

The effects of thinning and prescribed fire on seed production of Sierran conifers.

Kern, Ruth Ann^*,1, Bono, Lori^*,1, ¹ California State University, Fresno, Fresno, CA

ABSTRACT- Seed rain is being monitored in experimental forest treatment plots to investigate the effects of thinning and prescribed fire on seed production and seed dispersal distances of Sierra Nevada conifers. 18 1-ha forest research plots, established in the Teakettle Experimental Watershed, Sierra National Forest, have been manipulated in a 2 x 3 factorial design (fire or no fire; shelterwood thinning, California Spotted Owl protocol (CASPO) thinning, or no thinning) with three replicates of each treatment. 25 0.25m2 seed traps have been installed on a 25-m grid in each of the 18 plots. Seed traps were installed in the control plots in summer 2000 and 2001 and in the treatment plots in summer 2001 and 2002, following completion of logging and fire treatments in summer and fall 2001. Preliminary analyses show large annual variation in seed production with 2002 and 2004 producing significantly more seeds by white fir and incense cedar. In untreated plots, there is significant variation in number of seeds produced among species, with white fir generally dispersing the largest quantity of seeds, followed by red fir and incense cedar. The early effects of thinning and burning treatments appear to be an increase in seed production by white fir, and to a lesser extent incense cedar, as a result of burning alone, and an increase in both white fir and incense cedar when thinning and burning are combined. Further analyses and additional years of seed rain data will help us to understand the individual and cumulative effects of the two methods of logging and of prescribed burning on seed production and seed dispersal distances in White Fir, Red Fir, Sugar Pine, Jeffrey Pine, and Incense Cedar.

Key words: conifer, seed, thinning, fire