PARENT SESSION
Oral Session # 96: Disturbance Ecology: Wind and Water.
Presiding: L Battaglia
Friday, August 8. 8:30 AM to 12:00 PM, SITCC Meeting Room 202.

Microsite vegetation and environmental differences in salvaged and unsalvaged wind-disturbed forest.

Leach, Andrea^*,1, Peterson, Chris¹, ¹ University of Georgia, Athens, GA

ABSTRACT- Intense winds are an important component of the disturbance regime in eastern North American forests, disturbing thousands of hectares annually and creating patches (or microsites) that are differentially favorable for germination of seeds and survival and growth of seedlings and saplings. As a result, the abundance, arrangement, and composition of microsites may in large part determine patterns of regeneration. While natural wind disturbance creates characteristic patterns of microsite abundance and composition due to treefall pits and mounds and downed tree crowns, salvage logging creates distinct microsite types, such as slash piles and skid trails, that may not have close natural analogs. We established 380 0.5 m² circular plots across salvaged and unsalvaged wind-damaged forest in which we measured percent cover of herbaceous vegetation, height of tree seedlings and saplings, soil moisture and temperature, and percent canopy openness of five different microsite types (treefall pit, treefall mound, downed tree crowns, bare soil areas, and patches of Vitis rotundifolia). We found that percent canopy openness and soil temperature differed between post-windthrow treatments (ANOVA, p<0.001) with microsites in salvaged areas having both more light and higher temperatures. Soil moisture and soil temperature differed between microsite types (ANOVA, p<0.001). Soil on treefall mounds had the lowest moisture levels and highest temperatures contrasted with pits having the wettest soils with the lowest temperatures. Canonical Correspondence Analysis using log-transformed environmental variables demonstrated that soil moisture and temperature most strongly influenced species composition of microsites. We conclude that microsite type is an important factor in determining environmental conditions and vegetation and may overshadow whether the disturbed forest was salvage-logged.

Key words: pit and mound microtopography, wind disturbance, salvage logging