PARENT SESSION
Oral Session #107: Forest Ecology: Disturbance.
Presiding: H. Regan
Friday, August 9. 9:00 AM to 12:00 PM. Mesquite Room, Radisson.
Influences contributing to high understory diversity in managed old growth white pine forests in the Lake States.
Galbraith, Betsy*,1, Cook, James1, David, Clive1, Pubanz, Dan2, 1 University of Wisconsin-Stevens Point, Stevens Point, WI2 Menominee Tribal Enterprises, Keshena, WI
ABSTRACT- The Menominee Forest provides a unique opportunity to study some of the oldest white pine communities in the Lake States. Despite active management for white pine for almost 140 years, a dense hardwood intermediate layer is present. Understory composition represents a mixture of species found in white pine and northern hardwood forests. Although white pine has directly influenced the community over the last 140 years, we hypothesized the understory composition was dominated by northern hardwood species. Eleven plots were established throughout three different white pine stands and understory composition sampled in 176 quadrats. By comparing frequency and species richness data from our plots with those sampled by John T. Curtis approximately 50 years ago, we determined our stands most closely represented a northern hardwood community. A total of 102 species were observed during sampling with a mean species richness of 39. In the Upper Peninsula of Michigan an herbaceous species richness of 18 was reported in northern hardwood stands. A mean value of 27 was observed for total species richness in pine and hardwood stands in the nearby Chequamegon National Forest. Species diversity in our stands (H'=2.41) was higher than reported for comparable pine and hardwood stands (H'= 1.83) in the Chequamegon. Due to the lack of intense disturbance, mesic site conditions, and overstory composition, richness and diversity on our sites are higher than similar forest types in the region. In addition to vegetation sampling, seed bank samples were randomly collected in 192 locations across six plots. Results from ongoing greenhouse germination tests will be incorporated into analysis of community type.
KEY WORDS: Menominee Forest, Pinus strobus, plant diversity , mesic site conditions