| Abstract Detail
Ecological Section Cobo, María Carmen [1], Arévalo, José Ramón [1], Bond, Steven [1], Hussain, Mumtaz [1], Palmer, Suzanne M. [1], Sasaki, Kiyoshi [1], Shirakura, Fumiko [1], Thomas, Shyam [1], Palmer, Michael W. [1]. Convergence and divergence in species composition of two Minnesota forests during 21 years following catastrophic windthrow. Catastrophic windthrow is the main natural disturbance in many temperate forests. We followed the response of two forests in Cedar Creek Natural History Area, Minnesota, following a 1983 windstorm. One forest (the "oak site") was originally dominated by Quercus ellipsoidalis and Populus grandidentata. Another forest, the "pine forest", is of secondary origin, and was dominated by Pinus strobus. Both showed no differences in soil, slope or hydrology, and no signs of recent anthropogenic disturbance. In both sites, we mapped all tree stems. We also followed understory species composition in 1m2 quadrats (100 in the oak site and 120 in the pine site) and on tipup mound topography in the pine site. The storm resulted in a loss of 58% in basal area and 38% in tree stems in the oak site, and 71% in basal area and 60% in stems in the pine site. During the last 21 years, both forests exhibited similar trends in tree density and basal area, though the pine site did not achieve pre-disturbance levels, and the oak site levelled or surpassed them. Both sites changed in overstory composition. Tree species richness increased markedly in the pine site, and was roughly constant since 1993. There is a trend towards convergence in tree species composition of both sites, but no hint of return to pre-disturbance conditions. In contrast, understory species composition diverges in both forests, with no return to pre-disturbance conditions. Microsites associated with tipup mounds exhibit a complex pattern: the two sides of the mound (new soil and old soil) converge in species composition through time, except for the pits, which diverge from the mounds and become more similar to the understory.
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Related Links:
1 - Oklahoma State University, Department of Botany, College of Arts and Sciences, 104 Life Sciences East, Stillwater, Oklahoma, 74078, USA
Keywords:
disturbance
succession
tipup mound
treefall
windstorm
forests dynamics.
Presentation Type: Oral Paper
Session: 47-4
Location: Salon F - Austin Grand Ballroom/Hilton
Date: Wednesday, August 17th, 2005
Time: 11:00 AM
Abstract ID:84 |
