The Gordon Natural Area (GNA) serves as a natural laboratory for a range of class research projects. In a Geography Field Methods course led by Dr. Fritschle, students established five permanent carbon-study plots in 2008. Since then, students have returned to these plots to measure the carbon stock of standing trees in five plots located along a topographic gradient: floodplain, ridge-top, lower mid-slope, mid-slope and upper mid-slope. Using U.S. Forest Service established guidelines, all trees greater than 5 cm and up to 73 cm in diameter at breast height (DBH) were measured and identified within each 40 m circular plot. To ensure the same trees were measured each year, distance and azimuth from plot center were also collected. The woody species composition, forest structure, and carbon stock were compared between plots and across years using non-metric multidimensional scaling. While Tulip poplar (Liriodendron tulipfera) and American beech (Fagus grandifolia) remained the most single dominant overstory and understory species (respectively) through time, the analysis did suggest the forest is likely changing. Specifically, carbon stock appears to be declining; however no significant difference was established for data from one year to the next. This is further suggested by the paucity of understory trees compared to the overstory. Previous studies by students have found that these five plots are not statistically different from the rest of the "Big Woods" area in the GNA. More study is needed as these permanent plots do point to a potential decline in standing tree carbon stock in the GNA over the last five years. Given the importance of forests in mitigating the negative effects of climate change, this finding is especially of concern.
Available at: http://works.bepress.com/joy_fritschle/7/