Long-term changes in forest biomass, tree species composition and nitrogen fixation following land use disturbance

These data are from long-term vegetation plots at the Coweeta Hydrologic Laboratory in western North Carolina. Data collection began in 1934-1935 and was repeated roughly a few times each decade between 1970 and 2013. Three different types of disturbances were applied in this study: selective cutting, clear cutting, and agricultural abandonment. The selective cutting experiment included 274 plots located in reference watersheds that received no subsequent disturbance after a selective cutting event in the early 1900s. There were 24 clear-cut disturbance plots which were located in watershed 7, which was clear-cut in 1976-1977. The 34 agriculture abandonment plots were located in watershed 6, which was logged and tilled in 1958 and planted with grass and maintained with fertilizer and herbicide, until abandoned in 1968. This data publication includes the following plot-level data: cumulative nitrogen fixation estimated from Robinia pseudoacacia (ROBPSE) tree density data and a model parameterized with local nitrogen fixation data as well as the maximum total above ground biomass (agb) of ROBPSE at any survey date. In addition, the following data are provided for each survey date (year) and plot: total agb and the mycorrhizal association for 27 common tree species, fraction of agb comprised by arbuscular mycorrhizal (AM) trees (excluding ROBPSE), and total agb (excluding ROBPSE, CASDEN and TSUCAN).
Data were collected to understand changes in forest composition over time and following disturbance. In our study, we examined how historical land use and symbiotic nitrogen fixation relate to patterns in forest composition.
For more information about this study and these data, see Wurzburger et al. [In press].