Title: Plant and soil nutrients in young versus mature central Appalachian hardwood stands

Author: Gilliam, Frank S.; Adams, Mary Beth

Year: 1995

Publication: In: Gottschalk, Kurt W.; Fosbroke, Sandra L. C., ed. Proceedings, 10th Central Hardwood Forest Conference; 1995 March 5-8; Morgantown, WV.: Gen. Tech. Rep. NE-197. Radnor, PA: U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station. 109-118

Abstract: Most models of forest succession and forest recovery following disturbance predict changes in nutrient availability. The purpose of this study was to compare soil and herbaceous layer plant nutrients between two young (~20 yr) and two mature (~80 yr) forest stands on Fernow Experimental Forest, Parsons, West Virginia. All sampling was carried out within 15 circular 0.04-ha sample plots per watershed, for a total of 30 plots for each age category. All vascular plants ≤1 m in height (herbaceous layer) were identified and estimated visually for cover in each of 10 circular 1-m² sub-plots. All above-ground portions of plants in the two sub-plots in each sample plot with the greatest herb layer cover were harvested and analyzed for nutrient content. In addition, a soil sample was taken to a 10-cm depth from each harvest sub-plot. Soils were analyzed for organic matter, texture, pH, and extractable nutrients. There were no significant differences related to stand age for soil pH, organic matter, cation exchange capacity, or any of the extractable nutrients. With the exception of significantly higher herb layer N for the young stands, there were few differences in herb layer tissue nutrients between young and mature stands. There were, however, differences in correlations among soil nutrients and other soil variables (e.g., texture and organic matter) which varied with stand age, with extractable nutrients more highly correlated with organic matter and texture in the young stands than in the mature stands. Furthermore, herb layer tissue nutrient concentrations were correlated significantly with soil organic matter for virtually all nutrients in young stands; in contrast, none were correlated with soil organic matter in mature stands. These results suggest minimal change in nutrient availability between 20 and 80 years of forest recovery from disturbance. Data in this study further emphasize the importance of soil organic matter decomposition as a source of available nutrients in these hardwood forests following disturbance and suggest that this importance might decrease with stand age. Finally, these results are consistent with the hypothesis that herb layer dynamics are controlled by nutrient availability early in succession, but that other factors, such as light, become more important later in succession.