Institute of Ecosystem Studies

2007 BES Annual Meeting Presentation and Poster Abstracts


Land Use and Forest Succession in the Gwynns Falls Uplands
 
Brush, Grace
Co-Authors: Grace S. Brush and Daniel J. Bain
 
Abstract: Random sampling of vegetation in the Gwynns Falls uplands shows that water availability is the predominant factor determining tree species distributions. While some species grow on a variety of soil types, many species are restricted by high or low water availability. Based on regional pollen profiles, the present species composition is similar to that occurring on this landscape over the past 6000 years. However, land use has altered the disturbance regime, affecting the landscape successional mosaic. We propose that as agricultural activity declined in the Baltimore region, beginning about 1900, the first fields abandoned were marginal lands on erodible, steep slopes. In contrast, the flatter less erodible fields would have remained in agriculture for a longer period of time, with afforestation, where it occurred, beginning later. The data summarized in the accompanying table show the relation of successional stage of species with erodibility (the product of slope and soil k factor) and 1992 forest cover within a 0.5 km radius. On average, late successional species occur in plots with higher erodibility and more forest cover, indicating that these areas have been undergoing afforestation for a longer period of time than areas dominated by early successional species which tend to occupy areas of low erodibility and less forest cover.
 
 
successional stage (no. species) mean (range) erodibility mean (range) percent forest cover
early (6) 1.05 (0.4-2.1) 0.3 (0.2-0.4)
early to intermediate (5) 1.35 (0.5-1.9) 0.4 (0.3-0.6)
intermediate (6) 1.5 (0.8-2.3) 0.4 (0.2-0.5)
late (18) 2 (0.9-4.4) 0.5 (0.1-0.8)