PS 89-105
Impacts of forest structure on watershed performance

Friday, August 14, 2015
Exhibit Hall, Baltimore Convention Center
Lara Brindisi, Plant Biology, Rutgers University, New Brunswick, NJ
Deirdre Casey, Landscape Architecture, Rutgers University, New Brunswick, NJ
Jean Marie Hartman, Department of Landscape Architecture, Rutgers University, New Brunswick, NJ

Spreading urbanization continues to reduce and fragment forest cover, potentially posing a threat to the benefits that healthy forests provide to watersheds, the land area into which surface water drains and collects. Unhealthy forests can result in impaired watersheds, which jeopardizes drinking water, intensifies weather, and pressures local economies. The purpose of this study is to establish how urban fragmentation of forests is threatening the Raritan watershed in order to update the information that scientists and policymakers use to manage water quality and quantity of the region. The research team identified differences in soil composition and function, infiltration, percent cover, point quarter, and species of vegetation. The data collection follows a two-way analysis of a variation model by using statistical analysis to evaluate the results for differences between forest centers and edges, and for differences between site locations.


Soil analysis concludes statistically significant longer infiltration rates, lower percentages of organic matter, higher structural stability, and a closer to neutral pH of the soil in the edge transects compared to that of the center transects, suggesting that forest edges have less water-absorbent and more nutrient-poor soil. Vegetative analysis concludes statistically significant variations between edge and center transects regarding percent cover and species abundance. Both soil and vegetative data confirm that fragmentation is disrupting forest structure by reducing healthier center conditions and expanding inferior edge conditions. Future studies can reveal if increasing forest fragmentation and reduction is, in fact, increasing water runoff and threatening watershed stability.