Date of Award


Document Type

Restricted Thesis

Terms of Use

© 2002 Amanda E. Schneider. All rights reserved. Access to this work is restricted to users within the Swarthmore College network and may only be used for non-commercial, educational, and research purposes. Sharing with users outside of the Swarthmore College network is expressly prohibited. For all other uses, including reproduction and distribution, please contact the copyright holder.

Degree Name

Bachelor of Arts


Biology Department

First Advisor

Roger Latham


Distinct barrens and forest vegetation types grow in close proximity on the Pocono Plateau of northeastern Pennsylvania. This study investigated whether organic chemicals produced by ericaceous shrubs in the barrens inhibit the growth of forest tree species. Germination of Betula populifolia (Gray birch, Marshall, Betulaceae) and Tsuga canadensis, (Eastern hemlock, L., Pinaceae) were not inhibited by aqueous extracts of barrens leaf litter or organic soil. Activated carbon applied to tree seedlings planted in the barrens and forest reduced mortality of Acer rubrum (Red maple, L., Aceraceae), Prunus serotina (Black cherry, Ehrh., Rosaceae), and Betula lenta (Sweet birch, L., Betulaceae) in the barrens but not in the forest. It increased the growth of Acer and Prunus seedlings in the barrens, but did not increase their growth in the forest. Organic chemicals that were absorbed by activated carbon in this experiment may contribute to the persistence of distinct forest and barrens vegetation types. These chemicals may reduce nutrient availability in the barrens, contributing to the continued dominance of ericaceous shrubs that are adapted to low nutrient conditions.