Epsilon Archive for Student Projects

Abstract

Fire and browsing are two disturbance factors which greatly affect future stand development, yet the two have rarely been studied together in a boreal forest environment. A good opportunity for studying the combined effects of browsing and fire on stand development in a boreal forest environment was provided by the 1999 fire in Tyresta National Park, where an exclosure was set up shortly after the fire. The objective of this study was to examine the influence of browsing on post-fire stand development. For this purpose, the browsing effects on tree seedlings were examined, inside and outside an exclosure (1 ha) in the burned area. The areas inside and outside the exclosure were each divided into a low and a high fertility site. Sample plots were established at each of these sites, and inventoried in 2002 and 2007. Dense seedling populations established after the fire with on average 31,000 Salix caprea and 10,000 Populus tremula per ha. Results show that species composition and mortality were not directly influenced by browsing, whereas browsing effects on height development and height distribution were great. Eight years after fire, the heights of dominant seedlings of P. tremula and S. caprea were nearly double in the fenced area compared to the un-fenced area. In order to limit browsing effects on deciduous plants, fencing or browsing refugia should be used.