Epsilon Archive for Student Projects

Abstract

Forest disturbances are significant in shaping vegetation structure, composition and ecosystem development in boreal forests. In modern Swedish forestry, clearcutting is the dominant type of disturbance while prescribed burning is sometimes used to restore ecological processes historically associated with wildfire. This study compared early vegetation structure and composition following prescribed burning and clearcutting in boreal Scots pine (Pinus sylvestris) forests in Klenemåla, Småland, Sweden, with an additional control stand representing long-term stand development without recent disturbance. Vegetation sampling was conducted using 40 ground vegetation plots per site, combined with structural measurements in randomly selected larger plots. Species composition, vegetation cover and stand structure were compared among the three disturbance types.

The results showed clear differences in vegetation development depending on treatment type. Both burned and clearcut sites exhibited a higher total species richness, with nine species each, compared to the four species found in the control, when combining all 40 sampling plots within each treatment. However, at the single-plot scale, the single-factor ANOVA and post-hoc Tukey’s test showed that the only statistically significant difference in mean species richness per plot was between the burned and clearcut treatments, where the clearcut had a higher average number of species per plot. Furthermore, the two disturbance types differed in vegetation composition and structural variation. Grasses and raspberry (Rubus idaeus) characterised the clearcut site. The absolute mean total vegetation cover was high and roughly equal to the other treatments, but the variation between plots was low. The burned site, in contrast, showed greater heterogeneity in vegetation cover between plots and stand structure, with a mixture of early successional species and forest understory species such as bilberry (Vaccinium myrtillus) and cowberry (Vaccinium vitis-idaea).

These findings indicate that disturbance type influences not only the total species richness, but also species composition and structural diversity. Prescribed burning may therefore contribute to greater ecological variation than clearcutting, with implications for long-term biodiversity and forest management. The study highlights the importance of considering different disturbance regimes and types when evaluating vegetation development and biodiversity in managed boreal forests.