Irja Löfström

Scenic Impacts of Retention Trees in Clear-cutting Areas

The aim of this study was to examine the ways in which the volume, physical appearance and location of retention trees affect the scenic quality of clear-cutting areas. A total of 373 respondents rated 40 digitally edited images. If only a few retention trees remained in the cutting area, they did not seem to affect the ratings, but when 3 m3 ha−1 was retained the scenic quality of the clear-cutting area improved. The better the condition of the retention trees, the more they were appreciated. Retention trees in a poor condition did not enhance the scenic quality of clear-cutting areas. Mature retention trees were found to be more attractive than undergrowth. Even undergrowth was preferred to clear-cutting areas without any trees. Respondents also preferred retention trees standing alone to trees in groups. Forest owners provided higher overall preference scores than visitors. The scenic quality of clear-cutting areas can be substantially improved if there remains an adequate volume of mature retention trees that are in good condition.

Short-term effects of mechanical and biological treatments on Sorbus aucuparia L. sprouting in mesic forests in Finland

Abstract In reforestation areas in Finland, rowan (Sorbus aucuparia L.) can form dense thickets restricting the growth of commercially more valuable conifers. In this study we compared three different management methods to control excessive growth of rowan. These methods were traditional (mechanical cutting 10–15 cm above ground level), 1 m cut height treatment (saplings were cut 1 m above ground level), and biological control (as traditional method, but freshly cut stumps were squirted with mycelium of a fungus, Chondrostereum purpureum [Pers. ex Fr.] Pouzar). The short-term results one year after the treatments revealed that biological control was the best way to restrict rowan sprouting as the proportion of dead stumps was highest. Furthermore, the number and height of stump sprouts were even two times lower in the biological control than in the mechanical treatments. Although the biological control had the highest number of root suckers, the total number of stump sprouts and root suckers together was indicatively lower than in the other methods (p < 0.10). Based on our results C. purpureum treatment seems promising. Yet, more efficient fungus strains and better methods to spread the fungus on stumps are needed before this method is applicable at commercial scale.