Characteristic of browsing damages in Norway spruce stands

Abstract

Browsing damages are becoming more common due to almost doubling of population densities of cervids in Latvia during last 20 years; however, the figures are still lower than those observed in western and northern European countries. Consequently, the frequency of damages in young stands is increasing, too. Protection against browsing becomes more difficult, as the trees grow older, also the bark-stripping may result in a long-term deterioration of stem quality. Therefore, the aim of the study was to assess the factors affecting bark striping damages in pole-stage Norway spruce stands. Data were collected in 4 sample plots in damaged Norway spruce stands in western Latvia, measuring the tree parameters: height, diameter, branch characteristics and damage parameters: size, proportion from the stem circumference. Results of the modeling reveal that both damage parameters were significantly influenced by the branch length and thickness in the whorl closest to the breast height and the size of damages-also by breast height diameter of the tree. It suggests that increasing productivity of trees would not reduce the browsing problem. Since the silvicultural goal is the reduction of the size of branches, especially in bottom-log of the stem, protection against bark-stripping needs to be developed and cervid population densities controlled to reduce the problem.