Reducing predation of conifer seeds by clear-cutting Rubus fruticosus agg. in two montane forest stands

Natural regeneration of forest trees is negatively affected by dense ground cover of brambles (Rubus fruticosus agg.) in montane forests in southwestern Germany. Seed predation by rodents is one potential factor which may reduce establishment of tree seedlings in these sites. In winter and early spring seed predation of two conifers (Abies alba Mill., Picea abies (L.) H. Karsten) was studied in bramble patches and in adjacent cleared plots (6 m×6 m, respectively) in two montane Abies-Picea stands. Losses of seeds from experimental dishes were higher under bramble vegetation than in the cleared plots in both forest stands in winter. Seed predation was consistently lower for Abies than for Picea. The results were similar in early spring. Predation was reduced after adding conifer litter into the dishes. Rodents were responsible for the seed losses, and rodent abundance was lower in the experimental clearings. The results are discussed with respect to natural succession on clearings and its practical relevance in forestry, i.e. clear-cutting of bramble patches as a measure to reduce seed predation by rodents.