Skonsam föryngringsmetodik för bok- och ekskogar - En studie med fokus på Bruces skog i Helsingborg

Sammanfattning: Deciduous forests and especially oak (Quercus robur) and beech (Fagus sylvatica) are very important for biodiversity and provide habitats for many threatened species. They are also good environments for recreation. Bruces forest in Helsingborg is a nature reserve where rejuventation of deciduous forest is a main objective. Hence, this study examined factors influencing rejuvenation, different rejuvenation methods, their advantages and disadvantages, ecosystem impacts and possible implementation in Bruces forest. A literature review and interviews were performed to answer these questions. The main factors influencing rejuvenation was light supply, soil conditions, water supply, climate, vegetation, vicinity to seedling trees, pasture, previous management and pollution. There are three methods for rejuvenation of oak and beech; natural rejuvenation, sowing and planting. Natural rejuvenation is most often used for beech. It is cheap and has a very small impact on the ecosystems but it is not always successful. Sowing is cheaper than planting but more expensive than natural rejuvenation. However it is not used much because of high predation of the acorns and beechnuts. Planting is most often used for oak. It is the most expensive method because fences around the plants and soil scarification are often required. Soil scarification can have negative impacts on the biodiversity if heavily performed. In Bruces forest natural rejuvenation is recommended for beech. Furthermore, the pH-value is very low which might inhibit rejuvenation, hence liming is also recommended. Planting in clusters with fences is suitable for oak. Putting up baskets with acorns for birds to spread and rooting of pigs instead of soil scarification is also recommended. To convert coniferous plantations to deciduous forests planting new trees and thinning out the old stand is recommended.