Kan biologisk mångfald ökas i ett avsatt skogsområde? : skötselplan för Storskogsberget på Holmen skogs marker, distrikt Umeå

Sammanfattning: The biodiversity of the Swedish forest has degenerated since the beginning of the 19th century when fire suppression and large scale logging first occurred. Together with a changed land use, these actions today have had a negative influence on many forest dwelling species, due to gradual reduction of natural processes, successions and different structures from the forest ecosystem. The Swedish Forest Act, together with different environment certifications, have today encouraged private persons and forest companies, among them Holmen Skog, to work actively to improve nature conservation. The aim of this study was to, by field inventories of already existing nature values, literature studies, recommendations from scientific reports and ecological gap analysis as a basis, make a management plan, for a non-production area, to conserve or improve the prerequisites for biodiversity. "Storskogsberget" is located in the coastal area of Västerbotten County, 35 km from the city of Umeå. The area has a 70 hectare pine dominated woodland key habitat that is surrounded by another 200 hectare of conifer dominated forest. I have inventoried conservation values, created a management plan by the help of GIS, quantified the timber volumes out coming from the management actions and also analysed how to increase the recreation values. The inventory of nature conservation values reveals areas with high biodiversity, but to improve biodiversity prerequisites to a higher level, I have planned management actions like 1) make some stands more open, create sunlit stems, reduce the competition between trees, 2) create gaps, to enhance heterogeneity and create new areas where flora and tree seedlings can establish, 3) releasing of pioneer trees, to increase stem widths and also create sunlit stems, 4) precommercial thinning to reduce the understory of spruce, 5) prescribed burning to create a primary succession, create burned wood and lower tree-vitality, and also reduce the ground vegetation, 6) create dead wood or dying trees by tipping, cutting or scarify trees. The action to create dead wood is to be done at the same time as the other actions and on specific places. All actions are planned to be carried out by harvester or by chain saw. Also 7) free development is suggested to parts of the area. The quantified timber volume indicates that I could have planned to create even more dead wood or dying trees, the actions that I have planned now only creates 2,4 m3fub per hectare on the area where actions are proposed. To increase the recreation values I have suggested two paths that will take the visitor to the top of the hill. On the way up there is opportunity to see traces of the past as a tar pit, house grounds and different kinds of culturally modified trees. I consider, by these biodiversity actions, that it definitely is possible to increase the prerequisite for biodiversity in Storskogsberget. I recommend this area to be re-inventoried in about 5-15 years to see if biodiversity has increased and if the goals, according to the retrospective gap analyses and other recommendations, are achieved.