Rumslig fördelning av grov gammal tall i Uppsala stad med tallticka som indikator på höga naturvärden

Sammanfattning: Fragmentation and reduction of forest area is a threat for many forest species and their habitat. Deficiencies in forest quality, such as lack of dead wood and old trees, are one explanation of the threat. The most important action to prevent the continued loss of forest types is to protect forest, but also to restore and to create areas that not previously had high nature values. Hence one of the key strategic roles for Fritid- och Naturkontoret, Uppsala municipality, is to monitor biodiversity in the context of urban planning. The majority of the Uppsala municipality residents live in urban areas and most of them spend some of their spare time in natural areas in cities and their immediate surroundings. Exploitation in and around Uppsala is high, but it is important that there is enough nature close to houses to meet the residents' needs of recreation. In order to have an adequate amount of recreation area available in the future, there is a limit to how much you can allow the green areas to disappear. Old pine Pinus silvestris stands are characteristic for Uppsala and are preserved in the town and its surroundings. Old coarse pine is a particular responsibility of the municipality's nature conservation actors because they are rare in the rest of the landscape. The fungus Phellinus pini is a species that signals forests with high conservation nature values which require special care. Phellinus pini establish on pine when the tree have formed heartwood and thus reached the age of c. 100 years. At that advanced age habitat pine often houses many rare and red listed species of e.g., insects. The aim of the study was to investigate the spatial distribution of coarse old pine in Uppsala city, with Phellinus pini as an indicator of urban natural areas of pine with high nature values. This was done by examining the spatial distribution of pine stands and environmental variables that affect the presence of Phellinus pini. All pine stands, a total of 97, in the study area were inventoried with respect to age, density of trees, quantity of young broadleaves, the presence of pine regeneration and Phellinus pini. With binary logistic regression the effects of the environmental variables and connectivity were tested. Pine exists in the whole study area, Uppsala city, with concentration to the esker Uppsalaåsen. Phellinus pini occurs in one third of the stands. The probability of occurrence of Phellinus pini increased with increasing age, and with increased density of pines in the stand. Increased proximity to other stands of pine with presence of Phellinus pini also increased the probability of occurrence of Phellinus pini. 75% of the stands have no pine regeneration while the other 25 % contained 1100-7700 regeneration pine trees per hectare.