Omgivningens betydelse för jätteekar (Quercus) : Hur marktyper och befolkningstäthet påverkar storlek och förekomst

Sammanfattning: The oak (Quercus) population has decreased greatly over the past two centuries. Oaks are important habitats for thousands of species dependent on the oak’s special microhabitat, trunk circumference, rising age and dead wood. Urbanization, intensified agriculture and altering land use are examples of threats facing the giant oak. The study investigated whether there is any connection between population density or land type and the giant oak's trunk circumference in Vara municipality. The study used data from Central Bureau of Statistics, the Swedish Environmental Protection Agency and the Species Observation System. The extracted data were analyzed using ANOVA and Tukey HSD, which showed a significant relationship between population density and the size of the giant oak's trunk circumference. The study found no significant relationship between habitat and giant oak trunk circumference. The giant oaks are significantly larger in unpopulated areas than in areas with human population of 1–49 inhabitants per km2. Most giant oaks were found in open areas. The fact that the giant oaks are largest in unpopulated areas is probably due to lack of anthropogenic activities, which has had a positive effect on its growth. The fewest individuals were found in densely populated areas, which suggests that urbanization has a negative effect on giant oaks. As few individuals were found in densely populated land types, it is important that conservation measures focus to prevent overgrowth of important habitats. To preserve giant oaks, further studies should investigate what affects the occurrence and trunk circumference of giant oaks.