The analysis of thinning effects and climate change on stand development in certain scotch pine (Pinus sylvestris L.) populations

Scotch pine (Pinus sylvestris L.), one of the most important primary forest tree species in our country, is of great value in the forest products industry as its wood has a wide range of uses and it is the main species in high mountain forests. For the sustainability of the species, durable and healthy forests should be created by applying maintenance techniques according to age and bonitet differences. Plots were sampled according to age and bonitet differences to determine the response of normal (centre) and marginal (edge) populations to climate change and to make silvicultural projections. The study plots were selected from pure and natural stands where Scotch pine is distributed and subjected to different levels of thinning and are located within the boundaries of the Trabzon, Giresun, Amasya, Kayseri, Erzurum and Artvin Regional Forestry Directorates. In these stands, stand establishment was determined by quantitative measurements and growth and development relationships were determined by stem analysis and graphical methods as both diameter and height dependent functions. In order to reveal the effects of climate change on the studied Scotch pine stands, the areal status of the Scotch pine stands was estimated at certain time intervals using climate scenario models. Geographical Information Systems (GIS) and advanced modelling techniques were used to determine the ecological niche and habitat selection of Scots pine and to analyse the determining effects of environmental variables on the distribution of the species. The high predictive power of the applied models allowed to identify possible spatial changes between the periods 2020-2040, 2040-2060, 2060-2080 and 2080-2100 and to determine the future potential distribution areas of Scots pine stands.