Survival, height and health status of 20-year-old Pinus sylvestris and Pinus contorta after different scarification treatments in a harsh boreal climate

altura arbre forestier date de plantation enfermedades fungosas forest health forest plantations forest trees fungal diseases godronia hauteur height maladie fongique neige nieve pinus contorta pinus sylvestris planting date sanidad de los bosques scarification snow suecia supervivencia survie survival sweden