The introduction of exotic tree species with special reference to Pinus contorta in northern Sweden : review and background

摘要: The background to the large-scale planting of Pinus contorta in northern Sweden is reviewed with an account distribution and characteristics within its natural range western North America. Swedish Forestry Act 1979 places restrictions on programme contorta. threats successful exotics are discussed relation historical background. Attention also drawn parasitic fungi which infecting Canada, potential threat they represent indigenous sylvestris Sweden.