PROCEEDINGS EDITORS Tom Morén Lena Antti Margot Sehlstedt-Persson Editor’s Note Authors are responsible for the quality of their paper. Neither IUFRO nor the Luleå University of Technology shall be responsible for statements and opinions advanced in this publication. Additional copies may be obtained by contacting LTU Skellefteå SE-931 87 Skellefteå, Sweden Phone: (+46)910-58 53 00 Email: marseh@ltu.se