DEVELOPMENT OF PLANTED PINUS-SYLVESTRIS AND P-CONTORTA AFTER SOIL PREPARATION IN A NORTHERN CLIMATE

Survival and height development of planted Scots pine (Pinus sylvestris L.) and lodgepole pine (P. contorta Dougl. ex Loudon) were followed during a 13-year period in a soil preparation experiment in northern Sweden. The experiment comprised three soil treatments: no scarification, patching, and mounding. The results indicated that the duration of the positive effects of the soil treatments on survival and height growth was at least 13 years. Mounding resulted in the highest mean heights for both species, but the dominant height for lodgepole pine seemed to be less influenced by the type of soil treatment than seemed the dominant height for Scots pine. No scarification led to significantly higher survival and dominant height for lodgepole pine than for Scots pine. The results do not support the hypothesis that Scots pine saplings run an increased risk of dying when they start emerging above the prevailing snow cover. The reason is probably that the Scots pine provenance used is well adapted to the local conditions.