Hyggesbränning på Orsa besparingsskog - en studie på tillväxt och föryngring,15år efter etablering

Abstract: The main purpose with this study was to investigate whether the tree growth differs or not in prescribed burnt areas compared to mechanically scarified. Together with the result from the main purpose, answers of whether it's possible or not to combine nature conservation with tree production in prescribed burnt areas was presented. In these areas the regeneration were analyzed to see if there was enough tree plants to comply with the Swedish Forestry Act regulations terms for approved regeneration. A field survey was conducted at 6 objects, three objects for prescribed burning and three for mechanically scarification. All objects were planted within the same year. On these objects plots where put out to collect data on volume growth, height, diameter and numbers of plants. This data was used for making a comparison between the two methods. The results showed a marginally higher volume in areas where mechanically scarification was performed. But prescribed burned areas had a slightly higher tree height and number of stems. As the results shown no major differences in volume growth between the both methods there may well be possible to combine nature conservation with tree production. Previous studies has shown that trees in prescribed burnt areas where provided with much nutrients several of years after the burning. The plants grows well at the beginning but can in a later time in the life cycle decrease in production. This because the ground can suffer from nitrogen deficiency as a result of prescribed burning. This phenomenon can be prevented with the use of nitrogen fertilization.