Epsilon Archive for Student Projects

Abstract

Managing tree heights near powerlines via helicopter topping has been a new subject of interests to forest owners and the energy sector. However, tree topping may have consequences on tree growth and tree health, as well as economic ramifications. This thesis aimed to evaluate the effects of heli-copter topping on tree growth and the possible occurring economic losses.
On four locations topped and not-topped trees were selected and felled. Stem samples in form of discs were taken at specific heights, polished and used to measure tree rings. The tree-ring data was then analysed in R. Other stem samples were used to check for occurrence of pathogenic fungi.
The results showed that spruce trees are affected by topping, while pine trees are not. An analysis regarding the influence of pathogenic fungi showed occurrence of infection, but no influence on volume growth. Economic losses could be calculated for both species. Monitoring of topped trees for a longer time after topping and a larger sample size is recommended for better understanding of growth- recovery, influence of fungi infections and the effects of climatic factors like increased temperature and water stress on tree performance.