En objektiv metod för att bestämma läplanteringars läverkan

Sammanfattning: An objective method for calculating shelter effect of shelter belts - The projekt describes a method for objective classification of shelter effect for natural shelter belts. lt is aimed at producing a number of diagrams from which the shelter effect of a natural shelter, with a photographically determined porosity, can be predicted. Measurements of shelterbelt porosity has been made by analyzing black and white photographs with a computer aided image analyzing system (EBBA). The measured sheltereffect from a number of shelterbelts was correlated with the photographical porosity at six points with increasing distance from the shelterbelt. It was found that the correlation was good, and for every scattergram a regression-line with determined confidence limits was calculated. It has been shown that prediction can be made with acceptable accuracy at distances 5 ; 7,5 ; 10 ; 12,5 and 15 h from the shelter.