THE EFFECTS OF TAPHRINA-BETULINA INFECTION ON GROWTH OF BETULA-PUBESCENS

The impact of infection by Taphrina betulina on the growth of Betula pubescens was studied in naturally regenerated stands in the North East of Scotland. Infection by T. betulina was associated with a significant reduction in height growth and poorer developmental tendency, vigour, and stem quality of B. pubescens, whereas diameter at breast height was little affected. Tree height was reduced by an average of 25% over all diameter classes, with the greatest effect in smaller trees. For brooms of 100 mm diameter and over, numbers and sizes were strongly correlated with diameter at breast height and tree age. Reductions in height and vigour were not correlated with the number and size of brooms present, but were more pronounced in younger, smaller trees.