The role of phenols in sprouting and wood decay of birches

Abstract

Changes in the total phenol content after coppicing of Betulapubescens Ehrh. were studied in the stumps, basal buds at different stages of growth, and sprouts of various ages to determine the role of phenols in sprouting. The phenol content of the wood at the cut surface of stumps had clearly decreased 24 h after cutting, and another apparent decrease occurred about 2 weeks later, when the suppressed buds on the stump started developing. High phenol levels were maintained the longest in the light wood of the inner parts of the stump, but remained relatively low in the brown, mycelium-containing wood. Total phenol content in the dormant basal buds was highest at the beginning, over 9% of dry weight, but rapidly fell during the bursting of buds and further growth in the sprouts. Total phenol content declined still further in the stumps, sprouts, and seedlings with age. Seasonal changes in phenol content were found in seedlings of both B. pubescens and Betulapendula Roth, with the highest levels occurring in September and March. In general, total phenol content seems to be highest in young, healthy but inactive tissues. In contrast with previous studies, injury was found to decrease total phenol content in the stumps of birches. Development of the basal buds into sprouts is inhibited by phenols, so felling is a precondition for sprouting, as it leads to a decline in the phenol content. On the other hand, a decrease in phenols in the stump seems to diminish sprouting by predisposing it to wood-rotting fungi.