Changes in chemical constituents in the sapwood of Pinus sylvestris due to debarking

To induce lightwood formation, the stems of three Scots pine (Pinus sylvestris L.) trees were longitudinally debarked, leaving a 10-cm bark bridge. Increment core samples were taken on different occasions and, as a response to debarking, a statistically significant increase in the concentrations of resin acids, oxidized resin acids, fatty acids and pinosylvins was observed on at least one sampling occasion. At the end of the first growing season, i.e. 10 weeks after debarking, the highest concentrations of compounds were observed in the lightwood opposite the bark bridge, except for pinosylvins and resin acids were statistically significantly increased. The amounts of soluble sugars and lipids decreased significantly.