XYLEM FLECKS: A NOTE ON SOME UNEXPLAINED ABNORMALITIES IN THE WOOD OF EUROPEAN LARCH AND OTHER TREES

Summary Small patches of abnormal tissue in the wood of European larch, termed xylem flecks, are described. They are particularly prevalent in the wood formed in the penultimate internode. Similar tissues were also seen in four other tree species. Fleck formation varied from year to year. Although xylem flecks resemble the tissue abnormalities associated with frost damage, it seems unlikely that their causation is climatic. All larch trees suffering from epidemic dieback contained xylem flecks and the possibility of an association with adelgid infestations is discussed. It is concluded that the flecks may have been a response to stress conditions, although a positive correlation in one tree between numbers of flecks and annual radial increment indicated a less simple explanation.