Natural clonal variation of wood extractives in Populus tremuloides
Analysis of the potential genetic variation in quaking aspen (Populus tremuloides Michx.) wood extractives was performed by sampling nine natural clones at breast height. Significant clonal differences were found not only in the levels of total acetone extractives but also in the levels of sterolstriterpenes, steryl esterswaxes, and triglycerides, all of which are known to contribute to pitch formation in pulping and papermaking. In addition, extractive compounds known to elicit toxic effects in aquatic organisms showed statistically significant differences between natural aspen clones. In some cases (e.g., flavonoids), these compounds formed a part of the defense system in the living tree and, thus, were affected in part by the presence of decayed wood.