Patterns of Monoterpene Variation within Individual Trees in Ponderosa Pine

We surveyed variation in both the concentration and composition of monoterpenes in six tissues within individuals of ponderosa pine to determine (1) whether variation exists between different tissues; (2) whether variation occurs between samples from the north and south sides of the tree within a tissue, and (3) whether composition of one tissue is correlated with that of others. Wood, roots, and resin exuded from the trunk have similar monoterpene compositions within trees. Phloem and cones contain a higher proportion of -pinene with less carene than resin, while needles are distinguished by high proportions of -pinene. Samples of the same tissue taken from the north and south sides of the tree differed little and were strongly correlated. Correlations were moderate across tissues within the groups sharing similar monoterpene compositions (e.g., phloem vs. cones), but correlations between tissues in different groups were weak (e.g., phloem vs. needles).