Chemosystematic studies in the genus Pinus. V. Variation in the leaf oil terpene composition of young and old lodgepole pine trees from different moisture regimes near Prince George, British Columbia

Abstract

The leaf oil terpene composition of lodgepole pine stands from contrasting moisture regimes (400–1200 mm precipitation) within upland and bog sites in the Prince George area of central British Columbia was investigated. In addition to the terpene patterns recorded previously, a new one with relatively high percentages (5–28%) of the terpinene group was found. This pattern was encountered mainly in old trees with very low yields (less than 0.1%) of volatile oil, especially in trees from shaded stands. The absence of resin canals in the leaves of such trees may be the reason for the low yields, but the reason for the link with relatively high terpinene group percentages is obscure. Young trees growing in the vicinity of such stands had mainly the normal patterns. No differences between upland and bog sites or dry and wet sites were found in young trees. Hence, old trees from bogs or wet sites east of Prince George provided progeny with the normal terpene patterns, even though many of the old trees have the new terpene pattern. Samples from two 12- to 13-year-old provenance trials originating from west and east of Prince George had terpene patterns similar to those of the young trees from the natural stands.