Chemosystematic studies in the genus Pinus. VI. General survey of the leaf oil terpene composition of lodgepole pine

Abstract

The leaf terpene composition of 645 individual lodgepole pine trees and 79 bulked samples from 111 different sites or provenances and from one putative and three western jack pine populations (10 trees each) were analyzed by gas chromatography. Numerical analysis by a centroid cluster analysis of the mean squared Euclidean distances was carried out, and percentile distributions of the individual terpenes were plotted. The data obtained confirmed the previous subdivision into the major terpene pattern types A, B, and C (or H) and five subgroups (based on the high modes in bimodal distributions); four additional subgroups were added. Except for typical coastal populations, inter- and intra-populational terpene pattern variation was high. Centroid clustering and assignment of terpene types and subgroups lead to some distinct geographical groupings. Coastal populations (ssp. contorta) were found to be rather unifornm and only a minor difference appears to exist between northern and southern populations. Those near Haines, Alaska, the Skeena Valley, southeastern Vancouver Island, and the Puget Sound showed intermediacy with interior (ssp. latifolia) stands. The Fort Bragg (ssp. bolanderi) and Samoa populations from northern coastal California contained many trees with unique terpene patterns. The interior populations (ssp. latifolia) were highly variable and inverse frequencies of the type A (high near the coast) and type B (high in and near the Rocky Mountains) were recorded in several west-east transects. Introgression with jack pine, as measured by the frequency of type C/H patterns, was extensive in northeastern Alberta and the Peace River area of British Columbia. However, some difficulty in describing recent introgression was encountered. A unique (possibly archaic) population was encountered at Petitot River. The ssp. murrayana from the southern Cascades of Oregon and northern California could not be distinguished from ssp. latifolia further north by the terpenoid data.