GEOGRAPHIC PATTERN OF ADAPTIVE VARIATION OF LODGEPOLE PINE (PINUS-CONTORTA DOUGL) WITHIN THE SPECIES COASTAL RANGE - FIELD PERFORMANCE AT AGE 20 YEARS

A plantation comprising 79 lodgepole pine provenance samples from all four geographic races was established in 1972 at a site on southern Va ncouver Island, British Columbia. Provenance adaptability was assessed in 1991 after 20 growing seasons based on: total height, diameter, su rvival, crown condition, crown density, tree form, western gall rust a nd sequoia pitch moth damage, and principal component (PC) scores deri ved from PC analysis. Regression models depicting geographic trends in adaptive variation accounted for 33% (pitch moth) to 81% (PC1) of pro venance variance. The results showed a strikingly narrow ecological ad aptation of lodgepole pine within its coastal range. Only provenances from a narrow strip along eastern Vancouver Island in the rain shadow zone, with a climate similar to the test environment, showed no sympto ms of declining vigor. Implications in the context of evolutionary sig nificance, genetic resource management, and seed movement are discusse d.