Abstract
Changes of genetic parameters for tree height with stand development were examined on 21-year performance data from 4 open-pollinated progeny tests of Abies sachalinensis in Hokkaido, Japan. Differences in tree height among families were significant on each site, while aniong regions were unclear. Large genotype-environment (GE) interaction was observed. Heritability was highest at the youngest age, and showed a tendency to decrease with stand development. Genetic juvenile-mature correlation was almost always higher than phenotypic correlation. Expected genetic gain in height by early selection was comparable to that by selection at 21 years.