PERFORMANCE OF RED ALDER SEED SOURCES IN FRANCE

We report on a series of 7- and 8-year-old genetic trials of red alder (Alnus rubra Bong.) planted in France as an initial exploration of it s growth potential and genetic needs. Red alder is native to the Pacif ic Northwest coast of North America. Seed for the French plantings was collected in four Pacific Northwest river drainages (Santiam, Nisqual ly, Nooksack, and Hoh), which cover a wide latitudinal and elevational range. Of the four sites at which the red alder seed was planted, the best growth was observed at Rouvray in northwestern France, a site wi th deep sandy soil and adequate summer precipitation. Growth here was above average for red alder in its native habitat. Poor soil drainage at the other three test sites resulted in much poorer performance. Tre es from Santiam River seed sources were generally the poorest performe rs at all test sites; the source river(s) for the best performing tree s, however, varied by test site. Comparing performance of trees from t he same source drainage, elevation of seed collection location correla ted at best only weakly with growth; the level of nonsystematic variat ion was high. Regression on principal components derived from seed col lection location environmental variables indicated that the best growt h performance was associated with seed sources from warmer areas with low moisture demands. In general, this combination of climate conditio ns exists in low-elevation coastal areas; in this study, all seed coll ection locations fitting this description were in northwestern Washing ton state.