Field Performance in Southeast Alaska of Sitka Spruce Seedlings Produced at Two Nurseries

A study of nursery stock performance was conducted on four sites in the Tongass National Forest in southeastern Alaska: two sites at Fire Cove (Ketchikan Ranger District [R.D.]) and one each at Anita Bay (Wrangell R.D.) and Eight Fathom (Hoonah R.D.). Containerized Sitka spruce seedlings used in the study were grown at USDA Forest Service nurseries in Petersburg, Alaska, and Coeur d'Alene, Idaho, from seed sources appropriate for each of the three locations. Seedlings from the Petersburg nursery were taller (33 centimeters versus 18 centimeters) and had greater shoot dry weights (1.51 grams versus 0.67 gram) than those from Coeur d'Alene; however, seedlings from Coeur d'Alene had a more favorable shoot-to-root ratio (2.1 versus 4.3). Survival after the first growing season exceeded 96 percent for all seed sources and sites. After three growing seasons, survival for the local seed source at each site ranged from 71 to 98 percent for the trees from Petersburg and 52 to 93 percent for trees from Coeur d'Alene. Cause of mortality differed among sites: animal damage was most important at the Fire Cove sites and frost damage was most important at the Eight Fathom site. Initial seedling height was greater for the Petersburg seedlings, a difference that still existed after three growing seasons. Third-year height growth of the Coeur d'Alene seedlings was equal to or greater than that of the Petersburg trees; thus, the difference in mean total height between seedlings from the two nurseries decreased during the 3 years. Our preliminary conclusion is that seedlings intended for outplanting in southeast Alaska can be grown in nurseries in the Pacific Northwest if appropriate Alaska seed sources are used.