Variation in early growth and survival of Pinus ponderosa provenances established in Southern Chile

Abstract

Pinus ponderosa P. & C. Lawson was introduced in Chile as a promising species for the diversification of the forest productivity and to optimize the soil productivity in areas where the traditional species have failed to develop satisfactorily; however, the introduction of exotic species in a new environment requires the selection of appropriate source of seeds as a first step for long-term breeding. In this study we assessed growth and survival on 30 Pinus ponderosa provenance seedlots from the Pacific and North Plateau races in the United States established in a common-garden experiment. The study included 3 seedlots from the coastal and inland regions of Washington State, 20 from Oregon, and 7 from California. Seedlings were planted in 2002 in a site characterized by high rainfall and snow. Tree height, root collar diameter, and survival were recorded, and a stem volume index calculated, at ages 1, 3, and 6 years since planting. At age 6 years, the best provenance seedlots from the Pacific race averaged 696 cm³ year⁻¹ for stem volume index and 0.36 cm year⁻¹ for height. The slowest-growing seedlot, of the North Plateau race, averaged 197 cm³ year⁻¹ for volume index and 0.22 cm year⁻¹ for height. Differences in survival were not large, ranging from 85% for a seedlot from interior Oregon to 98% for a Californian provenance. At age 6 years, the average survival across all seedlots was 91%, suggesting good adaptation of the species to the site conditions. The study suggests that provenances of the Pacific race could provide appropriate planting material for forest plantations in Southern Chile.