Performance After Planting of Four Types of Container-grown Lodgepole Pine Seedlings

Abstract

Four types of container-grown lodgepole pine (Pinuscontorta Dougl. var. latifolia Engelm.) seedlings differing in age and rearing regime were transplanted into a controlled laboratory environment and into the field. After 12 weeks, seedlings were excavated and stem length and dry weight of shoot and roots were measured, these and derived parameters were compared with values obtained at the time of planting. Survival was uniformly high, the largest seedlings prior to planting performed best under all conditions. In the controlled environment experiment, initial shoot weight, total weight, and ratio of shoot weight/shoot length were significantly correlated with final root weight, an important factor in initial establishment; in addition shoot and total weight increment were significantly and positively correlated with initial shoot/root ratio. In the field no overall significant correlations were obtained. Shoot/root ratio decreased slightly in the controlled environment and significantly in the field after outplanting. Results suggest that the largest plant which can be grown and planted economically shows largest increment and achieves largest final total dry weight and root dry weight in the first growing season after outplanting. The need for a physiological rather than morphological grading of seedlings is stressed.