Growth reduction and root deformation of containerized lodgepole pine saplings 11 years after planting

Abstract

Root system architecture and field performance of 90 twelve-year-old lodgepole pine ( Pinus contorta var. contorta Dougl.) saplings, initially raised in containers for one year (1979) before planting, were compared with 60 naturally regenerated lodgepole pine saplings of the same age. The naturally regenerated saplings were significantly taller, and leader increments for 1989–1990 and 1990–1991 indicated that they performed better than the planted saplings during the two most recent growing seasons. Planted saplings displayed root morphologies which differed markedly from their natural counterparts; these included poor structural lateral root symmetry, fewer first order lateral roots, a greater distance from the ground surface to the first structural lateral root, and a greater root collar diameter and concentration of lateral roots 10 cm below the groundline. In addition, root stocks of planted saplings possessed remnants of vertical container shaping and a number of deformed roots that were either constricted, coiled and/or kinked. Naturally regenerated saplings illustrated elaborate sinker root development, and an assortment of self-grafted roots which were not observed on planted saplings. Possible effects of containerization on root morphology are discussed in relation to difficulties which may arise from artificial regeneration of cut-over sites.