Comparative Growth and Development of Planted and Natural Stands of Jack Pine

Abstract

This study compares growth yield, and stem quality differences at age 21 between plantations spaced at 2.13 × 2.13 m (2204 stems/ha) and 4.27 × 4.27 m (548 stems/ha), and a nearby natural jack pine stand of identical age (initial density of 29 800 stems/ha). Merchantable volume/ha was greatest at the 2.13 m spacing, followed by the less dense plantation and natural stand. Total volume/ha (trees > 1.3 m height) was also greatest in the 2.13 m plantation, followed by the natural stand and the 4.27 m plantation. Individual tree mean merchantable volumes decreased with increasing density. Height growth decreased with increasing density. Height 4.27 m plantation relative to the 2.13 m plantation. Stem quality of the natural stand was markedly better than in both plantations. A comparison of an older natural stand and a plantation in the same area suggests that superiority of tree form of denser natural stands will continue through to rotation. High mortality in the natural stand was largely the result of snow and ice damage which caused patchy and irregular stocking. These results imply that widely spaced plantations of unimproved jack pine will produce large individual tree sizes, but at the expense of quality. Key words: Pinus banksiana, plantations, natural stands, stem quality growth and yield, stand density, mortality, spacing, silviculture.