Some Effects of CO2, Daylength and Nutrition on the Growth of Young Forest Tree Plants I. In the Seedling Stage

Abstract

An experiment was carried out to investigate the possibilities of accelerating seedling growth in three of the most important forest tree species by increasing CO ₂ concentration, daylength and nutrition. Doubling the frequency of application of a standard liquid feed increased plant height by 8–10 per cent but extending the daylength to 18 h had only a small initial effect which was not sustained. Increasing the CO ₂ concentration significantly increased growth in both Sitka spruce and lodgepole pine but similar increases with Corsican pine were not statistically significant. The results indicated that under the conditions of the experiment the tree height normally achieved after 16 weeks could be attained in 14 to 15 weeks by increasing the CO ₂ concentration fourfold.