SEASONAL GROWTH PATTERNS OF SEEDLING HEIGHT IN RELATION TO SEED MASS IN DECIDUOUS BROAD-LEAVED TREE SPECIES

Abstract

Seasonal growth patterns of seedlings in open and shaded conditions were recorded for 31 deciduous broad-leaved tree species. Heavy seed species had a shorter growth period than light seed species to attain their maximum height. Early attainment of maximum height is advantageous to heavy seed species ; establishment in the forest understory, and in small gaps where there is sufficient light, can then occur before the leaf expansion in the canopy layer. Hypocotyl length or height of first leaf of heavy seed species were higher than those of light seed species. With long growth periods, light seed species could attain maximum heights comparable to those of heavy seed species. In shaded conditions, the growth period of light seed species became shorter, and height was lower than that of heavy seed species. Light seed species were assumed to be adapted to growth in open sites where light conditions are more favorable throughout the growing season than in the forest understory.