Abstract:

Several Schima superba pure stands and S. superba-Chinese Fir mixed stands afforested during 1968-1997 were selected to study the effect of slope position, slope direction and mix planting with Chinese Fir on growth and wood basic density of S. superba plantation in Jian'ou, Fujian Province. The results revealed a significant effect of slope position and slope direction on the growth and stem form of S. superba, but lower effect on wood basic density. The increment of crown and height was enhanced, and stem form was improved at sunny slope and down-slope, compared with shady slope and mid-slope, whereas DBH increment was higher in shady slope with higher soil water content. When S. superba were mixed with Chinese Fir at appropriate ratio(such as the ratio of 1 :3), stem form and the growth of DBH, height and crown all were improved significantly. The probability of stem forking(SF) of S. superba was fluctuating within 22.50%-35.75%, which mainly was single fork lower than 0.5 m. In pure stands on sunny slope or down-slope and mixed stands(ratio of 1 :3), the probability of stem forking was lower. Moreover, slope position had larger influence on stem fork formation than slope direction. The wood basic density was gradually decreased from pith to bark, was decreased sharply from 15^th to 20^th rings, and reached the minimum during 35^th to 40^th rings. The reduction velocity of wood basic density from pith to bark was increased with the increasing of the diameter increment. The ring width was increased at first and followed by a reduction, with the largest wood formation speed during 5^th to 15^th rings. Accordingly, it was proposed that S. superba plantations should be build on sunny slope and down-slope which had better condition of water, fertility and light. Based on the result, mixed planting at appropriate ratio,enhancing removing buds and shoots of young stand as well as tending and thinning of middle-age stand was proposed to control the stem fork formation, improve the diameter growth and promote plantation productivity in medium-later period and radial homogeneity, and finally obtain the cultivation objective on fast-growing and high-quality craft timber stands.

Key words: Schima superba, plantation, site conditions, mixed planting, growth, wood basic density