油松木材幼龄期与株内幼龄材分布

THE JUVENILE PEROID OF WOOD AND DISTRUBUTION OF JUVENILE WOOD IN STEMG OF CHINESE PINE

The demarcating criterions and error viewpoints as regrads to the juvenile period of wood were discuseed in this paper. Variation in the radial direction of fiber or the tracheid length and specific gravity' of trees within 1.3m of height were proposed to be used synthetically as the demarcating criterons for determining the juvenile peroid of Wood. Based on the radial variations of anatomy features (tracheid length, fibril angle), physical properties (specific gravity, coefficient of shrinkage of radial and tangential), mechanical properties (compressive strength parallel to the grain, modulus of rupture, tensile strength, modulus of elasticity in static bending) at a given level in the stems of Chinese pine, the juvenile period of wood decreased noticeably from base to top of tree, th volume of juvenile wood decreased in a similar patten. The deereaseing trends had a strong negative correlation with the increasing age of the cambial initial. The juvenile period of the Chinese pine is about 14 years old.