湿地松纸浆材材性变异的研究

本文报道了湿地松纸浆林管胞长度和长宽比、基本密度和化学成分的变异规律。管胞长度、长宽比、基本密度和纤维素含量径向由髓心向外都呈递增、稳定的模式,8—10年后趋于稳定;木素、多缩戊糖含量在径向上表现出递减、稳定的模式,10—12年后趋于稳定。树干纵向,管胞长度、长宽比由基部向上先增加而后递减,木材基本密度则呈递减的模式。湿地松木材幼龄期为10年左右,其幼龄材管胞长度短、长宽比小,基本密度小,纤维素含量较低,木素及多缩戊糖含量高。基于湿地松木材管胞形态、基本密度和化学成分含量等纸浆材原料工艺技术指标要求,确定湿地松纸浆林最低主伐林龄12年左右。

VARIATION IN WOOD CHARACTERISTICS OF SLASH PINE FOR PULPWOOD

The variation in tracheid length. specific gravity and composition of slash pine for pulpwood were reported in this paper. In radial direction. tracheid length. specific gravity and cellulose content of wood increase from pith outward, and level off after 8 to 10 years old; Lignin and pentosan content decrease from pith to bark. and level off after 10 to 12 years old. Along the stem height, tracheid length first increase. then decrease; and specific gravity decreases from base upward. The radial and axial variations of tracheid length-width ratio within tree is similar to the pattern of tracheid length. Based on radial variation of tracheid length and specific gravity at 1.3m height within trees. the duration of juvenile peroid is determined about 10 years old. The juvenile wood of slash pine is characterized by shorter tracheid length. lower specific gravity. higher lignin and pentosan content, lower cellulose content than mature wood.Based on variations in the whole tree's tracheid length. tracheid length-width ratio, tracheid wall thickness-diameter ratio, specific gravity. and chemical content, the shortest havesting age of slash pine for pulpwood is about 12 years old.