樟树人工林株间株内材性变异及其材性预测的研究

VARIATION OF WOOD PROPERTIES WITHIN AND BETWEEN CAMPHOR TREE PLANTATION AND THEIR PREDICTING MODELS

樟树人工林株内纤维长度径向变异由髓心向外递增 ,而后趋于稳定 ;木材基本密度髓心处稍大 ,由髓心向外先稍递减而后递增 ,再趋于稳定 ;纤维长度和基本密度性状与生长轮年龄关系模型可用来预测其性状值。樟树木材幼龄期约为 7～ 9a ,株内幼龄材基本密度较成熟材小 1.0 %～ 9.9% ,株内幼龄材与成熟材基本密度差异多不显著 ;其浸提物含量幼龄材与成熟材之间差异不显著。纤维长度株内变异系数大于株间 ,木材基本密度均值和浸提物含量二性状则是株间变异大于株内变异。生长速度对樟树木材纤维长度、基本密度、浸提物含量等性状影响不显著。

Fiber length within trees of plantation of Cinnamomum camphora increases from pith to bark in radial direction and it levels off after the 10～11 rings. Wood basic density decreases from pith to the 4 th ring, then increases gradually and levels off after the 9 th ring to bark in radial direction. The relationship model of fiber length (FB) of camphortree to tree age (x) is FB=626+73.5661x+0.4171x2-0.3639x3+0.0157x4-0.0002x5 (r2 =0.9545, 1x40) and that of wood basic density (BD) is BD=0.4674306/[1+0.095907x3·EXP (-0.1306871x)] (r2=0.8059, 1x40). Variation of fiber length within a given tree of Cinnamomum camphora is greater than that between trees. Variation of wood basic density and hot-extracts content are distinctly different from fiber length and their variation between trees are greater than those within a given tree of camphor. Juvenile wood range of camphor trees is within 1～7 th or 1～9 th rings near pith. The significant difference of fiber length between juvenile and mature wood within a given tree of camphor was found. No clear differences were found in wood basic density and hot-extracts content between juvenile and mature wood. Growth rate has no distinctly negative effect on fiber length, basic density and hot-extracts content of camphor tree. Variation of wood properties within camphor trees is very small and there is great variation of wood properties between the trees. Stem form of camphor trees is not straight and often lean in stand. Additionally there is more serious interlocked grain within trees. Controlling tree stem form and better its interlocked grain are main ways to improve wood properties of camphor trees through silviculture and tree genetic breeding.