火炬松种源木材气干干缩性的变异

１０年生火炬松３１个种源间木材弦向（ＴＳ）、径向（ＲＳ）、纵向（ＬＳ）、体积气干干缩率（ＶＳ）和差异干缩（Ｔ／Ｒ）存在着显著的差异，各个性状的广义遗传力大于６０．５％，环境方差占方差总量的３４．９－＝６３．９％，种源内各个性状的变异大于种源间的变异。３１０棵样木线性相关分析表明在α＝０．０１水平上，树高、胸径、材积与ＴＳ、ＲＳ、ＬＳ、ＶＳ呈显著负要关，与Ｔ／Ｒ呈显著相关；晚材率、基本密度、气干密度

VARIATION IN SHRINKAGE OF AIR-DRY WOOD OF 31 LOBLOLLY PINE PROVENANCES

Statistical differences in tangenial shrinkage percent ( TS ), radial shrinkage percent ( RS ), longitudinal shrinkage percent ( LS ), volume shrinkage percent ( VS ) of wood and the ratio of wood tengential shrinkage to radial ( T/R ) were found among 31 loblolly pine provenances of 10 years old. Each of their broad sense heritabilities was bigger than 60.5%. The proportion of environment factor in each variance pouplation was from 34.9% to 63.9%. Variant degrees of them were greater than that among provenances. Linear regression analyses from the data of 310 trees of 31 provenances for loblolly pine showed that height, diameter at breast height volume of these trees were negatively singnificant correlated with TS,RS,LS,VS respectively, and positively singnificant with T/R ( a =0.01 level); Latwood percent, basic density, air-dry density, and oven-dry density of wood were positively singnificant related to TS,RS,VS respectively, and negatively singnificant to LS,T/R . Compared with the mature wood of loblolly pine, RS and TS of its juvenile wood were smaller, but its LS and T/R were much greater than that of the mature wood. These results aboven mean that selectingfast provenances or individual tree with better provenances which possessess high latwood percent and high wood density in culturing industrial timber is beneficial to reduce LS and T/R of fast grown wood.