尾叶桉纸浆材化学成分等在树干高度上的变异

分析了５个试验地尾叶桉纸浆材的主要化学成分含量和ｐＨ值在树干高度上的差异和变化趋势．结果表明，在５个试验地中，尾叶桉材的化学成分含量及ｐＨ值在树干高度上的变异情况大致相同．在不同的树干高度上，木材热水抽提物含量、纤维素含量和木素含量的差异达１％显著性水平；质量分数为１％ＮａＯＨ抽提物含量和戊聚糖含量的差异达５％显著性水平；冷水抽提物含量和ｐＨ值无统计上的显著性差异．由树基向上，冷水抽提物、热水抽提物和木素的含量呈渐低趋势；戊聚糖含量和木材ｐＨ值呈渐高趋势；１％ＮａＯＨ抽提物含量树干中部较低，两端较高；纤维素含量树干中部稍高，两端稍低．

Variation of Chemical Component Contents and pH Value in Eucalyptus urophylla Pulpwood along Tree Stem

Variation of chemical component contents and pH value along tree stem were analyzed for Eucalyptus urophylla pulpwood from 5 plots.Results indicate that the sampled trees from the 5 plots showed a similar variation tendency.At different heights along tree stem,the differences for hot water extractives,cellulose and lignin contents arrived at 1% significance level;that for the content of 1% NaOH extractives arrived at 5% significance level;content of cold water extractives and pH value showed no significant difference in statistic sense.Going upwards from bottom of tree stem,contents of cold water extractives,hot water extractives and lignin tended to decrease;pentosan and pH value tended to increase;content of 1% NaOH extractives was higher around the middle of tree stem,lower at the two ends;and cellulose content,slightly higher around the middle and lower at the ends.