马尾松种子园2个无性系木材密度变异规律

在22年生马尾松（Pinus massoniana）初级种子园中选择2个无性系：桂GC427A和桂GC557A各3株伐倒,利用圆盘取样法于1.3m、5m和10m近伐根面各取厚3cm圆盘样品,采用最大含水量法测定纵向1.3m、5m、10m,径向外层、中层、内层的木材生材密度和基本密度共18个密度指标,研究其径向和纵向木材密度的变异规律。结果表明,木材密度径向变化表现为外层〉中层〉内层,纵向5m〉1.3m〉10m;径向中层的木材密度最接近平均密度,径向外层的木材密度与平均密度相差最远,不宜作为马尾松无性系的选择指标;2个无性系的径向和纵向均匀性均达0.93以上,具有良好的木材均匀性,幼龄材与成熟材的差异较小,其中以桂GC557A为优。

Variation Patterns of Wood Density on the Two Clonal Seed Orchard of Pinus massoniana

Three trees were cut down in each of two clones(GuiGC427A and GuiGC557A) from the primary seed orchard of Pinus massoniana in 22 years old.Disk method of sampling was used to get the disks from a tree in different high levels,including 1.3m,5m and 10m from the tree bottom,with the thickness of 3cm.The maximum moisture content was used to measure the green density and basic density of those disks in longitudinal and radial directions.We studied variation patterns of the radial and vertical wood density for different clones.The results showed that the radial variation patterns of wood density were very clear with inner 1.3m>10m.The radial middle wood density was closest to the average density levels of families,but the radial outer wood density cannot serve as an indicator for the selection of masson pine clones.The radial and vertical uniformity of two clones was good,and exceeded 0.93.There were less differences between juvenile woods and mature woods,of which GuiGC557A was superior.