青钱柳胸径生长和木材密度的地理变异规律

【目的】青钱柳是我国特有的单种属植物和具有开发利用前景的珍贵树种,通过探讨青钱柳胸径生长和木材基本密度的地理变异及径向变异规律,为青钱柳材用优良地理种源筛选提供依据。【方法】以天然分布的不同地理种源青钱柳为研究对象,选择群落中的优势木和亚优势木,用生长锥在树高1.3 m(胸径位置)处同一方位钻取单株木芯,共计钻取木芯197条,测定22个地理种源各单株木芯的胸径部年轮生长量和木材基本密度。【结果】22个青钱柳地理种源的胸径生长存在极显著差异(P<0.01)。林龄为20年生时,22个青钱柳地理种源胸径平均生长量为18.6 cm,变幅在16.7～20.9 cm,总体呈现出从西北到东南生长量递增的趋势; 青钱柳的胸径连年生长量在0.69～1.24 cm,随林木年龄递增,其连年生长量在波动中逐渐下降。不同地理种源青钱柳的平均木材基本密度存在极显著差异(P<0.001),22个地理种源青钱柳木材基本密度的平均值为0.470 g/cm³,变幅在0.400～0.510 g/cm³; 不同生长年轮间平均基本密度存在显著差异,其木材的平均基本密度随生长年轮的递增呈现径向递增的趋势,但前18 a其木材基本密度不存在显著差异。相关分析表明,青钱柳胸径生长与木材基本密度间存在显著线性负相关(P<0.05)。【结论】不同地理种源青钱柳的胸径生长和木材基本密度存在显著差异,为青钱柳材用优良地理种源筛选提供了良好空间和可能性。

Regularity on geographic variation in DBH growth and wood density of Cyclocarya paliurus

[Objective]Cyclocarya paliurus,the sole species in its genus,is a highly valued Chinese tree species that possesses multiple functions.The objective of the present study was to investigate the effect of location on variation in the DBH growth and wood density of C.paliurus,in order to establish a basis for location-based selection.[Method] Wood cores were sampled from 22 geographic locations throughout the natural distribution of C.paliurus in China(197 cores in total),and both ring growth and basic density of the cores were measured using traditional methods.Variation in DBH growth and basic density among the sampled locations were then compared.[Result] Extremely significant variation in DBH growth was observed among the 22 C.paliurus provenances (P＜0.01).At stand age of 20,the mean DBH of trees from the 22 locations was 18.6 cm,ranging from 16.7 to 20.9 cm.In general,DBH growth increased from the northwest to the southeast,and the annual change in DBH ranged from 0.69 to 1.24 cm,but gradually decreased with increasing stand age.There was a extremely significant difference in the basic density of core samples from different locations(P＜0.001),and the mean basic density of the cores taken from the 22 locations was 0.470 g/cm3,ranging from 0.400 to 0.510 g/cm3.In addition,the mean basic density of the cores also varied significantly among growth rings and exhibited a consistent pith-to-bark trend in density.However,no significant difference in basic density was observed among the first 18 growth rings.Correlation analysis indicated that there was a extremely significant negative relationship between basic density and annual DBH growth(P＜0.01).[Conclusion] The significant variation observed in DBH growth and basic density of the sampled locations provides a basis for breeding programs interested in improving the growth and wood quality of C.paliurus.