‘中山杉118’与落羽杉胸径生长及木材密度的比较研究

【目的】研究‘中山杉118’(Taxodium hybrid ‘Zhongshanshan 118’)和落羽杉( Taxodium distichum)的胸径生长及木材密度差异和变异规律,为‘中山杉118’、落羽杉的品种选育和木材加工利用提供科学依据。【方法】测试‘中山杉118’和落羽杉木材的生材含水率、生长轮宽度以及木材基本密度等指标,分析对比‘中山杉118’木材和落羽杉木材的差异。【结果】‘中山杉118’木材生材含水率靠近髓心心材位置平均为145.86%,心边材交界位置平均为93.69%,靠近树皮边材位置平均为199.68%;落羽杉木材生材含水率靠近髓心心材位置平均为121.32%,心边材交界位置平均为81.93%,靠近树皮边材位置平均为203.84%。‘中山杉118’在第9~14年单株之间生长差别明显拉大,前12年处于快速生长的时期;落羽杉在第7~14年单株之间生长差别明显拉大,前9年处于快速生长的时期。‘中山杉118’木材基本密度平均为0.314 g/cm³,变异幅度为0.292 ~0.346 g/cm³;落羽杉木材基本密度平均为0.332 g/cm³,变异幅度为0.292 ~0.359 g/cm³。【结论】‘中山杉118’木材平均含水率比落羽杉木材大;‘中山杉118’与落羽杉的幼龄期分别为12 a与8 a;‘中山杉118’木材基本密度随年轮的递增呈现先递增后略微减小,落羽杉木材基本密度随年轮的递增呈现径向递减;‘中山杉118’连年胸径生长与木材基本密度存在正相关,落羽杉连年胸径生长与木材基本密度呈负相关。

Comparative study on DBH growth and wood density of Taxodium hybrid ‘Zhongshanshan 118’ and Taxodium distichum

【Objective】In this study, we compared of the increase in diameter at breast height (DBH) and wood density of specimens the Taxodium hybrid ‘Zhongshanshan 118’ with Taxodium distichum, to provide a scientific basis for the breeding of T. hybrid ‘Zhongshanshan 118’ with T. distichum, and document the appropriate processing and utilization of T. ‘Zhongshanshan 118’ and T. distichum wood. 【Method】Five single tree of plantation T. ‘Zhongshanshan 118’ and five strains of plantation T. distichum were collected from a single site, under similar conditions, each single tree was 16 years old. Measurements of green wood moisture content, growth ring width, and basic wood density were recorded and compared. 【Result】The average green wood moisture content of T. ‘Zhongshanshan 118’ was 145.86%, 93.69% and 199.68% for the pith, intermediate wood, and sapwood, respectively. For T. distichum, values were 121.32% (pith), 81.93% (intermediate wood) and 203.84% (sapwood). The increase in diameter at breast height ofT. ‘Zhongshanshan 118’ trees was significantly accelerated from the 9th to the 14th year; in T. distichum increased from the 7th to the 14th year. For the first 12 years of growth, T. ‘Zhongshanshan 118’ specimens exhibited rapid growth; T. distichum specimens grew rapidly for the first nine years. The basic density of T. ‘Zhongshanshan 118’ wood averaged 0.314 g/cm³, but ranged from 0.292-0.346 g/cm³. The basic density of T. distichum averaged 0.332 g/cm³, with a range of 0.292-0.359 g/cm³. 【Conclusion】The green wood moisture content of T. ‘Zhongshanshan 118’ was higher than that of T. distichum. Juvenile wood was produced until the age of 12 and 8 years, for T. ‘Zhong-shanshan 118’ and T. distichum respectively. For T. ‘Zhongshanshan 118’, the radial variation in the width of growth rings increases moving away from the pith until the age of 6 years, and then decreases slowly to a stable value. In T. distichum, the radial variation of the width of the growth rings decreased annually. We found a positive correlation between current growth and wood basic density in T. ‘Zhongshanshan 118’. By contrast, T. distichum samples exhibited a negative correlation between current growth and wood basic density.