南方红豆杉人工林树干干形异常的诊断及处置

【目的】为培育高质量南方红豆杉干材,提出南方红豆杉人工林干形异常的诊断及处置技术。【方法】在福建明溪通过建立南方红豆杉树干尖削度模型,揭示冠内树干尖削度主导影响因子,确定树干干形异常阈值,进行干形异常处置试验,从而形成完整的树干干形异常的诊断及处置技术体系。【结果】侧枝直径和、侧枝最粗直径、侧枝数量等因素显著影响着南方红豆杉冠内树干尖削度,影响冠内树干尖削度因子重要性由大到小依次为:侧枝直径和S_(BD)、侧枝最粗直径I_(BD,max)、侧枝数量N_(BD)。提出南方红豆杉冠内树干尖削度模型为y=0.296+0.326S_(BD)+0.736 I_(BD,max)+0.011N_(BD),经检验,模型预测效果良好,拟合精度高;树干干形异常阈值为冠内树干尖削度6.84 cm/m;修除树干异常位置的轮生枝,可显著降低树干尖削度,改善树干干形。【结论】树干干形异常的诊断及处置技术体系作为珍贵树种优质干材培育技术,具有操作性强、精确度高等特点,可极大地提高南方红豆杉干材品质,从而为珍贵用材培育提供技术参考。

Early judgment and disposal technology for stem form abnormity of Taxus chinensis var.mairei plantation

Objective] Propose early warning and disposal technology systems for stem form abnormities in a Taxus chinensis var.mairei plantation to cultivate high-quality stems.Methods]The complete early warning and disposal technology systems for stem form abnormities of T.chinensis var.mairei were established in Mingxi County,Fujian Province by optimizing a trunk taper model,thereby revealing dominant impact factors on the trunk taper in the crown.We determined the threshold of abnormal trunks and conducted a disposal test.Results] The results showed that the sum of branch diameters,maximum branch diameter,and branch number significantly affected the trunk taper in the crown of T.chinensis var.mairei with the order of importance as follows:the sum of branch diameter,maximum branch diameter,and number of branches.The optimal trunk taper in crown model for T.chinensis var.mairei was y =0.296+0.326 SBD+0.736 IBD,max+ 0.011 NBD.Model prediction effect and fitting precision were good.The threshold of abnormal trunks in the T.chinensis var.mairei plantation was 6.84 cm/m for the trunk taper in the crown.Pruned whorled branches at abnormal trunk position significantly reduced the trunk taper in the crown,and improved the stem form quality of T.chinensis var.mairei.Conclusion] The early warning and disposal technology system for stem form abnormities (highquality stem cultivation technology for valuable trees) had strong operation and high accuracy,and could greatly improve lumber quality of T.chinensis var.mairei,and provide a technical basis for cultivating valuable timber.