Pilodyn方法评估阔叶树种人工林立木的基本密度

Use of Pilodyn tester for estimating basic density in standing trees of hardwood plantation

该文采用Pilodyn设备评估立木的基本密度,以建立一种快速准确预测立木基本密度的方法。首先以我国种植的I-72杨、粗皮桉、尾巨桉和尾叶桉等4种阔叶树种人工林为研究对象,选择立木胸高位置处南北向进行Pilodyn测试,然后在Pilodyn测点位置附近钻取生长锥锥芯,并测定木材基本密度,最后比较立木的Pilodyn测试结果与木材基本密度之间的相互关系。结果表明,在未剥除树皮条件下,使用Pilodyn方法评估立木胸高处外侧的基本密度比整个径向的基本密度更具有优势,其中I-72杨、粗皮桉和尾巨桉的Pilodyn测试结果与外侧的基本密度均存在较好的负相关性,但尾叶桉的Pilodyn测试结果与外侧及整个径向基本密度之间没有显著相关性(P>0.05)。在剥除树皮条件下,粗皮桉和尾巨桉的Pilodyn测试结果与外侧及整个径向基本密度之间均存在显著的负相关性(P<0.001),高于未剥除树皮时的结果;而尾叶桉的相关性不显著(P>0.05)。虽然Pilodyn方法在预测立木木材密度上存在一定的局限性,但通过剥除树皮的方法可显著提高其预测立木外侧及整个径向基本密度的准确性。

The objective of this paper is to introduce and develop a convenient and accurate method for estimating basic density of standing trees by Pilodyn tester. Four hardwood species （ i. e. , Populus euramericana cv. ‘I-72’, Eucalyptus peUita , E . urophyUa × grandis and E . urophylla ） were selected for field test. Pilodyn readings were obtained at breast height of south-north side. The increment core was drilled at the measuring point of Pilodyn for measurement of wood basic density. Subsequently, the relationship between Pilodyn results and basic density was analyzed. The present results indicate that the Pilodyn measurements provide a more reliable and accurate assessment on basic density of outerwood than that of whole radial region for unbarked wood. It was observed that significantly negative correlations between Pilodyn results and outerwood basic density of P. euramericana cv. ＇I-72＇, E. peUita and E. urophyUa × grandis. Poor correlations between Pilodyn results and E. urophylla were showed （ P 〉0.05）. For barked wood, basic densities of outerwood and whole radial region of E. pellita and E. urophyUa ~ grandis had higher negative correlations （ P 〈 0.001 ） with the Pilodyn measurements than that of unbarked wood, however the poor correlations were showed in E. urophylla （ P 〉 0.05）. Although some limitations of Pilodyn tester affect the accuracy, the debarking method can provide better anticipation for basic density of standing tree. It can be concluded that Pilodyn method is a potential way to be adopted for quick, accurate and cost-effective assessment on wood density of standing tree.