青冈栎人工林树高曲线模型研究

2021-04-01 09:41:39王怡汤景明孙拥康
森林工程 2021年1期

王怡 汤景明 孙拥康

摘 要:为研究青冈栎人工林树高和胸径的生长关系模型,以九峰国家森林公园的青冈栎人工林为研究对象,将484组树高和胸径数据分成建模数据和检验数据,选用10种常见树高曲线模型分别对建模数据进行拟合。结果显示,10种树高曲线模型均达到极显著水平(P<0.01),其中二次曲线模型的残差平方和(SSE)、均方根误差(RMSE)最小,决定系数(R2)最大,符合最优模型的筛选原则,最优模型的残差分析无异常值出现,并且将检验数据代入最优模型得到的树高预测值和实测值之间也无显著差异(Sig.= 0.159>0.05)。结论表明,二次曲线模型可以对青冈栎人工林树高进行有效预测。

关键词:青冈栎;胸径;树高曲线;模型研究

中图分类号:S758    文献标识码:A   文章编号:1006-8023(2021)01-0001-05

Abstract:In order to study the growth relation model between tree height and DBH of Cyclobalanopsis glauca plantation, Cyclobalanopsis glauca plantation in Jiufeng National Forest Park was taken as the research object. 484 groups of tree height and DBH data were divided into modeling data and test data, and 10 common tree height curve models were selected to fit the modeling data respectively. The results showed that all the 10 tree height curve models reached extremely significant level (P<0.01), among which the quadratic curve model had the smallest SSE and RMSE and the largest R2, which accorded with the screening principle of the optimal model. The residual analysis of the optimal model showed no significant difference, and there was no significant difference between the predicted and measured tree height values obtained by substituting test data into the optimal model (Sig.= 0.159>0.05). The conclusion showed that the quadratic curve model could effectively predicted the height of Cyclobalanopsis glauca plantation.

Keywords:Cyclobalanopsis glauca; DBH; tree height curve; model research

0 引言

樹高和胸径是森林调查和经营过程中最基本的测量因子,是用来计算材积、立地指数以及预估林木生长和收获的重要数据[1]。在实际调查中,胸径属于易测因子,而树高的获取则相对困难,且精度不高。通过建立树高曲线模型,对胸径和树高的相关关系进行描述,利用胸径准确预测树高,对于生产实践和科学研究都具有非常重要的意义[2-3]。

青冈栎(Cyclobalanopsis glauca)属壳斗科青冈属,是良好的珍贵用材树种,其适生范围广泛,是我国亚热带常绿阔叶林带的主要优势树种和造林树种[4]。当前已有许多关于各树种树高和胸径相关模型的研究[5-7],但未见有关青冈栎树高和胸径模型的研究报道。本研究以青冈栎人工林为研究对象,以树高和胸径实地调查数据为基础,建立青冈栎树高-胸径模型,以期能为该地区青冈栎的经营和研究提供科学依据。

1 研究区概况

研究区位于武汉市九峰国家森林公园,地处武汉市东郊,距武汉市中心12 km ,地理中心位置为114°29′50" E, 30°31′4" N,占地面积约330 hm2。……

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