JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 2017, Vol. 60 ›› Issue (02): 111-116.doi: 10.3969/j.issn.1000-2006.2017.02.016

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Monthly distribution of tree volume growth rate based on continuous monitoring data of fixed sample plots

TAO Jixing, WANG Wenwu, XU Da, ZHANG Guojiang, JI Biyong, WU Weizhi, TAN Ying   

  1. Center for Forest Resources Monitoring of Zhejiang Province,Hangzhou 310020,China
  • Online:2017-04-18 Published:2017-04-18

Abstract: 【Objective】In the wake of the shorting cycle and the reducing area of the forest resources monitoring, the precision monitoring became inevitable and the error control became the focus of the forest resources monitoring. 【Method】In this study, we used continuous monitoring results of fixed sample plots from 2004 to 2015 in Zhejiang Province as key data sources. These data were classified into 12 study groups based on four types of tree species(pine, Taxodium, hard and soft broad-leaved tree species)and three diameter at breast height(DBH)classes(small, medium and large). Furthermore, an entire year was classified into eight growth months(April, May, June, July, August, September, October and November to March of the following year). The monthly and annual volume growth rates of each group in each growth month were obtained by sampling estimation of the monthly growth rates of the 12 study groups. Based on these data, the monthly growth rate fluctuation curve of each group was analyzed. 【Result】The analysis indicated that the monthly volume growth rate fluctuation curve was different for the various tree species. In the main growth season, the ratio of the highest to lowest monthly growth rate was between 2.0 and 2.2. Two growth peaks with different appearance time and height were identified for the pine, Taxodium and soft broad-leaved tree species, whereas the hard broad-leaved tree species showed only one peak. However, when the DBH increased, the volume growth rate decreased significantly. The growth rate of trees with medium DBH was 77%-88% that of trees with small DBH. The growth rate of trees with large DBH was 64%-90% that of trees with medium DBH, and 56%-77% that of trees with small DBH.【Conclusion】There were large differences existing in the monthly volume growth rates of Zhejiang Province. Therefore the time error correction and the origin error correction were necessary in short cycle investigation of forest resources. It was appropriate to choose June, July or August as the correction month of time error. Based on this, the regulative coefficient of natural forest is 0.908 6, and the regulative coefficient of man-made forest is 1.091 4 in Zhejiang Province.

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