Abstract:

In order to reduce the influence of error value caused by spatio-temporal difference in forest resources monitoring,a spatio-temporal error correction method of annual growth rate of forest volume (AGRFV) was studied in this paper. Both the date of AGRFV from 2004 to 2014 in the Zhejiang Province Forest Resources Survey and the date of AGRFV from 2014 to 2019 in the Zhejiang Province & Eleven Cities Forest Resources Survey were collected and analyzed. The monthly growth rate of forest volume (MGRFV) and the AGRFV of all 12 groups,which are divided into different groups according to the breast high were statistically analyzed and estimated.The results showed that:(1) on the time scale,for all the 4 tree species,the ratio of monthly growth rate to annual growth rate (RMGRAGR) in April or October was 7%~10%,the RMGRAGR in May,June,July,August or September was 10%~17%,and the RMGRAGR between November to next March was lower because of the low growth rate; (2) on the spatial scale,except for Jiaxingin special situation,the ratio of AGRFV in each of other 10 cities to the provincial average value were between 0.95~1.06; (3) for the temporal error,it was better to set the correction base month as June,July or August,and the steps of calibration process were firstly original survey data correction and then statistical summary; (4) the spatial error can be corrected after the temporal error correction of the original survey data,and then the statistical summary data of eachcity can be corrected.

Key words: forest resources, annual monitoring, forest volume, temporal error, spatial error, Zhejiang Province