杉木是我国重要的用材树种之一,开展杉木单木位置和株数密度提取研究对调控其林分空间结构和功能、提高林分质量具有重要作用。基于无人机遥感影像,以浙江龙泉市杉木纯林为研究对象,采用改进的局部最大值法提取杉木单木位置和株数,并与参考株数进行对比分析。改进的局部最大值方法的采样间隔参数对单木位置和株数提取精度起到重要影响。在合适的采样间隔参数下:密和疏两种郁闭度样地单木位置提取总体精度分别为82.10%和80.17%、错分误差分别为24.12%和18.18%、漏分误差分别为17.90%和19.83%;密和疏两种郁闭度样地的监测株数和参考株数都十分相近,相对精度分别为93.77%和98.35%;林分株数密度与总体精度和错分误差呈负相关,与漏分误差呈正相关。改进的局部最大值方法能够较准确地提取不同郁闭度的杉木单木位置和株数,为智能、快速、准确地提取杉木单木位置和株数提供了一种可行的方法。

Chinese fir is one of the important timber species in China.The extraction of individual tree position and density plays an important role in regulating its stand spatial structure and function,and improving stand quality.Based on the unmanned aerial vehicle(UAV)remote sensing image,taking the Chinese fir pure forest in Longquan City of Lishui as the research object,the improved local maximum method was used to extract the crown position and number of Chinese fir trees,which was compared and analyzed with the measured number of trees.The results show that the sampling interval parameter of the improved local maximum method had an important influence on the extraction accuracy of individual tree number.Under the appropriate sampling interval parameters,the overall accuracy of individual tree position detection for sample plots with dense and sparse tree density were 82.10% and 80.17%,commission errors were 24.12% and 18.18%,and omission errors were 17.90% and 19.83%,respectively.The detected tree density and measured tree density for sample plots with dense and sparse tree density were very similar,and the accuracy was 93.77% and 98.35%,respectively.The tree density had a negative correlation with the overall accuracy and commission error,and a positive correlation with the omission error.The improved local maximum method can accurately extract the number of individual trees of Chinese fir forest with different tree density,which provides a feasible method for intelligent,fast and accurate extraction of individual crown position and tree density of Chinese fir.