基于地面摄影测量的平朔矿区林分蓄积量研究

蓄积量是评价森林数量和质量的重要指标。为了分析露天开采和土地复垦对林分生长的影响,需要快速准确地测定开采未损区、开采受损区和受损治理区的林分蓄积量。由于矿区环境复杂多变,为了避免危险性,提出以非接触地面摄影测量方式进行外业数据采集,然后以五棵树法为原理,再结合推导形数法快速计算蓄积量的方案。为了证明地面摄影测量方法测量的精度满足林业上的精度要求,把用地面摄影测量量取的25棵树的胸径与对应每木检尺法测量的胸径结果进行对比,平均胸径绝对误差为0. 23 cm,相对误差为1. 35%,表明非接触地面摄影测量方法可以代替每木检尺法进行胸径测量。采用地面摄影测量结合五棵树法分别对平朔矿区开采未损区、开采受损区和受损治理区树木进行调查,结果显示受损区相对未损区平均胸径减小21. 26%,蓄积量相对减小41. 14%,治理区相对受损区平均胸径增加1. 46%,蓄积量增加17. 80%,说明露天开采影响了平朔矿区林分的平均胸径和蓄积量,尤其对蓄积量的影响较大,土地复垦一定程度上改善了树木的生长状况。

Ground Photogrammetry for Investigation of Stand Volume in Pingshuo Mining Area

The accumulation volume is an important indicator for evaluating the quantity and quality of forests. In order to analyze the impact of open pit mining and land reclamation on stand growth, it is necessary to quickly and accurately determine the stand volume of unaffected areas, damaged areas and treated areas. Due to the complex and varied environment of the mining area, in order to avoid danger, it was proposed to use the ground photogrammetry method to collect field data, and then use the five tree method as the principle, and combine the derivation shape method to quickly calculate the volume of mixed forests. Comparing the DBH of the 25 trees measured by the ground photogrammetry with the DBH measured by the wooden ruler method, the absolute error of the average DBH was 0.23cm, and the relative error was 1.35%. It was indicated that the non contact ground photogrammetry method can replace the method of measuring the diameter of breast with each wood ruler. The ground photography and the five tree method were used to conduct tree surveys on the unaffected areas, damaged areas and treatment areas of Pingshuo mining area. The results showed that compared with the unaffected area, the average breast diameter of the damaged area was decreased by 21.26%, and the accumulated amount was decreased by 41.14%. Compared with the damaged area, the average breast diameter of the treated area was increased by 1.46%, and the accumulated amount was increased by 17.80%. It was showed that open pit mining affected the average DBH and accumulation of forest stands in Pingshuo mining area, especially the impact on the accumulation volume. Land reclamation improved the growth of trees to some extent.