ABSTRACT

Diameter at Breast Height (DBH) plays an important role in forest management. New technologies such as airborne and terrestrial Light Detection and Ranging (LiDAR) are expensive and time-consuming. We explored the iPad LiDAR sensor to measure DBH considering affordability and availability. The study was carried out at a research forest plantation near Thunder Bay, Ontario, Canada. Five plots were selected for differences in stem spacing, average DBH and species, and made 360° scans separately. A manual circle fitting method was used to produce circular features for the estimation of DBH. The coefficient of determination (R²) between estimated DBH and field measurements was 0.52, indicating a moderate accuracy. The Root Mean Square Error (RMSE) of DBH estimation ranged from 2.82 cm to 8.24 cm. The accuracy of smaller red pine trees was found to be relatively higher than that of larger red pine and white spruce trees. These accuracies did not change with the distance from the scanning location to trees. Therefore, results showed the potential use of an iPad LiDAR Scanner for DBH estimation. We recommend developing an application combining the iPad’s location and LiDAR sensors and incorporating a precise positioning method for fieldwork, and further broad field testing.

摘要

胸高直径（DBH）在森林管理中起着重要作用。机载和地面光探测与测距 (LiDAR) 等新技术既昂贵又耗时。考虑到可负担性和可用性，我们探索了 iPad LiDAR 传感器来测量 DBH。该研究是在加拿大安大略省桑德贝附近的一个研究林场进行的。根据茎间距、平均胸径和物种的差异选择了五个地块，并分别进行了 360° 扫描。使用手动圆拟合方法生成用于估计 DBH 的圆形特征。决定系数 ( R ²) 估计的 DBH 和现场测量值之间的值为 0.52，表明准确度适中。DBH 估计的均方根误差 (RMSE) 范围为 2.82 厘米至 8.24 厘米。发现较小的红松树的准确度相对较大的红松树和白云杉树的准确度较高。这些精度不会随着从扫描位置到树木的距离而改变。因此，结果显示了 iPad LiDAR 扫描仪用于 DBH 估计的潜在用途。我们建议开发一款结合 iPad 的定位和 LiDAR 传感器的应用程序，并结合用于现场工作的精确定位方法，并进一步进行广泛的现场测试。