The use of computer vision to estimate tree diameter and circumference in homogeneous and production forests using a non-contact method

Abstract

Abstract Tree diameter and circumference measurements are important metrics that should be monitored periodically and which can be used to determine rates of plant growth, timber production (wood), rubber tapping time, and to estimate the nutrient content of the soil in agroforestry especially for rubber and Albizia sp. trees. In this study, we evaluated the use of optical sensors, including a smartphone camera, which were analyzed by an image processing technology to estimate tree circumference of homogeneous and production forests especially rubber and Albizia forest plantations, through a real-time tree diameter measurement approach. Camera measurements were carried out for the diameter at breast height (DBH) and a certain distance of each tree (with the diameter of tree range of ∼6–50 cm). The results show that the use of smartphone camera measurements is highly correlated with manual measurements obtained using a tree caliper or meter tape in estimating tree circumference with coefficient of determination (R 2) and RMSE of 0.95 and 7.9 cm, respectively. Thus, this tool can be employed as an alternative method for measuring tree diameter and circumference.