Evaluation of the effectiveness of carbon sink restoration in ecological conservation and restoration areas at the engineering scale

The monitoring and evaluation of the effectiveness of carbon sinks in ecological protection and restoration at the engineering scale have raised higher requirements for the spatial resolution and data accuracy of carbon storage and sink estimation in forestry. Through the UAV tilt photogrammetry technology for individual tree segmentation and key parameter extraction in forest stands, the estimation of carbon storage at the individual tree scale was achieved. This study explores the feasibility of drone-based carbon storage and sink estimation in small-scale ecological protection and restoration monitoring and evaluation work. The results show that: (1) Drone-based oblique photography can effectively achieve individual tree segmentation, with an overall segmentation accuracy exceeding 87%. (2) The tree height and diameter at breast height data extracted based on drones and tree height-diameter models have small errors compared to actual measurements, with average absolute errors of 0.25 m and 1.01 cm, respectively. (3) Drone-based estimation of individual tree carbon storage can finely demonstrate the spatial differences in tree carbon storage within a small area, meeting the high spatial resolution requirements for carbon storage estimation in small-scale ecological protection and restoration monitoring and evaluation.