Accuracy of common stem volume formulae using terrestrial photogrammetric point clouds: a case study with savanna trees in Benin

Abstract Recent applications of digital photogrammetry in forestry have highlighted its utility as a viable mensuration technique. However, tropical regions little research has been done on the accuracy this approach for stem volume calculation. In study, performance Structure from Motion estimating individual tree relation to traditional approaches was evaluated. We selected 30 trees five savanna species growing at periphery W National Park northern Benin and measured their circumferences different heights using tape clinometer. Stem volumes sample were estimated nine volumetric formulae solids revolution, including cylinder, cone, paraboloid, neiloid respective fustrums. Each photographed determined taper function derived tri-dimensional models. This reference compared with results formulaic estimations. Tree profiles further decomposed into portions, approximately corresponding stump, butt logs logs, suitability each solid revolution assessed simulating resulting shapes. calculated fustrums paraboloid closest bias root mean square error 8.0% 24.4%, respectively. Stems closely resembled neiloid. Individual portions assumed follows: more prevalent stump breast height, while matched shapes beyond point. Therefore, accurate estimate attained when stems considered composite least three geometric solids.