Estimativa de volume do tronco por reconstrução tridimensional e triangulação de contornos

Abstract

Accurate quantification of wood volume is vital for sustainable forest management and serves as the basis for production planning. The methods for estimating the volume of wood present in the forest that rely on upper-stem diameter measurements assume that the stem can be approximated by the union of various sections of a geometric solid, which can result in inaccurate estimates. With the advancement of technology, new tools and methods are being developed to add greater precision and richness of information to forest inventories. Techniques such as digital image interpretation and sensors like terrestrial laser scanners can be applied to generate point clouds that can be converted into precise measurements of tree diameters and heights. This study proposes a new method of three-dimensional reconstruction of tree volume using digital photographs. The results show that the proposed method has potential application in the forestry sector due to its low cost and high precision, requiring only a digital camera and a studio box. Volume estimates using the proposed method, when compared to the volume obtained by the xylometer, were superior to conventional methods using caliper and measuring tape. Analysis of variance and the Tukey test at a 1% significance level indicated the use of digital images for obtaining the sectional area as the method with the lowest error compared to the xylometer (2.19%). The triangulation methods with two wooden discs (2.32%) and three discs (2.34%) were statistically equal to the caliper (2.72%). The measuring tape showed the worst results (6.03%). Under the analysis of scatter plots of residual distribution, the triangulation methods behaved similarly to the digital image method, being superior to the methods using caliper and measuring tape. Therefore, the proposed methods present themselves as promising alternatives to improve the accuracy of commercial volume estimates, contributing to the efficient and sustainable management of forest resources, especially in the context of estimating multiple products, where the knowledge of the stem shape is more important than the total individual tree volume.