http://mcfns.com/index.php/Journal/issue/feedMathematical and Computational Forestry & Natural-Resource Sciences (MCFNS)2023-11-21T05:53:19+00:00MCFNS System Manageradmin@j.mcfns.comOpen Journal Systems<p>The mission of MCFNS is to publish peer-reviewed basic and applied research in Mathematical and Computational Forestry and Natural-Resource Sciences. This research can include analytical solutions, proofs, derivations, software developments, and simulations, in forest management, growth and yield modeling, and other natural resource related studies. Journal items are published collectively as part of an issue with its Table of Contents biannually, currently in <strong>April</strong> and <strong>October</strong>.</p>http://mcfns.com/index.php/Journal/article/view/15.4Using 3d Scanning Technique for Estimating Forest Standing Volume2023-11-21T05:50:12+00:00Nguyen Van Thinhnguyenthinhfsiv@hotmail.comTran Lam Dongtranlamdong@gmail.comPham Tien Dungphamtiendungvafs@gmail.comNguyen Van Tuanvantuanvfu@gmail.comDoan Trung Hieuhieudoan2018@gmail.comNguyen Huy Hoangnguyenhuyhoangvfu@gmail.comNguyen Viet Cuongnguyenvietcuong06031994@gmail.comNguyen Thi Thu Phuongphuong.nguyen45c@gmail.comVo Dai Nguyenvodainguyenvnuf@gmail.comNguyen Van Bichbichnv.fsiv@gmail.comThe use of 3D (three-dimensional) scanning in calculating tree's volume is discussed and suitable equations are fitted for estimating stand volume based on stem diameter at breast height (DBH) and height in the form of power and logarithmic functions. One hundred eighty-four individuals of <em>Hopea odorata</em>, <em>Dipterocarpus alatus</em> and <em>Afzelia xylocarpa</em> were scanned. Then, 3D images were used to calculate an individual tree's volume, based on sectioning the main stem and branches by assuming the cylinder of each section. The results indicated that 3D image calculations underestimated volume by 2.1-4.8% compared to the water displacement method by testing spiral branches of 4.3-15.7 cm diameter. The logarithmic function is the best-fitted model for each species and the combination of three species. <em>A. alatus</em>, <em>H. odorata</em> and combination of three species require both DBH and height, while <em>A. xylocarpa</em> needs only DBH in volume estimation. All four best fitted equations have Adjusted R-Squared > 0.88 and underestimate < 0.9% 3D volume. The smallest underestimate of 0.02% 3D volume belongs to the best-fitted equation for combination of three species, indicating the potentiality of using a combination of three species equation for estimating the volume of all species, especially in natural forests. It is concluded the suitability of using the 3D scanning technique for calculating individual tree's volume with high accuracy and establishing volume equations for multiple species applications, especially in the tropical forest.2023-10-30T00:00:00+00:00Copyright (c) 2023 Mathematical and Computational Forestry & Natural-Resource Sciences (MCFNS)http://mcfns.com/index.php/Journal/article/view/15.5Alternative Method for Determining Trunk Diameter at Different Heights on a Standing Tree2023-11-21T05:53:19+00:00Madina H. Abishovamadina.abishova@adau.edu.azBrad M. Kardb.kard@okstate.eduKamil H. Hasanovkamilhasanov012@gmail.comZohrab S. Ismailovismayilov@zzohrab.comAygun X. Bagirovaaygun3562@mail.ruValeh K. Shukurovvsukurov897@gmail.comTarana S. Babakishiyevat_axmedova@mail.ruIqbal A. Aliyeviqbaleliyev1973@gmail.comSima Z. Hasanovasima.hesenova.1982@mail.ruJeyhuna A. Hajiyevaceyhuneelvin79@mail.ruVidadi S. Samadovsamedovvs@yahoo.comReliably determining trunk volume of a growing tree and accurately measuring changing diameters along the trunk at different heights are important data to foresters world-wide. Existing methods for determining trunk diameter of a growing tree assume the horizontal cross-section is a circle. However, to an observer standing beside a tree and looking upwards along the trunk, the imaginary cross-section of the trunk does not look like a circle but appears elliptical. As the observer stands closer to the tree and the higher the established point where the diameter of the trunk is measured, the elliptical shape of the cross-section becomes more pronounced. Conversely, the smaller the tree and the farther the observer stands from the tree, the imaginary cross-section of the trunk becomes more circular. In this paper we describe a method that makes it possible to accurately determine the diameter of a trunk regardless of the above two distance factors. Using the mathematical parameters of an ellipse, the objective of this study was to provide an accurate method to calculate the diameter at any height on the trunk.2023-10-30T00:00:00+00:00Copyright (c) 2023 Mathematical and Computational Forestry & Natural-Resource Sciences (MCFNS)