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Generalized height-diameter models for five pine species at Southern Mexico
Wenceslao Santiago-Garcıa,Antonio Heriberto Jacinto-Salinas,Gerardo Rodr ıguez-Ortiz,Adan Nava-Nava,Elıas Santiago-Garcıa,Gregorio Angeles-Perez,Jose Raymundo Enrıquez-del Valle 한국산림과학회 2020 Forest Science And Technology Vol.16 No.2
Generalized height-diameter at breast height (D) models are essential for the estimation of the timber stocks of a forest stand, as well as in the generation of base information to develop forest growth models, and as basic inputs in the development of forest management plans. Generalized models were developed to estimate total height (TH) based on the D and stand variables, of five Pinus species in forests under forest management of Ixtlán de Juárez, Oaxaca, Mexico. The data used come from a timber forest inventory, where n = 1041 sampling plots of 1000 m2 each were established based on a stratified-systematic sampling design. The species selected according to their relative abundance were: Pinus patula, Pinus oaxacana, Pinus ayacahuite, Pinus teocote and Pinus leiophylla. Five nonlinear equations were fitted using regression techniques to predict the TH of the trees under several silviculture regimes and forest management conditions. The statistical criteria of goodness of fit used were: adjusted coefficient of determination (R2adj), root mean square error (RMSE) and absolute average bias in the prediction (Ē). Likewise, the graphic analysis of the predictive capacity of the equations was considered. The D and the stand variables (quadratic mean diameter, dominant diameter and dominant height) for these species explained between 75 and 83% of the variability of the TH data. The predicting variables to apply the developed generalized models to estimate tree's total height require less sampling effort and are derived from conventional forest inventory data, which allows to reduce costs and time in field work.
Arcelio Martinez-Dominguez,Faustino Ruiz-Aquino,Wenceslao Santiago-Garcia,Pablo Antunez,Miguel Angel Lopez-Lopez,Cesar Valenzuela-Encinas,Rossy Feria-Reyes 한국산림과학회 2020 Forest Science And Technology Vol.16 No.3
The estimation of tree biomass serves as a parameter of forest productivity; in addition, it is a method to estimate carbon fixation and storage. Studies on total biomass that include the belowground component for the Pinus genus are scarce in Mexico due to the difficulty and high costs for its quantification. In this study, allometric models were fitted to estimate the total biomass of Pinus patula Schiede ex Schltdl. & Cham., from the pine-oak forest of Ixtl an de Juarez, Oaxaca, for which a destructive analysis was made of 25 trees distributed in five diameter classes, classifying the biomass by components (root, stem, branches and foliage). With the component biomass data, different models were fitted by nonlinear regression techniques, using the diameter at breast height (D, cm) and the total height (TH, m) as independent variables. The model with the best fit was an exponential type y ¼ eðb0þb1 ln ðDTHÞÞ : In this study, it was observed that the studied species stores 22.62% of the biomass in the root, 69.61% in the stem, 5.67% in the branches and 2.11%, in the foliage. The models proposed in this study allow the estimation of total biomass and by structural component independently and additively. Its use is recommended in trees of P. patula, in the range of 5 to 25 cm of diameter at breast height, in forests with similar growing conditions.