Tree volume modeling for forest types in the atlantic forest: Generic and specific models

Abstract

National Forest Inventories are important primary data sources for large-scale forest resource surveys, in which volume estimates of sampled trees are es-sential for quantitative analysis. Volume prediction models in natural forests are scarce in Brazil due to legal restrictions for cutting trees, especially in the Atlantic Forest. This study aimed to fit volume models for the main forest types and timber species of the Atlantic Forest in Rio de Janeiro state, consid-ering two hypotheses: (I) generic volume models provide greater generalizabil-ity of estimates; however, (II) they may reduce the accuracy of forest type-and species-specific predictions. Four linear models with logarithmic transfor-mation of variables were evaluated to fit volume models for generic and specific datasets, which correspond to the main forest types and timber species. Goodness-of-fit statistics were calculated to compare the accuracy and effi-ciency of the models, and selected models were validated through leave-one-out cross-validation procedures. The estimates obtained by generic and specific models were compared by non-parametric hypothesis tests. Generic models showed similar predictions to the specific models for forest types and timber species, with similar potential for stem and total volume predictions. Therefore, generic models can be used for Atlantic Forests in Rio de Janeiro state, while specific models are recommended to obtain more detailed local estimates. © SISEF.