Modeling of tree height-diameter relationships in the Atlantic Forest: effect of forest type on tree allometry

Tree height is one of the most important variables for quantitative assessment of forest stocks, but it is difficult to directly measure. Such allometric relationships of trees can vary between geographical regions, however, mainly due to climatic, edaphic, and floristic gradients. Based on the hypothesis that different forest types influence the generic modeling of tree height-diameter relationships on geographical scales, this study aimed to (i) fit equations to estimate tree height in Atlantic Forest types in the state of Rio de Janeiro, Brazil; (ii) compare efficiency and precision between generic and specific equations for forest types; and (iii) test the effect of different forest types and species on the height-diameter relationship. Four allometric models were tested for all forests (generic) and three main forest types (specific). Effects of tree size, forest types, and species on tree height estimation were analyzed using multiple linear models and mixed-effect linear models. A significant effect of forest type and species on tree height was seen, showing the need to apply local specific equations to minimize the effects that are not captured by generic equations. Differences in tree allometry between forest types were associated with temperature, rainfall, soil, and forest structure. These results confirm the effect of the local environment on the height-diameter relationship of trees as found over large scales in tropical forests.