Growth models based on tree-ring data for the Neotropical tree species Calophyllum brasiliense across different Brazilian wetlands: implications for conservation and management

Abstract

Site-specific growth modeling based on tree-ring data is demonstrated to be an efficient tool for conservation and sustainable forest management of an economically important tropical tree species, Calophyllum brasiliense. One of the main challenges in the sustained management of natural tropical forests is obtaining reliable data on tree growth, which is prerequisite information for determining harvesting volumes and felling cycles. In this study, we apply growth models based on tree-ring data and allometric equations to estimate site-specific management options for timber resources of the commercial species Calophyllum brasiliense (Calophyllaceae) comparing 16 wetland sites across different Brazilian ecoregions, the Amazon, Cerrado (savannah), Pantanal and Mata Atlântica (Coastal Atlantic Rainforest). By modeling diameter, height, and volume growth parameters, we estimate site-specific minimum logging diameters (MLD) and felling cycles analyzing a total of 341 trees. Between ecoregions, the mean diameter increments varied slightly between 4.3 ± 1.6 mm year−1 in the Amazon region (average of six sites), 4.0 ± 0.8 mm year−1 in the Cerrado and Pantanal (average of seven sites), and 4.5 ± 1.2 mm year−1 in the Mata Atlântica (average of three sites). However, between sites, we observed significant differences in diameter and volume increment rates, resulting in felling cycles varying from 14 to 63 years and MLDs in the range of 35–81 cm. This clearly indicates that forest management practices in Brazil, which generally applies a feeling cycle of 25 years and a diameter-cutting limit of 50 cm cannot guarantee a sustainable timber harvest. Timber resource management of this species requires site-specific criteria and should be restricted at sites with a low wood productivity. Moreover, long-term monitoring of the population structure and dynamics is necessary for a better understanding of the relationship between environmental factors and population dynamics, especially concerning the regeneration processes.