Behavior of wood basic density according to environmental variables

Abstract

The relationships between climate conditions and wood density in tropical forests are still poorly understood. To quantify spatial dependence of wood density in the state of Minas Gerais (MG, Brazil), map spatial distribution of density, and correlate density with climate variables, we extracted data from the Forest Inventory of Minas Gerais for 1988 trees scaled throughout the territory and measured wood density of discs removed from the trees. Environmental variables were extracted from the database of the Ecological-Economic Zoning of Minas Gerais. For spatial analysis, tree densities were measured at 44 georeferenced sampling points. The data were subjected to exploratory analysis, variography, cross-validation, model selection, and ordinary kriging. The relationships between wood density and environmental variables were calculated using dispersion matrices, linear correlation, and regression. Wood density proved to be highly spatially dependent, reaching a correlation of 96%, and was highly continuous over a distance of 228 km. The distribution of wood density followed a continuous gradient of 514–659 kg m−3, enabling correlation with environment variables. Density was correlated with mean annual precipitation (− 0.57), temperature (0.63), and evapotranspiration (0.83). Geostatistical methods proved useful in predicting wood density in native tropical forests with different climate conditions. Our results confirmed the sensitivity of wood density to climate change, which could affect future carbon stock in forests.