Behavior of wood basic density according to environmental variables

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 corre-lation 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.

Protection status as determinant of carbon stock drivers in Cerrado sensu stricto

Aims Natural vegetation plays an important role in global carbon cycling and storage.Thus,the Cerrado(Brazilian savannah)is considered a carbon sink because of its intrinsic characteristics.Our aim was to evaluate how the aboveground biomass and biodiversity relationship change between three Cerrado remnants with different protection status:a‘control area’(Legal Reserve area),a protected area(PA)and a non-protected area(Non-PA).Methods All three studied fragments are situated in northern Minas Gerais state,Brazil.We estimated the aboveground carbon stocks based on the forest inventory.We also measured three dimensions of biodiversity metrics for each plot:functional trait dominance,taxonomic diversity and functional diversity.The following functional traits were evaluated for the species:wood density,maximum diameter and seed size.We carried out generalized linear models seeking to evaluate how carbon stocks,community-weighted mean(CWM)trait values,species richness and diversity,and functional diversity indices differ among the remnants.Important Findings The Cerrado areas without protection status had lower carbon stocks,species richness,species diversity,functional richness and functional dispersion,whereas both PA and Non-PA had lower CWM maximum diameter and seed size compared with the Legal Reserve control area.Generalized linear models showed that carbon stocks,species and functional richness metrics were correlated within and across sites,and thus,species richness could serve as a good proxy for functional richness and carbon stocks.The carbon stocks were positively driven by species richness and CWM maximum diameter,while they were negatively driven by functional dispersion.Functional richness,species diversity and CWM seed size appeared in the set of best models,but with no significant direct effect on carbon stocks.Thus,we concluded that absence of protection in the Cerrado areas decreases both species richness and carbon stocks.