Fig. 4
From: Driving factors of tree biomass and soil carbon pool in xerophytic forests of northeastern Argentina
Redundancy analysis (RDA). Explanatory variables (forest structure and abiotic factors) were indicated by arrows. Arrows pointing toward a response variable (tree biomass and soil carbon pool) indicate a high positive correlation. Arrow lengths indicate the strength of the relationship between carbon pools and explanatory variables. Forest structure data (density, basal area, canopy cover, relative dominance of P. nigra) and abiotic factors (elevation, slope, soil clay content, soil CEC, soil pH, and soil C:N ratio) explained 84.0% of the total variance in carbon pools (tree biomass and soil), with 73.9% of the variance on RDA axis 1 and 12.0% on RDA axis 2. pH  soil pH, C:N  soil C:N ratio, CEC  cation-exchange capacity, CLC  clay content, SLO  slope, ELE  elevation, PND  relative dominance of P. nigra, TCC  tree canopy cover, TD  tree density and BA  basal area