Contrasting drivers of aboveground woody biomass and aboveground woody productivity in lowland forests of Colombia

The relative importance of abiotic and biotic factors in shaping forest biomass stocks and fluxes remains a controversial issue. Here, using data gathered from 39 1-ha plots located in flooded and terra firme mature tropical lowland forests of the Amazon and Orinoquia regions of Colombia, we evaluated the importance of climate, soil fertility, flooding as well as tree taxonomic/phylogenetic diversity and forest structural properties, in determining the aboveground biomass stocks (AGB; Mg ha-1) and aboveground woody productivity (AWP; Mg ha-1 y-1). Using information-theoretic multimodel inference and variance partitioning we found that forest structural features, such as the number of trees with diameter at breast height ≥ 70 cm and wood density, are the main drivers of variation in AGB. However, taxonomic diversity also contributes to AGB because it is associated with more large trees in these forests. In contrast, the key drivers of AWP in these forests were soil P and Mg concentration..., This study was conducted using tree census data collected at 39 1-ha forest inventory plots situated across a latitudinal range from -3.8° to 4.8°, a longitudinal range from -77.1° to -67.8°, and an elevation range from 79 m asl to 963 m asl, in Colombia.  The mean annual temperature (MAT) of plots ranged from 21.5 to 25.5 °C (mean = 24.7 ± 0.6 °C; mean ± SD) and mean annual precipitation (MAP) of the plots ranged from 1797 to 3716 mm y-1 (3076.4 ± 299.9 mm y-1) (External Databases S1). There were 8 plots located in the Orinoquia region (González-Abella et al. 2021) and 31 in the Amazonia region of Colombia (Fig. S1). Plots were censused between 2005 and 2021. In the locality of Amacayacu, the data employed come from a continuous 25-ha plot located on Tierra firme soils derived from the Pebas formation (Zuleta et al. 2017).  Therefore, to avoid pseudo replication and over representation of this site, we only used the minimum, maximum, and mean value of the AGB, AWP, and AWRT at the 1-ha..., , # Contrasting drivers of aboveground woody biomass and aboveground woody productivity in lowland forests of Colombia

Tree census data collected at 39 1-ha forest inventory plots situated in the Orinoquia region and Amazonia region of Colombia. Plots were censused between 2005 and 2021. We aim to assess the importance of abiotic and biotic factors in controlling the variation in aboveground biomass stocks and fluxes. In each plot, all stems of trees and palms (hereafter trees) with tree diameter at breast height (DBH; tree diameter at 1.3 m height) ≥ 10 cm were measured. The aboveground biomass (AGB) of each tree was estimated using the allometric equation proposed by Chave et al. (2014). All plots were censused at least twice (elapsed time ranged between 2 and 10 years), and the aboveground woody productivity (AWP in Mg ha-1 y-1), and aboveground woody residence time (AWRT in y) of each plot were estimated. To estimate soil fertility, samples of soil A horizon (i.e., the mineral soil...