2:1 for fallows and 15.1:1 for pastures. A damaged trunk usually resprouts with multiple shoots, many of which develop into stems during the consecutive fallow period. Once cut

by the next slash-and-burn event, each of these resprouted stems may develop several shoots. The result is a progressive increase (F = 19.365; p < 0.001) in the number of stems each time the individual resprouts ( Fig. 2c). However, the BN tree also exhibit self-thinning, as we inferred from the significant decrease (T = 4.923, p < 0.001) in the number of stems on resprouts growing at recently cultivated sites compared to those in fallows older than ten years. Under the assumption that the nearest productive BN tree represented selleck chemical the putative seed source, we calculated the average distance between the established propagules and the nearest parent trees as 70 m, with the distances ranging from 6 to 277 m. Arranged by 20-m width frequency classes, 80% of the regeneration occurred within a radius of 100 m of the closest productive adult. The remaining 20% occurred at distances of up to RGFP966 solubility dmso 200 m. Only two individuals were found growing further apart (Fig. 3). The size of the sites can also influence the dispersal distance, and area was significantly related to regeneration density (F = 9.045, p = 0.005). The regeneration density significantly influenced (T = 4.375, p < 0.001) the extractivists’

decision to preserve fallows sites spontaneously enriched these with BN trees from further conversion into crops or pastures ( Fig. 4a). We investigated the protection of individual BN trees and confirmed the existence of an informal management practice directed at preserving at least some of the individuals encountered in fallows selected to be replanted. The differences between the log10 height (T = 2.689, p = 0.007) ( Fig. 4b) and log10 diameter (T = 3.965, p < 0.001)

( Fig. 4c) of regeneration found inside and on the perimeter of the agricultural sites were both significant. Observed regeneration density did not vary significantly either with the current agricultural use (F = 3.221, p = 0.051) or with the fallow period since the last slash-and-burn event (F = 0.442, p = 0.51). Of all of the variables related to regeneration density, the number of cultivation cycles was clearly the most influential (Fig. 1). This close relationship also characterized the finding of a previous sociological study that compared BN collecting and itinerant agriculture as economic choices of an indigenous population living by the Solimões River, Amazonas (Pereira and Lescure, 1994). The authors noticed a gradient in BN tree density that increased from the inner portion of the territory (1.79 trees ha−1) to the river’s margin (3.09 trees ha−1), which was precisely the zone occupied by the mosaic of itinerant crops and fallows. Our results confirmed this impression because the BN density increased with the number of SC cycles (Fig. 2a).