Anatomical characterization of the roots, leaves and culms of Guadua weberbaueri in different growing environments

There has been increasing interest in the use of bamboo for a variety of purposes. In the western Amazon region, specifically in the state of Acre, Brazil, native bamboo (Guadua weberbaueri Pilg.) grows in great abundance, which calls attention to its possible sustainable exploitation. Thus, this project aims to perform the anatomical characterization of the culms, leaves and roots of G. weberbaueri in different environments, both inside and along the border of a forest. For the analysis, samples were collected from culms, leaves and roots at the Zoobotanical Park of Federal University of Acre, and permanent slides were visualized by optical microscopy. We observed that the vascular bundles of the central leaf veins were wider in leaves from the border of the forest than in those from inside the forest. In contrast, the study of root anatomy showed differences in the diameter measurements of the xylem vessel elements, which were larger in those inside the forest than those from the border of the forest. The vascular bundles of culms did not present a difference, although a new characteristic found in this species is described.

Allometric derivation and estimation of Guadua weberbaueri and G. sarcocarpa biomass in the bamboo-dominated forests of SW Amazonia

Bamboo-dominated forests in Southwestern Amazonia encompass an estimated 180,000 km2 of nearly contiguous primary, tropical lowland forest. This area, largely composed of two bamboo species, Guadua weberbaueri Pilger and G. sarcocarpa Londoño & Peterson, comprises a significant portion of the Amazon Basin and has a potentially important effect on regional carbon storage. Numerous local REDD(+) projects would benefit from the development of allometric models for these species, although there has been just one effort to do so. The aim of this research was to create a set of improved allometric equations relating the above and belowground biomass to the full range of natural size and growth patterns observed. Four variables (DBH, stem length, small branch number and branch number ≥ 2cm diameter) were highly significant predictors of stem biomass (N≤ 278, p< 0.0001 for all predictors, complete model R2=0.93). A secondary field model (containing DBH and branch number > 2cm diameter), proved highly significant as well (N= 278, p< 0.0001 for both predictors, R2=0.84). The belowground biomass was estimated to be 19.2±6.2% of the total dry biomass of the bamboo species examined. To demonstrate the utility of these models in the field and derive stand-level estimates of bamboo biomass, ten 0.36-ha plots were analyzed (N= 3,966 culms), yielding above + belowground biomass values ranging from 4.3–14.5 Mg·ha-1. The results of this research provide novel allometric models and estimates of the contribution of G. weberbaueri and G. sarcocarpa to the total carbon budget of this vast and largely unexplored Amazonian habitat.