Dataset for estimate coarse root and root collar biomass in ecotone forests on the eastern of Maracá Island, northern Brazilian Amazonia
The dataset provides information on coarse root (≥ 20mm) and root collar (area just below the soil line where the roots join the main stem) biomass, for trees (stem diameter ≥ 10cm) in ecotone forests located on the eastern of Maracá Ecological Station, northern Brazilian Amazonia. This area represents an ecotone zone dominated by mosaics of ombrophilous and seasonal forests. Our sampling took into consideration 65 trees characterized as natural treefalls (live trees toppled by wind or individuals that were physically felled by other trees that fell against them) observed in the PPBio (Biodiversity Research Program) 25-km2 research grid installed in the eastern of Maracá Island. The selection criteria for including trees in the sample took into consideration a careful inspection in order to choose only recently fallen individuals (live or dead) that were in a good state of preservation, discarding all individuals with hollow trunks, broken stems, broken canopies or with signs of rotting, as specified in Barbosa et al. (2019). Acta Amazonica 49: 81-90. The fieldwork was carried among July/2015 and October/2016 when we collected biometric measures (total height and stem diameter) and estimate the coarse root/collar root biomass by indirect measures for each individual tree. All sampled trees had most of the coarse roots exposed (≥ 20mm), being possible to measure each one (diameter and total lenght) and estimate its individual volume (m3). The sum of each individual volume (= total volume in m3) was multiplied by its specific gravity (g cm-3; roots) to estimate the coarse root biomass (Mg) by each tree. The root collar biomass was estimated using the measurements of the collar lenght (distance between the soil line and the first insertion of coarse roots) and the stem diameter. So, we calculated the individual volume (m3) of each tree and estimated its biomass applying the specific gravity (g cm-3; stem). Our dataset has one file (coarse_root) where are presented the code for each sampled tree (treeID), associated to its taxonomic identification (family; species), sampling date, altitude (m a.s.l.), drainage (well/poor), POM (point of measure of stem diameter), stem diameter (cm), total height (m), root collar lenght (cm), specific gravity (g cm-3; stems and roots), and estimates for coarse root and collar root biomass (Mg). The dataset was supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq - Brazil), project “Crescimento e mortalidade de árvores em florestas ecotonais de Roraima: efeito das condicionantes ambientais e da variabilidade climática” (Proc. CNPq n. 403591/2016-3). The CNPq also provided a fellowship for R.I. Barbosa (CNPq 304204/2015-3). P.N. Ramirez-Narvaez and C.D.A. Villacorta were supported by postgraduate fellowships from the Organization of American States (OAS). Instituto Chico Mendes de Conservação da Biodiversidade (ICMBio) provided authorization for the study (SISBIO n. 52017).