Estimativa de biomassa arbórea-arbustiva em floresta tropical sazonalmente seca

Abstract

The growing demand for natural resources has aggravated the degradation of land, where, in addition to the condition of semi-arithme, the history of occupation reveals a strong pressure and degradation to natural resources in the Brazilian semi-arid region. The seasonally dry tropical forest (FTSS) comprises a unique biome, standing out for its high biodiversity and degree of endemism, as well as a provider of ecosystem services. One of the ways to indirectly measure the production of tree-shrub biomass has been the use of allometric equations. This work aims to develop general and specific allometric equations to accurately estimate shrub-tree biomass in successional stages of the Caatinga. Data on Caatinga species were obtained from Sustainable Forest Management Plans (PMF's) located in the state of Ceará. Moreover, it also had climatic, lithological and edaficos data. for the characterization of the relief, the scenes of the Palsar ALOS referring to the dry season of 2014 were used, and through the processing of the EAD, the corresponding slope of the settlement projects was determined. For each PMF, the following parameters were obtained in the field: diameter at breast height (DAP), diameter at ground level (DNS), in addition to the height of the trees (H). In the definition of the forest inventory of the vegetation in the sample plots, lots with dimensions of 20 m x 20 m (400 m²) were considered. Climatic, lithological and edaphical diversities resulted in differences in the parameters of cylindrical volume and height of individuals among the PMF's studied. Allometric equations achieved significant results in general, the presence of pioneer species and secondary succession: Marmeleiro (Croton sonderianus Muell.Arg.), Sabiá (Mimosa caesalpiniifolia Benth.), and the climax pau branco (Auxemma oncocalyx) contributed substantially to the results of the parameters between the evaluated areas and, consequently, the applicability of the equations for each management plane. The vegetation conditions with Caatinga in initial succession (PA São José – Tianguá), stood out for presenting the highest levels of gravimetric humidity, the highest concentrations of individuals per unit of area, lower heights and therefore the lowest volumes of wood when compared to the intermediate and conserved areas. The vegetation conditions with conserved Caatinga (PA Frios – Canindé), stood out for presenting the lowest vegetation humidity and concentration of individuals per unit of area, higher heights of individuals and then the highest volumes of wood when compared to the intermediate and initial areas. For all stage conditions studied, it is found that the models of specific allometric equations revealed better performance when they use as an independent variable the diameter at breast height and total height, obtaining superior performance than the general models.