Definição do tamanho de unidades amostrais para florestas nativas

Abstract

The forest inventories allow to know the ecological structure of the forest and provide important information for forestry activities, such as volumetric, floristic and biomass. A relevant stage in the execution of the inventory is the definition of the sample unit size. In dealing with forest surveys of native vegetation, the shape, size, and interval between sample units are a big question. In this context, the objective of this work was to estimate the optimum size of plots for the inventory in four phytophysiognomies, Cerrado sensu stricto, Cerradão, Deciduous Mesophytic Forest and Semideciduous Mesophytic Forest, based on basal area and carbon stock, taking into account the behavior of floristic structure and inventory results. Data from the Forest Inventory of Minas Gerais were used, with plot areas ranging from 100 to 2000m². For the evaluation of the estimates, the variables basal area and above ground biomass (carbon stock) were used. The estimates of the optimal plot size were based on four different methodologies, according to Smith's Empirical Law, Modified Maximum Curvature, Reason Quotient Method and Segmented Linear Model with plateau response. All evaluated methods presented good estimates of plot size for native forest inventory. When evaluated the different sizes of plots defined by the methods, the structural standards and floristic similarity were similar. Based on the inventory processing and ecological relationships, the definition of sample unit size was based on biomass. It was defined 600m² for Deciduous Mesophytic Forest, Cerrado and Cerradão and 1000m² for Semideciduous Mesophytic Forest. Thus this research was able to aggregate accurate information on the optimal size of plots, contributing to the optimization of financial resources and time spent in fieldwork.