Comparison of sampling methods for description of floristic-structure in woody vegetation

The purpose of the present study was evaluation of the efficiency of the 'Fixed area', Strand, Prodan and Quadrat sampling methods to understand richness, diversity, floristic composition and horizontal structure of natural forest wood species.A census survey was carried out on a cerradão fragment, in which 27 fixed area plots were randomly established with dimensions of 20 × 20 meters.The center of each fixed area plot was considered a sampling point for the alternative methods of sampling, Prodan and Quadrat.For the Strand method, a line was established parallel to one side of the plot cutting it to the center.Richness and diversity of woody species in each method were evaluated by the rarefaction/extrapolation curves using the first three hill numbers.Finally, to characterize the horizontal structure, the Import Value Index percentage (IVI%) and the confidence interval of the basal area and number of individuals per hectare were calculated.The census survey registered a total of 82 species in the cerradão fragment, distributed among 59 genera and 33 botanical families.The study showed that the Fixed Area method was the best survey method regarding the richness, diversity and floristic composition.As for the horizontal structure of the forest, all methods differed, but the Fixed Area and Quadrat methods were the closest to the forestry survey census.