Métodos de amostragem de área variável para a regeneração natural de Eremanthus Erythropappus (DC.) Macleish

Abstract

Sampling methods of variable area applied to natural regeneration of Eremanthus erythropappus (DC.) MacLeish. The objective of this study was to apply and assess the performance of sampling methods of variable area in natural regeneration of the species Eremanthus erythropappus in areas subject to management system with seed-trees. Data were collected in 46 Study Units with natural regeneration of the species. Structural variations of Strand’s and Prodan’s sampling methods were simulated to estimate the number of plants per hectare and average height. The estimated values for each case were compared to a given reference value by means of regression, Pearson’s coefficient of correlation, and Willmott’s concordance index. The performance was assessed by the association of Pearson's correlation with Willmott’s index. The nonparametric Kruskal-Wallis’ test was applied to verify significant differences between the estimated and referential means. Strand’s sampling method with lines of 4 and 5 m was precise and accurate for estimating density and average height. Prodan's sampling method overestimated density, but it was accurate to estimate height. We concluded that Strand’s sampling method, using a line of 4 m in length, can be used for sampling natural regeneration of E. erythropappus, which presents aggregated spatial pattern.