Methodology for the assessment of aspects and qualitative data in forest inventory audit

Abstract

Considering the importance of high quality data for the forest production planning, the concern to ensure good provision of services and to quantify the occurrence of errors in forest inventories, the objective of this study was to develop and apply a methodology to assess the installation of sample plots (qualitative aspects) and the qualitative classification of trees for a forest inventory (qualitative data). Six of a total of 120 plots from an Eucalyptus sp. stand forest inventory were randomly selected, retaking the data strictly according to the same methodology, that is, were measured again. Potential errors were classified and scored according to the magnitude of the influence of these errors on the forest production planning (Priority Hierarchy). The assessment of the plots was performed by multiplying the number of errors found by the respective scores, adopting as criteria of disapproval of plot the sum equal or higher than 21 points, and, for the evaluation of the inventory, the approval of at least 60% of the plots. Pareto graphs were also made for the occurrence of errors, affected wood volume and sum of the scores. All the audited plots presented errors, and two were reproved, the Pareto charts presented little difference and pointed out the most representative errors. It was verified that the forest inventory carried out presented a large number of errors. The audit methodology allowed the identification of the errors, in which plots these were found and provided accurate information for mitigating actions