The Efficiency of Sampling Methods for Dendrometric Estimates of Thinned Stands of Pinus taeda L. in Santa Catarina, Brazil

Abstract

This study aimed to compare the efficiency of the sampling methods: Fixed Area, Bitterlich, Prodan and Modified Prodan to estimate the commercial volume and other dendrometric estimators for a 34 years old of Pinus taeda L. stands located in Campo Belo do Sul, Santa Catarina, Brazil. It were distributed a total of 10 sample units of the following methods: Fixed Area with 200, 400 and 500 m² of area, Bitterlich, Prodan and Modified Prodan were distributed, both with 6, 7, 8, 9 and 10 trees. In addition to collecting dendrometric data, the installation time of the sample units was timed, whereby the relative efficiency for each method was calculated. The comparison between the harvest volumes and the volumes estimated by the methods was performed by the Skott Knott test, and the results that did not differ statistically were weighted by the parameters of relative error, relative efficiency and proximity to harvest. All variations of the Modified Prodan and Prodan methods had sample insufficiency. The number of trees per hectare presented higher values for the 200 m² Fixed Area method and lower values for Prodan with 10 trees. Prodan with 6 trees got the shortest time. The Bitterlich method obtained sample adequancy at 10% error and presented the best result. Among the alternative methods to Fixed Area, Modified Prodan with 7 trees can be indicated for pilot inventory. However, when more precise results are needed, the Bitterlich method is indicated.

EFFECTIVENESS OF SAMPLING METHODS FOR THINNED AND NON-THINNED Pinus taeda L. PLANTATIONS IN THE MOUNTAIN REGION OF SANTA CATARINA, BRAZIL

“…The conditions and management developed in the forest, the type of relief, and the data collection region (among other characteristics) directly influence the efficiency of the different sampling methods (Corte et al, 2013;Farias, et al, 2019). Therefore, testing sampling methodologies in different situations becomes a decisive factor when planning the forest inventory, since, according to Ubialli et al (2009), the adequacy of the most effective sampling method will enable maximizing the accuracy of the results and minimize the execution time, reflecting in a cost reduction with field work.…”

“…Some studies have compared fixed area methods (Zator Filho et al, 2020) with variable area methods in planted forests in Brazil (Druszcz et al, 2010, Miranda et al, 2015, Santos et al, 2016, Farias et al, 2019and Miranda et al, 2022. However, studies which used the Strand method are uncommon (Miranda et al, 2022), mainly implementing the selection criteria of the basal area factor (BAF) for its proportional-to-diameter approach, which unlike Bitterlich, does not present an ideal number of trees in the sampling unit Figueiredo Filho, 2014) for selecting a suitable BAF.…”