Abstract

TAMARIT-URIAS, Juan Carlos et al. Optimal sampling strategy for timber inventory planning in commercial plantations of Tectona grandis L.f. Rev. mex. de cienc. forestales [online]. 2021, vol.12, n.68, pp.58-80.  Epub Feb 28, 2022. ISSN 2007-1132.  https://doi.org/10.29298/rmcf.v12i68.1074.

The objective of this study was to evaluate the statistical efficiency of six sampling estimators to propose an optimal sampling strategy in terms of precision and time that allows conducting operational timber inventories that support decision-making aimed at improving the technical management of commercial forest teak plantations (Tectona grandis) established in Campeche, Mexico. Data used were from 8 830 sampling sites of a planted area of 2 207.5 hectares. Each sampling site was rectangular of seventy-two m2 included nine stocks, the number of living trees was counted and their diameter at breast height was measured. The total height and volume of each tree were estimated with Chapman-Richards and Schumacher-Hall models, respectively. Basimetric area and total volume per site were obtained and extrapolated at hectare. Plantations were stratified by age classes; the basimetric area and the age of the plantation were used as auxiliary variables. The sampling strategy to estimate the mean volume was formed by associating simple random sampling as the sampling design with the specific ratio estimator in stratified sampling, with a stratification by age classes of one year and basimetric area as auxiliary variable; this gave the accuracy of 0.21 %. The sample size in stratified sampling could be reduced to 68.3 % with an accuracy of 2.5 % of the original sample. This means less sampling effort and economies by reducing the time for forest inventory.

Keywords : Sampling estimators; stratification; forest inventory; sample size; teak; auxiliary variables.

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