Size and Shape of Sample Units in Native Forests and Plantations

Sylvio Péllico Netto, Julio Cesar Rodriguez Tello, Rafael Romualdo Wandresen

Department of Forest Science, University Federal of Amazonas, Manaus, Brazil.
Department of Forest Science, University Federal of Paraná, Curitiba, Brazil.
Department of Professional and Technological Education, University Federal of Paraná, Curitiba, Brazil.

DOI: 10.4236/ojf.2014.44043                

Abstract

The size and form of sampling units-SU have always been variables considered in planning and structuring forest inventories, being performed in forests or in plantations. The experimental work outlined to deal with the problem was conducted in an area of araucaria forest, in Sao Joao de Triunfo, PR, Brazil. The forms of sampling units circle, square and rectangular were evaluated, whose areas ranged from 200 m² to 1000 m². Time was recorded using a stopwatch and computed separately for locomotion and measurement. The power model was used to adjust the relations of the times of locomotion and measurement, as well as a hyperbolic one for the coefficient of variation, all taking as function of the SUs sizes. To achieve the analytical solution for the optimum size of the SU, it was necessary simulating the behavior of the three functions until the size of 10,000 m². By taking the derivative of the combined function it was found the maximum point, which allowed optimizing the size of the SU in 600 m² for the structured experimental conditions. This result proved the formulated hypothesis, performing even a critical analysis of the inclusion of other relevant variables, such as size of the area to be inventoried, number of SUs performed in one day of work, average distance between the SUs, average speeds for locomotion between SUs and for taking all respective measurements.

Keywords

Optimization of the Size of Plots, Sampling of Fixed Area, Efficiency per Day of Work, Mixed Tropical Forest

Conflicts of Interest

The authors declare no conflicts of interest.

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