Size and Shape of Sample Units in Native Forests and Plantations


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.

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Netto, S. , Tello, J. and Wandresen, R. (2014) Size and Shape of Sample Units in Native Forests and Plantations. Open Journal of Forestry, 4, 379-389. doi: 10.4236/ojf.2014.44043.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] Cesario, A., Engel, O., Finger, C., & Schneider, P. (1994). Comparacao dos métodos de amostragem de área fixa, relascopia e de seis árvores, quanto a eficiência, no inventário florestal de um povoamento de Pinnus sp. Ciência Florestal, 4, 97-108.
[2] Cochran, W. (1963). Sampling Techniques (2 ed.). New York: John Wiley and Sons Inc.
[3] Freese, F. (1962). Elementary Forest Sampling. Washington: US Department of Agriculture.
[4] Lessman, K., & Atkins, R. (1963). Optimum Plot Size and Relative Efficiency of Lattice Designs of Grain Sorghum Yield Test. Crop Science, 3, 477-481.
[5] Loetsch, F., Zohrer, F., & Haller, K. (1973). Forest Inventory (2 ed., Vol. II). Munich: BLV Verlagsgesellchaft.
[6] Messavage, C., & Grosenbauch, L. (1956). Efficiency of Several Cruising Designs on Small Tracts in North Arkansas. Journal of Forestry, 54, 569-576.
[7] Pearce, S. (1953). Field Experiments with Fruit Trees and Other Perennial Plants. Technical Communication No. 23, East Malling: Commonwealth Agricultural Bureaux.
[8] Péllico Netto, S. (1979). Die Forstinventuren in Brasilien: Neue Entwiecklungen und ihr Beitrag für eine geregelte Forstwirtschaft. Mitteilungen aus dem Arbeitskreis für Forstliche BIOMETRIE. Freiburg: Tese de Doutorado, Albert-LudwigsUniversitat zu Freiburg im Breisgau.
[9] Péllico Netto, S., & Brena, D. A. (1997). Inventário Florestal. Curitiba: Federal University of Paraná Press.
[10] Prodan, M. (1965). Holzmesslehre. Frankfurt: J.D. Sauerlander’s Verlag.
[11] Queiroz, W., Péllico Netto, S., Valente, M., & Pinheiro, J. (2011). Análise Estrutural da Unidade Conglomerada Cruz de Malta na Floresta Nacional do Tapajós, Estado do Pará, Brasil. Floresta, 41, 9-18.
[12] Richter, A., & Grossmann, H. (1951). Untersuchungen über Prokreis Groβe und Netz Punktdichte bei Holzvorratsinventuren. Archiv für Forstwesen, Heft 11.
[13] Silva, R., Xavier, A., Leite, H., & Pires, I. (2003). Determinacao do tamanho ótimo da parcela experimental pelos métodos da máxima curvatura modificado, do coeficiente de correlacao intraclasse e da análise visual em testes clonais de eucalipto. Revista árvore, 27, 669-676.
[14] Simplício, E., Muniz, J., Aquino, L., & Soares, A. (1996). Determinacao do tamanho de parcelas experimentais em povoamentos de Eucalyptus grandis Hill ex-Maiden: I, parcelas retangulares. CERME, 2, 53-65.
[15] Smith, H. (1938). An Empirical Law Describing Heterogeneity in the Yields of Agricultural Crops. Journal of Agricultural Science, 28, 1-23.
[16] Stohr, G. W. (1978). Importancia e aplicacao do estudo do trabalho. Floresta, 9, 27-38.
[17] Strand, L. (1957). The Effect of the Plot Size on the Accuracy of Forest Surveys. Meddelelser fra det Norske skogforsoksvesen, 48, 621-649.
[18] Tello, J. (1980). Eficiência e Custos de Diferentes Formas e Tamanhos de Unidades de Amostra em uma Floresta Nativa de Araucaria angustifolia (Bert.) O. Ktze no Sul do Brasil. Dissertacao de Mestrado, Curitiba: Universidade Federal do Paraná.
[19] Zaide, B. (1980). Plot Size Optimization. Forest Science, 26, 251-527.

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