COMPARISON AMONG METHODS FOR TOTAL TIMBER VOLUME EVALUATION PER HECTARE FOR PARANA PINE IN THE SOUTHERN STATES OF BRAZIL

Abstract

The objective of this research was to compare results of volumes per hectare and per diameter class obtained with the following evaluation methods: 1. Conventional forest inventory. 2. Stand volume table; 3. Diameter distribution. The data came from the Parana Pine (Araucaria angustifolia) forest inventory carried out in 1977 and 1978 in southern region of Brazil. Diameter at breast height (DBH), and height of every tree with DBH ³ 20 cm were measured in 322 plots with dimensions of 20 x 125 m (2500 m²), (167 plots located in old growth forests and 156 plots in secondary forest of Parana Pine), scatered over the whole region of natural distribution of this tree species in Southern Brazil. After data processing it was obtained total volumes outside bark of 435.00 m³ and 167.62 m³ per hectare respectivly for forest type I and II, estimated through method 1. Results from method 2 were 444.21 and 177.46 m³ per hectare respectively, and from method 3 were 404.43 and 165.64 m³ per hectare for types I and II, respectively. Statistical comparison of results obtained from the three evaluation methods was done through analysis of variance with a randon bloks design. When a significant difference was identified, the Scott-Knott test of means comparison was performed at 5% of probability. For the ANOVA the methods were considered as treatments, and the diameter classes, as blocks. This test detected that the results from the methods 1 and 2 were statisticaly identicals, but both differred from the results obtained by method 3 for forest type I. The same analysis performed for forest type II did not showed any significant difference among treatments. Thus, for forest type II all methodos provided statiscally similars volume estimates per hectare.