ESTOQUE DE NECROMASSA LENHOSA EM FLORESTA OMBRÓFILA MISTA USANDO DIFERENTES MÉTODOS DE AMOSTRAGEM

Abstract

This study aimed to quantify the stock of necromass present in a fragment of Mixed Ombrophyllous Forest from different sampling procedures. The study area is within the Irati National Forest, municipality of Irati, Parana State, Brazil. The data were collected in permanent plots established by the Department of Forestry (UNICENTRO). We evaluated three sampling procedures, a) fixed area sampling units with 2500 m? (50 m x 50 m) - FA1 b) fixed area with sample units of 500 m? (10 mx 50 m) - FA2 e c) line intercept sampling (LIS) with lines of 50 m. Were measured pieces of wood fallen dead and dead standing trees with diameter ? 10 cm. The dead wood was evaluated by species, diameter and decomposition classes. The tested sampling procedures were evaluated by the following statistics: Coefficient of Variation (CV%) and relative sampling error (RSE%). For comparisons of results between sampling procedures were used the nonparametric test Kruskal-Wallis and Dunn`s post-test for multiple comparisons. The volume of fallen dead wood estimated to FA1, FA2 and LIS units was 16.77 m³.ha?¹, 18.89 m³.ha?¹ and 16.31 m³.ha?¹, respectively. The estimated volume of dead standing wood for FA1 was 5.11 m³.ha?¹ and FA2 3.67 m³.ha?¹. The total necromass estimated weight was 7.39 Mg ha?¹ (FA1), 7.48 Mg ha?¹ (FA2) and 5.26 Mg ha?¹ (LIS). FA1 procedure had less variation in the volume, but the FA2 procedure showed lower sampling error. The fallen and standing dead wood volumes did not differ statistically between the procedures. The procedures estimated similar values of volume, weight of necromass and carbon, but to achieve a 10% sampling error is necessary a high sampling intensity. The LIS procedure is more practical compared to the FA procedure, however to conclude what the best procedure to estimate necromass stock are needed further study.