Quantitative Estimation of Logging Residues by Line-Intersect Method

Line intersect sampling (LIS) is a method used for quantifying forest residues after logging operations. In conventional LIS theory, forest residues are considered as separate pieces of cylindrical shape, they occur horizontally, and are randomly orientated and randomly distributed. In the case of cut-to-length (CTL) logging operation, forest residues represent separate clusters, consisting of pieces of branches, twigs, tips, etc. So the application of the conventional LIS theory for quantifying forest residues after CTL logging is difficult. The purpose of the article was to assess the accuracy of the modified LIS method for quantifying forest residues after CTL logging. The studies were conducted by computer simulations. In the models, the forest residues are represented as clusters in the form of circles. The laws of distribution of the radius of the clusters and their position in the plot were determined by field measurements. In the simulations, 4 types of clusters were considered: Þ type 1 – clusters uniformly distributed within the entire cutting area (Fig. 7) Þ type 2 – clusters uniformly distributed along the X-axis and five stripes on the Y-axis (Fig. 8) Þ type 3 – clusters uniformly distributed along the X-axis and three stripes on the Y-axis (Fig. 9) Þ type 4 – clusters uniformly distributed along the X-axis and one stripes on the Y-axis (Fig. 10) It was determined through simulation that the formula of the modified LIS method estimatedappropriately forest residues after CTL logging. According to the results of simulation experiments,it was found that when the location of the lines of sample are across the area of Fig.7, 8 (across the stripes with clusters), the results are in good agreement with the theoreticalformulas. Differences are within error of 20%.