Simulation Studies on Line Intersect Sampling of Residues Left After Cut-to-Length Logging

Upon carrying out logging, residues remain in the cutting area. Logging residues are an additional source of wood raw material for the production of fuel chips to be used in bioenergetics. In order to plan the logging residues collection and processing technology, it is necessary to gather information on the amount of this type of waste and its distribution within the cutting area. The article deals with the line intersect (LIS) method. The aim of this article was to assess the accuracy of the LIS method for quantifying logging residues after cut-to-length logging (CTL), uniformly distributed within the technology traffic lanes (strips) of width b on the cutting area of arbitrary shape S. The studies were conducted using computer simulations. In the models, logging 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, clusters uniformly distributed along the X-axis and stripes on the Y-axis were considered. The samples of lines were the set of lines of different length and mutually perpendicular and parallel to the coordinate axes X, Y. In the simulations, four types of stripes were considered with a different angle to the Y-axis. Type 1 – angle = 0°, type 2 – angle = 15°, type 3 angle = 30°, type 4 – angle = 45°. It was determined through simulation that the estimated mean radius of the clusters is greater by 24% than the true mean radius. The LIS method formula is appropriate for estimating the amount of forest residues after CTL logging provided the true mean radius is taken. According to the results of simulation experiments, it was found that the results are in good agreement with the theoretical formulas if the location of the sample lines is mutually perpendicular and parallel to the coordinate axes X, Y of the area. Differences remain within the limits of 20% error

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%