Effect of the conversion factor *212 on the estimation of log volume in the forest industry of Durango, Mexico

Abstract

The methods for round wood cubing are combined using conversion factors without documenting the differences between one and the other. The objective was to analyze the Doyle and Smalian cubing methods, and to compare their performance in the application of conversion factors in the forest industry in Durango. A total of 38,731 logs were measured in different logging yards, classified by diameter category (cm) and length (m) and cubed using the Doyle (board feet) and Smalian (m³) methods. The volume calculated with the Smalian method was multiplied by the conversion factor “212” to obtain the volume in board feet. The volume estimation by diameter category and length were analyzed with the Kruskall-Wallis test to detect significant differences (P≤0.05) between the Smalian equation multiplied by the factor 212 and Doyle. It was found that the volume is significantly higher with the Smalian equation; on the other hand, from 65 cm diameters onwards, the estimated volume is higher with Doyle. For log diameters from 37 to 55 cm, and for log lengths from 2.44 to 6.71 m, the conversion factor is close to the estimated volume. It is concluded that the cubing methods should not be mixed, since the conversion factor currently used, Smalian x 212, is not equivalent in terms of round wood cubing.