Evaluation of Processing Head Measurements in Merchandizing Southern Yellow Pine in the Southeast US

Abstract

Today’s timber market in the Southeast US demands a specific size log; thus, the harvested trees need to be processed at the landing. The utilization of a processing head in the logging industry is encouraged due to the presence of technological advancement on the machine that allows the loggers to merchandize and top the logs by specifying the desired measurements into the processing head’s computer program. This study evaluated the accuracy of processing heads in merchandizing logs by analyzing the bias and precision of measurement differences. The results showed that the processing heads resulted in a biased measurements but very low precision in measuring length, butt diameter, and top diameter. The majority of produced logs (62% of the observed data) were on acceptable length as they were produced between trim allowance. It was also found that processing heads showed better performance in measuring top diameter than butt diameter (0.55 inches and 0.71 inches of overall measurement differences respectively). Butt diameter measurement differences that were equal to zero were found on 25% of total observation, while it was found that 42% of the total top diameter measurements were showing equal reading with the post measurements. In addition, it was found that the measurement difference had a positive correlation with the length of merchandized logs with an R-squared of 3%. Longer logs were likely to contribute to a higher difference between processing head and manual measurement.