Tree-Length System Evaluation of Second Thinning in a Loblolly Pine Plantation

A productivity study and system evaluation was carried out on a tree-length operation working in a second thinning of loblolly pine near Greenville, North Carolina. The average tree volume was 8.1 ft3 and the average dbh was 8.4 in. The machines studied in the system were the Tigercat 720B feller-buncher, the Tigercat 630 skidder, and the tracked loader Tigercat 245. The goal was to reduce the standing timber from 225 trees/ac down to 92. Standard time-study methodology and multivariance statistical analyses were used to capture and evaluate the data. The key productivity parameters identified for the feller-buncher was piece volume and number of trees in the bunch, and for the skidder extraction distance, average piece volume and number of bunches picked up to make a turn. The ability of the loader to process increasing number of trees as average tree volume decreased, and the increased difficulty of delimbing the larger trees resulted in no significant variance for average piece size. Productivity functions were developed for the feller-buncher and the skidder. The system evaluation discusses the productivity balance between the machines for the given range of piece size as well as potential operational improvements based on in-field observations. South. J. Appl. For. 27(2):77–82.