Abstracts Engineering

Hungry Bob Harvest Production Study : mechanical thinning for fuel reduction in the Blue Mountains of northeast Oregon

by Elizabeth Dodson Coulter

Fire exclusion in the western U.S.A. has caused fuel loads to build up and overall forest health to decline. Managers are now looking for ways to reduce these fuel loads while reintroducing some of the desired effects of natural wildfire. One method to do this is thinning using mechanical harvesting methods to reduce fuel loads. This study looks at mechanical thinning in ponderosa pine (Pinus ponderosa) and Douglas-fir (Pseudotsuga menziesii) stands in the Blue Mountains of Northeastern Oregon. A 409 acre (165.5 ha) unit of 7.1 inch (18 cm) average diameter at breast height was studied during the summer of 1998. Three feller-bunchers and three forwarders were observed in this cut-to-length (shortwood) operation. The three feller-bunchers were a Rottne SMV Rapid EGS, John Deere 653E, and a Caterpillar 320L Excavator, and three forwarders were a Timbco TF8 15-C, Rottne SMV Rapid, and a Rottne Rapid. These six machines operated on 409 acres (165.5 ha) removing a total of 15,786 tons (14,320 metric tons), 73.4% as sawlogs with the remaining 26.6% as pulp. Felling and processing costs for the three feller-bunchers were $5.20/ton (5.35 euros/mton) for the Rottne, $6.63/ton (6.83 euros/mton) for the John Deere, and $7.97/ton (8.21 euros/mton) for the Caterpillar Excavator. Forwarding costs were $7.12/ton (7.33 euros/mton) for the Timbco, $7.61 (7.83 euros/mton) for the Rottne SMV Rapid, and $7.58/ton (7.80 euros/mton) for the Rottne Rapid. Total stump-to-landing costs ranged from $12.27/ton to $15.81/ton (12.63 to 16.28 euros/ton).