Productivity and cost of the Ponsse 15-series, cut-to-length harvesting system in southern pine plantations
1997
Machine productivity data were collected for a Ponsse HS-15 harvester and S-15 forwarder from study sites in central Alabama during a second thinning. Tree size, in terms of diameter at breast height and volume, and the number of pieces processed per tree, were the variables-with the greatest impact on harvester productivity. The distance from the machine to the tree was also important. Observed productivity averaged about 34.6 m3 per productive machine hour (PMH) and ranged from 8.8 to 65.2 m3 per PMH. For the forwarder, loading and unloading times were affected by the number of pieces per load and load volume. Travel speed was influenced by slope and load volume. Predicted productivity was about 29.2 m3 per PMH in pulpwood and 33.8 m3 per PMH in small sawtimber. Machine costs were about $81 per PMH for the harvester and $53 per PMH for the forwarder. The number of trees per hectare harvested, tree size, and the forwarding distance were the most significant factors affecting system productivity.
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