Modeling operational forestry problems in central Appalachian hardwood forests.

摘要

Because of the species diversity, varied site conditions and growth rates, it is really challenging to manage the central Appalachian hardwoods. Examining the harvesting techniques and interactions among stand, harvest, and machines is becoming a concern to the researchers in the region. A simulation system was developed to aid these efforts by estimating the productivity, cost, and traffic intensity of different harvesting configurations under a variety of harvesting prescriptions and stand conditions.; Stands used in the simulation were generated by using the stand generator that was validated by comparing the generated stands with the actual mapped stands statistically. Results indicated its validity and have shown that it can be used to visualize the stand structure and composition of hardwood stands and perform dynamic analyses of various management prescriptions.; Three harvesting systems of chainsaw (CS)/cable skidder (CD), feller-buncher (FB)/grapple skidder (GD), and harvester (HV)/forwarder (FW) were modeled and simulated on five generated stands of different ages in the study. Five harvest methods of clearcut, shelterwood cut, crop tree release cut, diameter limit cut, and selective cut were examined. Simulation results showed that felling production and cost were primarily affected by tree size removed, removal intensity, distance traveled between harvested trees, and felling machines. The feller-buncher was the most cost-effective and productive machine and harvester was more sensitive to individual tree size (DBH). Clearcutting always presented the highest productivity while the shelterwood cut was the least productive method. Unit cost of harvester was higher than that of feller-buncher or chainsaw. Extraction operation was sensitive to payload size, average extraction distance, bunch size, extraction pattern, and extraction machine. The forwarder was the most productive machine under the simulated extraction prescriptions. The cable skidder resulted in higher unit cost than that of grapple skidder or forwarder.; System productivity increased from chainsaw/cable skidder system to harvester/forwarder system, and to feller-buncher/grapple skidder system. The feller-buncher/grapple skidder system could produce 28484 ft3 or 177 thousand board feet (MBF) per week with a unit cost of {dollar}27 per 100 cubit feet (cubit) or {dollar}44/MBF. For chainsaw/cable skidder and harvester/forwarder systems, the weekly production rate was 12146 ft3 (76 MBF) and 16714 ft3 (104 MBF), with unit cost of {dollar}35/cunit ({dollar}57/MBF) and {dollar}44/cubit ({dollar}70 MBF), respectively.; TI3 and TI4 are the major concerns since they caused the most soil compaction. Harvester/forwarder system was associated with more unaffected areas while fellbuncher/grapple skidder system affected more areas. TI3 and TI4 level was 20% of the total area affected with harvester/forwarder, 23% with chainsaw/cable skidder system, and 44% with feller-buncher/grapple skidder system. A total of 49% of extraction site was recorded as TI3 and TI4 level for SP1, which was more than two times higher than that recorded for SP5.