Thinning Mixed Conifer Stands

 

1. Name - Thinning Mixed Conifer Stands

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This second project from the Klamath Falls Resource Area, entitled "Utilization of Small Diameter Conifers for Biomass in Mixed Conifer Plantations and Young Natural Stands,” was designed to utilize material from what would previously have been considered a pre-commercial thinning. The stands, some of which were in a WUI, were thinned in order to improve tree vigor, growth, and resiliency to insects and fire. About 50% of the trees were removed to break up continuity of live fuels and connecting crowns. As with the other case studies from the Klamath Falls Resource Area, the BLM used a ten-year stewardship contract to treat the area. This was the first time that the BLM thinned a young plantation outside of its normal timber sale contract stipulations and utilized the material in lieu of letting it remain on site. So far approximately 600 acres have been treated, and another 1,500 acres have been tasked out.



In place of thinning the stand with a slash buster and leaving the material on site, the contractor and BLM agreed to thin and utilize the material as clean chips. The treatment was initially tasked out for slash busting, in which the small diameter trees would be thinned first and then masticated using the same machine. Treatment costs for slash busting would have been about $266 per acre, however, this would not have generated any products or offset value. The contractor proposed thinning the stand and utilizing the thinned material for clean chips. The BLM agreed to modify the task order to pay the contractor to cut and yard the material to a loading point. The contractor would then grind up the trees and haul the material away.

The contractor used Timbco mechanized harvesters, large 566 John Deer skidders, delimbers, large grinder and/or chippers depending upon the product, and chip vans. Project design minimized soil impacts by ensuring that the skid trails and landing affected less than 20% of the area.  All trees were cut and moved to designated skid trails with mechanical harvesters. The costs for cutting and yarding were about $345 per acre (cutting was $265 per acre and yarding was $80 per acre). The value of the clean chips that were removed was approximately $39,000 or $89 per acre. The net cost of cutting, yarding and removing the biomass in lieu of slash busting it was $256 per acre, which was about $10 per acre less than the original slash busting cost of $266 per acre. The BLM choose to apply the positive value that the clean chips generated to helped pay for approximately 270 acres of pruning on residual trees at approximately $143 per acre. Hauling costs were an additional $2 per mile.



There was a market for clean chips at a hardboard mill in Klamath Falls, and a hog fuel market within 100 miles, which helped make the project feasible.  The trees were ground up into clean chips, which were used in multiple hardboard products locally. The BLM received $8 per ton for the chip material. This relatively high price for chips reflected a percentage of small sawlogs (5 to 6 inch diameter and 16 feet long) that were also chipped. The BLM and contractor negotiated a price, approximately $15 to $30 per MBF, for these small sawlogs.

• Lakeview District of the Bureau of Land Management