Harvesting costs for potential bioenergy fuels in a fire risk reduction programme.

This paper documents the harvesting costs for a representative wildland-urban interface zone project around Flagstaff, Arizona—the 134-ha Fort Valley Research and Demonstration Project. The economic impacts of three treatment prescriptions on three types of Pinus ponderosa P. Lawson et Lawson (ponderosa pine) stands utilising three different harvesting techniques were analysed. In addition, the opportunities of two potential bioenergy markets were examined from the harvesters' revenue perspective. The costs of fully mechanised harvesting of the whole tree (WT) and hauling merchantablesize logs equalled US$28/m3, when averaged over the three different prescriptions in the three blackjack (BJ) units. There was little variation in WT cost from unit to unit; Under a direct cost hand-felling and mechanised-forwarding scenario (HD) scenario, the predicted costs, when averaged over the three blackjack-yellow pine (BJ/YP) units, equalled US$25/m3. Similarly, the cost to treat the three yellow pine (YP) units with a small cut-to-length forwarder system (CTL) averaged US$26/m3. The variation from unit to unit, however, for the HD and CTL operations was significant. The costs were a function of volume per unit area and average volume per tree and varied from a low of US$19/m3 to a high of US$43/m 3. A comparative analysis of the three harvesting operations found the WT operation to be the most cost-effective in BJ and BJ/YP units. A slow forwarding system limited HD and CTL effectiveness. In the YP units (characterised by excessive numbers of closely spaced, very small, blackjack trees surrounding widely