In an unmanaged stand, most trees die and fall in situ, resulting in downed dead wood primarily composed of large pieces. In a managed stand, most standing wood is removed during harvesting, resulting in a smaller amount of downed dead wood primarily composed of short, broken pieces. This project was designed (a) to assess the operational feasibility and cost-effectiveness of harvesting practices that retain clumps of coarse woody debris (CWD), stubs and immature trees; and (b) to determine whether increased levels of desired CWD attributes are attained when harvesting crews are given specific instruction in terms of preset target levels, compared to general instruction on clumped retention. Three operational trials were conducted, one in each of the SBSdk, SBSmc2 and ESSFmc biogeoclimatic subzones. Results are available for the SBSdk and ESSFmc; results of the SBSmc2 trial will be assessed in 2004. In the SBSdk, the clump-retention units retained more of the pre-harvest CWD volume than did the control unit, and retained much more of this volume in relatively intact long pieces. In the ESSFmc, both clump-retention and control units retained CWD volumes somewhat higher than pre-harvest levels, but the clump-retention units retained much more of this volume in relatively intact long pieces, compared to short, broken pieces in the control unit. There was no discernable difference between units where crews were given targets for CWD attributes and units where only general instruction was given. None of the three licencees reported increased logging costs attributable to the clump retention (other than operator training time) although cost differences could have been masked by terrain differences or other factors unrelated to CWD management that affect ease of harvesting. Potential costs due to merchantable wood being inadvertently left on the cutblock will be assessed in 2004. Using clumped retention of structural elements appears to offer improved management of CWD with little or no discernable increase in logging costs.
by Ruth A. Lloyd.
Lloyd, Ruth A.. 2004. Results of operational trials: to manage coarse woody debris in the northern interior. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report. FIA2005MR350
Topic: FLNRORD Research Program
Keywords: Forest, Investment, Account, (FIA), Forestry, British, Columbia
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