In response to a request by the Chief Forester of British Columbia, we evaluated the accuracy (unbiasedness) of the Site Index by Biogeoclimatic Ecosystem Classification site series (SIBEC) estimates for use in supporting allowable annual cut (AAC) determinations. Using data from the Old Growth Site Index project, we found that the first approximation SIBEC estimates are less biased than the site index estimates used in the forest inventory for old-growth stands. We therefore concluded that the first and second approximation SIBEC estimates are suitable for supporting AAC determinations and other timber management decisions (such as silvicultural investments). Estimates of site productivity in the second approximation SIBEC estimates are based on a minimum sample size and have a known level of precision. SIBEC estimates of productivity are generally higher than inventory estimates of productivity for old-growth stands. Ongoing SIBEC sampling is required to calibrate the SIBEC model. This will further improve the quality of the estimates for application in resource management.
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Updated May 17, 2007