Quantitative review of riparian buffer width from Canada and the United States

摘要

This paper reviewed the provincial, territorial, and state guidelines for the retention of treed riparian buffers after timber harvest in Canada and the United States. Comparisons amongst jurisdictions were facilitated through the use of a standardized template for the classification of waterbodies. Mean buffer widths varied from 15.1 to 29.0 m for different waterbody types when both countries were combined. However, Canadian jurisdictions had wider buffers (except for intermittent streams). In part, this was due to the high percentage of Boreal jurisdictions in Canada and Southeast jurisdictions in the United States. The Boreal region had the widest buffers while Southeastern jurisdictions had the narrowest buffers. Just under half (～ 44%) of the jurisdictions investigated had three or more modifying factors in the guidelines. Of these, waterbody type, shoreline slope, waterbody size, and presence offish were the most common. Boreal and Pacific jurisdictions tended to have a more diverse set of waterbody size classes, waterbody types, and other modifying factors. Jurisdictions from the Midwest, Northeast, and Southeast maintained relatively simple 'one-size-fits-air guidelines. Jurisdictions without modifying factors for slope or presence of fish applied wider baseline buffers than jurisdictions with these factors. A large percentage of jurisdictions (～ 80%) allowed some selective harvest in buffers. However, these were often accompanied by relatively restrictive prescriptions. In comparison to the ecological recommendations, buffer widths for most jurisdictions were adequate to protect the aquatic biota and habitats but were, generally, less than recommended widths for terrestrial communities. In the future, two management trends are likely to continue, the shift towards more complicated guidelines and the expansion to larger-scale, watershed planning of riparian areas.