Considerations for Rehabilitating Naturally Disturbed Stands: Part 2. Stand Level Treatments and Hydrological Equivalent Clearcut Area

Abstract

Large wildfires near communities in southern BC, and the extensive outbreak of mountain pine beetle (MPB) throughout pine forests of the BC Interior, have created many new issues for forest managers. A particular concern is managing the cumulative effects of large natural disturbances in combination with forest management activities. In the past, planning for multiple values focused on forest development plans for normal commercial forest harvest in landscapes dominated by mature forest. Now, increasing pressure to recover disturbed stands for biofuels has resulted in multiple overlapping volume-based tenures, and an increased rate and extent of large-scale commercial salvage.

Natural Disturbance and Post-Disturbance Management Effects on Selected Watershed Values

“…• The primary effect of mountain pine beetle (MPB) on peakflows is through the death of the forest canopy, which decreases the interception of precipitation, resulting in snow melting earlier and more rapidly. Stands or watersheds with a larger proportion of pine cover have the potential for larger effects on peakflows, while greater understory vegetation may somewhat reduce these effects (Huggard 2011). It is predicted that, following MPB infestation, the frequency distribution of peakflows will change such that events of a given magnitude may occur more frequently, or conversely, events of a given frequency (e.g., a 1 in 10 year event) will be of larger magnitude (Schnorbus et al 2011).…”

“…To better understand the potential effects of salvage harvesting following disturbance, the model developed by Lewis and Huggard (2010) provides a starting point to evaluate the ECA tradeoffs between salvage harvesting and retaining dead canopy and understory trees. While the data may not be available in all locations to fully implement this model, the conceptual framework allows management and operations staff to make informed decisions about salvage harvesting (Huggard 2011). This analysis could take the form of a formal risk analysis to assist in making decisions on where and how much salvage harvesting is appropriate (Grainger and Bates 2010;Milne and Lewis 2011).…”

“…Interior and Coastal Watershed Assessment Protocols: http://www.for.gov.bc.ca/tasb/legsregs/fpc /FPCGUIDE/wap/WAPGdbk-Web.pdf MPB-Salvage ECA model (Lewis and Huggard 2010;Huggard 2011).…”

Considerations for Rehabilitation of Naturally Disturbed Forests (MPB); Part 1 Watershed Hydrology

“…In Part 1 of this series, we explore watershedlevel considerations when planning stand rehabilitation activities. Part 2 (see Huggard [2011], page 66 in this issue) provides a more detailed summary of the effects of different stand-level treatment options on the rate of hydrologic recovery using stand-level equivalent clearcut area (ECA) as an index under a range of pre-treatment forest conditions (i.e., site index, pine mortality, and existing understorey regeneration).…”

“…See Forest and Range Practices Act, Forest Planning and Practices Regulation, Section 8.2: http://www.bclaws.ca/EPLibraries/bclaws_new /document/ID/freeside/12_14_2004#section8.2 5 See Forest and Range Practices Act, Forest Planning and Practices Regulation, Section 8.1: http://www.bclaws.ca/EPLibraries/bclaws_new /document/ID/freeside/12_14_2004#section8.1 6 As measured by stand-level equivalent clearcut area; seeLewis and Huggard (2010) orHuggard (2011).7 We assume clearcutting and overstorey removal are synonymous, as most treated stands would have little secondary forest structure to be eligible for treatment, and this structure would be removed or damaged during overstorey tree removal.…”