Introduction:

Modification of forest fuels is a recommended treatment to reduce wildfire intensity. Treatments may include thinning, surface fuel removal, and pruning. The premise for fuel modification is not to stop fires, but reduce potential fire intensity to a level that can be suppressed. Fuel modified forest patches that have located strategically around communities could reduce fire intensity to a level so that the fire can be stopped before losses are incurred.

As well, thinning is an important silvicultural treatment that occurs across boreal landscapes. Industry and government agencies want to know the effect commercial and pre-commercial thinning will have on fire behavior. This knowledge may help them to analyze risk potential for thinning and plan future suppression capability

This study will examine how thinning, as a part of a fuel modification strategy, affects fire behaviour and wildfire ignition potential in conifer stands. 

Methods

Potential fire behavior will be quantified by determining crown fire thresholds (Van Wagner 1977) and crown fire behavior (Van Wagner 1989) in thinned and unthinned conifer stands. Recently developed fire behavior models (Cruz et al. 2003, 2004, 2005) will also be used to predict potential crown fire initiation, occurrence and rate of spread. Observed fire behavior will be determined by recording fire behaviour and fuel consumption in thinned stands. A series of thinned plots will be established within prescribed fires. Detailed fuel measurements will be taken before and after the burns, and fire behaviour will be recorded during the burn using in-fire cameras and rate of spread sensors.

Projects

• Ignition probability trials at Bear Lake (near Kelowna). This mature lodgepole pine site was established by the BC Forest Service and the Canadian Forest Service as a part of DEMO 2000. Ignition trials and fuel sampling was done during June, July, and August, 2002. See FERIC Advantage report below (scroll down to documents).

• Fairholme prescribed burn (Banff National Park) - mature lodgepole pine. The park conducted a large prescribed burn in the Fairholme range during 2003 . FERIC established a site with 3 plots (control, thinned and slash removal, and thinned only). The thinning treatment approximates conditions prescribed for community protection and mountain pine beetle risk reduction. Unfortunately the plots burned when spring holdover fires flared up late in the summer and the fire behavior could not be recorded.

• Dead and down woody debris at Calling Lake (Athabasca) - mature white spruce. This project is a commercial thinning/white spruce regeneration study being conducted by Vanderwell Contractors, Canadian Forest Service, FERIC, and Forintek. Three prescriptions are being tested here - 30%, 50%, and 70% basal area removal.

• Fuel load collection at Jasper townsite (Jasper Natioanal Park) - mature lodgepole pine. Jasper Park is planning an extensive thinning program to reduce fuels around the townsite. As part of the park's mandate to include fire, they intend to use prescribed burning as mutch as possible to do fuel management.

• Community fire protection trials (Fort Providence, NWT) - jack pine and black spruce. An extension of the International Crown Fire Modelling Experiment (Canadian Forest Service/NWT Government), this project allows fire researchers to conduct experiments, including fire behavior, using crown fires. FERIC has established three research plots that will allow fire to burn from an untreated plot into a fuel managed plot. One plot was successfully tested in 2005 (scroll down to docmuents below for link to report).
  
  
• Crowsnest Pass community protection research. The 2003 Lost Creek fire threatened several communities in the Crowsnest Pass (southern Alberta). As a result FERIC has been asked to research fuel management effectiveness and costs within the Crowsnest Pass. The emphasis will be on comparing fuel loads before and after treatment (including thinning), long term site maintenance issues (e.g., blowdown) and treatment costs. No test fires are planned.

Ignition trials at Bear Lake

2 ignition tests, same site (thinned, no slash removal), but different fine fuels(1200 LST: 27` C, 34% RH)

Thinned plot at the Fairholme Bench site

3 m inter-crown spacing, 2 m pruning, slash removed, but stems left on site. The unplanned fire was very intense and the effect of thinning was inconclusive because the behaviour was not observed or recorded. However, it should be noted that the fuel treated plots were severly burned (including crowns), as shown below. It is suspected that strong wind gusts caused the intense fire behavior.

Acknowledgement

FERIC thanks the following for assisting with the projects:Banff and Jasper National ParksTed Makokis and Ken Creighton - Coast Range Contracting

• Cordy Tymstra, Stew Walkinshaw - Alberta SRD

• Darrin Woods - Dept. of Conservation (New Zealand)

• Glenda Russo - BC MOF

• Canadian Forest Service - Northern Forestry Centre (Edmonton)

• Canadian Forest Service - Pacific Forestry Centre (Victoria)

• Judi Beck - BC MOF Protection Program (Victoria)

• BC MOF Forest Protection Branch (Penticton Fire Zone)

• Vanderwell Contractors

Documents:

Effectiveness of Forest Fuel Management: A Crown Fire Case Study in the Northwest Territories, Canada work  2/21/2007

Modelling ignition probability of thinned lodgepole pine stands  6/29/2006

Considerations for Mitigating Windthrow Due to Forest Fuel Treatments  3/17/2006

New fuel management test plot  8/17/2005

NWT Fuel Modification Study  3/18/2004

Stand-density project in NWT 2003  7/21/2003

Effects of thinning on fuel parameter - a field study in Fairholme prescribed burn (Banff National Park)   6/12/2003

Stand Density Effects on Fire Behavior  6/27/2002