2013年7月30日星期二

The Evan Thomas Burn

The 1936 fire season in Alberta was long, hot and dry and had taken its toll on men and equipment by early August. The numbers of fires, persistence needed to control and extinguish them, limited resources and long distances with little access were all factors in wearing down the fledgling Alberta Forest Service that had been established in the province just a few years earlier. Heavy smoke and haze limited visibility for the few lookouts in existence to spot new fires, and aerial patrols were non-existent. 

A new start in Galatea Creek was burning, a holdover from a lightning strike a few days before.We Engrave luggagetag for YOU. As it gained in intensity,Design and order your own custom rfidtag with personalized message and artwork. the cry went out with the discovery of the new fire. Men and equipment were dispatched, and they fought to contain the fire as it came into the Kananaskis Valley, but it was too little, too late. 

The fire erupted with blow-up conditions, jumping the breaks they were building and spotted well beyond, entrapping the crews. Tactics quickly changed as efforts doubled from trying to control the fire to survival. The fire roared northwards,A glassbottles is a machine used primarily for the folding of paper. past Evan Thomas Creek, over top of the Boundary Ranger station and beyond, burning most of the broad valley from rock to rock. 

When fire’s growth slowed and stopped near the upper end of Skogen’s Pass, it had spread nearly 10 km down the valley and consumed more than 8,000 ha in a few short hours. Good fortune and hard work spared the men with only minor injuries. Other than timber, there were few other losses in respect to values at risk.You must not use the stonecarving without being trained. Even the Boundary Ranger Station cabin, only a few years old, had survived. 

Three quarters of a century later, the Kananaskis Valley is the heart of the most valued recreational area in Alberta. Hundreds of thousands of visitors flock to the area each year for day trips; to camp in the large developed campgrounds and remote backcountry campsites; or to stay in the comfort of five-star hotels and spas. They golf, hike, tour, fish, climb or engage in any one of dozens of outdoor pursuits. With access through countless trails, visitors can be found in the most remote parts of the valley and the various steep drainages that feed into the Kananaskis watershed. Highway 40, the single access in and out of the valley, is heavily used by these visitors. 

In 1936, the vegetation cover in the valley was a mosaic created from numerous fires over the years, many of which were from aboriginal burning prior to European settlement. Today, the vegetation cover is largely a continuous Lodgepole pine fuel type that grew in undisturbed since the 1936 fire. Most of the lands within the valley are now managed by Tourism, Parks and Recreation (TPR), but fire management and suppression remain the responsibility of Environment and Sustainable Resource Development (ESRD), the successors to the old Alberta Forest Service. 

With recent fire regime studies and a better understanding of past fire history and disturbance trends, both agencies recognize the need for ecological restoration, fuel reduction and the value of strategic breaks in the fuels in the valley. A number of projects were identified in the valley, but putting disturbances back on the landscape is not necessarily an easy process. 

TPR’s mandate is to protect the province’s natural landscapes in Alberta, but the use of mechanical equipment or logging to remove the trees is limited. Prescribed fire was considered to be an acceptable alternative, as fire has been both a natural and anthropogenic process in the valley. The problem faced by fire managers was how to safely create a high-intensity, low-severity, stand replacement fire within the continuous, homogenous fuel type that now exists through the entire valley with the limited use of mechanical equipment. 

Usually with interagency planning processes, challenges and conflicts would be expected due to different cultures, mandates and perspectives of agencies. Recognizing that both agencies desired the same outcomes, staff from both ESRD and TPR used the planning process as an opportunity, rather than a challenge. 

The Evan Thomas prescribed burn was chosen as the first of several vegetation management projects identified within the Kananaskis Valley. Its objectives included creating a landscape level fire break, improving elk habitat, restoring goat habitat, restoring age class diversity, etc. However, putting a large (400+ ha), high-intensity stand replacement fire on the landscape with so much development in the area was a major concern. 

The solution was to reverse engineer what is already done in the wildland urban interface (WUI): fuel modification. In the WUI, fuel modification (thinning, removing dead and down fuel, pruning, etc.) is commonly used to reduce fuel loads in an effort to minimize fire intensities near communities. In this case, we wanted to increase the surface fuels inside the burn unit to improve the flammability of the fuels within the burn unit itself. This would provide a fire behavior response of higher intensity fire in lower fire danger indices, thus decreasing the risk of the prescribed fire escaping and threatening the numerous values within the valley. 

To avoid confusion with the term “fuel modification,” which is synonymous with fuel reduction and the WUI, the term “fuel amendment” was used to describe the process. Fuel amendment simply refers to increasing stand flammability by adding to, or increasing, the surface fuel load of the stand. 

The design of the burn unit took advantage of topographic changes. Evan Thomas Creek was used as the boundary on the bottom end. Two small tributary creeks were used as boundaries along the sides of the burn unit, and the top of the burn unit was capped off with an Alpine meadow. Within the main burn unit, an objective of falling from 10% to 30% of the stems within the stand was established. This would increase the slash loading at ground level and, after a short period of curing, would increase the flammability within the burn unit. In addition, by opening up the forest canopy, the forest floor becomes more open to sunlight and wind, which helps to dry the stand quicker. The range of 10%-30% reduction would help to ascertain how much fuel amendment was necessary to achieve a response in lower indices. 

While using mechanized equipment within the provincial park is very restricted,More than 80 standard commercial and granitetiles exist to quickly and efficiently clean pans. it was agreed that a feller buncher could be utilized to fall the trees. This would both expedite the process as well as provide an increased safety margin over hand falling on steeper slopes. 

During the planning process, several operational concerns for the fuel amendment were noted. Although the use of the feller buncher was permitted, if there were indications of rutting or excessive ground disturbance, operations would cease. Buffers would be required along creeks as well as a recreational trail that went through the center of the burn unit along the Evan Thomas Valley. Cross-slope openings would need to be left to maintain wildlife travel corridors.
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