Controlled Burn Protects Reservoir Vital To Payson


The good news is we have made it past the really scary fire season. Granted, fall won’t actually start until Sept. 22, but a wet monsoon season helped Rim Country through another year of wildfire Russian roulette.

Now the bad news: Damp conditions should get the controlled burn season off to an early start, now that the summer crowds have deserted the forest.

Coconino National Forest lit the first spark with plans to ignite controlled burns to thin dangerously overgrown forests. Tonto National Forest should follow suit soon, with thousands of slash piles from previous hand thinning piled up on the outskirts of Pine, Strawberry, Payson and Star Valley.

Crews from the Coconino National Forest set fires west of Blue Ridge Reservoir and south of Highway 87 and Forest Road 751.

Payson has a vital interest in that project, since its future water supply depends on the carrying capacity of the 14,000-acre-foot Blue Ridge Reservoir.

The reservoir is surrounded by steep terrain and mountains that snag passing weather systems so reliably that the Salt River Project measurements show it produces more runoff per square mile of terrain than anyplace else in the state.

However, like the rest of the forests in Rim Country, the watershed is badly overgrown.

Payson officials have said a wildfire on the Blue Ridge watershed could have major consequences. An uncontrolled wildfire like the Rodeo-Chediski Fire burns so hot that it incinerates almost every tree in the area and often sterilizes the soil, fusing it so that it cannot absorb water normally.

A similar fire on the Blue Ridge Reservoir watershed could cause a dramatic increase in erosion into the narrow, steep-sided reservoir. That, in turn, could sharply reducing the storage capacity of the lake. Currently, Payson hopes to import 3,000 acre-feet of water from Blue Ridge, doubling its water supply and laying the foundation for most of its plans for any future growth.

The controlled burns on that watershed represent a dramatic shift in the U.S. Forest Service’s approach to managing the forest.

The Forest Service has spent millions of dollars in the past five years clearing buffer zones around forest communities.

Such hand-clearing projects pile up slash, let it dry, then set fire to the piles in the cool, moist fall and early spring. Such projects often send smoke drifting through Payson and other communities, triggering complaints from residents — especially people with breathing problems.

Such hand-thinning projects typically cost more than $1,000 per acre. That’s still a lot less than fighting a major fire — for instance it cost more than $60 million to battle the Rodeo-Chediski Fire. However, the cost of hand thinning has sharply limited the buffer zones the Forest Service has managed to create.

Controlled burns like those under way this week cost much less — about $300 to $500 per acre. In the case of controlled burns, crews clear fire lines along features like an existing road to box in the fire.

They then set the fire inside that box on a low-risk day and let it consume the downed wood and small trees.

Such a low intensity fire in damp conditions will typically not climb up into the larger trees.

The whole system is adapted to those low intensity fires, which actually increase the growth rate of the larger trees by clearing out the competing saplings, return nutrients to the soil and increase the diversity of wildlife.


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