The U.S. Forest Service wants to drastically thin the overgrown forest surrounding the Mogollon Rim lakes on which the region’s tourist economy depends.
However, the proposal to cut some of the largest trees on 33,000 acres surrounding tourist draws like Bear Canyon and Willow Springs lakes atop the Rim could cast a shadow across a hard-won consensus on forest restoration between loggers and environmentalists.
“The forest will end up much more open than it is now,” said Dee Hines, head ranger for the Black Mesa District atop the Rim. “You’ll see through it further. You’ll see clumps of large, old trees left — sort of interspersed with younger trees and medium sized trees.”
The Rim Lakes Forest Restoration plan would dramatically reduce fire danger, improve conditions for endangered species, increase forest health and sharply reduce the threat of a catastrophic fire that could chase tourists away for decades.
However, the plan also calls for cutting maybe 40,000 of the nearly 300,000 trees larger than 16 inches in diameter.
That element of the plan could spell trouble for a much larger effort to thin a million acres of forest, dramatically reducing the fire danger to Rim Country communities. That larger, 4-Forests Restoration Initiative (4-FRI) won the rare cooperation of conservationists and loggers with a plan to thin a million acres, while sparing almost all the trees larger than 16 inches in diameter. The Forest Service is currently seeking bids from contractors for the first phase of that larger project, but hasn’t yet revealed whether it would stick to the limit on cutting the larger trees on which the consensus plan rested.
Gila County Supervisor Tommie Martin said the coalition pushing for the 4-FRI plan has been pushing hard to convince the Forest Service to accept the near-ban on cutting trees larger than 16 inches, the key agreement that opened the door to reconciling conservation groups and loggers.
So the just-completed blueprint for the Rim Lakes Restoration project offers a trial run for a detailed restoration plan.
The plan to thin the 33,600 acres surrounding the most popular fishing areas in the state illustrates the tradeoffs of the attempt to reduce fire dangers and improve forest health in a ponderosa pine forest.
Hines said the Apache-Sitgreaves is currently seeking feedback on the draft plan for the Rim Lakes thinning project. The forest managers prefer a prescription that would allow them to cut many 16-inch trees to create a more varied, patchy forest. Tree densities have increased an estimated 33-fold in the past century.
The study area on the Black Ranger District of the Apache-Sitgreaves National Forest runs along much of Forest Road 300 and includes the areas around four popular Rim lakes and also abuts the community of Forest Lakes. The area remains one of the most vital areas to the region’s tourist economy. Firefighters struggle to contain an average of 23 fires a year in the tinder-dry months of May and June, about half of them caused by humans and the rest by lightning strikes.
Currently oaks and pines are packed so tightly that the whole area remains vulnerable to devastating crown fires, which could deforest the area for generations, dealing a mortal blow to the economy and posing a catastrophic danger to places like Forest Lakes.
The thinning project would slash the fire danger. Currently, the whole stretch of overgrown forest remains in the highest category measuring fire danger. Moreover, nearly 70 percent of the forest has thickets of trees with their upper branches intertwined — perfect conditions to carry a crown fire. After the thinning project, most of the land would go from the highest rating for fire danger to the lowest.
Reducing the risk of crown fires that race from treetop to treetop instead of burning along the ground remains critical. Firefighters have little chance of stopping a crown fire until it hits an open area that forces it to drop to the ground. Moreover, ponderosa pine forests are well adapted to low-intensity ground fires, which clear away dead wood, remove saplings and return nutrients to the soil without hurting the big trees. But a crown fire consumes everything in its path and often creates temperatures so intense that they sterilize the soil and leave behind a crust that leaves the ground less able to absorb rainfall. As a result, intense crown fires like those that plagued Flagstaff last summer and scorched more than 700 square miles in the White Mountains are often followed by flash floods and devastating mudslides that carry away topsoil and delay forest recovery by decades.
The environmental study of the proposed thinning project depicts a tree-choked, unhealthy forest. For instance, parasitic mistletoe infests most of the area. In some hard hit areas, 72 percent of the trees are struggling with the debilitating effects of mistletoe growths, which can kill the tree in drought years. Normally, infected trees develop twisted, mutated branches relatively close to the ground. In a healthy forest, this infestation makes those trees more vulnerable to the frequent, low-intensity ground fires — which means those fires limit the spread of the infection. But decades of grazing and fire suppression have prevented those cleansing fires, allowing the parasite to spread to almost every tree in some places.
The environmental study of the proposed thinning project rejected the alternative that would have left almost all of the 16-inch and larger trees standing. The report concluded that tree densities would remain too great and too uniform without some removal of the larger trees. Instead, the forest managers came down in favor of a plan that would remove 11 percent of the large trees.
The report concluded that if the crews left behind those big trees they would have to re-thin the area much sooner. If they left all the big trees, only 54 percent of the remaining forest would have the interlocking branches that would make a crown fire possible. Without the big trees, that percentage would drop to 33 percent.
However, the report also noted that a previous harvest in 1996 that removed almost every tree larger than 12 inches in diameter at chest height played a big role in creating the current unhealthy conditions, with a monoscape of close-packed trees almost all of the same age. It takes a century or longer on average for a ponderosa pine seedling to grow to the 16-inch size.
The plan did try to take into account the needs of two endangered species found in the area — the Mexican spotted owl and the goshawk. Both species should gain benefits from the project, which would leave patches of thicker forest for spotted owl nesting.
In addition, the more open understory and the greater variety of tree densities and clusters would most likely benefit the goshawks, dexterous fliers that hunt squirrels and rodents beneath the forest canopy. In more open areas, the goshawks generally lose out to competitors like red-tailed hawks, which soar overhead watching for the movement of rodents down on the ground.
The 33,000-acre stretch of forest includes 11,000 acres of habitat critical to spotted owls and 22,000 acres of prime habitat for northern goshawks.