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Study looks at how burning, thinning improve forest health

Fort Lewis College professor leads effort near Pagosa Springs
Ian Fullinwider, left, Hailee McOmber, center, and Stacey Tabb, members of a Fort Lewis College research team, count and identify plants last week in an area that was thinned and burned 10 years ago. The work is part of a forest management study northwest of Pagosa Springs. The summer work was supported by a $93,000 federal grant.

Returning more of the San Juan National Forest to a healthy and resilient state will require more proactive thinning and managed fires.

“When we have a resilient ecosystem, it reduces the potential for catastrophic wildfire, it reduces the risk for disease and for insect infestation,” said Chris Tipton, fire management officer with the San Juan National Forest.

In the early days of the 416 Fire, areas that were thinned or saw prescribed burns helped firefighters protect homes and make better decisions about how to fight it, he said. For example, near the entrance to the Rockwood subdivision where the forest was thinned, firefighters could see and fight small spot fires, he said.

“It was a tremendous help for the first series of spot fires that we received over the line,” he said.

In the Hermosa Creek Special Management Area, more than 10,000 acres that burned in the mid-2000s also saw a less-intense blaze than other areas, Tipton said.

Historically, the forest, particularly areas dominated by ponderosa pines, burned frequently and at a low intensity, he said. Before widespread fire suppression across the West, fires tended to move along the surface in more open forests, consuming grasses and shrubs rather than entire stands of trees.

In the San Juan National Forest northwest of Pagosa, fire and forest ecologist and Fort Lewis College professor Julie Korb, with the help of current and former students, is studying the long-term ecological effects of active forest management.

They have found that thinning and burning is the best way to restore the forest back to the way it was before fire suppression, logging and grazing in the West, she said.

It is also the best way to reduce the severity of fires – by lowering the number of trees, increasing the height of the canopy and reducing the amount of ladder fuels and litter on the forest floor, Korb said.

The work started in 2002 as a partnership between FLC and the Ecological Restoration Institute at Northern Arizona University.

The study sites stretch across more than 720 acres in a warm, dry mixed-conifer forest, where white fir, ponderosa pine, Douglas fir and aspen trees are found, Korb said.

The team introduced fire only in some areas, thinned and burned in other areas and left other sections untouched.

In forest management, the goal isn’t to eliminate all high-severity fires because those play a role in the subalpine areas where forests are evolved to burn less frequently and at much hotter temperatures, which kills most or all of the trees.

However, where ponderosa pines dominate, a high-severity fire that kills all of the trees can trigger a conversion to a shrub-dominated landscape because the seed sources for new ponderosa pines have been eliminated, she said.

Long-term forest management should include a combination of strategies, including thinning and burning, just burning, and leaving some areas of dense forest to promote resiliency, especially as the climate continues to change.

“Our forests, right now, are more homogeneous than they have ever been,” Korb said.

A diverse environment also supports wildlife, which relies on a diverse landscape, from burn scars to dense forests.

“The goal is to get those diverse habitats back,” Korb said.

Her research has shown wildlife moving through all the habitat areas in her study area at different times, she said.

There are limited resources to manage the 1.8 million acres of San Juan National Forest, so Forest Service staff members take a targeted approach, focusing on those areas where forest management can have multiple benefits, such as improving recreation and habitat, and protecting structures. The highest priority areas are always those near homes and other structures, Tipton said.

In the last five years, the Forest Service has actively managed 15,000 acres in the Columbine District, he said.

This year, the Forest Service staff is planning to prescribe-burn 12,000 acres when conditions are right.

“We closely monitor those conditions, the fuels, the air quality, all those things and even the socio-economic and political side,” he said.

There is also vegetation thinning going on near Tween Lakes and Enchanted Forest north of Bayfield and at Purgatory.

A timber sale was also recently awarded near Trout Creek at the top of Beaver Meadows, where trees have been killed by insect infestation.

Long term, the Forest Service is also considering in the Missionary Ridge area.

While some areas, particularly ponderosa pine forests, may have burned in recent history, it’s important to continue to burn the landscape on a regular cycle, Tipton said.

Based on the total number of ponderosa pine in the Columbine District, the Forest Service staff should be prescribed-burning between 6,000 to 12,000 acres per year on a 10-year cycle to maintain forest health.

Some areas of the San Juan National Forest are healthy. For those ponderosa pine forests in need of management, it could take 10 to 20 years to see the health of the forest improve, Tipton said.

“This is something the community wants to see,” he said.

Holistic landscape change will take collaboration between local governments, federal agencies and private landowners, Korb said.

“Everyone has to work together if you want to make these areas resilient,” she said.

mshinn@durangoherald.com

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