Aspen Restoration Put to the Test

 by Mary O'Brien, Utah Forests Director

The real test of a group comes when problems arise — say, for example, that your proposed restoration plans aren’t working. For eight years, the Monroe Mountain Working Group has been trying to restore struggling aspen in Fishlake National Forest. We’ve had great success, award-winning, actually, by unanimously agreeing on restoration approaches, including prescribed burns, cutting down trees, and setting limits on browsing (eating) of aspen sprouts by livestock, elk, and deer. 

Our recommendations made it into the U.S. Forest Service’s 10-year restoration plan for the mountain. Now, three years into that plan, we have a problem. Elk and cattle are exceeding the browse limits we set. As a group, we’re going to have to figure out what to do about it.

A little background

MARY O'BRIEN

Two major problems have contributed to aspen decline on Monroe Mountain: decades of fire suppression, which led to fir and spruce trees shading out aspen, and too much browsing. Elk, deer, sheep, and cattle eat leaves and stems off the tops of aspen sprouts, preventing young aspen trees from growing tall and replacing aging ones. Over time, the aspen have dwindled.

To address these problems, we came up with two strategies for stands of aspen mixed with spruce and fir, specified in the 10-year plan:

1. Controlled burns on thousands of acres of mixed forest lands to restore a healthier balance of aspen, spruce, and fir.
2. Mechanical thinning (cutting spruce and fir trees) in mixed aspen-conifer stands that are small or near private property within the national forest.

The hope is that cattle and elk will spend their lunchtimes in the newly restored burned areas rather than in the struggling, thinned stands. While the Trust has been skeptical about this hope from the beginning, the plan states that if treated stands continue to be excessively browsed by elk, deer, cattle, and/or sheep, other actions will have to be taken.

We’ve reached that point.

What the monitoring shows

Since 2016, the Richfield Ranger District, a Brigham Young University monitoring team, and the Monroe Mountain Working Group have been watching and taking measurements. Monitoring shows that the carefully executed burns have gone well, and hundreds of thousands of aspen sprouts are now reaching for the sky. But the monitoring also shows that aspen sprouts in mechanically thinned stands are being too heavily browsed — mostly by elk and deer, as cattle are not allowed in recently thinned stands. The aspen sprouts are more scattered than after a fire, and so even a few animals can halt restoration in those stands.

JIM SHULER, UTAH DIVISION OF WILDLIFE

You may be wondering: elk and deer have to eat something, so what’s an acceptable number of browsed aspen? The Forest Service, in its plan, calculated the percent of aspen sprouts per acre that can be browsed, while leaving enough untouched sprouts to reach the healthy threshold of 500 grown-up aspen trees per acre. Currently, browsing of thinned stands exceeds that limit.

What to do? 

Cattle can be temporarily kept out of aspen stands, but elk and deer, which move freely throughout the mountain, cannot. We can surround thinned stands with 8-foot-tall fences (the height needed to prevent elk from jumping over the top), but it’s expensive and requires frequent maintenance. Elk numbers could be reduced by increasing the permitted hunting tags. The state legislature could stop the mandated killing of coyotes, allowing the natural predators to decrease deer numbers on Monroe Mountain and thus give aspen a better chance to thrive.

Or perhaps the thinning itself will have to be re-examined. 

The Monroe Mountain Working Group and the Richfield Ranger District are thoughtfully considering and discussing options that will stay the course toward restoration. This mountain wants to grow aspen, and this group wants to help that happen. Stay tuned.

Read more about the Monroe Mountain Working Group ›