VALLECITO – The open meadows along the Pine River north of Vallecito Reservoir are as popular with humans for fishing as they are for osprey, but increasingly, this portion of the Weminuche Wilderness is being invaded by noxious weeds.
In some areas, fishermen must wade through thorny thistles before they can wade into the river, and hikers get covered with sticky houndstongue seeds if they venture off-trail. More weeds also mean less of the native wildflowers many come to the area to enjoy.
The weed infestation in this scenic area is not only degrading its recreational values, but also crowding out native forage for wildlife and livestock, and decreasing its wilderness character.
After years of manual weed-pulling efforts provided limited results, the U.S. Forest Service has turned to using spot herbicide treatments. When the flower head of one musk thistle can produce up to 10,000 viable seeds, it’s easy to see that, without aggressive intervention, noxious weeds are hard to stop. Forest Service range and wilderness crews teamed this month to continue the effort to slow the spread of weeds up the popular Pine River Trail.
“The weeds are using the first few of miles of the Pine River Trail as a gateway into the wilderness,” said Beth Jones, a botanist and range manager with the Columbine Ranger District. “The goal is to concentrate our efforts so that we treat the vectors used by the weed seeds to invade the backcountry.”
Just getting the necessary equipment up the trail was a challenge. Motorized transportation was not an option, because the treatment area is within designated wilderness.
Agency horses Easy, Nelson and Opie, and Dweeb the mule, stepped up to transport tanks that use carbon dioxide as a propellant to spray water mixed with herbicide. The “Saddle Light” horseback system is used by land-management agencies nationwide.
To minimize the use of chemicals, each weed was sprayed individually, and each species targeted with the most effective and safe combination of approved herbicides. The work was tedious, with care taken to prevent spills and contamination of water sources, but the results are expected to be worth the effort.
“The timing of our treatment was excellent, as most of the thistles were just beginning to bloom, so our treatment will be very effective in preventing the release of viable seeds and controlling the spread of these invasives,” said Justin Marler, Columbine District range technician.
Wilderness is defined in the 1964 Wilderness Act as: “an area of undeveloped federal land retaining its primeval character and influence, without permanent improvements or human habitation, which is protected and managed so as to preserve its natural conditions and which generally appears to have been affected primarily by the forces of nature, with the imprint of man’s work substantially unnoticeable.”
On the surface, using chemicals in wilderness areas might seem contradictory, but longtime Columbine Wilderness Ranger Anne Dal Vera said the weed treatment will help sustain the primeval character and native ecosystems of the Weminuche.
“Invasive species can dramatically alter pristine areas in a short period of time,” she said. “This carefully controlled application of herbicide will make a big difference in preserving the wilderness character of this area for future generations.”
Ann Bond is the public affairs specialist for the San Juan National Forest.
