A migrating bug is finding the pine trees and drier climate in Southwest Colorado more appetizing, a cause of concern for public land officials.
The round mountain pine beetle has landed on a forested mesa above the Lower Dolores River Canyon, and is killing ponderosa pines, reports Derek Padilla district ranger for the San Juan National Forest.
“It is the first report of this type of beetle in southwest Colorado,” Padilla said. “Normally it resides in northern New Mexico and Arizona and has been causing problems in those areas.”
The immigrant beetle swarm has infested a 300-400 acre swath of ponderosa forest in the Lake Canyon area, approximately 5 miles north of the Bradfield Bridge.
Forest officials are taking an aggressive and immediate stance against the intruder. Foresters will be thinning, burning, and conducting logging sales in that area to prevent the spread of the beetle, which prefers ponderosa, but will also dine on pinon pine.
“The treatment plan is to get ahead of the bug’s life cycle,” Padilla said. “The eggs are laid in fall and the bug emerges in spring to feed on the tree, eventually killing it. Then as adults they fly on to the next tree and the cycle is repeated.”
Strange as it sounds, one part of the plan is to remove uninfected healthy trees ahead of the bugs path in order to starve it out and slow its infestation, he said.
“They move in ¼ to a one-mile increments, so the plan is to get ahead of it and reduce density levels.”
Sustained drought has weakened ponderosa pines in the Southwest, limiting their defenses against pests. Lack of moisture is the culprit, and removing some trees allows the remaining ones to absorb more water to stay healthy and fight off bugs.
Padilla said the voracious round mountain beetle has a 70-80 percent mortality rate, or put another way, it kills up to 80 trees per 100 it hits.
Foresters are hopeful the infestation will be contained. Natural barriers — to the west the Dolores River Canyon; to the east the Narraguinnep Burn Area — may help to prevent wide-spread infestations.
“Its not something to ignore, so we have an expedited treatment plan. They can fly, so they conceivable could get across those natural barriers,” Padilla said. “They requires a warmer climate, and whether you believe it is global warming or not, this area is experiencing increasing temperature gradients that are stressing our forests and making them vulnerable.”
jmimiaga@cortezjournal.com
