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With evergreens, it's only natural shedding

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Wednesday, Sept. 16, 2015 7:12 PM
Area evergreen trees are showing seasonal discoloration, a natural phenomenon, according to the Colorado State Forest Service. It is not beetle kill.
Evergreen trees in the region are showing seasonal discoloration, a natural phenomenon, according to the Colorado State Forest Service. It is not beetle kill.

Invasive beetle kill has reached La Plata County, but forest officials are reminding residents that the evergreen trees in Southwest Colorado with needles turning yellow and orange is a natural shedding process.

"It's a natural phenomenon, not beetle kill," said Colorado State Forest Service Forester Ryan Cox. "A tree fading because of beetle kill would have the entire tree fading, not just the inner needles you see with these trees."

The process is part of the evergreen's growth cycle, shedding old, interior needles on low portions of the crown and close to the trunk. The tree turns yellow, then a reddish-brown color a. This can be seen in early September through fall, sometimes even into early winter.

"Most of the inquires received about the phenomenon relate to ponderosa pine, but other conifer species exhibit fall needle drop as well," said the Colorado State Forest Service in a prepared statement.

However, beetle kill has reached La Plata County. Cox said reports of the die-off have been reported above Vallecito Reservoir, on the west side of the county near Mancos and even in the Shenandoah region.

"It's kind of hit or miss. It's all over the place," he said.

But Cox doesn't think the forests of La Plata County will experience the same devastation as the mountains around Wolf Creek, which are striking for the expanse of dead trees as a result of beetle kill.

He said it's because Wolf Creek is at a higher elevation, which creates a habitat for spruce trees. There, the outbreak of spruce beetles has infested the mountainsides, creating a surreal landscape.

In La Plata County, Cox said there are bark, pine and Ips beetles, but not in great numbers - yet.

"We're at a lower elevation with more ponderosa and there hasn't been a big outbreak," he said. "Certainly nothing like what happened up on the Front Range."

Still, Cox acknowledges a risk of a beetle-kill outbreak always exists, and the best preventive measure is "good forest management."

He said that at the turn of 19th century, loggers for the mining and railroad industry created an even-age forest by excluding a natural fire regime from happening. As a result, pine forests are overgrown and dense.

"All the trees are competing for the same resources - sunshine and water - weakening the entire forest," he said.

The best practice, he said, is to thin out forests and create openings so fewer trees compete for a limited amount of nutrients. That way, the trees will be stronger and healthier to fight infestations.

He couldn't pinpoint the exact amount of projects that are intended to fight beetle kill, but he said it happens often.

"We undertake them on a case-by-case basis," he said. "But there's lots of stuff going on from us or other groups. There's a lot of grant money going into projects."

jromeo@durangoherald.com

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