Bark beetle damage is expanding in Colorado.

The number of dead and dying spruce and fir trees is increasing at an alarming rate. The main cause is the spruce beetle. Across the higher elevations of the Colorado mountains, the tell-tale signs of damage are becoming more and more visible.

Signs of trouble are needles turning a yellowish-green color and falling to the ground whenever there's a strong wind. Those needles start falling from trees in its second summer after infestation. Boring dust from the beetles working the tree will start accumulating in the bark and around the base of the tree as well. Streams of resin on the main trunk are signs too a tree has been recently attacked.

According to the Colorado State Forest Service, the bark beetle outbreak is spreading. Since 2000, the bark beetle has killed trees on more than 1.8 million acres of Colorado land. That's about 40% of the spruce and fir forest. Approximately 178,000 acres of high-elevation Engelmann spruce trees were infected by beetles last year alone. The higher elevations on The Grand Mesa are showing signs of infestation. The primary threats are in and around the Rocky Mountain National Park, portions of the San Juans, West Elk, and the Sawatch Mountain Ranges. For an interactive map and information about Colorado's infestation, click HERE.

What's the cause of the problem? Mostly the ongoing drought. That along with record-warm temperatures has provided an environment favorable for the beetle's population explosion.

Credit: Fox 31