DENVER -- Our dry conditions may be causing more changes than in just low water levels and how often we water our lawns. It may also change when aspen trees in the high country change color ane even what colors they change to.

"There's no definitive answer," said Phil Schwolert, a forester with the Colorado State Forest Service. "There are lots of factors involved."

The autumn change of colors is reflective of moisture, elevation and temperature.

Aspen typically start changing about the first of September and peak three weeks later, but the Forest Service says drought could play a role this year that is hard to predict, but will likely mean an earlier peak.

"What we would typically expect to see in a drought is probably an early onset to the fall colors. Sometimes, that's the response to any kind of stress, particularly drought," said Randy Wilkerson, of the U.S. Forest Service.

Brilliancy also is an annual question that is hard to predict.

With the shorter days and lower temperatures of autumn, the trees stop producing chlorophyll, the green chemical that is a byproduct of photosynthesis. As that drains from the leaves, the underlying yellows and reds are revealed.

Aspen, with their interconnected root network, actually tend to fare reasonably well during droughts, sharing and conserving moisture.

Aspen ecologist Dale Bartos of the U.S. Forest Service said the declining number of aspen stands throughout the West is a greater concern.

"Aspen is a fire-dependent species that thrives best when it gets killed by burning, and it regenerates by putting up root suckers after a fire," he said.

After the fires we've had this summer, that could mean a significant change in Colorado's landscape, 7NEWS reported.