Some of Colorado's most popular destinations are getting greener, but not in the way rangers would like.

Rangers with JeffCo Open Space say they've always heard of people smoking marijuana and taking edibles on trails. Lately, it seems to be causing more problems, according to Mary Ann Bonnell with JeffCo Open Space.

"We see it as an emerging thing that we want to get ahead of," Bonnell said. "We're keeping an eye on it and trying to figure out how to stay ahead of it."

An increased use of marijuana on trails is something Boulder County Open Space has had to deal with as well. Marijuana use became so prevalent, policies were changed last March to allow rangers to issue citations, officials said.

In Jefferson County, rangers say it seems people are not just high, but reckless, too.

Last Thanksgiving, 14 first responders had to hike several miles to rescue an injured mountain biker who didn't know where he was, Bonnell said.

"He had fallen on his bike and injured himself. The mountain biker was unsure of what park he was in and unsure of what trail he was on," Bonnell says, "He was very straight forward and said he tried an edible and tried to be a hero on this rocky section."

In Jefferson County, several areas have emerged as popular areas for social marijuana use: Apex Park, Lookout Mountain and Crown Hill Park.

"Our main concern is public safety," Bonnell said. "We're very concerned about visitors particularly if they're trying a new product."

Bonnell says tourists sometimes visit the trails and experiment with marijuana, which can be unpredictable and dangerous.

There have been a series of incidents involving marijuana at Apex Park. First responders helped someone who became violently ill after taking edibles. In another incident, a fire started near the top of the park after someone left marijuana pipe that had not been put out.

"There are homes up here so this is potentially very dangerous to peoples homes, families pets and children," Bonnell said.

While it's on a case by case basis, rangers say they typically will not go out of their way to cite someone just because he or she is high.

They typically reserve citations for those who cause problems or compromise safety.

Colorado Parks and Wildlife says out of 7,000 citations handed out in 2016, only 25 were for marijuana use.