The life of a Christmas tree is short: It spends a month or so in warm comfort, decorated with glowing lights, before it’s thrown out at the end of the year.

For the past 25 years, Denver Recycles, a program run by the city Public Works Department, has tried to combat that with Treecycle, which takes used Christmas trees and turns them into garden mulch.

Charlotte Pitt, a manager at Denver Recycles, said she enjoys the closed loop nature of the program — trees helping to provide new life in Denver gardens instead of sitting in a landfill. Because no oxygen gets to organic matter in landfills, decomposition creates methane, Pitt said.

“Recycling doesn’t work if you don’t have somewhere to put the end product,” she said. “Keeping the trees out is a great way to decrease methane production in the landfills.”

For the last 10 years, Denver Recycles has collected about 20,000 trees per year during the Treecycle event, Pitt said. How many trees are sold in Denver is a harder number to gauge. Dozens of organizations around the city sell real trees, and Denver’s proximity to the mountains means people can cut their own trees there.

The mulch from Christmas trees is given away in May during a one-day event with Denver Parks and Recreation. Last year, 855 cars came through the main site, and the city gave away about 5,000 cubic yards of mulch. The trees are stored until March, when Denver Recycles brings in a company to shred them, Pitt said.

“We know people aren’t thinking about mulch until May,” she said. “It just makes sense for us to wait.”

The city also adds additional branch debris to the mulch to give it a more varied consistency. The mulch is not decorative and should be used as a first layer in gardening, Pitt said.

Turning trees into mulch is only one way to recycle, said Doug Hundley, a spokesperson with the National Christmas Tree Association (NCTA). The organization, based in Littleton, has a page on its website dedicated to different recycling efforts across the nation. In Illinois, trees are being used to create habitat for herons.

“People do a lot of creative things with these trees,” Hundley said.

The NCTA represents about 15,000 tree farmers nationwide. Each year, the organization donates the official Christmas tree to the White House.

To recycle the trees in Denver, Pitt said it’s important that all decorations be removed.

Denver Recycles serves the city and county of Denver’s Solid Waste Management customers. Customers can place their trees on the curb in their regular trash collection spot. If placed on the side of the curb, they should not be bagged.

To make sure it collects as many trees as possible, the program takes a page out of the book of Saint Nick himself by having the program run through two weeks of trash services in January.

“We drive by every home twice,” Pitt said.