WITH JUST 235,000 RESIDENTS, Boise, Idaho, is not the biggest city in the United States. But it has made an outsized commitment to reforestation. Boise is in the first cohort of cities that made a pledge in August to the U.S. Chapter of 1t.org, a global movement to conserve, restore and grow 1 trillion trees by 2030. The city pledged to plant 335,000 trees.

Other cities to make pledges then to the chapter, which is led by American Forests and the World Economic Forum, are Tucson, Ariz., Detroit and Dallas.

The momentum for this started building more than a decade ago, when Idaho’s Community Forestry Program brought together a few dozen people to discuss the rapid development happening in the Treasure Valley, where Boise is located. People in the valley jumped into action. Over the next few years, they compiled data about the impact the region’s trees have on air quality, created forest management tools to help determine where to plant trees, and founded the Treasure Valley Canopy Network, which is the catalyst for collaboration and investment in the valley’s trees.

A phone call last spring to Lance Davisson, who leads the network, took all of this good work to the next level. The call was from Boise City Council President Elaine Clegg, who had the vision to plant 100,000 trees (one for every household) in Boise and 235,000 tree seedlings (one for every city resident) in surrounding Idaho forests by 2030. The City of Trees Challenge was born a month later.

“People love trees,” Clegg says. “Trees clean the air and water. Planting a tree for every household is an easy idea for our residents to embrace so they can step up in helping combat climate change.” Treasure Valley is well on its way to being an even greater treasure.