Jim Mann wants you to go shirtless at your next race.

Forty-three-year-old Jim Mann looked around his gear closet and sighed. There were piles upon piles of cotton shirts and tech tees accumulated from various races over the years. Most were in pristine condition – they had never been worn. Even in his heaviest training weeks, the champion ultrarunner didn’t need this many shirts. No one did.

“I started talking with other runners about this, and it turned out lots of people felt similarly,” says Mann. “We had this huge number of race t-shirts we had never worn.”

For years, races have given away shirts as part of their “swag” bag – the endurance athlete’s acronym for “Stuff We All Get.” Shirts check a lot of boxes for race organizers: in addition to giving athletes a souvenir from their big day, t-shirts organically transform athletes into a walking billboard for the event and its sponsors. It’s no surprise then, that shirts have become the standard giveaway at just about every race, be it the Ironman World Championship or a small-town fun run.

But Mann began to wonder if maybe his overflowing closet was a symptom of something bigger. Surely all that swag couldn’t be good for the environment. As he followed his curiosity down the rabbit hole, he was alarmed by what he found. 

“A single cotton t-shirt takes as much water to produce as a person would drink in two-and-a-half years,” says Mann, incredulously. “The fashion industry consumes more energy than aviation and shipping combined, and accounts for 8% of total greenhouse gas emissions.”

There’s also the trash factor. Many athletes donate their excess clothing and gear to charity organizations, assuming the goods will be put to use with the less fortunate. But that’s not always the case. Historically, unwanted secondhand clothes were sent abroad, but some countries have started to reject these donations, saying they have more than they can handle. When charities can’t unload their clothing donations elsewhere, they’re sent to local trash heaps. As it stands, 84% of all unwanted clothes end up in landfills. In New York City alone, this comes to about 400 million pounds thrown away every year.

Mann knew simply refusing a shirt at his next race wouldn’t solve the problem. Instead of languishing in his closet, the fabric would simply take a direct route to the landfill. To create real change, he’d have to do something big. The opportunity appeared when Mann, who lives in the Scottish city of Inverness, acquired land in Scotland that was badly razed and in need of reforestation.

“I read a few studies that showed the single best solution for combatting climate change is planting trees,” says Mann. “Now I had land that needed trees, and a group of people who cared about doing something positive for the environment. I thought, ‘What if we could give people the option of planting a tree, instead of receiving a t-shirt they would never wear?’”

With all the pieces of the puzzle in place, Trees Not Tees was born. The organization, which formally launched in February 2020, partners with race directors to give athletes the option of foregoing a free race shirt. 

“When they register, the athlete can simply tick a box next to the t-shirt sizing selection on the entry form, which says I don’t need another t-shirt. Please plant a tree for me instead,” says Mann. “Instead of buying too many t-shirts, the organizer simply pays us for the cost of the t-shirt, and we plant a tree for the participant instead.”

Once the tree is planted, Trees Not Tees sends a PDF certificate via email to the participant with a picture of their young tree, details of the species of tree planted, and a geo-location address. For those who still really that race tee, don’t fret – swag is still an option: “We understand that t-shirts can be great memories, especially if you’re just starting out, or if they’re from a special race,” says Mann. “But many athletes are already thinking about environmental issues, and when they hear about Trees not Tees, the reception is incredibly positive.”

The Trees not Tees organization hopes to be a force in transitioning away from millions of unused or single-use t-shirts from races to planting millions of trees instead.

“We want to change the habits of the industry and encourage everyone to adopt a more sustainable and environmentally-friendly outlook,” says Mann. “We think simply offering to plant a tree instead of getting a race t-shirt will be enough to encourage many people to make more positive and sustainable choices.”