TORONTO — There’s no telling when a good idea will strike. Just ask Tentree cofounders Kalen Emsley and David Luba, who stumbled upon a retail business brainwave that would change their lives — and the environment — while hiking and surfing in Hawaii in 2011.

“We were having one of the most positive weeks of our lives in Hawaii. But, in the news, we were seeing lots of negative things about the environment and climate change,” said Luba, Tentree’s vice president of sales.

The friends noted that many of their fellow travelers were embracing socially responsible clothing companies like Toms, a brand that built a strong following by giving away shoes to needy children. “Lululemon was also trying to do pants made with seaweed at that time,” said vice president of content Emsley, who had spent his high school years running a tree-planting company with his brother, Derrick.

After mulling over these events during a morning hike, the Regina, Saskatchewan, natives hatched the idea of creating an environment-conserving clothing brand that would plant 10 trees for every purchase made in endangered forests around the world.

The rookie retailers also promised that if they returned home and made a sustainable tank top that would sell, they’d proceed with Tentree’s launch. “We sold out in two days,” said Emsley, whose brand now boasts 2.3 million followers on Instagram and more than 500,000 on Facebook.

Indeed, since its debut in 2012 the Vancouver-based brand has gained an international e-commerce following for its outerwear and loungewear staples for women and men.

Tentree shoppers were also hooked by the tree tokens received with each purchase, which allowed them to register online to learn more about their item’s back story, where their money was going, and where their tree would be planted.

“Being sustainable and comfortable aren’t mutually exclusive. But we’re doing all that we can to nudge Millennials away from bad consumerism, revitalize the environment, and inspire a generation to believe that they can do the same,” said Tentree chief executive officer Derrick Emsley.

As part of that mission, this month Tentree will unveil its Earth Day capsule collection of “adventure gear” for Millennials designed with a proprietary blend of Tencel, organic cotton and recycled polyester. The antimicrobial, moisture-wicking fabric also bears new graphics and motifs inspired by nature. As well, for every item purchased, 10 trees will be planted in Indonesia.

Tentree has also aligned this debut with the launch of its Earth Week social media campaign on April 22, when the company will challenge followers to use their smartphones to save the environment.

On that day, Tentree will upload a special post across Facebook, Instagram and Twitter in honor of Earth Day. For every 10 likes it receives, the company will commit to planting one tree in designated planting sites on Biak Island, Indonesia, after the five-day campaign concludes.

“For Earth Week we hope to plant 500,000 trees with this environmental impact story,” said Derrick Emsley.

To date, sales of Tentree’s streamlined basics have helped plant 25 million trees worldwide. The brand’s goal is to plant one billion trees by 2030.

Consumers can also expect to see Tentree introduce a biodegradable capsule collection for fall that can be planted in the soil once they are done wearing it.

“Sometimes living sustainably is hard because we are fallible people living busy lives,” said the ceo. “That’s why we’ve become the environmentalists consumers can turn to at Tentree so they can lead more environmentally friendly lives.”