A new environmental campaign is asking doughnut lovers to think about the effect their Boston cream doughnut or apple fritter is having on the rainforests halfway around the globe.

There's a good chance that oily residue left on your fingers after enjoying a doughnut is, in part, palm oil.

Some of North America's leading doughnut makers, including Tim Hortons, source palm oil from suppliers that are clear-cutting tropical rainforests to make way for palm oil plantations, according to a by NGO Forest Heroes.

As a result, endangered species, including Sumatran tigers and orangutans are caught in the crosshairs, as their habitats are being destroyed.

The group released its "Deforestation Doughnuts" report last week which called on Tim Hortons, Dunkin' Donuts and Krispy Kreme to use palm oil suppliers that implement a no-deforestation policy.

"When I started campaigning on this issue many years ago, we were talking about the last remaining 500 Sumatran tigers," Forest Heroes campaigner Kevin Grandia told CTVNews.ca from Vancouver. "Now we’re talking about the last remaining 400 Sumatran tigers.

Grandia said more than 77,000 square kilometres of forest have been cleared to make way for palm oil plantations in countries such as Indonesia, Papua New Guinea and Malaysia.

He said virgin rainforests are being burned down or ripped out with tractors to plant palm trees, even though companies can plant on tens of millions of acres of already degraded land that is available for development. 

Tim Hortons plans to use palm oil from 'sustainable sources'

Tim Hortons confirmed that its doughnuts are made using palm oil in the shortening and in other ingredients.

Tim Hortons spokesperson Olga Petrycki said in a statement to CTVNews.ca that ultimately, the company's goal is to purchase 100 per cent of its palm oil from verified sustainable sources.

Petrycki says the new palm oil policy will be announced in the company's next sustainability report, which is published in the spring of each year.

"In the meantime, we continue to significantly advance our work within our supply chain," she said.

Grandia said the organization has worked with major food companies including Kellogg's and Nestle, which have, in a short amount of time, committed to deforestation-free palm oil policies.

He said Dunkin' Donuts has also committed to an "aggressive timeline" to deal with the palm oil issue.

"Nowadays the number of major companies that have committed to deforestation-free palm oil are so numerous, and so large that it's not hard for a company like Tim Hortons to move quickly on this issue," Grandia said.

Grandia said he’s not asking Canadians to stop buying doughnuts, but he's urging individuals to sign Forest Heroes' that urges doughnut makers to use palm-oil suppliers that adopt deforestation-free policies.

He said there's a "visceral response" when individuals learn of the impact palm oil plantations have on critically endangered species, as well on the forests that act as carbon sinks.

"These forests are holding a ton of carbon and greenhouse gas, and we’re literally ripping them out and burning them and putting those gases into the atmosphere," Grandia said.