Humans Improved One Rainforest; How Can We Improve the Rest?

Trees that are taller, wider and healthier as a result of 13,000 years of human inhabitation in the forest sounds too good to be true, but that's exactly what researchers found in a temperate rainforest along the coast of British Columbia.

Scientists from the University of Waterloo, the University of Victoria and the Hakai Institute published their findings in Nature Communications on Tuesday. Shells and fire contributed to the exemplary health of the forest.

"It's incredible that in a time when so much research is showing us the negative legacies people leave behind, here is the opposite story," study lead and professor in the Faculty of Environment at the University of Waterloo Andrew Trant said in a press release.

"These forests are thriving from the relationship with coastal First Nations. For more than 13,000 years -- 500 generations-people have been transforming this landscape. So this area that at first glance seems pristine and wild is actually highly modified and enhanced as a result of human behaviour."

Shellfish are a staple of the First Nations' diet. The disposed shells covered thousands of square meters in the forest, and at some places were up to five meters deep.

Nutrients from the shells nourished the forest soil. The breakdown of shells is a slow process that distributes nutrients in a sort of time release.

The nutrients from the shells, combined with common use of fire, provided important benefits that allowed the forest to thrive. Scientists found that the First Nations inhabited forest had a more favorable soil pH and better soil drainage.

Trant expects to find similar results along other global coastlines. Future research is planned to study more landscapes that have historically been influenced by humans. Notably absent from the studied forest are plastic pollution, deforestation and significant use of fossil fuels.