If you’ve ever had doubts about how compost can transform your garden, look no further than the illuminating tale of how a bunch of orange rinds revived a Costa Rican forest. That study—which spans two decades and involves a Supreme Court lawsuit, a juice company, and some intrepid researchers—provides deep insights into how we might resolve billions of acres of deforestation worldwide. It might just inspire you to go out and get a compost bucket for your own kitchen counter.
If Del Oro, which had recently started production on the northern border of world heritage site Área de Conservación Guanacaste (ACG) donated part of its forested land to the conservation, the company could dump its orange peel waste on deforested parkland at no cost. The offer was one Janzen and Hallwachs had settled on after working with the ACG for years and turning over all kinds of harebrained reforestation ideas for barren lands within the park.
The biodegradation plan was controversial, to be sure. Nevertheless, paperwork was signed, and in the next year 12,000 metric tons of orange peels dropped onto three hectares of land formerly grazed by upon by cattle—much of which had become nutrient-poor and rocky.
Those 1,000 or so truckloads of orange peels dumped by Del Oro yielded very positive results. Researchers took note of rich, black soils and the appearance of multiple species of plants. Another deal was drawn up between ACG and Del Oro for another 1,000 truckloads of orange waste to be dumped at ACG annually for the next 20 years.
But all this hand-shaking riled up another Costa Rican juice company called TicoFruit, which sued Del Oro for desecrating a national park. The case was brought to the Supreme Court, and TicoFruit won. The deal between ACG and Del Oro was thus scrapped, and the land already covered by orange peels forgotten for the next 15 years.
Timothy Treuer, a graduate student in Princeton Department of Ecology and Evolutionary Biology, in 2013 talked to Janzen about the ACG project and decided to conduct a follow-up study to see what had happened to that orange peel-riddled land, after all. While in Costa Rica for another research project, Treuer swung out to the ACG to check out the site. Except, he couldn’t find it.
“It was so completely overgrown with trees and vines that I couldn’t even see the seven-foot-long sign with bright yellow lettering marking the site that was only a few feet from the road,” Treuer told Princeton University. After half an hour of searching for the sign, Treuer had to reach out to Janzen for more detailed directions on finding the location. A week later, he found it.
“I knew we needed to come up with some really robust metrics to quantify exactly what was happening and to back up this eye-test, which was showing up at this place and realizing visually how stunning the difference was between fertilized and unfertilized areas.”
The plot of land where orange scraps had been dumped had 24 different species of thriving vegetation, compared to land standing adjacent that boasted just one species of tree.
Overall, the three-hectare area where orange waste was dumped shows a 176 percent increase in biomass, with richer soil, more tree species, and more forest canopy closure than adjacent land in the same area. “This is one of the only instances I’ve ever heard of where you can have cost-negative carbon sequestration,” Treuer told Princeton. “It’s not just a win-win between the company and the local park – it’s a win for everyone.”
“Plenty of environmental problems are produced by companies, which, to be fair, are simply producing the things people need or want,” study co-author David Wilcove told Princeton. “But an awful lot of those problems can be alleviated if the private sector and the environmental community work together. I’m confident we’ll find many more opportunities to use the ‘leftovers’ from industrial food production to bring back tropical forests. That’s recycling at its best.”