The story of how discarded orange peels turbocharged a Costa Rican forest

The story of how discarded ora...
On the right is the lush forest that was loaded with orange peel waste and on the left is the untreated land
On the right is the lush forest that was loaded with orange peel waste and on the left is the untreated land
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The land immediately after it was loaded with orange waste in the late 1990s
The land immediately after it was loaded with orange waste in the late 1990s
Before, during and today
Before, during and today
The Princeton team investigating the orange-enriched forest in 2014
The Princeton team investigating the orange-enriched forest in 2014
On the right is the lush forest that was loaded with orange peel waste and on the left is the untreated land
On the right is the lush forest that was loaded with orange peel waste and on the left is the untreated land
View gallery - 4 images

Sixteen years after a controversial biodegradation plan allowed 1,000 truckloads of orange peels to be unloaded onto a barren, deforested area of Costa Rican land, a team of Princeton researchers has discovered unexpectedly positive results. The area that was covered with orange waste is now a lush, overgrown forest with richer soil and more tree species than the adjacent land that was untreated.

The Area de Conservación Guanacaste (ACG) is a World Heritage-listed and government-managed conservation area in northwestern Costa Rica. In the early 1990s, it was discovered that a large-scale orange plantation was being established on one of the ACG's borders in order to sustain a new orange juice manufacturing plant called Del Oro.

In 1996, two ecologists from the University of Pennsylvania, who had worked for many years with the ACG, had a radical suggestion. What if the organic waste from the orange juice factory could be recycled to accelerate the reforestation of some barren spaces in the conservation area?

A deal was signed and the orange juice company dumped 12,000 metric tons of orange pulp and peels onto a three-hectare stretch of former cattle pasture. Many newly designated conservation areas in the ACG suffer from rocky, nutrient-poor soils due to the prominent history of overgrazing and fire-based land management in the region. The hope was that this plan would be the perfect synergy between industry and conservation.

The land immediately after it was loaded with orange waste in the late 1990s
The land immediately after it was loaded with orange waste in the late 1990s

The initial results were positive, yielding rich black soils and a variety of multi-species broadleaf herbs. A follow-up deal was struck between ACG and Del Oro, with ACG agreeing to take 1,000 truckloads of orange waste a year for 20 years.

But all was not well in the competitive orange juice business in Costa Rica.

A rival orange juice company, Ticofruit, was not happy with the deal between the government and its competitor, so it launched a court case against Del Oro, claiming this dumping of orange waste was "sullying a national park." Despite the fact that the original deal was actually between the government and Del Oro, Ticofruit's lawsuit went all the way to the country's Supreme Court and politics ultimately prevailed over common sense.

Ticofruit won the lawsuit, and the court determined the deal between ACG and Del Oro must be terminated. Progress on the initiative halted, and the land strewn with orange peels was left alone, untouched for the following 15 years.

The Princeton team investigating the orange-enriched forest in 2014
The Princeton team investigating the orange-enriched forest in 2014

Fast forward to 2013 and Timothy Treuer, a graduate student at Princeton was on the hunt for research topics. In his talks with one of the original ecologists who worked on the ACG project it was suggested that a follow-up study on the effects of the orange peel on the land had never been properly done. So Treuer went to visit the site and was stunned by what he found.

"It was so completely overgrown with trees and vines that I couldn't even see the 7-foot-long sign with bright yellow lettering marking the site that was only a few feet from the road," says Treuer. "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."

Before, during and today
Before, during and today

He returned to the site in 2014 with a team and thoroughly examined just what was going on inside this lush, overgrown forest. Comparing the orange-peel site with an adjacent control plot, the team found the orange-peel site had accelerated in growth significantly compared to the control.

As well as a three-fold increase in the richness of woody plant species, the team calculated a 176 percent increase in aboveground woody biomass compared to the control area. Deep in the soil the team also identified significantly elevated levels of macro and micronutrients.

"Plenty of environmental problems are produced by companies, which, to be fair, are simply producing the things people need or want," say study co-author David Wilcove. "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."

The project not only highlights how the industrial impact on land can be mitigated through clever environmental work, but how agricultural waste can actually prove to be beneficial in regenerating land that has previously been damaged.

The team's research study was published in the journal Restoration Ecology.

Sources: Princeton University, University of Pennsylvania

View gallery - 4 images
Any competent gardener or allotment holder could have told you what would happen with mulching and composting , common sense really
As tacheonabike said every gardener could tell you this would work. This story also highlights the stupidity of business, lawyers and the courts in continually undoing good things all in the name of money or egos.
Jose Gros-Aymerich
Nice story, and an use for orange waste plenty of ingenuity. This reminds me a tale by a teacher of Physics, about an Agricultural engineer who pointed a farmer his land was in need of gypsum; the countryman didn't believe the engineer, so he went at night, and spread gypsum on the land, making the letters 'Gypsum', when the time for harvest arrived, a set of healthier, taller, greener plants draw the name: 'Gypsum'. This is marketing, and not other more childish approaches!
I wonder why the "after" photo wasn't taken from the same vantage point as the "before" & "during"?
Hmm, that triptych at the end shows two nearly identical photos, but the one on the right (after) isn't the same. Poorly done, researchers. I think you got the pic of the untouched area mixed up with the treated area. Anyway, if the orange peels do so much good, why aren't we hearing of similar good projects here in CA and FL, at minimum? Could they help restore fire forest damage more quickly? Let's do it!
Actually... I think what this shows is "some" was better than extreme.
Had the deal not been halted continued dumping in the same area may not have produced the same results. So some good may have resulted. And they may have gotten lucky on the quantity dumped, type soil it was dumped on and local vegetation thriving in such a soil mixture.
That may not have been the case if they continued to dump the amount the proposed over 20 years.
And I agree, and decent horticulturist could have taken soil samples of the proposed dumping area and giving close results on what will happen to the soil and what would be best suited to grow there.
Perhaps this area could be used as the new control area for future dumping plans.
Gregg Eshelman
Much of the South American jungle isn't completely natural. Ancient peoples burned wood to charcoal and spread it on the land for fertilizer. Before they did that, the land was barren or grassland.
When their civilizations declined (a process started long before the Spanish and Portuguese arrived) and they abandoned their charcoal fertilized farmland, the other plants and trees thrived on the rich but thin soil.
Forward some centuries and farmers cut down everything and burn it, returning nutrients to the soil. But then they planted and harvested without additional fertilizer or deep tilling and depleted the soil nutrients.
The environmentalist 'solution' is to just stop farming to grow food.
They tend to fly into fits should anyone try to discuss applying fertilizer and deep tilling to improve the soil quality so that more food can be grown on less land, and to enable better regrowth of the jungle.
If the fertilizer can be natural food processing waste like orange peels, so much the better. Even better than simply dumping it would be tilling it in down to a half meter or deeper so that it can support deep root systems for trees.
Lawyers can destroy anything.
amazed W1
A brilliant positive result but so many negatives. 1) that the nobody is willing to get the UN onto overgrazing and so onto the absolute need for population control of the humans, not just the cattle. 2) that both the slash and burn techniques and the so-called civilised equivalent, a.k.a. deforestation are not banned 3) that such a ridiculous lawsuit should be brought and the court decision did not include allowing Del Oro to claim for all costs if the environmental benefits became so obvious.
Don Duncan
Aross & npublici: Business/lawyers are unethical, not stupid. They benefit from govt. force at our expense. But in the long run, we all suffer, thanks to pubic support of the use of institutionalized violence (govt.). Replacing that paradigm with a voluntary system would give reason, not force and corruption, a chance to change the present political chaoic societies into peaceful and properous ones. It's only logical, even if it doesn't comply with the age old paradigm of faith in force.
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