1 00:00:02,040 --> 00:00:07,360 Speaker 1: Welcome to brain Stuff from how Stuff Works. Hey, brain stuff, 2 00:00:07,360 --> 00:00:10,719 Speaker 1: it's Christian Seger. Imagine if some of Earth's most barren 3 00:00:10,760 --> 00:00:15,200 Speaker 1: waste lands could be transformed into dense, productive forests by 4 00:00:15,200 --> 00:00:20,479 Speaker 1: the most unlikely of helpers, discarded fruit peels. It sounds 5 00:00:20,520 --> 00:00:23,200 Speaker 1: like wishful thinking, but that's exactly what happened. In the 6 00:00:23,280 --> 00:00:29,360 Speaker 1: nineteen nineties. During a promising ecological experiment, orange juice manufacturer 7 00:00:29,480 --> 00:00:34,440 Speaker 1: del Oro plunked twelve thousand metric tons it's around thirteen thousand, 8 00:00:34,440 --> 00:00:38,720 Speaker 1: two hundred twenty eight tons of orange peels on top 9 00:00:38,840 --> 00:00:43,400 Speaker 1: of bleak Costa Rican pasture land, eventually transforming it into 10 00:00:43,479 --> 00:00:47,680 Speaker 1: a lush, fertile forest. But it's a success story that 11 00:00:47,840 --> 00:00:52,640 Speaker 1: almost wasn't told. Del Oro donated a seven acre or 12 00:00:52,840 --> 00:00:56,120 Speaker 1: three hacked or plot on the edge of the Wanna 13 00:00:56,120 --> 00:01:01,959 Speaker 1: Caste conservation area after being approached by University of Pennsylvania 14 00:01:02,040 --> 00:01:07,559 Speaker 1: researchers Daniel Jansen and Winnie Hall Walks, who wondered how 15 00:01:07,600 --> 00:01:11,800 Speaker 1: the companies discarded orange peels could benefit the soil. In 16 00:01:11,920 --> 00:01:16,640 Speaker 1: nineteen ninety eight, the company deposited one thousand truckloads of 17 00:01:16,640 --> 00:01:20,800 Speaker 1: orange skins onto the degraded land as part of the agreement, 18 00:01:21,200 --> 00:01:25,760 Speaker 1: but rival orange squeezer Tico Fruit, sued del Oro a 19 00:01:25,840 --> 00:01:29,720 Speaker 1: year into the contract, claiming the company was defiling a 20 00:01:29,880 --> 00:01:34,160 Speaker 1: national park. Costa Rica's Supreme Court agreed, and after only 21 00:01:34,200 --> 00:01:38,000 Speaker 1: two years, the experiment came to a halt. That could 22 00:01:38,000 --> 00:01:39,920 Speaker 1: have been the end of the story were it not 23 00:01:40,080 --> 00:01:45,000 Speaker 1: for Timothy Truer, a curious ecologist at Princeton University in 24 00:01:45,080 --> 00:01:49,600 Speaker 1: Truer and a team of researchers traveled to Costa Rica 25 00:01:49,880 --> 00:01:53,240 Speaker 1: for unrelated research and decided to look up the orange 26 00:01:53,240 --> 00:01:57,080 Speaker 1: peel plot. The site's sign was so covered with vines 27 00:01:57,200 --> 00:02:00,240 Speaker 1: and the land so densely filled with trees that it 28 00:02:00,280 --> 00:02:03,920 Speaker 1: took the team years and dozens of site visits to 29 00:02:04,040 --> 00:02:07,800 Speaker 1: discover it. The team sampled and studied the soil at 30 00:02:07,840 --> 00:02:10,280 Speaker 1: the site and compared it to samples that were taken 31 00:02:10,280 --> 00:02:13,760 Speaker 1: in the year two thousand. It also noted tree diameter 32 00:02:14,120 --> 00:02:17,800 Speaker 1: and species from the orange peel site and that of 33 00:02:17,840 --> 00:02:22,480 Speaker 1: a nearby pasture that wasn't treated with peels. The researchers 34 00:02:22,480 --> 00:02:26,920 Speaker 1: found that the treated area had richer soil, more tree biomass, 35 00:02:26,960 --> 00:02:30,600 Speaker 1: and a broader variety of tree species, including a fig 36 00:02:30,639 --> 00:02:36,040 Speaker 1: tree with a circumference equivalent to three armspans. The precise 37 00:02:36,120 --> 00:02:39,520 Speaker 1: reasons for this one hundred and seventies six percent increase 38 00:02:39,800 --> 00:02:44,040 Speaker 1: and above ground biomass are still being investigated, but the 39 00:02:44,120 --> 00:02:49,200 Speaker 1: researchers contend dumping massive amounts of nutrient rich organic waste 40 00:02:49,400 --> 00:02:53,640 Speaker 1: had a nearly immediate effect on the land's fertility, changing 41 00:02:53,680 --> 00:02:58,960 Speaker 1: its lifeless soil into a thick, rich, loamy mixture. The 42 00:02:59,080 --> 00:03:03,360 Speaker 1: researchers proposed it's also probable that the orange peels suppressed 43 00:03:03,400 --> 00:03:06,760 Speaker 1: growth of an invasive grass that was keeping the forest 44 00:03:06,880 --> 00:03:10,919 Speaker 1: from flourishing. Not only is the rediscovery of the experiment 45 00:03:11,000 --> 00:03:15,280 Speaker 1: a boon for barren landscapes and agricultural waste, but it 46 00:03:15,400 --> 00:03:19,200 Speaker 1: also could have a major impact on Earth. If more 47 00:03:19,280 --> 00:03:25,040 Speaker 1: companies institute similar environmentally friendly solutions to waste, the resulting 48 00:03:25,320 --> 00:03:29,520 Speaker 1: richly vegetated land could help isolate harmful carbon dioxide in 49 00:03:29,520 --> 00:03:34,000 Speaker 1: the air and improve Earth's polluted atmosphere. So consider this 50 00:03:34,440 --> 00:03:38,960 Speaker 1: an estimated of all fresh produce in the United States, 51 00:03:39,320 --> 00:03:44,040 Speaker 1: or roughly sixty six million tons or sixty million metric 52 00:03:44,080 --> 00:03:48,400 Speaker 1: tons of produce is thrown away annually, making it the 53 00:03:48,520 --> 00:03:59,480 Speaker 1: single largest ingredient in American landfills. Today's episode was written 54 00:03:59,520 --> 00:04:02,320 Speaker 1: by Laurie Ill. The produced by Dylan Fagan, and for 55 00:04:02,400 --> 00:04:05,400 Speaker 1: more on this and other topics, please visit us at 56 00:04:05,400 --> 00:04:17,680 Speaker 1: how stuff works dot com.