The land area of the Central American country Costa Rica is only half the area of Jiangsu Province in my country. However, such a small country has 6% of the world’s species, which can be said to be a treasure house of biodiversity. At the end of the 20th century, in a damaged rainforest in Costa Rica, a group of ecologists conducted a bold ecological restoration experiment.
A juice processing factory erected in the rainforest
In 1995, a processing plant for a large juice company was built on the outskirts of the Guanacaste Reserve in Costa Rica. The waste and wastewater generated during the factory production process, as well as the cars transporting raw materials and finished juice… various factors will have an inevitable impact on local flora and fauna.
Jensen and Horwax, ecologists who are conducting biodiversity surveys in Costa Rica, opposed the project. To this end, they signed a strange agreement with the juice processing factory on behalf of the reserve authority. Its content is: first, it is not allowed to use pesticides in excess of the standard during the planting process of the processing factory; second, the garbage dumped by the processing factory within the protected area can only be the pomace by-products after juice processing, which is mainly orange peel and dried juice. Orange pulp; third, the processing plant must extract the limonene in the orange peel before dumping the pomace.
The factory originally thought that closed buildings would be built in the garbage dumping area to prevent the odor from spreading, but Jensen and Horwax said that the pomace can be dumped directly in the open and can be used for ecological restoration. According to the agreement, for 20 years, the factory will dump 1,000 loads of fruit pomace in the specified area every year.
Tens of thousands of tons of garbage dumped in protected areas
On a sunny noon in 1997, several heavy trucks appeared in the Guanacaste Nature Reserve and finally stopped on a grassy field in the reserve. Within minutes, tons of orange peel and squeezed pulp were dumped on the grass. Over the next year, trucks came regularly to dump the pomace, with a total of about 12,000 tons dumped.
Over the course of a year, a total of 12,000 tons of pomace were dumped in the reserve.
The pomace was dumped in an area of the reserve that was once used for grazing, covering an area of approximately 30,000 square meters. Years of grazing have severely degraded the nutrient-rich soil.
Because this factory saves a lot of garbage disposal fees, it is equivalent to reducing the cost of juice production, so the price of their juice products becomes more competitive in the market, which of course attracts the jealousy of competitors. A complaint filed against the juice processing factory in the local court listed various evidence that the factory dumped garbage in the protected area and damaged the local ecology. Soon after, the project of dumping garbage in the open was stopped.
Tens of thousands of tons of orange pomace were piled randomly on the grass in the reserve. Since no new pomace was transported, just six months later, with the help of flies, worms and microorganisms, mountains of fruit pomace piled up on the surface. The slag was transformed into a layer of loose black soil more than ten centimeters thick. The result is that the local soil has become so fertile for the first time since it was degraded by grazing.
In sixteen years, the grassland turned into a forest
Sixteen years after the project was halted, some scientists accidentally mentioned the project when discussing ecological projects at hand. They decided to go back to the place where the pomace was dumped to find out.
After arriving at the reserve, they searched for the location recorded in the literature for a long time, but found no trace of the garbage dump. Eventually, a dump sign made them realize they were in a garbage dump, but instead of a grassy meadow with sparse trees, it became a dense forest.
A huge fig tree appeared during this period of more than ten years, and there are also meerkats, a small mammal, living in this tree. The final statistical results showed that a total of 24 tree species were found in the pomace dumping area, while only 8 species were found in the surrounding areas. 12,000 tons of pomace have greatly improved the ecology of this grazing area in more than ten years, and a healthy and vibrant forest miraculously “emerged” from the original wasteland. By improving soil quality, Jensen and Horwax successfully restored the local ecology.
Pomace helped a lot
Some of the outer parts of this protected area in Costa Rica are used by local people for grazing. However, herders have introduced some exotic grasses, causing large areas of vegetation in grazing areas to be replaced by exotic grasses. Grazing causes the land to be trampled firmly by cattle, making it difficult for plant seeds to take root and sprout even if they fall to the ground. Only invasive grasses that had previously taken root can survive in this pastoral area, which seriously hinders the growth of forest trees in the reserve.
After tens of thousands of tons of pomace were piled in the grazing land, the grass was covered tightly. The grass could not breathe and gradually rotted into compost. While not all organic matter smothers grass and restores soil, terpene-rich orange peels can inhibit grass germination and rooting. When the pasture is suffocated by the pomace and completely degraded into fertilizer, the nitrogen, phosphorus and potassium rich in the pomace inject rich nutrients into the soil, thus promoting the growth of native plants. Coupled with Costa Rica’s rainy tropical climate, it took only 16 years for this land to complete its transformation from sparse grassland to forest.
The reason why it is specifically stipulated in the agreement that pesticides cannot be used in the orange growing process is to prevent harmful components from affecting the biological transformation process of pomace into soil. It is also true that limonene must be removed from orange peels, because limonene will harm earthworms and insects, so it must be removed.
Coffee cherries can also restore soil
Inspired by the pomace experiment, American scientists used locally grown coffee berries to improve the soil in Hawaii in 2018. Coffee beans are the seeds of the coffee tree. When they are still on the tree, they are covered with seed coat, pulp and peel. The seed part only accounts for about 50% of the weight of the entire coffee cherry. Similar to the terpenes in orange peels, the caffeine in coffee pulp can also inhibit the growth of pasture. As expected, after two years of stacking coffee cherries, 80% of the originally barren experimental area was covered by vegetation.
Whether it’s orange pomace or coffee pulp, scientists’ approach of using natural means to restore soil allows us to see nature’s self-healing ability. However, we cannot do whatever we want with the mentality that “nature will solve everything anyway”. Instead, we should think about how to make our development fit with nature. After all, humans cannot live alone without nature.