SAN GERARDO DE RIVAS, Costa Rica — About 5,000 feet above the crashing waves of Costa Rica’s poorest region, the Brunca, sits the town of San Gerardo de Rivas. The thick fog that visits every day, and the fact that the forest here receives more precipitation vertically than horizontally, makes this a cloud forest, one of the most rare biomes on the planet. Cloud forests play a vital role in capturing, storing and releasing water, and are biodiversity hotspots.
While the poverty here isn’t the grinding kind that might be found in drought-stricken parts of sub-Saharan Africa, it is still apparent. Steep slopes, leached soils and persistent clouds make farming a challenge. A growing population and easily erodible land means that expanding production into the surrounding forests will continue and the forests will suffer.
Clarice Esch, a Fulbright scholar who also studies trees at a biological research station near the town, is acutely aware of all this. Talking to her advisor one afternoon, they stumbled upon the subject of grafting tomatoes. On a previous trip to San Gerardo de Rivas, Esch noticed the massive tomato fields above the town. She applied for a grant from the Fulbright program and started working in January of 2015.
When she first got there she needed a plot to grow her tomatoes. She remembers knocking on many doors and explaining her interest in tomatoes to the farmers. Fortunately, the farmers were curious and they struck a deal. Esch would get enough space to plant 200 tomato plants, and all of the crops would go to the farmers as rent.
In addition to the steep slopes, nutrient-drained soil, and strong rains, tropical farmers face another challenge. The absence of a winter season means that pests and diseases do not die off. Tomato farmers consistently struggle with diseases.
By grafting tomatoes, Esch was able to choose a sturdy, disease-resistant rootstock and a productive scion, the small shoot of a plant that produces red, juicy fruit. Naturally occurring disease resistant rootstocks produce small, green tomatoes, which are hard to sell at the market.
The grafting process took place over four to six days in a warm and humid environment. In this case, it was in a sunlit room that was kept humid by a slow cooker. After that time, the plants could be taken out to the field to grow naturally. Preliminary data showed that Esch’s plants were yielding higher amounts of desirable fruit than the conventionally grown tomatoes.
The process required for growing and taking care of grafted tomatoes differs just enough to make the transition for local farmers a hurdle. Two sets of seeds need to be started, the plants then need to be grafted and the scion must stay above ground to avoid growing roots.
“It is exciting, but difficult,” Esch says.
Still, Esch has enjoyed the “good exchange of ideas” she has had with the local farmers. She is looking to get more involved with MAG, the Costa Rican ministry of agriculture and livestock, to keep up the momentum of tomato grafting.
If adopted, this new method could mean that a significant percentage of land could be taken out of production and, over time, become a habitat for the endangered species that live in the area, including Baird’s Tapirs and Black-handed Spider Monkeys.
Protecting habitat for wildlife has become another interest for Esch. The community of San Gerardo de Rivas is big on ranching. Ranchers clear-cut the forest, sometimes leaving a few of the biggest trees that are too difficult to cut down. Esch is looking at the connections between large trees left on pasture land and the forest composition beneath them. The goal is to develop a framework to see how many trees can be left on pasture land that will provide habitats, make reforestation efforts more effective and not harm the productivity of the land.
These farmers, constrained by both time and money, are unable to make the type of investments that would be necessary to increase yields by a sufficient amount to save the forests. Those investments, if made however, could help develop a rural community and increase the incomes of poor farmers. This, in turn, can protect globally important forests and allow for the production delicious tomatoes.
Sources: Council for International Exchange of Scholars, International Union for the Conservation of Nature, Tapir Specialist Group, Tico Times, United Nations Environment Programme, U.S. Bureau of Educational and Cultural Affairs 1, U.S. Bureau of Educational and Cultural Affairs 2, U.S. Bureau of Educational and Cultural Affairs 3, U.S. Bureau of Educational and Cultural Affairs 4, U.S. Bureau of Educational and Cultural Affairs 5, U.S. Senate, White House, Clarice Esch: Interview on 09.22.2015.