Lin is currently a Science and Technology Policy Fellow with the American Association for the Advancement of Science in Washington, D.C. The other author of the BioScience paper is John Vandermeer of the U-M Department of Ecology and Evolutionary Biology.
The livelihoods of more than 100 million people worldwide are tied to coffee production. In Latin America, most coffee farms lack irrigation---relying solely on rainwater---which makes them especially vulnerable to drought and heat waves.
Shade trees help dampen the effects of drought and heat waves by maintaining a cool, moist microclimate beneath the canopy. The optimal temperature range for growing common Arabica coffee is 64 to 70 degrees Fahrenheit.
Shade trees also act as windbreaks during storms and help reduce runoff and erosion.
Lin's work in southern Mexico showed that shady farms have greater water availability than sunny farms, due in part to lower evaporation rates from the coffee plants and soils. More shade also reduced peak temperatures between 10 a.m. and 2 p.m., when southern Mexican coffee plants experience the greatest heat stress.
"These two trends---increasing agricultural intensification and the trend toward more frequent extreme-weather events---will work in concert to increase farmer vulnerability," Lin said. "We should take advantage of the services the ecosystems naturally provide, and use them to protect farmers' livelihoods."
|Contact: Jim Erickson|
University of Michigan