【英语时差8,16】农夫和树（在线收听）

Farmers And Trees Dear Don and Yale: For a long time now, decades probably, I've been hearing about deforestation. But who, exactly, is cutting down all the trees? Y:If I had to guess,I'd say it's farmers clearing land for planting crops.Am I right？ D:That would seem to make sense.Farmers do need to clear space to plant their fields. But actually, farmers around the world have just as much to do with planting trees as they do with chopping them down.A study using satellite pictures looked at around 2.5 billion acres of farmland around the world. It found that about ten-percent of it is covered by trees. That’s an area twice as large as the Amazon rain forest. Y:That's pretty surprising.I mean why would farmers want so many trees taking up space? Don’t they want their fields to be as large as possible? D:Yes, generally. But other studies have found that trees are very useful for farmers. They help keep soil healthy. And they can be harvested to feed animals, provide timber and wood for burning, and produce fruit. Trees also help prevent soil erosion and improve groundwater quality. Y:So farmers grow trees because they’re profitable. D:Basically farmers have to make a living, and if trees made it harder to make a profit then farmers wouldn’t keep them around.Of course, deforestation is still a big problem. Many farmers, especially in the Brazilian rain forest, cut down thousands of trees to make way for fields. But in many other places, farms and forests work together.