VOA慢速英语2009年-Agriculture Report - Study Finds More Tree

This is the VOA Special English Agriculture Report.

Farmers, especially in developing countries, are often criticized for cutting down forests. But a new study suggests that many farmers recognize the value in keeping trees.

Researchers using satellite images found at least ten percent tree cover on more than one billion hectares of farmland. That is almost half the farmland in the world.
　
Land used for farming can also support trees

The World Agroforestry Center in Kenya led the study. The findings were reported last week in Nairobi at the second World Congress of Agroforestry.

Earlier estimates were much lower but incomplete. The authors of the new study say it may still underestimate the true extent worldwide.

The study found the most tree cover in South America. Next comes Africa south of the Sahara, followed by Southeast Asia. North Africa and West Asia have the least.

The study found that climate conditions alone could not explain the amount of tree cover in different areas. Nor could the size of nearby populations, meaning people and trees can live together.

There are areas with few trees but also few people, and areas with many trees and many people. The findings suggest that things like land rights, markets or government policies can influence tree planting and protection.

Dennis Garrity heads the World Agroforestry Center. He says farmers are acting¹ on their own to protect and plant trees. The problem, he says, is that policy makers² and planners have been slow to recognize this and to support such efforts.

The satellite images may not show what the farmers are using the trees for, but trees provide nuts, fruit, wood and other products. They provide windbreaks and shade from the sun. They also help prevent soil loss and protect water supplies. Even under drought conditions, trees can often provide food and a way to earn money until the next growing season.

The important thing, says one expert, is to find the right tree for the right place for the right use.

Some trees act as natural fertilizers. They take nitrogen out of the air and put it in the soil. Scientists at the agroforestry center say the use of fertilizer trees can reduce the need for chemical nitrogen by up to three-fourths. And they say it can double or triple crop production.

Trees also capture carbon dioxide, a gas linked to climate change.

Wangari Maathai is a Kenyan environmentalist and Nobel Peace Prize winner. She says the study shows that trees are critical to agricultural production everywhere.

And that's the VOA Special English Agriculture Report, written by Jerilyn Watson. I'm Jim Tedder³.

1 acting   

n.演戏，行为，假装；adj.代理的，临时的，演出用的

参考例句：

• Ignore her,she's just acting.别理她，她只是假装的。
• During the seventies,her acting career was in eclipse.在七十年代，她的表演生涯黯然失色。

2 makers   

n.制造者，制造商（maker的复数形式）

参考例句：

• The makers of the product assured us that there had been no sacrifice of quality. 这一产品的制造商向我们保证说他们没有牺牲质量。
• The makers are about to launch out a new product. 制造商们马上要生产一种新产品。 来自《简明英汉词典》

3 tedder   

n.（干草）翻晒者，翻晒机

参考例句：

• Jim Tedder has more. 吉姆？特德将给我们做更多的介绍。 来自互联网
• Jim Tedder tells us more. 吉姆？泰德给我们带来更详细的报道。 来自互联网