Because of climate change, more and more land that was once used to grow crops or provide food for animals is turning to dry, unusable desert land. There are many proposals about how to stop this process, known as desertification. A number of proposals involve growing trees, because trees can help protect soil and provide many other benefits to fight against desertification. Some scientists have proposed that the best way to grow trees in dry areas in danger of desertification is by using a box-shaped device surrounding the young tree.The device collects water that condenses from vapor in the atmosphere and helps the tree to grow. However, other scientists believe that this device will not be successful in fighting against desertification for the following reasons.
First, at a cost of 25 U.S. dollars each, the device would make growing trees a prohibitively expensive process. Meaningful efforts to fight desertification involve growiing millions of trees. Some countries most affected by desertification cannot afford to buy devices for millions of trees
Second, plans for fighting desertification involve asking local people to install and maintain the devices. People living in some of the areas most affected by desertification work long days in harsh conditions: sometimes barely managing to provide food for their families. It would be difficult to motivate these people to look after trees that cannot serve as a source of food for them.
Third, the device's ability to collect and conserve water is limited. Each one provides only enough water to keep a small tree alive. Trees that have outgrown the device have to deal with unforgiving environmental conditions on their own. In some places where the devices are being tried, six months can pass without a drop of rain. Once the trees become too big for the device, they may not be able to survive in such a harsh environment.
According to the reading passage, using the box-shaped devices to grow trees will not be effective iu dealing with disertification. However, in the lecutre, the professor opposes this idea by stating three reasons.
First of all, although as the reading states, such water collecting device is too expensive to be adopted in large quantity, the speaker believes that the cost in fact can be much more reasonable than predicted. Once trees get bigger, the device can be removed and be reused to grow new trees.Each device can be reused twenty times or more. Thus, considering the number of trees each device can be used for, the cost could be affordable and acceptable.
Secondly, in the reading passage, it is believed that people will not be motivated to maintain the device and look after trees that cannot provide food for them. However, the speaker points out that the device can also be used to collect water for other plants, such as vegetables, which means that people could grow more food with installing and maintaining the box-liked devices. Also, when trees grow up, their branches can be used as fire wood. Therefore, people will be motivated to help with this project.
Finally, the writer claims that the trees that have outgrown device are not able to survive in the harsh environment on their own. On the contrary, the lecturer argues that with the help of the device, the young trees could grow long roots, which will reach down the wet soil beneath the dry desert surface. Being able to reach the water source underground, the trees could survive without the devices.