FLOODS AND DROUGHT
Trees play an extremely important role in the control of floods and droughts. Dering torrential rains the leaves in the forest canopy break the fall of rain drops, reducing their impact on the soil and young plants below. The spaces in the soil made y tree roots than help the water to soak in. Forests work like huge sponges soaking up rainfall and releasing it slowly throughout the year into streams and topping up underground water supplies.
Land covered with trees and other plants absorbs 20 times as much rain water flows over the surface of the land causing floods. And because only a small proportion of the rain water soaks into the ground there is often too little left for the rest of the year.
Philippine disaster:- In November 1991 flash floods faced down the hillsides above the coastal town of Ormoc in the Philippines. Within minutes the water rose to 4 m deep in the streets. Seven thousand people were drowned.
The tragedy was blamed on illegal logging, which had stripped the hills of the dense rain forest that once clothed them. Without the forests to absorb it, the torrential tropical rain raced down valleys,
Indian floods:- India is a good example of how the cutting down of forests causes floods and droughts. About 60 million hectares of land in India are now vulnerable to flooding, more than twice as much as 30 years ago. And in the Indian state of Uttar Pradesh alone where there has been heavy logging activity the number of villages that are short of water has risen from 17,000 to 70,000 in the last twenty years.
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