Tree - lungs of the world!
Trees are useful man in three very important ways: they provide hum with wood and other products; hey given him shade; and that help to prevent dought and floods.
Unfortunately, in many of the world, man has not realized that the third of these services is he most important. In his eagerness to draw quick profit from the trees, he has cut them down on large numbers, only to find that with them he has lost the nest friend he had.
Two thousand years ago a rough and powerful country cut down its trees to build warships, with which to gain itself an empire. Hegemony he empire fell to pieces, the home country found itself faced by floods anh starvation.
Even here a government realizes the importance of a plentiful supplY of trees, it is difficult for it to persuade the villagers to see this. The villagers want wood to cook his food with; and he can earn money by making charcoal or selling wood to the traders. He is usuallY too lazy or too careless to plant and look after new trees. So, unless the government has a good system of control, or can educate people, the forests slowly disappear.
This does not only means that the village's sons and grandsons have fewer trees. The results are even more serious: for where here are trees their roots break the soil up - allowing the rain to sink in - and also find the soil, thus preventing it being washed away easily; but where there are no trees, the rain falls on hard ground and flow away on the surfaces, causing floods and carrying away with it the rich top-down, in which crops grow so well. When all he top-down is gone, nothing remains but worthless desert.