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i(i leaves which are afterwards shed, are a most valuable ferti- 

 lising agency of surface soils. Beneath the shade of trees a 

 fcich layer of humus is formed which keeps the roots cool in 

 summer and warm in winter, besides absorbing and retaining 

 a great quantity of water. It is in this way that trees grow 

 luxuriantly even on the poorest soils and change the character 

 of the soil permanently for the better. Trees also have a bind- 

 ing effect on the land which without them would be liable to 

 be washed away or denuded by rain. Trees are also believed 

 to induce a heavier rainfall. In the Delta of the Nile there used 

 to be on the average only 6 rainy days in the year ; but since 

 the planting of millions of eucalyptus trees there during the 

 Last 40 years, there are now on the average 40 rainy days 

 perrannum. In Algiers, Napoleon III. caused millions of trees 

 tq.be planted, which has doubled the number of rainy days in 

 that country. There is an arid belt running through Australia, 

 Africa &c. but wherever forests cross that belt as in New 

 South Wales and W. Australia there is a heavy rainfall. The 

 Himalayas on one side is almost a desert now, but was once 

 very populous until the forests were destroyed. The other side 

 of the same mountains which is heavily timbered, has a large 

 number of big rivers and it maintains an immense population. 

 The propagation of trees also results in a perennial supply of 

 fuel and fodder of the highest value. Trees also act as a barrier 

 against epidemics and such aromatic trees as the eucalyptus 

 and the conferae are considered especially valuable for this 

 purpose. The casuarina tree which is a conefer, yielding a good 

 fuel and Inga dulcis, which yieldsagood fodder, are both very 

 fast growing trees, and their propagation is recommended on 

 poor soils. The propagation of the babul for fodder, and 

 timber required for agricultural purposes, is also highly, 

 pecommended. Slow-growing but valuable timber-trees, such 

 as, mahogany, tun, sal, teak, sisoo, should not be grown in 

 agricultural tracts but in poor and arid tracts which are 

 considered unsuitable, for ordinary agricultural pursuits, 

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