Page:A primer of forestry, with illustrations of the principal forest trees of Western Australia.djvu/28

22 the crown. That this action of the forests is felt at distances from the forests is another important point in the chain of evidence proving the indirect value of forests, for it means that districts possessing a high percentage of forests have a more equable climate than those possessing a low percentage or no forests at all. A most interesting research was made in Europe to investigate this very matter. A belt of country right through Europe along the 46th parallel of latitude, from La Rochelle in France to the mouth of the Volga in Russia, was examined, and it was found that, wherever there were large areas of forest, the extremes of temperature were not so marked, while over regions where the forests had been destroyed or where no forests existed, the extremes were very great. Work done in India has shown the same results, only the actual figures were more remarkable. In Assam, for instance, it was found that the mean temperature in July within the forests was 36.5° centigrade, while in the country Avhere the forests had been destroyed, though the latter region is situated nearer the sea-board, it was 57.4° centigrade.