PREFACE 



The subject matter of this book was briefly dealt with by 

 me iu three Chadwick Public Lectures, which were de- 

 livered at the Royal Society of Arts, London, in May 1917, 

 under the title of " Forests, Woods, and Trees in relation to 

 Hygiene." 



An effort is made in this book to interest the statesman, 

 the student of economics, the engineer, the physician, and 

 the layman, as well as the forester, in certain aspects of 

 forests and trees, about which vague notions are prevalent. 

 An endeavour is made in the first two chapters to recognise 

 and describe the far-reaching influences of forests and trees 

 on climate, flow of water, erosion of the soil, shelter from 

 wind, purity of air and water, etc. Such influences affect 

 directly the health and comfort of man. The value of 

 forest districts as sites for sanatoria and the history and 

 utility of parks, open spaces, and trees in towns are then 

 discussed. The afforestation of the desolate pit mounds in 

 the Black Country and other districts is shown to be a 

 movement of great interest, especially when, as in some 

 cases, it is taken up by school children. 



One effect of the war has been to bring home to think- 

 ing people the extreme importance of afforestation. The 

 ancient warning, " La France p(3rira faute de bois," is now 



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