4 o8 



NA TURE 



[September 23, 1922 



prove interesting to the statesman and the economist, 

 as well as to the forester and the industrialist. 



The first part trials of general principles. The 

 utility of forests is considered directly, when concerned 

 with actual products, such as timber, turpentine, tans, 

 etc. ; and indirectly, when it is a question of the in- 

 flueni e of forests on climate, soil erosion, hygiene, 

 aesthetics and ethics. The last three are more im- 

 portant than is generally believed; and Sir William 

 pleads for the creation of woodlands near large towns, 

 which will serve as recreation grounds for the people 

 and at the same time produce timber finding a ready 

 sale, so that the establishment of these city forests 

 need not be a financial burthen. Glasgow, renowned 

 for its municipal enterprise, is the first of our cities to 

 acquire a forest area for the enjoyment of its inhabitants, 

 the Ardgoil Estate. 



After the subject of the State in relation to forests 

 is discussed, the remainder of the book, some 300 pages, 

 deals with the actual condition of forestry in the 

 British Empire. The British Isles, India, Canada, 

 Newfoundland, South Africa, New Zealand, and the 

 Crown Colonies are treated separately. The natural 

 history of the forests, their resources in timber, the 

 modes of silviculture, government policy, education, 

 etc., are all carefully described, sketch maps and 

 statistical tables being added where required. 



(2) Considering the vast amount of information on 

 the practice of silviculture which is scattered in 

 British and American forestry journals and official 

 bulletins, it is remarkable how few formal text-books 

 on the subject have been published in English. The 

 present work by a Yale professor is therefore very 

 welcome. It deals primarily with conditions in the 

 United States ; but as the principles of silviculture 

 are the same everywhere, the book can be used by 

 British students with scarcely any change or comment. 

 It is a compilation, remarkably up-to-date, and 

 rendering matter available for study which otherwise 

 could be found only by long search in German and 

 French books. The author's presentation of facts is 

 clear, and well illustrated by suitable diagrams. 



There is, however, one serious defect, the omission 

 of the subject of reproduction of the forest by artificial 

 means, the reader being referred for information on 

 this point to " Seeding and Planting," a companion 

 book by Prof. Tourney, also of Yale University. 

 Artificial planting of trees is much more common with 

 us than natural regeneration ; and the necessity of 

 using another book will be irksome to British students. 

 Prof. Hawley's exposition of the methods of natural 

 regeneration is excellent ; but the best chapter in the 

 book is one dealing with " thinning," a difficult subject. 

 Another subject, also treated in a fresh and original 

 NO. 2760, VOL. I io] 



manner, is the disposal of the " slash " or rubbish 

 which is left on the ground after felling operations. 

 This is important, as on the removal of the " slash " 

 depends in great measure the freedom of the forest 

 from injury by fire, insects, and fungi. General 

 measures of protection against these three agents of 

 destruction, as well as damage caused by grazing, are 

 treated in four short chapters. 



An excellent feature of the book is an appendix of 

 more than forty pages on terminology, which is really 

 an alphabetical list with definitions of the terms used 

 in the science and art of forestry. This glossary, which 

 was drawn up in 1917 by the Society of American 

 Foresters, will serve to stimulate accuracy of statement 

 by foresters. German and French equivalents are given . 



(3) Prof. Chapman's " Forest Mensuration " is the 

 third text-book on forest mensuration which has 

 appeared in English, and it is well designed to become 

 the standard authority on the subject in the United 

 Slates. The system of measuring timber in North 

 America is totally different from ours. There, the 

 contents of trees and logs are expressed in terms of 

 the probable out-turn in sawn boards, according to a 

 certain log-rule; hence the phrase "board feet." In 

 the British Isles timber is measured as a raw material 

 in terms of the real cubic volume. The American 

 system introduces extraordinary complication into 

 forest mensuration, some thirty log-rules being now 

 in use in different parts of the country, no two rules 

 giving the same result in board feet. A considerable 

 part of the book is taken up with these log-rules and 

 the principles underlying their construction — all of 

 which is useless to the forester in Europe or India. 



Nevertheless, a large part of the volume is of interest, 

 for once log-rules are disposed of, the author is on 

 common ground with his European fellow foresters, 

 and gives a good account of recent developments of 

 forest mensuration by Swedish and German writers. 

 The accurate measurement of masses of standing trees 

 is difficult, but is obligatory for purpose of valuation, 

 and is of great use as a means of determining from time 

 to time the increment of a growing wood. Upon a 

 knowledge of the latter depends the fixing of the proper 

 time for felling. Part III. deals with the laws of 

 growth of stands of trees, and is by far the most 

 interesting subject discussed, as the principles involved 

 are the same in all countries where scientific forestry is 

 practised. The preparation of yield tables and their 

 application to predicting future yields are treated fully. 

 The book will be useful in the reference library, but 

 cannot be recommended as a handbook for British 

 students, on account of its preoccupation with American 

 practice. 



(4) Forest management is little understood in the 



