REVIEWS 817 



The maintenance of an acceptable soil cover and the continuation of 

 grazing demand the recognition of the following principles of range 

 management : 



1. Avoidance of overgrazing. 



2. Avoidance of too early grazing. 



3. The practice of deferred and rotation grazing. 



4. Artificial reseeding. 



5. The control and distribution of live stock. 



In certain cases damage from long overgrazing can only be overcome 

 by the total elimination of live stock and by later terracing, planting; 

 and dam construction in order to check the surface flow of water in the 

 eroded channels. 



The chief merit of the publication is the application of instrumenta- 

 tion and exact methods of study to problems of grazing and erosion 

 which heretofore have been approached by the observational method. 

 Although no entirely new principles have been brought to light, we 

 have in this bulletin more convincing evidence than heretofore that 

 grazing on public lands at high elevations demands expert supervision 

 or serious damage from erosion and soil depletion may result and the 

 nation thereby suffer great economic loss. J. W. T. 



Seasoning of Wood. By J. B. Wagner. D. Van Nostrand Com- 

 pany, N. Y., 191 7. Pp. 274. 



This book, which is distinguished mainly by its typographical excel- 

 lence, begins with a discussion of the structure of wood, largely ob- 

 tained from U. S. Forest Service publications. This is followed by the 

 inevitable "list of important woods," which contains much valuable 

 information, as, for instance, the assertion that the resinous smell of 

 western yellow pine is very remarkable. We learn that Douglas 

 "spruce" grows very large in the Pacific States, to fair size in all parts 

 of the mountains, in Colorado up to about 10,000 feet above sea-level ! 

 We also learn for the first time that Douglas "spruce," or, as the author 

 has it, Pseudotsuga douglasii, has a rival in Pseudotsuga taxifolia, of 

 "Red fir." Mr. Wagner akso presents the information that Tsiiga mcr- 

 tensiana is used for pulp wood, floors, panels, and newels, and that it is 

 not suitable for heavy construction, which will be comforting to a num- 

 ber of foresters in the Northwest who have occasional patches of moun- 

 tain hemlock under their care. Western hemlock is not even mentioned 

 by the author, which leads the reader to wonder if it was omitted in a 

 spirit of facctiousncss. Mr. Wagner also is apparently not aware of the 



