254 Forestry Quarterly. 



yield of New England forests. The tables published furnish a 

 means of answering the definite critical question, how much? 

 that in the last analysis must always determine whether or 

 not forestry is practical. The fact that a few of them do not 

 clearly show the basis on which they are constructed, or how 

 they are used, does not materially affect the value of the whole. 

 For instance, it is not especially important to determine the rela- 

 tive values of Tables XXXV and XXXVI, both giving the yield 

 of white pine in board feet. 



It would have been possible to review this book and find only 

 praise for the efforts of its authors, for apart from the fact 

 that it is thus early in the field it possesses merits far outweighing 

 the slight inaccuracies or deficiencies to which reference has been 

 made. Its lack of condensation is a positive disadvantage, but 

 with that let serious objection end. The assumption of the au- 

 thors that forestry has come to New England to stay may be 

 accepted. Surely there is no need of special pleadings in a 

 work like this. And it is not needful that one agree with all the 

 conclusions or recommendations. The authors themselves would 

 be the last to insist that the facts they publish are the only 

 facts, or *:heir word the final word. If a suggestion may be made 

 it is that the two parts be republished separately. There is room 

 for a popular manual of forestry like Part I, and also for one 

 giving the special information about the forests of New Eng- 

 land contained in Part II. 



A. G. 



The Wilting Coefficient for Different Plants and Its Indirect 

 Determination. By Lyman J. Briggs and H. S. Shantz. Bulletin 

 230, Bureau of Plant Industry, U. S. Department of Agriculture. 

 Washington, D. C. February, 1912. 



The wilting coefficient is defined by the authors as the moisture 

 content of the soil (expressed as a percentage of the dry weight) 

 at the time when the leaves of the plant growing in that soil first 

 undergo a permanent reduction of their moisture content as a 

 result of a deficiency in the soil-moisture supply. It is the point 

 at which the forces opposing the further removal of soil moisture 

 exceed the osmotic force exerted by the cell contents of the plant ; 



