532 BOTANICAL GAZETTE [December 



and there are here depicted the early periods of forest destruction, the fluctua- 

 tions in forest area associated with peace and war, and the growth of the 

 ideas of conservation and afforestation. The closing chapters consider changes 

 in the composition of forests and the problems of heaths and moors, which are 

 discussed from the viewpoint of origin, of destiny if left to themselves, and 

 of utilization by man. The great merit of this volume lies in its strongly 

 dynamic attitude, an attitude that cannot be too highly commended in all 

 phytogeographic work. — H. C. Cowles. 



The trees of Belgium 



Massart* has issued a profusely illustrated little book on the trees of 

 Belgium, his object being to present the subject so as to interest intelligent 

 lovers of the woods, rather than to make a manual for botanists or foresters. 

 The book is in no sense designed as a manual of identification, but rather it 

 presents the interesting problems about which the nature-lover is likely to 

 inquire. In the first portion of the book Massart considers wood structure and 

 tree architecture. Then follows a section on the relation between trees and 

 soil, and a similar section on the relation between trees and the atmosphere. 

 The final section presents the life-history of trees, dealing with birth, competi- 

 tion, decrepitude, and death. In the chapter on tree architecture, the author 

 discusses deliquescent and excurrent trees, regeneration of injured terminal 

 and lateral branches, the influence of isolation on the shape of the crown, and 

 enlarged trunk bases. The section on soil relations considers the distribution 

 of trees (an excellent detailed map of the Belgian woodlands accompanies 

 this), the influence of the soil on trees, and the influence of trees on the soil; 

 among the topics treated under the latter heading are rock disintegration, 

 fixation of dune sand, and chemical changes in the soil. In the final section 

 much attention is paid to tree diseases and insect pests. It is a pity that we 

 do not have many similar books to accommodate the rapidly increasing army 

 of nature-lovers. — H. C. Cowles. 



NOTES FOR STUDENTS 



The vegetation of the Nebraska sandhills. — The average traveler regards 

 the prairies and plains as regions of extreme monotony; particularly is this 

 true if his way takes him through a region of sandhills. The total incorrect- 

 ness of this view is admirably illustrated by the publication of Pool's researches 

 in the Nebraska sandhills.* From an earlier and semipopular presentation 



4MAS8AXT, J., Xos arbres. pp. \T\i+ 214. jigs. 238. map 1. Brussels: Henri 

 Lamertin. 191 1. 



s Pool, Raymond J., A study of the vegetation of the sandhills of Nebraska. 



Minn. Bot. Studies, III. 4:189-312. pis. 13. figs. 16. map 1. 1914. 



