660 SCIENCE PROGRESS 



former officers of the Indian Forest Service, yet they are in the main adaptations 

 or actual translations of German works and deal specially with European forestry. 

 Mr. Brown's book deals with tropical sylviculture and contains much information 

 collected by the author during his wide experience in the forests of India, Ceylon 

 and the Sudan. Mr. Brown evidently recognises that in dealing with problems 

 outside the mere routine work of continental forestry it is essential to have a 

 special knowledge of trees and of the conditions under which they feed and grow ; 

 accordingly he makes use of his well-known acquaintance with systematic botany 

 and his evident study of plant cecology in the opening chapters, which are devoted 

 to the discussion of the factors influencing the existence of forests. Much of this 

 information will also be of interest to botanists, for we find here interesting facts 

 concerning trees occupying soils differing in constitution or moistness and in sites 

 differing in climate or altitude or exposure. The examples described are largely 

 taken from forests in the tropics of the Old World. Very varied are the matters 

 discussed ; for instance, the significance of depth of root in relation to resistance 

 to drought is exemplified by reference to Mr. R. S. Pearson's account of the 

 damage done to forests in the Madras Presidency during the drought of 1899-1900. 

 Among the suggestive facts that came within the author's range of observation 

 may be cited the remarkable germination of a viviparous Dipterocarp {Vatica) 

 that grows in annually inundated sites in Ceylon. In the chapter dealing with 

 the living environment of trees the author gives interesting particulars and illus- 

 trative examples of matters varying from the succession of vegetation in forest 

 clearings to the kinds of seeds distributed by deer and elephants, the pollination of 

 parasitic Loranthaceae by birds, the damage done to forests by plagues of rats and 

 the intense dislike of elephants of white objects such as whitened posts or white- 

 barked trees, which are therefore wantonly destroyed by these animals. In the 

 chapter on " Man and Domestic Animals" Mr. Brown falls into the assumption, 

 which is by no means justified, that " in olden times . . . the greater part of the 

 globe was forest clad." An analysis of the climates of cold or dry deserts and 

 various grasslands renders it probable that "in olden times" there were always 

 immense areas not clad with forest. Yet the forester readily comes to Mr. Brown's 

 impression because he may have an exaggerated idea of the climatic change 

 induced by disforestation and in Europe he knows not only of wholesale destruc- 

 tion of forest by man and its degradation to heath or peat-bog but also of evidence 

 of the prehistoric existence of vast forests where bogs now prevail ; within the 

 tropics and subtropics the forester also sees the change of dense forest into open 

 savannah, grassland or waste area, induced by fire (perchance not due to man's 

 agency) possibly combined with the subsequent activity of grazing or browsing 

 animals. Instructive examples of such changes are described by Mr. Brown and 

 accounts are given of the forest-destroying powers of the goat and of the even 

 more destructive camel. To these two kinds of animals has been attributed the 

 disappearance of woodlands supposed to have existed formerly in the wadis of 

 Upper Egypt where desert now reigns. In connexion with the discussion on the 

 effect of fires the information is given that protection against fire has caused some 

 teak forests in Upper Burma to change into evergreen forest, in which teak can 

 no longer reproduce itself. Among the important factors influencing forests is 

 light and it seems a pity that Mr. Brown should not have given in his book some 

 discussion of its significance, since so much botanical work has been published 

 recently in regard to the amount of light required by various species of plants 

 including trees and the practice of forestry is so largely a matter of the proper 

 regulation of light. 



