490 



The Supplement to the Tropical Agriculturist 



"SILVICULTURE IN THE TROPICS." 



MR. A. F. BROUN'S WORK. 

 Mr. A. F. Broun, formerly of the Indian 

 Forest Service ; later Conservator of Forests, 

 Ceylon ; and lately Director of Woods and For- 

 ests, Sudan Government has just published his 

 book on Silviculture in the Tropics, through 

 Messrs. Macmillan & Co., Ltd., of St. Martin's 

 Street, London, and in every respect it is a 

 most useful work, both as a book of reference, 

 and as a text book of Forestry, The book was 

 originally intended to form one of a series of 

 volumes on Agriculture in the Tropics, but the 

 lamented death of the editor led to the ab- 

 andonment of the series. Considerable progress 

 having been made with Mr. Broun's book it 

 has been published as an independent volume. 

 The work is well illustrated, by photographs 

 and diagrams, most of the former being taken 

 by the author and his gifted and popular wife, 

 the ex-Ceylon Lady Tennis Champion; while the 

 classification and indexing is of a very praise- 

 worthy nature. A picture of the Ceylon screw 

 pine, showing its stilt roots, has been gold 

 blocked on the cover. 



Silviculture, it might be mentioned, is the art 

 of applying the knowledge of the requirements 

 of different trees, in tending and regenerating 

 existing woods or in rearing fresh woodland 

 crops, and in working them to the best ad- 

 vantage of the forest owner. Many different 

 factors and conditions have to be considered 

 in this connection ; it is here that the book now 

 discussed will prove its worth. The volume 

 has been divided into four parts. Factors gov- 

 erning and influencing the existence of forests ; 

 formation and regeneration of woodland crops ; 

 training and improvement forests, and of special 

 measures of maintenance and protection. Deal- 

 ing with soil the author says the functions of 

 soil in relation to plant life have not yet been 

 fully determined. Of late years a good deal 

 of attention has been paid to the matter by 

 American investigators but their theories have 

 not been entirely accepted in England. Pro- 

 ceeding he gives some of the more established 

 theories, and points out the difficulties which 

 exist in the tropics of saying what constitutes 

 deep or shallow soils owing to the much greater 

 range of distribution of moisture. In forestry 

 artificial improvement of the soil by means of 

 fertilisers is hardly practicable, except over 

 limited areas such as nurseries and plantations, 

 and the crop therefore has to depend on the 

 humus formed mostly from fallen leaves, fruit 



twigs, etc., and it will therefore be seen what 

 difficulties the sylviculturist labours under, 

 and his handicapping which does not affect 

 the ordinary culturist. Climate and " other 

 local factors, such as the constant comparative 

 humidity of the air as in the case of forests 

 not very far from the sea, may change th e 

 character of these forests. In Ceylon, for 

 example, the forests growing within this zone 



are to a large extent evergreen From an 



economic point of view these forests are capable 

 of yielding major produce such as timber and 

 firewood, minor produce — and even in some 

 cases rubber." The effect of climate is most 

 carefully deat with ; and the case of Ceylon 

 with its fine gradations of climate and temper- 

 ature, are frequently quoted in the chapter. 

 The effect of locality is also dealt with at length, 

 here again Ceylon is quoted a number of times 

 in describing the variation of forest floras. 

 Mr. Broun emphasizes that it is necessary for 

 the forester in swamping areas to study his 

 own forest flora, and not to try to introduce into 

 such localities such species as are unable to 

 struggle against stagnant humidity of the soil 

 in these areas. The next chapter deals with 

 plant and animal allies and enemies, excluding 

 man and domestic animals, particular attention 

 being drawn to fungus, which '' leaf disease " 

 destroyed the coffee plantations of Ceylon. 

 Forest enemies are numerous, and after reading 

 this chapter one wonders how ever the forest 

 manages to thrive at all. Rodents are very 

 damaging : the author mentions an invasion 

 of rats he saw at Nuwara Eliya in which young 

 trees were attacked, and the bark eaten away 

 to a height of four or five metres. Herds of 

 cattle, driven into the forest, he thinks might 

 be advantageous, provided that damage to 

 young plants is not likely to be enhanced by 

 this method. Elephants, of course, do a tre- 

 mendous amount of damage, and for these 

 pests ditching and fencing is recommended. 

 The effect of man and domestic animals is also 

 explained, as well as fires to which the writer 

 attributes the origin of patanas of Ceylon. Mr. 

 Broun gives valuable advice regarding the re- 

 afloresting of areas burned out or destroyes 

 temporarily for cultivation of rice, etc. The 

 theory that deforestation tends to reduce 

 rainfall is also treated in a chapter dealing 

 with the influence of forests, but Mr. Broun, 

 lays down no hard and fast definition of fact, 

 and agrees that much has to be done before 

 satisfactory data caQ be obtained. Forests, 

 he does show, have a rain-retaining effect, and 

 are useful to feed the supply of springs, and 



