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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN [Vol. 8, No. 3 



est view, the vegetation cover may be said to consist of closed forest, open 

 forest or woodland, and grassland, with types of open forest occupying by far 

 the greater part of the area. 



Shantz' vegetation map (1923) is unsatisfactory for this part of Africa, espe- 

 cially in that it shows the greater part of Nyasaland as occupied by his "Acacia- 

 tall grass savanna" instead of his "dry forest." Topham (1936), viewing the 

 vegetation of Nyasaland as a forester with extensive personal experience in the 

 area, has distinguished 26 "main plant communities which contain trees and 

 shrubs," and grouped them as follows: 



1. Forest types in the high mountain areas, above 5,000 feet (4 communities). 



2. Forest types on the lower mountain and plateau areas, between about 5,000 

 and 2,000 feet (4 moister and 13 drier communities). 



3. Forest types of the rift valleys (5 communities). 



In this very useful preliminary classification Topham designates characteristic 

 tree species for each of his 26 communities and includes valuable notes on 

 climate, soil, economics, and the incidence and effects of human disturbance. 



Willan (1940), in a vegetation map of the Protectorate, has applied the fol- 

 lowing broad physiognomic and floristic grouping of types of plant cover: 



1. Montane Rain Forest and Grass Land 



2. Brachystegia Woodland 



3. Brachystegia and Combretum [forest and woodland?] 



4. Pterocarpus-Bauhinia Foothills Forest 



5. Forest and Woodland of the Lake Plain and Shire Valley 



The montane grassland of Willan no doubt is very largely a secondary condi- 

 tion following the destruction of his montane forest by fire and in some degree 

 clearing for cultivation by the natives. 



Willan suggests that the Brachystegia woodlands, which occupy most of this 

 part of Africa, might perhaps be a secondary, degenerate type of vegetation re- 

 sistant to conditions brought about by man's activities in cultivating and burning 

 over a very long period of time. Gillman (1949) takes the opposite view for the 

 Brachystegia-Other- Species Woodland which occupies almost one-half of the land 

 surface of Tanganyika and is present on nearly every geological formation. He 

 considers this woodland a function primarily of climate; a view subscribed to by 

 the present writer. 



DISTURBANCE OF THE VEGETATION BY MAN AND FIRE 



Having traveled in Nyasaland, I can not agree to the statement in William 

 Vogt's book (1948) that since 1880 the vast forests which covered northern Nyasa- 

 land have been destroyed by native farmers, and that the Shire River has been 

 filled with silt. The statement in question is based on a report by Lord Hailey 

 which I have not seen. But, plainly, exaggeration has crept in somewhere along 

 the line of information. Nyasaland is still a country in which a road journey from 

 end to end leaves a dominating impression of trees in an open forest environment, 

 and this is especially so in the north. There has been some. general silting in the 

 Shire, and bars have obstructed its upper course, but as seen late in the dry 

 season of 1946 the river was flowing a strong stream, and its lower course was 

 still passable by river steamers to the former head of navigation. 



That large areas of land have been changed by human activities, and that the 

 destructive processes and their certain results are being accelerated through in- 

 creasing population pressure, there can, however, be no doubt. The local conges- 

 tion of population and consequent deterioration of the vegetation cover and soil 



