Chap. Ill] TROPICAL WOODLAND AND GRASSLAND 275 



RAINFALL IN MILLIMETERS OF THE HIGH-FOREST 

 IN MINAS GERAES. 



GONGO SOCO. 



1 9 58' S., 43 33' W., 1,090 meters above sea-level. Two years' observations. 

 (After Draenert in Meteorol. Zeitschr., 1886, p. 390.) 



Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Year 

 369-6 604-3 5377 253-0 172-0 57-9 55-1 34-0 20-3 93-2 169-7 573-5 2 939*3 



The climate, however, is not so unfavourable for tree-growth as to 

 prevent small xerophilous savannah-trees from establishing themselves 

 in the prairie and thus lending to it the character of a savannah. At 

 the points where water is more plentiful in the soil, where the winds 

 blow less strongly especially during winter, where atmospheric humidity 

 is greater, woodland prevails over grassland, so that the whole district 

 shows the alternation of both formations in its park-like features. 



In contrast with its southern portion, the middle part of Central Brazil, 

 the so-called Scrtdo district, possesses a xerophilous zuoodlaud climate. 



Here the year is hot throughout, at times very hot, and there are no 

 dry cold winter months that are so injurious to woodland ; on the other 

 hand, the climate includes factors unfavourable to grassland in the more 

 considerable heat and the small amount of precipitation over the greater 

 part of the district, except the coast. Finally, the vegetative season is 

 much interrupted by hot dry periods. 



The Sertao district is therefore much richer in woodland than is the 

 southern cooler campos district. Tree-growth is richer in the savannah, 

 extensive tracts are covered by savannah-forest and thorn-forest, in general 

 woodland strongly predominates over grassland. To explain in detail 

 why woodland occurs in one place, and why grassland in another, is at 

 present only partially possible, for there is a lack of accurate data of the 

 meteorology and local constitution of the soil, and the soil plays an 

 important part in such mixed districts 1 . 



Quite a narrow strip of coast in the province of Pernambuco possesses a very 

 heavy rainfall, a real high-forest climate (Pernambuco, 297 cm.). Tree-growth is 

 extremely luxuriant in the public grounds of the principal town, but there is no 

 information available regarding the indigenous vegetation. 



1 See Part III, Sect. I, Chap. V. 



T 2 



