TROPICAL WOODLAND AND GRASSLAND 261 



besides these, transitions are very frequent between savannah-forest and 

 savannah as well as between thorn-forest and open bush-formations, 

 which as intermediate forms connect the formations of woodland and 

 desert. 



Tropical grassland, wherever it has not been modified by human agency, 

 occurs chiefly as savannah, more rarely as steppe. The occurrence of 

 meadow, by which we understand hygrophilous or tropophilous grassland, 

 is rare in the tropics and is always due to factors that are merely local. 



Tropical desert has a vegetation consisting of scrub, that is to say, 

 of stunted trees and shrubs or of shrubs only, also of succulent plants and 

 perennial herbs. Most tropical deserts are near the tropics of Cancer 

 and Capricorn, and are allied to the far more extensive warm temperate 

 deserts. The climate of the tropical deserts will be treated of in a subse- 

 quent chapter together with that of the temperate deserts. 



2. HIGH-FOREST CLIMATE IN THE TROPICS. 



Brandis declares that really succcssfid forests occur only where the rainfall 

 attains forty inches, and that a luxuriant rich vegetation is limited to zones 

 ivhcre the annual rainfall is much greater. 



The available meteorological tables for tropical districts show, in regard 

 to land that is covered with or has been covered with high-forest (rain- 

 forest or high monsoon-forest), an annual rainfall of at least 180 cm., 

 excepting near large sheets of water where telluric moisture replaces 

 rain. Within the most extensive forest-district of the tropics, the Indo- 

 Malayan, including New Guinea, an annual rainfall of over two meters is 

 the rule ; wherever much less than two meters of rain falls, the indigenous 

 vegetation, so far as is known, forms less lofty woodland, as at many 

 spots in East Java, or creates savannah, as in Timor (Koepang in Timor 

 has a rainfall of 145 cm.). On the other hand, at many spots the rainfall 

 exceeds 300 cm. ; at several it exceeds 400, at Buitenzorg, for instance, 

 reaching 499 cm. 



Thanks to the excellent records of the numerous meteorological stations in Dutch 

 Malaysia, Woeikof l has been able to compare the conditions of rainfall of a great 

 number of localities there. In Java the annual rainfall is given for 62 stations ; it is 

 less than 200 cm. for twelve of them only, for five it is less than 150 cm., for none is it 

 less than 100 cm., the minimum (113 cm.) being at Probolinggo. Several of the above 

 localities are known to me personally, for instance Probolinggo, where the rainfall is 

 lowest. Probolinggo is in East Java, far from any forest, and there, except man- 

 groves, I found in the wild state only thorny brushwood, xerophilous in character. 

 The vegetation near Pasoeroean, where the rainfall is quite as small, is just like that 

 of Probolinggo. It cannot now be ascertained what kind of indigenous vegetation 

 formerly occupied these parts of the country, which are now covered with planta- 



1 Woeikof in Zeitschr. d. osterr. Gesellsch. f. Meteorol., 1885. 



