i63 FORMATIONS AND GUILDS [Part 



2. THE CLIMATIC FORMATIONS. 



i. CLASSIFICATION. 



Climatic formations may be traced back to three chief types — zvoodlaiu 

 grassland, and desert. 



Woodland is constituted essentially of woody plants, and is terme; 

 forest if trees grow in a closed condition ; bushicood, when shrubs are s 

 abundant as to keep the crowns of the trees from touching one another 

 s/inilni'ood, where shrubs constitute the chief feature. Herbaceous planlj 

 are always present on woodlands, but as accessory components onl_v^ 

 they are completely dominated in their oecology by woody plants. 



Grassland consists essentially of perennial grasses growing in tuftl 

 Other herbaceous plants, even if they should be just as numerous :' 

 the grasses, are merely companions of the grasses, for the existence < 

 the formation depends in the first place on its grassy covering. Gras 

 land, when hygrophilous or tropophilous, is termed nteadoiv ; when xer. 

 philous, steppe ; and xerophilous grassland containing isolated trees 

 savanna/i. 



Woodland and grassland stand opposed to one another like two equal 

 powerful but hostile nations, which in the course of time have repeated 

 fought against one another for the dominion over the soil. The climat 

 that now prevail have limited the domains of each of the opponeni 

 but merely slight changes of climate would suffice to revive the conte. 

 In districts which, in a sense to be explained further on, possess neith 

 a decided woodland climate nor a decided grassland climate, the actii 

 of mankind sutilices to start the struggle. Thus at the present tin- 

 owing to the clearance of forests in Eastern Java and a few other localiti 

 in the Malayan Archipelago, districts formerly occupied by woodlaij 

 are being invaded by grass. Although I have personally witnessed tl' 

 contest, yet I will give an account of it in the words of Junghuhn, t 

 veteran authority on Malayan vegetation, for it is hardh- possible 

 equal his clearness. 



When the soil remains uncultivated after clearing the forest, ' 

 a rule the social and dense-growing alang-grass (Imperata Koenig 

 Beauv.) first replaces the vanished forests, then areas extending for mil 

 even indeed for whole days' journeys, are transformed into a unifci 

 wilderness of dense grass three to five feet high, while on mounta- 

 slopes the same grass extends far beyond its original zone, and spread! 

 over everything it ranges up to altitudes of 6,coo-7,ooo feet, being almi 

 insensible to differences of temperature. 



' Its silken-haired seeds, light as the tenderest down, are wafted aw 



