xii, a, 5 Brown and Argiielles: Soils on Mount Maquiling 223 



analyses of a number of samples of similar tuff. These analyses 

 indicate that the tuff should disintegrate into a fertile soil. 

 Where the surface layers of the tuff are shallow and much 

 broken, they appear to have little if any effect in determining 

 the character of the vegetation. We have seen thick surface 

 layers only around the base, where the original vegetation has 

 been almost entirely removed. 



The climate of Mount Maquiling may be classified as mon- 

 soonal ; that is, the rains depend upon rain-bearing winds, which 

 shift their direction twice a year. This results in distinct wet 

 and dry seasons. The northeastern monsoon strikes Luzon on 

 its eastern coast and deposits a large part of its moisture in 

 passing over the divide between the Pacific Ocean and Laguna 

 de Bay; when it reaches Mount Maquiling, it is a drying wind. 

 This monsoon results in a decided dry season from January to 

 April. The most pronounced rainy season is from July to Sep- 

 tember during the southwest monsoon, when a large part of the 

 rains are the result of cyclonic disturbances (typhoons). 



Around the base and on the lower slopes of Mount Maquiling 

 there is a mixture of grassland and second-growth forest. Above 

 this there are three distinct types of original forest, which occur 

 at successively higher levels. 



GRASS AREA 



The mixture of grassland and second-growth forest at the 

 base has been described by Brown and Matthews. 7 This region 

 appears to have been originally covered with a tall dipterocarp 

 forest, which is the type occurring at the next higher elevations. 

 The original forest was removed, and the land was cultivated. In 

 the area under consideration cultivation was abandoned, and 

 much of the ground became covered by tall grasses, chiefly Sac- 

 charum spontaneum (talahib) and Imperata exaltata (cogon). 

 These grasses are very inflammable when dry. They were burned 

 at frequent intervals, the last fire occurring in 1911. The grass 

 fives kill nearly all tree seedlings, but appear to do little if any 

 damage to the rhizomes of the grasses. Saccharum spontaneum 

 (Plate 1, fig. 1) and Imperata exaltata both form dense stands, 

 the former frequently reaching a height of over 3 meters, while 

 the latter is shorter, being rarely more than 1.5 meters in 

 height. Mixed with the grass are areas of second-growth 

 forest, and since 1911 much of the grassland has changed to 



7 Op. cit. 



