xii, a, 5 Brown and Argiielles: Soils on Mount Maquiling 225 



MIDMOUNTAIN FOREST 



The forest occurring above the dipterocarp forest is much 

 smaller than the latter and is composed of only two stories of 

 trees (Plate II, fig. 2). This forest extends upward to an 

 elevation of approximately 900 meters. The soil samples con- 

 sidered in this paper were obtained on the top of a broad ridge 

 at an elevation of about 730 meters. In this locality the trees 

 of the top story reach a height of about 18 meters. The forest 

 is much more open than the dipterocarp forest (Plate III, fig. 1). 

 The most prominent large tree in it is Quercus solariana (cata- 

 ban), while Cratoxylon celebicum (guyong guyong), which is 

 somewhat smaller, is more numerous. The average height of 

 the second story is about 6 or 8 meters. The most numerous 

 species are Oreocnide trinervis (malatuba) , Neolitsia villosa, and 

 Sauraunia barnsii. The ground cover consists largely of ferns 

 and other herbs, of which species of Elatostema are the most 

 prominent. The herbs in this region require much moister 

 conditions than those in the dipterocarp forest. 



MOSSY FOREST 



The top of the mountain is in the cloud belt and is covered 

 with an elfin wood or mossy forest. This type is composed of 

 only one story and is characterized by having the trunks of the 

 trees thickly covered by mosses, mosslike plants, and other epi- 

 phytes. The ground cover is composed almost entirely of herbs, 

 among which Strobilanthus plurifomis, ferns, and species of 

 Selaginella are the most prominent. The most striking peculiar- 

 ity of the trees is a tendency to produce a large number of aerial 

 roots, which grow to such a size as to form, as far as function 

 goes, secondary trunks (Plate III, fig. 1). The soil samples 

 from this forest were taken within a few meters of the top of 

 the mountain. 



From the above description it will be seen that the chief 

 changes caused by increased altitude, which might conceivably 

 be connected with soil conditions, are a dwarfing of the vegetation 

 as higher elevations are reached and the occurrence in the ground 

 cover of plants requiring moister conditions at high than 

 at low altitudes. In order to see whether or not these changes 

 could be connected with soil conditions, we have made a chemical 

 and physical analysis of soil samples taken at a depth of 20 

 centimeters in the four different types of vegetation and have 

 determined the water content of the soils, for different weeks 



