230 



The Philippine Journal of Science 



The soil of the dipterocarp forest contains considerably more 

 water than that of the grassland. The greatest variation in 

 moisture content at a depth of 10 centimeters is from 59.1 per 

 cent on December 19 to 39 per cent on March 21. The latter 

 figure appears to be high for a minimum water content at this 

 depth, but during the dry season the effects of drought on the 

 dipterocarp forest are very evident. The foliage is much less 

 dense than at other seasons, while Parastaca plicata (bagtican 

 lauan) , the dominant tree, shows a greatly diminished rate of 

 growth. 9 The effect of drought in the dipterocarp forest is, 

 however, not so marked as in the grassland. 



The percentages of moisture shown in Table V for the mid- 

 mountain forest are considerably greater than those for the 

 dipterocarp forest, and the variation is relatively less. 



Table V. — Percentage of moisture in soil in midmountain forest (altitude 

 730 meters) on Mount Maquiling, Laguna Province, Luzon. 



1912. 

 November 16 



30. 



December 7. 



14. 



21. 



1913. 

 January 11 



77. 2 j 80. 1 



| 75.6 



76.8 | 



70.2 I 73.6 

 69.1 ! 72.8 



73.7 69.7 



74.6 I 73.1 



70.1 | 70.7 

 57.2 



1913— Cont. 



May 3 



10 



July 

 August 



October 4. 



25. 



November 1. 



29_ 



December 6. 



13. 



In this region there were no marked effects of droughts during 

 the dry season except on the epiphitic vegetation. The percent- 

 age of moisture in the soil is very high, being between 70 and 80 



" Brown and Matthews, op. cit. 



