418 The Philippine Journal of Science wh 



nearly so strong a wind, and although it brings rains on the 

 western side of the Archipelago a large part of the rains which 

 come at this season of the year is the result of cyclonic 

 disturbances (typhoons) which cause the deposition of rain on 

 both coasts. 



This difference in the character of rainfall between the 

 eastern and western halves of the Archipelago is pronounced on 

 Luzon, where there are large mountain masses running north 

 and south. Forest areas are very extensive on the eastern side, 

 where there is a nonseasonal climate. The same relation 

 between forests and rainfall is also evident to some extent 

 in the southern islands, particularly so in Mindoro, which like 

 Luzon has a high central mountain range running north and 

 south and a rather nonseasonal rainfall on the eastern side 

 which is also heavily forested. Cebu, on the other hand, which 

 lies farther east than Mindoro, is a relatively low island, and 

 being sheltered on its eastern side by Leyte and Samar has 

 a very distinct seasonal climate and is almost without forest. 



This relation between the distribution of forests and rainfall 

 is due to the seasonal character and not to the total amount of 

 rainfall. The average rainfall as taken at the weather stations 

 for the western, seasonal or monsoon, climate is 2,327.3 milli- 

 meters per year; for the eastern or nonseasonal climate, 2,273.7 

 millimeters.** Moreover, the total range of rainfall in each 

 climate is considerable, varying from 1,188.8 millimeters to 

 3,954.4 millimeters in the region of monsoon rainfall and from 

 905 millimeters to 3,859.2 millimeters in the region of nonseasonal 

 rainfall. Thus, it is evident that if any relation between forest 

 distribution and rainfall is to be established it must depend 

 upon the seasonal character rather than upon the total amount 

 of rainfall. What has been said in regard to rainfall will 

 apply over large areas, but the local configuration of mountain 

 masses will, of course, affect these conditions very considerably. 



It is very probable that, with the exception of certain limited 

 very dry regions, all of the Archipelago was originally covered 

 with forest, the greater part of which was dipterocarp in 

 character. The extensive grass areas and second-growth forests 

 which now occupy a large portion of the Islands are undoubtedly 

 due in large part to the influence of man. In this connection 

 it may be interesting to refer to the following table (Table I) 

 from Whitford : '" 



° Cox, loc. cit. 

 "Bull. P. I. Bur. Forestry. (1911), No. 10. 



