528 ^^^6 Philippine Journal of Science wm 



mometer, are compiled in the form of averages of the weekly 

 maxima and minima for periods of four weeks. 



An examination of Table XLIII would seem to show that there 

 is little difference betvs'een the temperatures in the undergrowth 

 and in the second storj'. 



The average weekly maximum is 5°. 9 higher and the minimum 

 0°.6 lower in the top of the dominant story than in the under- 

 growth, while the average weekly range is 12°.0 in the former 

 and only 5°. 5 in the latter situation. Since there is but little 

 difference between the minimum temperatures in the two places 

 and the average weekly maximum is 5°. 9 higher in the dominant 

 story than in the undergro^vth, the dominant story should have 

 the higher average temperature and the one most likely to cause 

 rapid growth. However, this temperature can hardly be re- 

 garded as high enough to be optimum for more than a small 

 portion of the time. 



The rainfall for the year is given in Table XLIV. It will be 

 seen that the dry season is pronounced, but that it is relatively 

 short, and that there is no month without rain. 



Saderra Maso ^° states that the average rainfall for the Archi- 

 pelago is 240 centimeters. The rainfall in the region under dis- 

 cussion is distinctly less than this. The rainfall in the forest 

 would be classed as seasonal. It is, however, more evenly dis- 

 tributed throughout the year than at most of the weather stations 

 where there are distinct wet and dry seasons. 



In Table XLIV there is also given a record of the percentage 

 of soil moisture for the year. The figures are averages of weekly 

 determinations, and the percentages are based on the dry 

 weight of the soil. All samples were taken at a depth of 20 

 centimeters. The percentage of moisture is always high, and 

 the seasonal changes while pronounced would hardly be called 

 excessive, as the table shows an extreme variation of from 43.2 

 to 58.2 per cent. 



Relative humidity was measured in the forest, at about 75 

 centimeters above the ground, by a Draper's recording hygro- 

 meter. The results are given in Table XLV in the form of 

 maxima, minima, means, averages of daily maxima, and aver- 

 ages of daily minima for periods of four weeks. The means 

 were obtained by using a planimeter. The table shows that the 

 humidity is very high and uniform throughout the year. 



" Saderra Mas6, M. S., Annual amount and distribution of rainfall in 

 the Philippines. Weather Bureau, Manila, P. I. (1914). 



