466 The Philippine Journal of Science i9i4 



times the number of species found in hardwood forest areas of 

 equal size in the temperate zone, the number of species being 

 frequently fifteen or twenty times as great on an equal area in 

 the Philippines. In the temperate regions an excessively over- 

 mature forest does not present a very serious management prob- 

 lem. In the first place, the forests of temperate zones do not 

 have an understory of a vast number of miscellaneous species 

 standing ready to claim the area as soon as the dominant class is 

 removed, and, secondly, seeds and seedlings of the most important 

 species in temperate regions are able to establish themselves 

 at once on the area from which the overmature timber alone 

 is removed, without having to enter into competition with 

 numerous weed species which do not normally exist in the area. 

 In the Philippines, however, both of the above conditions obtain, 

 and the result of removing the main portion of any tract of 

 forest has already been very fully discussed. 



It becomes evident from the above discussion that as a 

 measure of success from the standpoint of management neither 

 bulk nor perhaps even bulk and increment combined can be used 

 without taking into equal consideration the distribution of bulk 

 throughout the different size classes. The conclusion to which 

 we are forced is that in the Philippines where we have a 

 dipterocarp forest of exceptionally high volume per hectare we 

 have at the same time an unsatisfactory distribution of this 

 volume. It also becomes apparent, that as a measure for 

 successful forest management volume taken together with equal- 

 size distribution is a more satisfactory measure than either 

 volume alone or volume and increment combined. 



GROWTH 



GENERAL DISCUSSION AND METHODS OF MEASUREMENTS 



Temperature in the tropics throughout the year is uniform 

 and favorable for growth, and it has been generally believed 

 that the growth of tropical plants must be very rapid. This 

 is undoubtedly true for most plants growing in the open. 

 A striking example which is often quoted is that of the bamboo 

 which has been known to exceed 50 centimeters per day in its 

 period of most rapid growth. It should be remembered, how- 

 ever, that in this case almost the entire growth for a whole year 

 is made in a few weeks, while food is manufactured during 

 the entire year. The growth of tropical plants is usually dis- 

 tributed throughout the year, and the high annual rate of 

 growth, in the open, is due to the long season in which growth 

 is possible rather than to particularly favorable conditions at 



