414 'The Philippine Journal of Science i9u 



INTRODUCTION 



The fact that the dipterocarp forests are the most extensive 

 and important forests of the Indo-Malayan region has been 

 pointed out by a number of writers, but up to the present 

 time little or no attempt has been made toward an understand- 

 ing of the factors influencing their growth and development. 

 A clear comprehension of these factors is important from an 

 ecological point of view, and is absolutely necessary if the forests 

 are to be handled according to rational silvicultural practice. 

 The need of such data has led us, one a botanist and the 

 other a forester, to undertake this study with the hope that 

 it will result in a foundation which will help in the future under- 

 standing and management of these forests. Both of us have 

 been in full cooperation in all parts of the work, although 

 naturally some portions are more particularly the result of 

 individual investigations. The results here presented are, there- 

 fore, in effect the conclusions of both. 



We were particularly fortunate in having the assistance and 

 criticism of Dr. F. W. Foxworthy, who has made an extended 

 study of the trees of the Indo-Malayan region and especially 

 of the dipterocarps ; of Dr. E. B. Copeland, who is thoroughly 

 acquainted with the vegetation of the Philippines; and the as- 

 sistance of Mr. E. D. Merrill in the identification of specimens. 



A list of all the species mentioned is given at the end of 

 this article. 



GENERAL DESCRIPTION OF DIPTEROCARP FORESTS 



The dipterocarp forest is a tall, tropical lowland forest 

 characteristic of the Indo-Malayan region, usually occupying the 

 localities most favorable to tree growth. It receives its name 

 from the fact that species of the family Dipterocarpaceae are 

 the dominant trees. The forest may be composed almost wholly 

 of one dipterocarp species, as in some of the forests of Shorea 

 robusta of northern India and of Dipterocarpus tuberculatus of 

 Burma.- In other cases two or more different species may pre- 

 dominate. In many forests the numerical proportion of diptero- 

 carps may be small, but owing to their large size they may 

 yet give a characteristic appearance to the vegetation and form 

 a large proportion of the volume of timber. This condition 



' Brandis, D., An enumeration of the Dipterocarpaceae based chiefly upon 

 specimens preserved at the Royal Herbarium and Museum, Kew, and the 

 British Museum; with remarks on the genera and species, Joum. Linn. 

 Soc. Bot. (1895), 31, 1-148. 



