• STUDIES IN THE VEGETATION OF THE PHILIPPINES. 
I. THE COMPOSITION AND VOLUME OF THE DIPTEROCARP 
FORESTS OF THE PHILIPPINES. 
By H. N. Whitfokd. 
( From the Bureau of Forestry, Manila, P. I.) 
SUMMARY OF CONCLUSIONS. 
I. The virgin forest area of the Philippines comprises approximately 
40,000 square miles or about one-third the total area. 
II. Seventy-five per cent of the virgin forest area (30,000 square miles) 
is covered, with forests in which the members of the dipterocarp family 
predominate. 
III. The members of the dipterocarp family, comprising an average 
of 75 per cent of the volume, can, from a forester’s and lumberman’s 
standpoint, be divided into three tree groups, viz, the hard and durable 
yacals, the apitongs, and the lauans. 
IV. The apitongs and lauans can furnish by far the greatest amount 
of timber. The apitongs can be favorably compared to the hard pines 
in general mechanical properties, the lauans, to the soft pines. 
V. From many standpoints the dipterocarp family is to the Philip- 
pines what the pine and oak families are to the United States and other 
temperate countries. 
VI. Success in virgin forest growth should be measured in terms of 
bulk or bulk and annual increment combined. 
VII. The nearer the climatic, edaphic, and biotic conditions reach 
the optimum, the heavier the bulk of the forest and the simpler the 
systematic arboreal composition. 
VIII. If measured in bulk alone, some temperate regions as compared 
with the Philippines show greater success in forest growth. If annual 
increment is used in combination with bulk, the forests of the Philippines 
will compare favorably with forest growth in temperate regions. 
IX. If the tropics in general are like the Philippines in the above re- 
spects, they can be depended on to produce woods to compete with general 
construction timbers grown in temperate regions. 
X. An inventory of the forest resources of other tropical regions will 
give scientific and economic results of great importance. 
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