722 
WHlTFOliD. 
Diptcrocarpus grandiflorus and Dipterocarpus vernicifluus in shape of 
bole, habits of growth and wood as well as fruit, and Dipterocarpus 
tubercidatus occur scattered all through the forest and probably have as 
large a yield as there is of all other species combined. They are not 
logged, however, except in the more accessible places. I also noted a 
Parasliorea and a Shorea in the forest.” Fox worthy 12 states that if all 
woods other than the dipterocarps were excluded from the markets of 
the tropical East, the markets would hardly feel the difference. 
So much for the Asiatic tropics. Will the tropical regions of Africa 
and South America show similar quantities of general construction 
timbers in their virgin forest? So far as 1 know, economic and scientific 
explorations have been mainly attempts, from the viewpoint of the 
lumberman, to find valuable hardwoods of the mahogany grade or hard 
durable timbers. The forests as a whole have not been sized up from the 
standpoint of the forester with a view to the utilization of all the species. 
From the results of the investigations given above, made in the Philip- 
pines, it is probable that the virgin forests of South America and Africa 
will show that a greater part of their bulk will consist of woods suitable 
for general construction purposes of certain classes, which can, with the 
introduction of modern methods of logging and milling and with improved 
economic conditions that are sure to come with the development of the 
tropics, be placed in the markets of the temperate regions at a cost that 
will enable them to compete with woods of similar qualities found in 
virgin forests in temperate regions or grown there as successive crops. 
In the United States an inventory of the natural resources is being 
made with a view to conserving them. An attempt is being made to 
extend this conservation inventory to other parts of the world. So far 
as the forest resources of the world are concerned I believe that there is no 
problem that will ultimately yield greater scientific and economic results 
than an inventory of the forest resources of the tropical world. This will 
include a mapping of the forested areas, a rough estimate of the standing 
timber, and a brief description of the areas as regards their lumbering 
possibilities and the classes of timber found. 
Mention was made above (page 701) that increment should be con- 
sidered as a factor in an estimation of success in forest vegetation. In 
some forest trees of the Philippines rings of growth occur. In others 
these are lacking or obscure. It is not known whether these rings are 
annual or only seasonal. On this account no estimate can be made of 
the annual increment from rings of growth. Actual measurement of rate 
of tree growth in the tropics is not extensive enough to be of general 
application. It is believed, however, that the rate of growth in the 
tropics is much greater than in temperate zones, that generally speaking 
the soft wood forest trees will reach maturity in one-half to two-thirds 
12 Foxworthy, F. W. Indo-Malayan Woodsf'' This Journal 4 (1909) Botany 506. 
