34 PHILIPPINE RESINS, GUMS, AND OILS 



The sapwood is white; the heartwood white and reddish brown 

 with alternate light and dark rings, and very resinous. It is 

 used locally for house construction, mining props, etc. 



This species is found in the highlands of central and northern 

 Luzon at altitudes varying from 500 to 2,500 meters, but is best 

 developed at altitudes ranging from 900 to 1,500 meters. The 

 stands vary in density from those composed of scattered indi- 

 viduals to nearly closed patches. The ground in a pine area is 

 usually covered with grass. In the ravines, broad-leaved trees 

 occur and there is considerable evidence to show that nearly 

 the whole area now occupied by the pines was formerly covered 

 by broad-leaved trees, the pines being confined to steeper and 

 dryer situations, where the other trees did not flourish. Through 

 the activities of man in past centuries, the broad-leaved trees 

 have been cleared off", and repeated fires have prevented their 

 reproduction. The result of successive fires is usually to leave 

 the lands in the possession of grasses. The pines are less suscep- 

 tible to fire than are the broad-leaved trees and consequently the 

 former occur over wide areas. If fires were kept out, the pine, 

 in the absence of competition with the broad-leaved trees, would 

 quickly occupy the entire area, as its reproduction is abundant 

 and rapid. The pines would then gradually be replaced by 

 broad-leaved trees, as these will seed under the pines and cast 

 such a dense shade as to prevent the growth of pine seedlings. 



Measurements show a volume of 74 cubic meters per hectare 

 (equivalent to about 7,400 board feet per acre) of pine trees 

 which have a diameter of 25 or more centimeters. 



PINUS MERKUSII Jungh. (Fig. 8). Tapulau or Mindoro Pine. 



Local names: Agu-u (Mindoro); salit, tapulau (Zambales). 



TURPENTINE 



This species has not been investigated chemically, but its 

 products are probably similar to those of Pinus insularis. The 

 wood is apparently identical with the latter species, but seems 

 on the average to be even more resinous. 



Pinus merkusii is a tree reaching a diameter of about 90 cen- 

 timeters. The chief difference between this species and Pinus 

 insularis is that the needles occur in groups of two rather than 

 three. 



This species is found in Zambales and northwestern Mindoro, 

 occurring in the latter region in pure stands. In Zambales, both 

 Pinus merkusii and Pinus insularis are found at altitudes of 

 only one or two hundred meters. 



