544 ^^^ Philippine Journal of Science i9i4 



GENERAL CONSIDERATIONS OF MANAGEMENT 



It is not within the scope of this paper to enter into a discus- 

 sion of the details of forest management for any particular area, 

 nor are the data which would permit this at hand. It is possible, 

 however, to conclude our discussion of dipterocarp forests with 

 some general conclusions, and with these conclusions as a basis 

 to outline the broad principles of management for each of the 

 main types of forest here discussed. Upon these as a basis there 

 can be built up detailed methods or working plans. 



The conclusions with regard to the management of our dip- 

 terocarp forests may be summed up as follows : 



(1) From a management viewpoint, dipterocarp forests carry- 

 ing the heaviest stand per hectare present the most serious 

 problems. (2) Those dipterocarp forests in which the diptero- 

 carps have been able to dominate the stand and exclude the 

 major portion of species of other families, without at the same 

 time developing into a one-storied forest, present the easiest 

 problems from the management standpoint. (3) Those forests 

 in which the second and third stories have achieved undue 

 prominence, due to the action of man in opening the canopy, are 

 very difficult of management. (4) While Philippine forest 

 trees, growing in the open, often show more rapid growth than 

 forest trees in the temperate zone, the growth of individuals in 

 virgin forests is not as great as the growth of individuals in 

 temperate virgin forests, except in the higher diameter classes, 

 and the total volume production per hectare per year in Phil- 

 ippine forests is probably less than that in temperate hardwood 

 forests. (5) The maintenance of a fairly dense shelter wood is 

 necessary for the satisfactory reproduction of most dipterocarp 

 species. (6) Clear cutting on large areas will prove a failure 

 in nearly all instances, and if clear cutting must be undertaken 

 it should be confined to the smallest practicable unit of area. 



(7) A large majority of our dipterocarp forests, which ap- 

 parently contain a very heavy stand per hectare, are often much 

 reduced in volume, due to the presence of defects, and are either 

 equally balanced between growth and decay or are actually 

 deteriorating if decay is progressing more rapidly than growth. 



(8) Successful management of dipterocarp forests will depend 

 upon (a) a thorough understanding of the effects of environ- 

 mental factors on reproduction and growth, (&) accurate data 

 as to the distribution of volume throughout the various size 

 classes, (c) a knowledge of the various sizes at which the dif- 

 ferent species of the dipterocarps begin to produce seeds, and 



