548 1"^^ Philipinne Journal of Science i9i4 



proper representation of dipterocarps in the new stand. How- 

 ever, with careful logging, leaving a shelter wood for the most 

 part of species other than dipterocarp, it is possible to leave 

 the forest after logging with a stand of seedlings on the ground 

 averaging at least 1 dipterocarp to every 4 square meters and 

 to leave at the same time a shelter wood sufficiently dense to 

 insure the development of these seedlings into a new crop. 



As with the clear-cutting system recommended for the forest 

 of Negros, it is, of course, impossible to formulate at this time 

 any detailed rules for the application of the shelter-wood system 

 under the conditions just described. The factors of reproduction 

 are rarely found uniform over large areas in virgin forests, and 

 the application of the system must necessarily vary to meet these 

 changes in the factors of reproduction. In certain portions of 

 the forest of Bataan, it will be found that the representation 

 of dipterocarps in the main stand is much less than that of 

 second-story trees, which, due either to logging in the past or 

 to conditions especially suited to their development, have achieved 

 dominance. Where conditions such as these exist, it will be 

 necessary to prohibit almost entirely the cutting of dipterocarps 

 and to allow only the removal of such individuals of the second 

 story as the loggers think can be removed at a profit. Such an 

 operation as this should result in the improvement of the com- 

 position of the new stand over the one which exists at present. 

 In other places, it will be found that the whole of the forest 

 consists of a stand of thrifty rapid-growing species of diptero- 

 carps; in these the shelter wood will have to be composed of 

 timber having a very distinct market value at the present time 

 and which, when left on the ground, causes a very distinct loss 

 to the loggers. 



However, over the greater portion of the area it will be found 

 that it is possible to leave a proper representation of diptero- 

 carps in the shelter wood by leaving only the most overmature 

 and defective specimens, without any serious reduction in the 

 profits of the logging operation and without any great economic 

 loss due to the deterioration of timber which is of value at 

 present, but which will become valueless before the time of the 

 second cut. 



The successful practice of the shelter-wood system in any 

 forest in the Philippines calls for actual timber marking by a 

 trained forest officer. Experiments leading to the establishment 

 of this system in the forest of Bataan are already under way, 

 and hold out a very fair promise of success. Some 10 hectares 

 of forest have already been logged, and the bulk of the market- 



