IX, A, 6 Brown and Mathews: Dipterocarp Forests 549 



able portion of the crop has been removed. The forest remain- 

 ing appears to be in a condition which assures satisfactory- 

 reproduction, Plate XIII is a view taken of a portion of this 

 forest after all logging operations have been completed. As will 

 be noted from this view, a very fair shelter wood of species of 

 the second and third stories remains on the ground, while on 

 the left may be seen the trunks of 2 individuals of the main 

 story, which being defective have been left for seed distribution. 

 The large trees at the left of the picture are overmature speci- 

 mens of Shorea polysperma. Such trees, while they produce 

 large quantities of seeds and shelter the ground very effectively, 

 are absolutely worthless for timber, and their retention as a 

 portion of the shelter wood occasions no loss whatever. The 

 objections which could be raised to the practice of retaining 

 trees such as these in the shelter wood are that they might dis- 

 seminate fungous spores and that the seeds furnished by them 

 might be of less desirable quality than those from more thrifty, 

 rapid-growing individuals. However, the latter point is one 

 which has never been proved. The defect which exists in these 

 trees, rendering them valueless for timber, is acquired and is 

 probably not hereditarily transmissible. Such trees have passed 

 through all the stages incident to the existence of the species 

 in the stand, and are now in the last stages of existence due 

 to excessive fungous attack. They produce seeds in large quan- 

 tities, and although the seeds may possibly be less fertile than 

 those produced by younger trees there is no reason to believe 

 that such of these seeds as germinate will produce trees more 

 subject to fungous attack than trees which develop from seeds 

 of the same species in younger stages of development. 



In the discussion of the forest of northern Laguna, the regular 

 distribution of volume through the various size classes and the 

 presence of very dense reproduction in the ground cover and 

 in the second and third stories of the forest make the problem 

 of management very simple indeed. Either of the systems dis- 

 cussed above would probably prove successful here. The cli- 

 mate is so pronouncedly that of the nonseasonal belt, and the 

 composition of the forest so simple, that clear cutting in patches 

 or strips would probably result in a heavy reproduction of dip- 

 terocarp species. Likewise, the dense reproduction and large 

 volume representation in the lower diameter classes would per- 

 mit of the practice of the shelter-wood system, with the shelter 

 wood composed mainly of thrifty, rapid-growing dipterocarps. 

 The forest is also eminently suited to the practice of the selec- 

 tion system with a proper diameter-limit regulation. This is 



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