IX, A, 5 



Brown and Mathews: Dipterocarp Forests 



463 



diameter between forests in the Philippines and those of the 

 temperate regions, Wimmenauer's table for oak on site I is 

 presented here in the form of a model all-aged managed forest 

 for 1 hectare (Table XIV). There are 16 age classes in the 

 original table, the oldest being 160 years. The basal areas and 

 volumes for each age class have been determined by dividing 

 the volume and basal areas of an average stand of that age for 

 1 hectare by 16, so that there are represented that number of 

 distinct age classes in our table for 1 hectare. That is, the 

 volume and basal area given in Wimmenauer's table for the 160- 

 year class divided by 16 give the volume of that class in an 

 all-aged managed forest having represented in it trees of all 

 ages from 10 to 160 years. Likewise, the volume given in the 

 original table for an even-aged forest of 150 years divided by 16 

 gives the representation of that class in an all-aged managed 

 forest of 1 hectare and so on down to the youngest class repre- 



Table XIV. — Oak. Site I. Europe. 



Model all-aged forest of 1 



hectare. 



Age in years. 



Diam- Basal 

 eter. area. 



Volume. 



Age in years. 



Diam- 

 eter. 



Basal 

 area. 



Volume. 



10 



cm. 



2.54 

 6.10 

 10.90 

 15.60 

 20.80 

 25.10 

 29.00 



sg. m. 

 0.573 

 1.004 

 1.276 

 1.477 

 1.649 

 1.793 

 1 908 



eu. m. 



100 



cm. 

 39.40 

 42.90 

 46.70 

 49.80 



sq. m. 

 2.137 

 2.194 

 2.252 

 2.295 



cu. m. 

 34.12 

 36.39 

 38.43 

 40.31 

 42.06 

 43.77 

 45.43 



20. 



30 



40 



2.45 

 7.43 

 12.81 

 17.49 

 21.69 

 25.32 

 28.65 

 31.57 



110 



120 



130 



60 



60 ... 



140 



53.30 1 2.335 



150 



56.60 



2.381 



70. 



160 



59. 70 ( 2. 410 



80 . 





Total 



32.50 

 36.10 



2.008 

 2.079 





29. 774 



427.82 



90. 









sented — ^that of 10 years. The table which we have thus com- 

 puted for oak represents an average of even-aged managed stands 

 in which all ages occupy equal areas. Comparing this table with 

 that for one of our best dipterocarp forests, that of northern Ne- 

 gros (Table XV) , we see that in regard to volume and basal area 

 the two forests are not greatly dissimilar. Judging from the 

 standpoint of bulk alone, the virgin forest in the Philippines 

 seems to be somewhat more successful than a normal managed 

 forest, containing all ages, in the temperate zone. 



Although the total volume of the dipterocarp forest exceeds 

 that of the managed oak forest by 92 cubic meters, it will 

 be seen at a glance that the volume of the Negros forest is 

 distributed throughout diameter classes up to 170 centimeters, 

 while the largest diameter class in the managed forest is 60 

 centimeters. The conclusion that must be drawn from this 

 is that unless the dipterocarp trees produce, in the same length 



