536 



The Philippine Journal of Science 



1914 



centimeters, the dipterocarp forest is replaced by another of a 

 different type. As an example of what may happen to a forest 

 when such an apparently reasonable diameter limit is applied to 

 a heavy stand of dipterocarp timber, there is here presented 

 Table XLVII for the hectare of timber in Bataan, represented 

 in Table VII, after it has been cut over under a diameter limit 

 of 50 centimeters. These tables are summarized in Table 

 XLVIII. 



Table XLVIII. — CompaHson of stand of timber on a sample hectare in 

 virgin and logged forest. Bataan Province, Luzon. 



[Numbers show volumes in cubic meters.] 





Uncut After 

 forest, cutting. 



Amount 



logrged 



off. 



Trees less than 50 centimeters in diameter 



80.41 47.13 



32.28 17.63 



471. 49 59. 23 



33.28 



14.65 



412.26 



Trees more than 50 centimeters in diameter 



Dipterocarps more than 50 centimeters in diameter 



433. 69 42. 51 391. 18 



Total 



551.90 ' 106.36 1 445.54 







1 



The results presented in these tables indicate that the effect 

 on this forest has not been unduly severe; that is, we have left 

 106 cubic meters out of an original total of 551, and 42 cubic 

 meters of dipterocarps out of an original total of 433. In tem- 

 perate regions this would mean that the logging operation had 

 been very successful from the forester's standpoint. In the Phil- 

 ippines the reverse of this is true. A study of the table reveals 

 the fact that the main canopy of the forest has been almost 

 entirely I'emoved, that only 4 dipterocarps above 50 centimeters 

 in diameter remain on the hectare, and that the bulk of the 

 stand numerically lies in the tree classes from 5 to 40 centi- 

 meters. With the exception of the 4 trees over 70 centimeters 

 in diameter, all of the stand on the ground has developed entirely 

 under the shade of the main canopy. The result is that these 

 trees have very straggling thin crowns with broad succulent 

 leaves suited only to the conditions which exist under the dense 

 shade of the main canopy. The sudden exposure to full sunlight 

 results in the death of a great majority of the smaller trees 

 within a very short period. 



On this same hectare, before cutting, we had on an average 

 plot of 250 square meters a stand of 1,539 seedlings, 1,130 of 

 which were tree seedlings and 409 brush seedlings. Out of the 

 total of 1,130 tree seedlings, 259 were of the family Dipterocar- 

 paceae. After cutting, the number of seedlings on the same area 

 had been reduced to 191, only 38 of which are dipterocarp. The 



