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421 
reaches one the higher the value of the log. It has been shown that for 
some species of trees the board roots are not developed so long as the 
trees do not become dominant. If it be desired to suppress the buttress 
habit for such species, it will be found effective to adopt a sylvicultural 
treatment which will keep species of the same crown class together, so 
that throughout the entire rotation none will become dominant. In 
some parts of the Lamao Reserve such a system is already naturally 
realized. On the other hand, it may be expedient as fully as possible 
to develop the board roots, for certain timbers are valuable for broad 
table tops. In such cases a sylvicultural system, the reverse of the one 
just given, would produce the desired results. If the strain is the cause 
of the development of plank buttresses, then this could be concentrated 
by the removal of the less desirable ones, so that the others would receive 
more of it and thus become stimulated to better development. 
Fluted trunks.—In some trees at the top and at the base of the bole 
there is a tendency to develop a fluted appearance. In such individuals, 
especially if the trunk is short, the grooves are apt to be more or less 
continuous throughout the entire length, although the middle portion 
is more nearly circular in cross section. Huphoria cinerea, Bugenia lu- 
zonensis (Pl. VI), Dracontomelum cumingianum, Reinwardtiodendron 
merrillu, Turpinia pomifera, species of Ficus, and others may have such 
irregular trunks. Many trees do not have the buttress habit in any 
situation. Among those which may sometimes become dominant are 
. species of Anonacee, as Cyathocalyx globosus and Canangium odoratum, 
and in other families Bombax ceiba, Zizyphus zonulatus, and of those 
which seldom reach above the second-story vegetation, Strombosia philip- 
pinensis, Antidesma edule, and many others may be mentioned. 
Tree habit.—In the Anisoptera-Strombosia formation, aside from 
Bambusa, Gnetum gnemon, and Pandanus luzonensis, there are only a 
few scattered individuals of plants that have acquired the tree habit in 
the great groups of Pteridophytes, Gymnosperms, and Monocotyledons. 
Gnetum gnemon, as shown by Tables XIII and XIV, forms a conspicuous 
element in the second-story vegetation of the forests. It rarely reaches 
a height of more than 12 meters. It is easily distinguished by its very 
broad, opposite mesophytic leaves and the joints of the trunk. These 
latter cause the bole to resemble a bamboo with short, thick internodes. 
(See Pl. XIV.) The liliaceous Dracena angustifolia, represented only 
by a few trees over 4 meters tall, is nevertheless conspicuous by many 
specimens under this height and by its long, narrow, clasping leaves. 
Only one specimen of a tree fern, Alsophila contaminans, is present (see 
Pl. XXVI). This will be discussed in another connection. Near the 
upper limits of the Bambusa-Anisoptera formation there are two groves 
of the palm Orania palindan, and a few scattered specimens were noted 
elsewhere. One grove of eight trees of Cycas circinalis was found in a 
semi-open place within this formation. 
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