PDF - Wallace Online

I242 TROPICAL NATURE nposed to think this is caused by accident or decay, but repeatedexamination shows it to be due to the natural growthof the tree. The accompanying outline sections of one of thesetrees that was cut down exhibits its character. It was anoble forest tree, more than two hundred feet high, but ratherslender in proportion, and it was by no means an extreme exampleof its class. This peculiar form is probably producedby the downward growth of aerial roots, like some NewZealand trees whose growth has been traced, and of whosedifferent stages drawings may be seen at the Library of the LinnseanSociety. These commence their existence as parasiticalSECTIONS OF TRUNK OF A BORNEAN FOREST-TREE.1. Section at seven feet from the ground. 2. 3. Sections much higher up.climbers, which take root in the fork of some forest tree andsend down aerial roots which clasp round the stem that upholdsthem. As these roots increase in size and growtogether laterally they cause the death of their foster-parent.The climber then grows rapidly, sending out large branchesabove and spreading roots below, and as the supporting treedecays away the aerial roots grow together and form a newtrunk, more or less furrowed and buttressed, butno exhibitingother marks of its exceptional origin. Aerial-rooted foresttrees like that figured inmy Malay Archipelago (vol.i.p.and the equally remarkable fig-trees of various species,