TROPICAL CHARACTER OF FORESTS. 13 



always occur where the rainfall is greatest, many of the trees reach a 

 diameter of 4 feet, a height of 100 feet, and a clear length of 40 to 50 

 feet. The lehua trunk is straight, often twisted, deeply ribbed near 

 the ground, and frequently divided into several roots 10 or 12 feet 

 above the ground. The root system is very shallow, often spreading 

 right on the surface of the mineral soil. 



i" 11 



Though the stand of trees be thin, the normal forest, on account of 

 an abundant and luxuriant undergrowth, is impenetrable except as 

 one cuts his way with knife and axe. Many of the trees support 

 climbers such as the ie-ie vine, which grows into the crowns and may 

 lure together with rope-like stems the trees of an entire forest. Then 

 there is the fern growth, marvelous in its variety and luxuriance. 

 With species which range in height from a few inches to 30 feet, grow- 

 ing both on trees and on the ground, and running the whole scale of 

 shade endurance, the ferns do much toward making the virgin lehua 

 forest the impenetrable, dark jungle which it often is. Mosses in 

 places cover the ground, fallen logs, and tree trunks several inches 

 deep, and grow in bunches over a foot thick on suspended vines and 

 drooping twigs, giving an appearance of weird drapery. 



Undergrowth of this kind affords a great quantity of humus, and 

 possesses an enormous capacity for holding water. Even in a rather 

 dry time one may squeeze enough water from a few handfuls of moss 

 to obtain a good drink. Fallen logs, fern trunks, and all kinds of 

 debris are constantly saturated. Mountain ridges less than a rod wide 

 at the summit are often boggy where these conditions prevail. 



In so dark a forest it seems anomalous to find the lehua, a tree of 

 pronounced intolerance, reproducing itself generation after generation. 

 It does so through its singular habit of germinating on both standing 

 and fallen trees, and especially on the fibrous trunk of the tree fern, 

 which is admirably suited to its needs. Only in such places can it get 

 the light it requires. As soon as it germinates it sends down several 

 roots, which enter the ground and perform the normal functions of 

 support and nutrition. When the host decays, the tree is left standing 

 on these roots, which to all appearances are simply divisions of the 

 trunk. The natives have an adage that the amau (tree fern) is the 

 mother of the ohia lehua. (See frontispiece.) 



As one passes above an elevation of 4,000 feet, or out of the dis- 

 tricts of greatest rainfall, the lehua relinquishes its prominent place 

 and mingles with other species, such as the naio, kolea, kopiko, koaia, 

 and koa. 



Lehua wood is of reddish color, heavy, and in drying checks and 

 warps so badly as to be of little commercial use except for fuel. It 

 has been used frequently by the natives in the building of log houses, 

 and has also been used on the islands for railroad lies. 



The lehua forms the tallest and most impenetrable forests on the 



