Periodical Literature 85 



regions of heaviest rainfall, i. e., on the northeast slopes and the 

 mountain tops under 6,000 feet. It grows from 30 to 100 feet high 

 and in best forests often reaches 4 feet in diameter and 100 feet 

 in height. They are thin crowned trees and grow far apart in 

 pure stands. The trunk is straight though often twisted and 

 deeply ribbed near the ground, and frequently divided into several 

 roots 10 to 12 feet above the ground. The root system is shallow, 

 often spreading on the surface of the mineral soil. Although 

 the stand of trees is thin, the luxuriant imdergrowth of vines and 

 ferns is almost impenetrable. Climbers grow into the crowns 

 and lace together the trees of an entire forest. Fern species range 

 in height from a few inches to 30 feet and run the whole scale of 

 tolerance, adding much to make the virgin Lehua forest a dark 

 impenetrable jungle. Great quantities of humus are formed by 

 this undergrowth, which remains saturated even in the drier times. 



In so dark a forest it seems anomalous to find an intolerant 

 tree like the Lehua reproducing itself generation after generation. 

 It does so through its singular habit of germinating on both stand- 

 ing and fallen trees and especially on the fibrous trunk of the tree 

 fern. Only in such places can it get the light it needs. It sends 

 several roots down which enter the groimd and later perform 

 the functions of support and nutrition. When the host decays 

 the tree is left standing on these roots which appear as divisions 

 of the trunk. 



Above 4,000 feet elevation the rainfall is less, and the Lehua 

 there relinquishes its prominent place and mingles wath other 

 tree species. 



The Lehua forms the tallest and most impenetrable forests on 

 the Islands, and since they occtir in the regions of greatest rainfall 

 and on steep slopes they form the protective forests for the sources 

 of irrigation water and for fluming purposes. 



The Koa (Acacia koa) forms extensive forests of pure stands on 

 Hawaii and Maui. The trees are scattered in the stand; broad 

 crowned and short tnink, occasionally reaching a 6-foot diameter 

 and 75 foot height. In crowded stands the stem is long and slender 

 but rarely straight. It is intolerant at all ages and will not repro- 

 duce without a large amoimt of light. The forest also has a fern 

 tmdergrowth but not so luxuriant as in the Lehua, for here it is 

 drier. The best Koa now existing is at elevations of 4,000 to 6,000 

 feet where it contains some magnificent timber and is in a good 



