164 VAUGHAN MacCAUGHEY 



h. Arid sections. 



4. Middle Forest Zone (1800 to 5000 feet; variable). 

 a. Humid sections. 



h. Arid sections. 



5. Upper Forest Zone (5000 to 10,000 feet; variable). 



6. Bog Zone (peaks rising into the cloud belt). 



Each zone and section in inhabited by representative trees 

 and shrubs, that attain their best development in their respective 

 areas, and in many instances occur in no other regions. Many 

 Hawaiian trees and other plants are highly precinctive. The 

 kamani {Calophyllum inophyllum Linn) is distinctive of the 

 humid littoral; the beach sandalwood {Santalum Freycinetianum 

 Gaud. var. littorale Hillb.) of the arid littoral; the hau (Hibiscus 

 tilaceus Linn) of the humid lowlands; the wili-wili {Erythrina 

 monosperma Gaud.) of the arid lowlands; the kukui {Aleurites 

 moluccana (L) Willd.) of the lower forest; lehua ohia (Metro- 

 sideros polymorpha Gaud.) and koa {Acacia koa Gray) of the 

 middle forest; and mamani (Sophora chrysophylla Seem) of the 

 upper forest. 



From the standpoint of lumber supply, the only forests of 

 value are those of the ohia and koa. Great tracts of ohia occur 

 in the Puna district, on the island of Hawaii. These forests 

 have been cut for a number of years by local lumber companies. 

 The ohia here attains a height of seventy-five to one hundred 

 feet; the wood is dark red, close grained, hard, and very durable. 

 It has come into local prominence for flooring, railroad ties, 

 paving blocks, and other uses that require hardness and dura- 

 bility. For many purposes it is superior to the best oak. In 

 the vicinity of the famous active volcano Kilauea, on Hawaii, 

 are extensive groves of large koa or "Hawaiian mahogany." 

 These have been cut over, as the beautiful golden red wood is 

 prized for fine cabinet work, furniture and interior finishing. 

 The kukui or candle-nut is a conspicuous and abundant tree in 

 the lower forests of the various islands, but its wood is weak, 

 coarse-grained, and of little lumber value. Numerous com- 

 mercial efforts have been promoted to establish the kukui oil 

 industry in Hawaii, hut as yet these have not met with success. 



