332 



clear one zone without interfering and injuring the adjacent zone 

 is certainly a mistaken idea. 



It may not be out of place to point to the promiscuous cutting 

 of trails, especially in the mountains of Oahu where the moun- 

 tains are more or less precipitous. The trails are extremely de- 

 trimental to the forest. Landslides will always follow such a 

 practice and the surfaces of such landslides are taken up by such 

 pests as the Hilo grass, thus precluding any natural reforestation. 

 The encroachment of Hilo grass into a Hawaiian forest means 

 the death of the latter. The cutting of trails should be done ac- 

 cording to the native fashion of following the ridges. 



I. THE CONSERVATION OF WATER AND THE PROTECTION OF WATER- 

 SHEDS. 



The areas of wet forest zone have different contours on the 

 various islands or even on one and the same island. In some 

 places the wet forest covers level tracts of land where there is 

 often bad drainage, especially when the forest had been given 

 over to grazing ; the soil in such places is usually very sour and is 

 therefore unable to support a vegetation similar to a well drained 

 area. The Kailua forest on Maui serves as an example of this. 



It has been observed that such poorly drained areas usually 

 covered with Hilo grass have lost their native vegetation, (Kohala 

 Awini, Kailua, Maui), save certain species of trees belonging to 

 the Araliaceae and Euphorhiaceae. This shows that the Hawaii- 

 an Araliaceae are able to grow not only well but luxuriantly in 

 very sour soil. The planting of such Araliaceae as various spe- 

 cies of Tetraplasandra (Triplasandra), which grow readily from 

 seed as w^ell as cuttings, should be encouraged. It would be well 

 to introduce other species of Araliaceae from the Philippines and 

 China. 



I contend that Brassaia actinophylla, a tree belonging to the 

 Araliaceae and commonly planted in Honolulu, should be plant- 

 ed as a forest tree in the middle forests especially in sour soil. 

 The tree in question is not attacked by insects, it fruits profusely, 

 is easily grown from cuttings and seeds and as it thrives in the 

 cooler regions of Australia, where it is a native, it is well adapted 

 to our temperate elevation. 



Of native trees adapted to sour soil, mention must be made of 

 Antidesma platyphyllum, the Haa or Hajiie of the natives, which 

 has proved able to exist on lands where all other trees had suc- 

 cumbed to bad drainage. 



Where good drainage exists nearly all of our native trees of 

 that region will be found quite suitable. Acacia Koa will prove 

 one of the most useful trees. 



Of foreign trees the following may be enumerated as suitable 

 for planting in the wet forests : 



Albisma moluccana. — This tree, while short lived, is a valuable 

 forest tree, especially in areas with sour soil. It likes heavy vol- 

 canic clay and is a rapid grower. Experiments in Java with this 



