254 



Tjhe section between the cane fields and a forest fence con- 

 structed by Mr. Shipman at some distance above the Hne of his 

 lease, constitutes a part of the Hilo Forest Reserve, established 

 in July, 1905. 



Between the limits named the land is heavily wooded. On the 

 lower and middle sections the forest consists of a mixed stand of 

 Ohia Lehua and Koa trees, mainly of large size. At an eleva- 

 tion of approximately 4,500 feet is a belt of pure Ohia forest. 

 Above this and extending to and above the Shipman fence the 

 forest is again composed of Koa and Ohia, in mixture. Through- 

 out the forest is a heavy undergrowth consisting of tree-ferns, 

 low shrubs and small trees, and high growing ferns and brakes. 

 In places are tangles of ie-ie vine and uluhi. The soil where 

 exposed is a reddish clay, a foot to eighteen inches or more in 

 depth. 



The belt of pure Ohia is evidently the point of greatest precipi- 

 tation from the trade wind clouds ; though throughout the forest, 

 from the plantation clearing to the Shipman line, the rainfall is 

 heavy. All over the area are springs, pools and swamps that feed 

 the numerous small tributaries to the VVailuku River and its sev- 

 eral branches. Practically the whole drainage basin of this stream 

 is on Piihinua, for the water that comes from higher up than the 

 section watered by the trade wind clouds is limited to the fiojv 

 resulting from Kona and other local storms. 



Very little is known accurately of the actual sources of the water 

 in the streams, or from which part of the forest they are most 

 largely fed. But the indications are that from one-third to one- 

 half of the water comes from the area of pure Ohia forest, above 

 described, while the remainder is the result of springs and swamps 

 lower down. These springs are dependent for their sustained 

 and equalized flow on the protection afforded by the forest cover. 



At present the water from the Wailuku river is used for fluming 

 cane and for turning the power wheels of the Hilo Electric Light 

 Company. For these purposes it is diverted at points near or be- 

 low the 2,000 foot level. 



RECOMMENDATIONS. 



Having given the problem thorough and careful study, both on 

 the ground and in its various relations, I cannot report favorably 

 on the proposition to lumber this tract. My principal reasons for 

 this decision are three in number. 



First: I believe the greatest value of the forest on Piihonua 

 to be in the influence which it has on the drainage of the Wailuku 

 River and its branches, i. e. on the affect the forest exerts on the 

 vv^ater after it reaches the surface, by equalizing the flow and pre- 

 venting excessive run off. In view of its present use and possible 

 further development for water power, irrigation and even for 

 domestic supply — especially in connection with the growth of 



