339 
Those of the latter class, the commercial forests, are found in the 
districts where because of the absence of running streams water- 
shed protection does not figure. The forests of the first class are 
by long odds the most important, for in Hawaii the relation be- 
tween sustained stream flow and a watershed protected by a forest 
cover is intimate and peculiarly direct. 
Hawaii is a country essentially dependent on agriculture. The 
main crop is sugar cane. On more than half of the 54 plantations 
irrigation is essential for successful cultivation, for although the 
soil in the leeward districts is rich it requires water to be made 
commercially productive. Water is also needed on the non-irri- 
gated plantations for the development of power for the fluming of 
cane. The important part that irrigation plays in Hawaii may 
perhaps be made more apparent by the statement that over fifteen 
million dollars has been expended, wholly by private enterprise, 
in developing the irrigation systems that supply water to the cane 
fields of the irrigated plantations. 
The importance of the forest is generally recognized in Hawaii 
and has led to a strong public sentiment in favor of forestry. 
This finds expression in a Territorial Forest Service charged 
with the creation and administration of forest reserves and with 
the prosecution of other forest work. During the past five years 
under a definite forest policy systematically followed sixteen forest 
reserves have been set apart, with an aggregate total area of 
444,1 16 acres. Of this area 273,912 acres, or 61 per cent., is land 
belonging to the Territorial Government. The other 39 per cent, 
is in private ownership but for the most part the owners of the 
lands, fully aware of the benefits of forest protection, cooperate 
actively with the Territorial Government in the management of 
the forest reserves. 
There are three main types of forest in Hawaii, the Koa and 
Ohia forest lying between the elevations of two and six thousand 
feet ; the Mamani forest, a pure stand of another native Hawaiian 
tree found on the upper slopes of the higher mountains ; and the 
introduced Algaroba forest, which occurs at the lower levels on 
the leeward side of each of the larger islands. 
The typical Hawaiian forest is of the first type. The forest con- 
sists of a dense jungle of trees, high growing shrubs, tree-ferns 
and climbers, with much undergrowth and a heavy ground cover 
of ferns and bracken. Altogether it is a plant community admir- 
ably adapted for the conservation of moisture, for preventing 
erosion and for serving as a reservoir to feed the springs and 
streams that rise within its bounds. The most important trees are 
Ohia Lehua (Mctrosidcros polymorpha) and Koa (Acacia Koa). 
The forest in all the forest reserves is of this type. A recent 
compilation of the forest areas of the Territory shows that the 
Koa and Ohia forest covers approximately 1,175,000 acres. Of 
this area it is estimated that eventuallv about three quarters of a 
million acres will be included within forest reserve boundaries, of 
which about 70 per cent, will be Government land. 
