38 
The area under discussion, however, is much farther back 
toward the summits of the mountain range, in the very heart of 
the watershed, and none of the forest deterioration there can be 
ascribed to grazing because so far as can be ascertained, there 
has never been any stock on the land. We, nevertheless, find 
that Hilo grass is spreading through this forest, killing out the 
undergrowth and trees and preventing reproduction. In the 
absence of grazing stock the cause for the presence of this grass 
must be ascribed to the human visitant, and this indeed is proven 
by the fact that the grass is most noticeable along the routes and 
cut trails used by trampers. 
To be sure, the damage is done in all innocence, but the fact 
remains that so long as human beings traverse the area the seed 
of Hilo grass and of other foreign grasses and weeds will con- 
tinue to be introduced into this region and the areas thus occu- 
pied by this detrimental grass will be continually extended. 
The staghorn fern has also spread over portions of this area 
with detriment to the undergrowth and trees, forcing the ground 
coA-er back, smothering the smaller growths, and preventing nat- 
ural reproduction by an almost impenetrable mass of armed 
fronds which fully occupies the ground. This particular fern is 
probably a native of New Zealand, since it is such an aggressive 
intruder, botanists inform me that it is probably not an indigenous 
plant, but was brought here by the early Hawaiian navigators. 
Chamisso found it here in 1818 but it probably began to thrive 
here not many centuries before then. 
In this comparatively brief period, considering the antiquity 
of the native indigenous forest, the staghorn fern has spread over 
large areas with detriment to the forest growth, and it is certain 
that the introduced Hilo grass will make the same rapid strides 
that the staghorn is known to have made if its further introduc- 
tion into the delicate forest is allowed to continue. 
The immediate results of Hilo grass introduction are the 
choking out of the delicate ferns that cover the ground and 
the removal of the shady ground cover. This allows the soil 
to dry out and changes the moisture conditions for the shallow 
roots of the trees. With conditions thus disturbed the tree is 
weakened, and the forest is doomed. The process is familiar to 
all who tramp in the woods. 
On the area in question, although Hilo grass can be found 
on almost every 100 feet of the cut trail from Palolo Crater 
over Mt. Olympus and across the headwaters of the Manoa 
rivulets below Konahuanui to the Nuuanu Ridge, the most 
noticeable damage caused by this grass invasion is in the region 
of Palolo Crater. Here there is a natural reservoir which is an 
important feeder to the streams which have been used in the 
past as a source of city water supply and to the springs which 
have recently been developed by the City Water Works, and 
