6 
seed, which dropped on the stem of some stately tree fern or 
Cibotium; germinated there and sent down its own roots, sur- 
rounding the fern, until both for a time became as it were, 
one. Later, the fern stump having decayed, the Ohia stands 
supported by its 6wn roots. 
Further, it will be noticed that not only the Ohia, but also 
several other species of trees peculiar to these forests have only 
surface roots, and that these are not altogether dependent on 
the usually thin layer of rich but boggy humus, but as well, 
rely on the ground cover of mosses and roots of ferns with 
which their own roots are intermingled. 
Very many of our land owners, or those having the use or 
care of such forests, have the idea that if the trees themselves 
are not destroyed or disturbed, the forest will continue in its 
virgin state. These people forget that the very act of disturb- 
ing or destroying the undergrowth is in itself the main factor 
in causing.the trees themselves eventually to die back. The 
loss of numbers of trees from one cause and another naturally 
admits more sunshine to the undergrowth than the latter has 
ever been accustomed to or can stand. The natural conse- 
quence is its death, which in turn leads to the dying back of 
more trees, and to the still further destruction of the forest. 
Under such conditions it then becomes merely a matter of a 
short time, especially if animals are allowed to range in the 
forest, or if clearings are made for any purpose, before the 
Hilo grass or other rank growing introduced plant pests get a 
foothold. By the crowding out and prevention of the repro- 
duction of the native flora, there follows either the general de- 
struction of the forest outright or its degeneration to such an 
extent that it ceases longer to be of use for the purpose which 
it origmally served, viz—the retention and conservation of our 
water supply. 
As regards the encroachment of grasses into the forests and 
their effect on trees and other growths, it has been scientifically 
demonstrated by a long series of experiments in Europe and 
elsewhere, that the injury is not altogether due to the grass 
crowding out and mechanically interfering with the roots of 
other plants, but to a toxin excreted from, or resulting from 
the growth of the grass. However, as both effects are injurious 
to the forest it is clear that such pests must be excluded. 
From what has been said above the following can. be scienti- 
fically and therefore safely deduced, viz: 
