286 

 Susceptibility of the N^ati^T Forest. 



Let us now see what happens when cattle have access to the 

 wet native forest. The animals will first attack the most tooth- 

 some plants such as the ti leaf and ie ie vine around the outer 

 edges of the forest. Then they will work further in, destroying 

 the ferns and undergrowth not only by browsing and tearing 

 tnem up but also by trampling on them. The ground cover will 

 thus be removed and will disappear, the forest floor dry out, and 

 what was once boggy ground will, with the admission of the sun- 

 light, gradually become firm and hard. . From year to year, the 

 stock will work further back, thus increasing the zone of forest 

 deterioration. 



With the protective covering of the shallow roots of the trees 

 thus removed, the plant association is broken up, and the trees 

 are left alone to struggle for their existence. It is a mistake to 

 assume that if the trees themselves are not destroyed or disturbed 

 the forest will continue in its virgin state. With the root sys- 

 tems left thus unprotected, there will be a gradual dying off of 

 the weakened trees. The loss in numbers of weakened trees will 

 admit still more sunlight to the undergrowth, or what is left 

 of it, than it has been accustomed to and the consequence is its 

 further disappearance, which in turn increases unfavorable 

 ground conditions, with the further reactional effect on the trees. 

 With the damage once started, the mischief is done and it is a 

 mistake again to suppose that the grazing of a few head of cattle 

 m the forest for a short time will not result in any damage. 



With the deterioration once started, the opportunity is present- 

 ed for the attack of insect pests and fungus diseases and the in- 

 troduction of more rapidly growing plants and weeds which 

 will completely occup}^ the exposed ground and prevent the 

 natural reproduction of the native trees. 



These changes will go on until finally the once dark, wet forest 

 composed of trees, vines, ferns, undergrowth and moss, a com- 

 bination ideal for preventing excessive runoff* and keei)ing the 

 soil porous so as to increase subsurface percolation, will dis- 

 appear and in its place we will have a barren, open, useless waste, 

 inoperative as to water conservation and often covered with Hilo 

 grass, with perhaps here and there a few dead trees to testify 

 of what once occupied the land in a useful capacity. 



Forest Protection N^ecessary. 



The importance of keeping the native forest intact cannot be 

 over-emphasized, because injury done by one agency, although 

 slight, may simply pave the way for other far more destructive 

 agencies. The native forest, when given absolute protection and 

 allowed to remain in its virgin condition, is not generally subject 

 to attack by injurious insects or diseases. Not only must beasts 

 be kept out of it, but man also, as far as is possible, because 



