IX, C1 Merrill: Plants of Guam 31 
the bark, thus providing the proper habitat for the. ravages 
of certain endemic beetles which eventually kill the trees. 
These beetles have increased to an enormous extent in recent 
years due to the increase in breeding places, in turn directly 
due to introduced animals, so that the forests are suffering not 
only from the destruction of the undergrowth and young trees 
by the animals themselves, but the mature trees in many cases 
are succumbing to insect attacks primarily due almost entirely 
to the injuries inflicted to the trees by animals. With these 
checks on the indigenous forest vegetation must be included the 
introduced Lantana camara, Paspalum conjugatum, and other 
species, which over vast areas occupy the entire country, even 
in the forests, and effectually check the reproduction of the 
native species by preventing the growth of seedlings. In some 
areas forest fires have also been exceedingly destructive. 
In discussing the forest vegetation of the Island of Hawaii, 
Mr. Rock * gives us a picture of the very recent destruction of 
a vast forest area extending over 1,000 feet in altitude: 
“Between 2,000 and 3,000 feet elevation the forest has disappeared and 
only stragglers of tree ferns can be found standing, though ten times as 
many are lying dead on the ground and overgrown with all possible weeds, 
which the ranchmen have imported with their grass seeds. Among them 
is the composite climber, Senecio mikanioides, an awful pest, which has 
become well established on Hawaii. At 3,000 feet a few Koa trees can be 
found, together with Naoi, and here also was found a single native palm, 
Pritchardia sp., windswept and half dead. If one considers the natural 
condition in which this palm flourishes, as for example in the dense tropical 
rain forests in Kohala, and then looks at the single plant all alone in a 
field of Paspalum conjugatum, as the accuser of man the destroyer, it 
stands a witness to the fact that there, surrounding it, was once a beautiful 
tropical jungle.” 
That great areas in the Hawaiian Islands were denuded of 
their forest covering by the natives before the advent of the 
Europeans must, of course, be admitted, but we are witnessing 
- to-day in this group of islands a great and rapid decrease in 
the forested areas due to causes for which man is primarily 
responsible. What is to-day taking place in Hawaii may be 
applied to the past history of any of the inhabited islands in 
the Malayan and Polynesian regions. We have to take into 
consideration not only the ravages of man in preparing the land 
for agricultural purposes, but also the possible effects of in- 
troduced plants and animals on the vegetation, the matter of 
introduced insects, the question of rapid increase of indigenous 
il 
* The Indigenous Trees of the Hawaiian Islands (1918) 25. 
