88 PRACTICAL FORESTRY 
tender foliage of the tree, and an elephant with his 
powerful proboscis can uproot trees of considerable 
size with little difficulty. The moose not only eats 
the branches and bark of young trees, but by Jump- 
ing on saplings bends them over and holds them down 
while he eats their tender tops. The word moose, it 
is said, comes from the Indian word “ musu,” which 
means ‘‘ wood-eater.”’ 
Plants are usually protected against animals by 
poisons, disagreeable flavors, or spines. The holly 
possesses prickly leaves, and the lquidambar is 
usually left untouched because of its pungent flavor. 
Cattle eat the leaves of the mulberry with avidity. 
In Italy and many other countries, cattle and horses 
are fed upon leaves. Sheep are often used for the 
purpose of clearing land. They devour both the weeds 
and the young trees. When we consider the hordes 
of bison which wandered over our plains, to say noth- 
ing of the lack of moisture, compact soil, and periodic 
fires, there is little wonder that they are treeless. 
Disease due to insects may kill certain species 
and leave others untouched. Injurious insects have 
suddenly appeared, caused an immense amount of 
damage, and then suddenly disappeared. Several of 
our most beautiful and valuable tree species have 
been many times in jeopardy because of insect pests. 
The only insect defoliator or leaf-eater which has 
