4 The Colorado Experiment Station. 
composed of the decayed, castoff parts of the trees themselves. This 
layer of humus material possesses the ability to absorb water like a 
sponge and in this way check the rapid surface flow of water such as 
takes place on bare soil. Thus the water from melting snows and 
from heavy rains is held back to appear later from springs instead 
of rushing into the streams and giving rise to floods and high water. 
NATIONAL EOREST RESERVES. 
The extent of the forest reserves in this country indicates 
the importance which the government places upon the conservation 
of the forests. The first national forest reservation was established 
in 1891. On April i, 1907, the total extent of the forest reserves 
in the United States comprised one hundred and fifty-three reserves 
with a grand total of nearly one hundred and forty-eight million 
acres. California stands at the head of the list with an area of 
nearly twenty-two million acres, while Colorado comes fifth with 
eighteen reserves covering nearly sixteen million acres. These 
vast tracts have not been set aside, however, to become unproduc¬ 
tive holdings of the National Government. They are not even 
closed to the would-be settler on any agricultural lands within their 
boundaries nor to the prospector and miner in seeking and develop¬ 
ing claims. Grazing lands within the forest reserves can still be used 
as such with the added protection to the industry which the small 
fee carries with it. Neither is it the primary object of the forest 
reserve idea to stop the cutting and sale of timber but to regulate 
it in such a way as to make the forests more productive. 
In fact, the primary purpose is to prevent wasteful and destructive 
practices of lumbering, to protect the forests from fire, their most 
destructive enemy, and to get them in a condition where reforesta¬ 
tion may go on and thus make them a perpetual source of tim¬ 
ber supply. 
The principal forest trees of this state are those commonly 
known as evergreens. It is the purpose of the present bulletin to 
help familiarize the people of this state with our native evergreen 
trees and thereby strengthen the interest in their protection. Brief 
suggestions and directions are also given for their use in ornament¬ 
ing the home grounds and in planting for wind-breaks and screens. 
THE evergreens. 
In popular usage the term evergreen is applied to members of 
the pine or cone-bearing family of trees. This is due to the fact 
that most members of this family hold each season’s crop of leaves 
during several years so that at no time are they bare of foliage. 
Some true cone-bearing trees, however, such as the larches, shed 
all their leaves each autumn the same as other deciduous trees. On 
the other hand, some of the broad-leaved trees and shrubs hold 
