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OFFICE OF SILVICS. 
The office of silvics deals mainly with the general scientific problems 
underlying the practical management of National and private forests. 
It investigates the factors controlling the distribution of forests and for- 
est trees throughout the United States, the relation of forests to stream 
flow and climate, and the conditions cede which natural regeneration 
of cut-over, Bucued over, or otherwise denuded areas takes place. It 
studies the different requirements which commercial or otherwise 
important species have upon climate, moisture, soil, and light, and pub- 
lishes the results in the form of monographsupon species. It establishes 
experimental areas to determine the effect of grazing upon reproduc- 
tion, of thinnings upon the young growth of the stand, of the removal 
of leaf litter upon the growth of trees, and so on. Bacides obtaining 
new data through field studies, it also brings together and organizes, 
in the interest of systematic enouiledee! all information on the habits 
and behavior of trees in the forest already gathered by past studies 
of the Forest Service or accessible in other sources. Thus, there 
_ are now compiled data for 167 species. The range, rate of growth, 
light, moisture and soil requirements, and habit in pure stands and in 
mixture with other species are among the subjects treated. At the 
same time notes were gathered as to the silvical conditions of 60 
National Forests. 
Closely connected with the compilation of all available information 
regarding the life history of forest trees and forest conditions is the 
library of the Forest Service. This contains 10,900 books and pam- 
phiets on forestry and allied subjects, 27,500 photographs of trees and 
forest conditions, and 4,000 lantern slides. The library forms a most 
important working tool for all members of the Forest Service in the 
preparation of reports and bulletins, and is of greatest help in dissem- 
inating correct ideas regarding forestry among the people. The pho- 
tographic collection is extensively used by educators, newspaper and 
magazine writers, etc. When a request for photographs is received a 
selection covering the species desired is made and duplicates are then 
prepared from the original negatives and sent to the person making 
the request, the charge being practically the cost of printing. There 
is a large and increasing demand for the loan of lantern slides for illus- 
trating lectures on forestry. During the last fiscal year about 2,500 
slides were loaned. 
Branch libraries are being established in the offices of supervisors on 
the National Forests as rapidly as books can be secured for them. 
Already 117 such libraries have been started. 
OFFICE OF MANAGEMENT. 
This office deals with the problems of management offered by exist- 
ing forests, whether these are on the National Forests or on tracts 
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