RESEARCH METHODS IX STUDY OF FOREST ENVIRONMENT. 7 
FOREST EXPERIMENT STATIONS. 
Since it is practically impossible to follow all the changes which 
take place in a stand during its entire life of 100 years or more, the 
usual procedure is to carry on a number of observations simultane- 
ously. By distributing the observations over stands of the same 
character, representing a large number of age gradations, the entire 
100-year cycle of development of the stand may be encompassed in 
20 years. Even then it often happens that a forest stand, because 
of an accident, such as fire or insect infestation, may become un- 
suitable for further observations. It is evident, therefore, that for 
reliable silvicultural conclusions it is necessary to have under obser- 
vation a large number of forest stands for long periods of time, and, 
therefore, a permanent investigative organization, which will insure 
the completion of long-term experiments and correlate in a sys- 
tematic and uniform way the observations conducted by many in- 
vestigators throughout the country. The investigations which come 
as a general rule distinctly under the work of forest experiment 
stations are: (1) Forest meteorological observations; (2) distribu- 
tion of species and types in relation to climate and soils; (3) studies 
of the growth, volume, and yield of forest stands; (4) studies of 
the effect of the source of seed upon the resulting forest stand; (5) 
experiments with the introduction of exotic species; (6) experiments 
with different silvicultural methods of cutting for the purpose of 
securing natural reproduction; (T) methods of artificial reproduc- 
tion; (8) the study of the effect of different methods of thinning 
upon the growth of the main stand; and (9) studies of the effect of 
site upon the technical properties of the wood produced. These 
investigations are beyond the ability of an individual investigator 
to handle because their solution requires either a very long. period 
of years, often exceeding the life of a single man, or the simultane- 
ous establishment of many experiments in different places — a whole- 
sale method of observations — or expensive apparatus. It is true 
that some of the problems involved have been studied by individual 
investigators with very suggestive results, but there is no doubt that 
forest experiment stations, being less subject to the uncertainties of 
individual effort, can conduct such studies with greater uniformity 
and assurance of success. 
SHORT-TERM STUDIES. 
Although in the study of forest stands the most reliable results will 
be secured only by permanent, well-equipped experiment stations 
organized and maintained by the Federal Government, States, or 
institutions, much can be accomplished also by comparatively short 
studies of individual investigators. 
