RESEARCH METHODS IX STUDY OF FOREST ENVIRONMENT. 7 



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; j^)"^ethods of artificial reproduc- 

 tion; (8) the study of the ei^:\^different methods of thinning 

 upon the growth of the mai^stajaa; 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. 



Studies which do not involve continuous observations for a long 

 period of years or expensive stationary instruments and equipmentr- 

 for example, microscopic and chemical studies of woods or studies of 

 natural reproduction, distribution, and growth— may be conducted 

 without permanent forest experiment stations; and even observations 



