FOREST INVESTIGATIONS. 29 



Studies of stands must be largely studies of types, their origin, 



stand st die characteristics, development, and permanence. They 



should include the preparation of yield tables and 



studies of various methods of improvement and reproduction cuttings. 



The aim will be to produce in each type characteristic of the region 



a model forest. These model forests should be used for experimental 



purposes and to demonstrate methods applicable hi timber sale 



management. 



Studies of the indirect influences of forests should include thorough 

 investigations of the effects of forests upon meteoro- 



Indirect influences, i 1 T . T!L *i 



logical conditions, temperature, humidity, precipita- 

 tion, evaporation, and wind velocity, and upon run-off and water 

 supply. 



Special emphasis should be given to exact studies of the conditions 



involved in the reforestation of denuded areas, such 

 atton! ficlal reforest " as soil moisture, evaporation, seasonal conditions, 



presence of rodents, and the like, and to intensive 

 experiments calculated to develop the best methods applicable to 

 the various types in the district. 



SPECIAL SILVICAL STUDIES. 



Special investigations, covering the entire district or an individual 

 Forest or group of Forests, will be conducted to supplement the work 

 of the experiment stations. They will be of the same general char- 

 acter as the studies prosecuted at the stations and will be made under 

 the general supervision of the district forester either by men assigned 

 to Forests under the direction of the supervisors or by specialists 

 detailed from the district office. 



RANGE IMPROVEMENT. 



Studies of range improvement will be conducted either in connec- 

 cooperation with ^ }OI \ with experiment stations or as special projects 

 the Bureau of plant initiated by the Forester or the district forester. They 

 embrace the restoration of depleted ranges to normal 

 or maximum productivity, the development of ranges through the 

 introduction of better forage plants, and the most economical utiliza- 

 tion of forage crops. Such studies should be reviewed by the district 

 committee and correlated as far as practicable with silvical investi- 

 gations conducted upon the same types, but will be under the imme- 

 diate direction of the district chief of grazing or of grazing experts. 

 The general plan for each project which involves a study of plants and 

 grasses must be approved by the Bureau of Plant InSustry through 

 the Forester before the work is begun. Specimens of plants and 

 grasses may be sent to the Forester for identification by experts 

 employed jointly by the Forest Service and the Bureau of Plant 

 Industry. 



INSECT INFESTATIONS. 



Studies of insect infestations will ordinarily be made by experts of 



cooperation with ^ ne Bureau of Entomology in cooperation with the 



the^Bureau of Ento- Forest Service. They may, however, be included in 



the subjects assigned to men detailed to make special 



investigations or to Forest officers for report. 



