UNITED STATES DEPARTMENT OF AGRICULTURE 



jrt^^'^wv* 



k BULLETIN No. 791 



Contribution from the Forest Service 

 HENRY S. GRAVES, Forester 



Washington, D. C. 



PROFESSIONAL PAPER 



August 27, 1919 



PLANT SUCCESSION IN RELATION TO RANGE 

 MANAGEMENT. 



Aethue W. Sampson, Plant Ecologist. 



CONTENTS. 



Page. 



The problem 1 



Succession or the development of 



vegetation 2 



The plant types 7 



The wheat-grass consociation 8 



The porcupine-grass-yellow-brush 



consociation 22 



The foxglove-sweet-sage-yarrow 



consociation 32 



The ruderal-early-weed consocia- 

 tion 44 



The effect of grazing on plant suc- 

 cession 54 



Destructive grazing and its re- 

 lation to erosion 54 



Forage production on driveways 



and bed grounds 55 



Page. 



The effect of grazing on plant suc- 

 cession — Continued. 



Succession on moderately de- 

 pleted range grazed annually 

 prior to seed maturity com- 

 pared with succession on sim- 

 ilar range protected yearlong. 61 



Judicious grazing 64 



Summary of the effect of graz- 

 ing on plant succession on the 



range 65 



General summary 66 



Indicators and their use 73 



Application of plant succession to 



range management 73 



List of publications relating to plant 

 succession, page 4 of cover. 



THE PROBLEM. 



The carrying capacity of a large portion of the millions of acres 

 of western range has been materially decreased by too early grazing, 

 overstocking, and other faulty management. Stockmen generally 

 recognize this fact and are doing what they can to overcome these 

 faults in management and to increase the productivity of the range. 

 AVhere grazing has been subject to regulation for some years and the 

 stock has been handled according to most approved methods the pro- 

 ductivity of the range has been appreciably increased. 



One of the most serious drawbacks in the past has been the lack 

 of a means of recognizing overgrazing in its early stages. In decid- 

 ing upon the lands especially in need of improvement, the stockmen 

 and those regulating grazing have essentially relied upon general 



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