30 MISC. PUBLICATION 9 0, U. S. DEPT. OF AGRICULTURE 



course, be considered in estimating the carrying capacity of ranges. 

 If stock are left to follow their own inclinations, they may congre- 

 gate on one part of a range and overgraze it, while another part is 

 not fully utilized. Proper distribution often requires herding, water 

 development, fencing, etc. Many ranges could support more live- 

 stock if more effort were made to get livestock out on the areas where 

 forage is wasting. 



GRAZING AND TREE REPRODUCTION 



It is appropriate to consider the relationship of grazing to timber 

 reproduction. The following is a quotation from Range and Pas- 

 ture Management, by Sampson (7, pp. 197-198, 211-212) : 



The utilization of the forage on the better-timbered areas, especially on 

 important watersheds, has complicated the pasture-management plans. Many 

 instances are recorded of the seedling and sapling stand being badly injured by 

 grazing. In some places this has resulted in a depletion of the normal timber 

 growth, in the production of deformed and diseased trees, and in injury to* 

 important watersheds. 



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After many years of intensive investigation and wide observation by many 

 specialists in various parts of the West, it has been concluded that practically 

 all serious damage to timber reproduction is caused by too heavy grazing and 

 by faulty handling of the stock. 



The conclusions developed from the studies [made by Sampson] may be 

 divided into two classes (1) those of general application, and (2) those that are 

 applicable to certain regions. 



Conclusions of general application. — Overgrazing or bad handling of any class 

 of stock may result in injury to tree reproduction in varying degrees of serious- 

 ness. 



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Goats are inclined to browse upon a larger number of timber species than 

 do other classes of stock and may cause more damage than do other domestic 

 foraging animals. 



Where a good seed crop of the timber stand is produced, large areas often 

 support a good stand of young timber growth notwithstanding moderate graz- 

 ing each year by the various classes of stock. 



Topographic features, the season of grazing, the type of forage, and the way 

 in which the animals are handled are the most important factors that deter- 

 mine the degree of injury to- tree reproduction. 



Damage to the tree reproduction and, indeed, to other vegetation must be 

 expected on stock driveways or trails which are used annually as such for 

 several seasons in succession. Accordingly, such driveways should be located 

 where the timber is sparse or inferior, or where they will be of value in pro- 

 tecting the forest from destruction by fires. 



Conclusions of regional application. — Because of the rigorous climatic 

 conditions in the Southwest, notably in Arizona, New Mexico, and southern 

 Utah, the better cut over forest lands should not be grazed by sheep and goats 

 until a satisfactory stand of reproductoin, much of it about Sy 2 feet in height, 

 has been secured. 



As a rule it is safe to graze cattle and horses lightly on cut over or other 

 potential forest lands during the period required for reforestation. 



Where trees have been artificially planted, or where, although the timber 

 reproduction is greatly desired, the stand may be unsatisfactory, the area, 

 regardless of the locality, should be closed to grazing until a satsfactory stand 

 is obtained. 



From aspen range on which it is desired to perpetuate the aspen cover, sheep 

 and goats should be excluded for at least three years after the cutting. The 

 damage to aspen reproduction from moderate cattle grazing is practically 

 negligible ; hence cattle may be grazed on cut over aspen lands. 



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