REGULATION OF GRAZING 375 



tional Forests. Their report is not available. We have, however, a 

 review of their report on sheep damage investigation on the Tusayan 

 National Forest by G. A. Pearson in which Mr. Pearson comments 

 as follows : 



"The investigation agrees with previous ones in showing everywhere a great 

 amount of damage by sheep. The number of seedUngs over six inches in 

 height from 2 to 6 times as great within enclosed areas as on the sheep range." 



Regarding establishment of reproduction on the Tusayan, Pearson 

 states as follows : 



"An important point estabhshed by Kimball and Westveld is that on the 

 greater portion of the Tusayan ye,llow pine has restocked satisfactorily despite 

 heavy damage by sheep. This is explained on the theory that about 25 years 

 ago (my personal studies show a still greater seedling crop originating 36 

 years ago) there was a coincidence of favorable seed and moisture conditions 

 which resulted in establishing so many seedlings that, despite continued sheep 

 grazing, enough survived to give fairly good reproduction. This reasoning ap- 

 pears to me as being sound. At any rate I can see no other way to account 

 for the abundant reproduction which occurs over large areas on the Coconino 

 and Tusayan and which evidently came in while sheep were grazing on these 

 areas. 



"The failure to restock on the bunch grass areas north and south of Bejmont 

 during the period when good reproduction became established elsewhere is ac- 

 counted for by the supposition that the extraordinary coincidence of a heavy 

 seed crop and favorable moisture conditions which generally prevailed 25 years 

 ago did not occur on the areas in question. 



"Although the explanation of Kimball and Westveld may be accepted there 

 is one important point which they seem to have overlooked, namely, that these 

 areas which have failed to restock would undoubtedly now bear good stand of 

 seedlings and saplings if sheep had been excluded during the last 20 years. 

 This assertion is supported by their comparison of fenced and unfenced areas. 

 I personally have data in this region which prove beyond a doubt that these 

 areas will restock in about 20 years without the occurrence of extraordinary 

 seed crops and moisture conditions, providing that they are given protection 

 against sheep." 



Pearson in further discussion points out the advisability of taking 

 steps to insure protection of the ]9r.) seedling crop from sheep graz- 

 ing where reproduction is important. He points out that although 

 there is an average of perhaps 20,000 seedlings per acre at least 50 per 

 cent will disappear within a year, due to average climatic conditions 

 and the chances are that the losses will be inuch greater. On the other 

 hand, if the next two years should bring adverse climatic conditions 

 the loss would be so great that there would be no seedlings to spare 

 for sheep forage. He, therefore, concludes that not to give adequate 



