REPRODUCTION OF WESTERN YELLOW PINE. 49 



bare, save for occasional clumps of pingue (Hymen&xys floribunda) , 

 Senecio spartioides, or other obnoxious weeds which are not relished 

 by any class of stock (PL IX). 



In the foresnmmer of 1920 it was observed that pine seedlings in 

 stump patches were generally much larger than those growing in 

 adjacent bunch-grass areas. Later in the summer it also became 

 apparent that the seedlings in the stump patches were subject to 

 much more severe grazing damage than those in the bunch grass. 

 In August and again in November counts were made on a number 

 of plots in order to ascertain the true state of affairs. The results 

 are shown in Table 13 and Figure 6. According to the August 

 examinations, the plots on the open range showed 40 per cent of 

 the seedlings on stump patches classed as large, but on adjoining 

 bunch grass or natural areas only 7 per cent were thus classed. 9 

 The total number, however, was more than twice as great in the 

 bunch grass as around the stumps. Within a near-by inclosure 

 (sample plot 3a). where no grazing had been allowed for 10 years, 

 the same general relation held with respect to total numbers; but 

 with respect to size, it was strikingly reversed, there being very 

 few large seedlings around the stumps, while 14 per cent of those 

 at a distance from the stumps were classed as large. Outside the 

 fence the damage by grazing amounts to 11 per cent killed and 

 76 per cent severely injured (total 87 per cent) on the stump 

 patches, against 21 per cent killed and 2 per cent seriously injured 

 (total 23 per cent) in the bunch-grass areas. 10 Only one seedling 

 inside the fence showed any injury suggestive of grazing. This 

 may have been done by deer. Examinations in November and 

 again in the summer of 1921 show the same general relations as the 

 August, 1920, examinations. In September, 1921, three-year seed- 

 lings on stump patches were from 3 to 4 inches tall, while seedlings 

 of the same age in bunch grass were only from 1 to 2 inches tall. 



On August 30 determinations of soil moisture were made in the 

 four situations involved, namely, stump patches and natural or 

 bunch-grass areas outside the inclosure, and corresponding situations 

 inside, where all grazing had been excluded for 12 years. Table 14 

 gives the net available moisture content in each case. The results 



9 This classification is based upon ocular estimate and is therefore not exact, but is 

 accurate enough to bring out general relations. 



10 In the counts of August and November, 1920, the stump patches showed a com- 

 paratively small number killed and a large number severely injured, while in the bunch- 

 grass areas the reverse was true. The low percentage killed on the stump patches may 

 be partially explained by the fact that the large seedlings are seldom cut off below the 

 crown, and because of their great vigor they usually send out new shoots after being 

 injured. It is quite likely, however, that, owing to the extremely close grazing, many 

 seedlings had been entirely obliterated early in the season. 



90i°— 23 4 



