In this test, survival levels were compared on three sizes of scalps (2, 4, and 

 6 feet in diameter) and on burned spots. Three areas were selected, all on the same 

 soil type. Two areas had westerly aspects (A and B) , the third faced easterly. All 

 vegetation and the top 4 inches of mineral soil were removed by scalping. On the 

 other hand, the direct effects of spot burning probably did not exceed 1 inch in 

 depth. There were 287 ponderosa pine 2-0 seedlings planted in May 1962, of which 40 

 were on the east aspect. Survival counts were made each fall for 5 years (Appendix 

 II). The percent of survival in the fifth year was as follows: 



Treatment Aspect 



■^ast West "A" West "B" 



Peroent 



Scalps : 



2-foot 27.3 42.6 36.4 



4-foot 60.0 46.3 72.7 



6-foot 33.3 35.4 63.6 



Burned spots 55.6 55.8 69.2 



A chi-square test of the independence of the four treatments (testing the supposi- 

 tion that survival was not independent of site preparation) was not significant (p = 

 .05). However, a trend in the chi-square value, over the 5-year test period, was 

 apparent : 



Year Chi-square value 



1962 2.15 



1963 2.36 



1964 6.76 



1965 5.41 



1966 7.36 



p .05 = 7.81 



This trend suggests that if measurements had been continued for 1 or 2 years a signifi- 

 cant difference would have resulted. The burned spots and 4-foot scalps maintained the 

 greatest survival percentage after 1964. 



The effects from burning were not readily apparent; however, the size of the burned 

 spots which were about 4 feet across may have been as great an influence as the burning 

 treatment itself. 



In support of the idea that size of treated area is important, it does appear that 

 a 4-foot scalp gave better survival than either a 2- or a 6-foot scalp. Perhaps the 

 2-foot scalp (3.1 sq.ft.) was not as effective in preventing or retarding competition 

 as the 4-foot scalp (12.6 sq.ft.) which had four times the cleared surface area. The 

 reasons for the decrease in suirvival on the 6-foot scalp (28.3 sq.ft.) are not apparent. 



Test 3: Pits and Synthetic Mulches on Two Aspects^ 1962 



The straw mulch used in 1962 seemed to have a slight, beneficial effect on seed- 

 ling survival. Thus, the use of cheap effective mulches to reduce competition and 



6 



