RESULTS 



Environmental Modifications 



Although the study treatments called for 25, 50, and 75 percent scarifications, 

 actual levels of 22, 39, and 52 percent were obtained, as measured by mineral soil 

 exposure. Fifty-three percent of the broadcast-burned area had mineral soil exposed 

 after burning (fig. 2) . 



Site preparation, either by burning or scarification, slowed the recovery of tall 

 shrub cover but had little effect on low shrubs and herbs. The overall effect, however 

 was a general decrease in competition between tree reproduction and other vegetative 

 growth on the treated plots. Burning and heavy scarification were the most effective 

 in reducing this competition. 



Five years later, invasion of vegetation had nearly obliterated all early post- 

 treatment differences in seedbed conditions. The proportion of non-vegetated area on 

 the treated plots was reduced to approximately 30 percent regardless of treatment as 

 compared to 20 percent on the control area (fig. 2). Most of the regrow'th was in the 

 tall-shrub category which increased from an average of 26 percent coverage in 1955 to 

 44 percent coverage in 1960. 



Reproduction 



The five different treatments produced no significant differences in stocking on 

 the 4-milacre plots, if all tree species were considered and no distinction was made 

 between advance and subsequent reproduction. On this basis, stocking varied from 73 



100 



Figure 2. — Seedbed conditions 

 before and after treatment , 

 and 5 



years later. 



a 



m 

 h- 

 < 



LU 

 DC 

 I- 



C B L M H 



BEFORE 



TREATMENT 



C B L M H 



AFTER 

 TREATMENT 



C B L M H 



5 YEARS AFTER 

 TREATMENT 



4 



