RESULTS 



Plant Survival 



Planted-tree survival was excellent on all plots throughout the 4-year study 

 period (table 1). To illustrate, 6 of the 18 study plots had 100 percent survival at 

 the end of 4 years and only 2 plots had less than 95 percent survival. 



An average of 12 percent of the tree seeds placed on the plots at the start of the 

 study resulted in countable trees at the end of the first year; after 4 years, this 

 figure had dropped to 5 percent (table 1) . More trees were counted the third year than 

 the second. Causal factors probably include sampling error and the possibility that 

 natural seeding occurred from nearby trees. By the end of the study, there were far 

 fewer trees per acre on seeded plots than on planted plots. This, coupled with reduced 

 vigor of seeded trees on both fertilized and unfertilized plots, resulted in greatly 

 reduced canopy cover on seeded tree plots as compared to planted tree plots (fig. 3, 4, 

 and 5) . 



Plant density on the seeded grass plots decreased rapidly from over 17 plants per 

 square foot the first year to less than 1 plant per square foot the fourth year. Such 

 decreases are common on road fills seeded to grass in the vicinity. However, the lack 

 of vigor evidenced by the limited crown development on the grass plants in figure 6 

 was not expected. Lack of vigor was probably the result of a severe grasshopper in- 

 festation that occurred in this area during both 1971 and 1972. Grasshoppers seriously 

 damaged most shrubs, forbs, and grasses in the area, but had little effect on pine trees. 



Table 1. --Average plant survival by years on granitic road fills 



Year 



Planted trees 



\ Seeded 



trees 



Seeded grass 





Percent 



I^wnber/acre 



Percent 



Number/acre 



Plants /ft^ 



1969 



98.5 



13,199 



12.2 



6,700 



17.2 



1970 



97.9 



13,118 



9.3 



5,133 



2.6 



1971 



97.8 



13,105 



10.0 



5,500 



1.2 



1972 



96.9 



12,985 



5.0 



2,767 



0.8 



8 



