Table 4— Mean root index of trees on each site for both treatments and each of three root zones. 



Larger numbers represent more extensive root system coverage. See text for explanation. 

 Values followed by the same letter are not significantly different (a = 0.01). Mean com- 

 parison methods according to Gabriel (1978) 



Site and Zone 1 Zone 2 Zone 3 Zones 1+2 + 3 



treatment (0-4 inches) (4-8 inches) (8-12 inches) (0-12 inches) 



Allen's Canyon 9.8 ab 15.8 b 9.5 ab 35.1 



Dave's Hollow 8.2 a 12.1 ab 13.5 be 33.7 



Mammoth Cave 10.8 b 10.2 a 4.5 a 25.5 



Mammoth Creek Road 8.6 a 12.6 ab 9.7 ab 30.8 



Wilson Peak 9.2 ab 16.2 b 17.5 c 42.4 



Bareroot 8.8 12.8 10.5 24.4 



Containerized 9.7 13.9 11.3 28.5 



WStf-Li * 



Figure 3 — After five growing seasons on the Allen's 

 Canyon site, few signs of site preparation are evident. 

 The trees are still too small to be conspicuous from a 

 distance. The photo was taken in September 1985. 



terminal bud damage from shoot borers. Of all trees sur- 

 viving after the fifth growing season, 57 and 58 percent 

 showed signs of insect damage, respectively. Mammoth 

 Creek Road and Allen's Canyon sites had about half the 

 leader damage of Mammoth Cave and Wilson Peak (26 



percent); Dave's Hollow was intermediate, with 40 percent 

 of live trees infected. 



Figure 3 shows how the study site near Allen's Canyon 

 looked in September of 1985, five growing seasons after 

 planting. Most of the vegetation had recovered to prestudy 

 condition. 



DISCUSSION 



Survival and growth of the ponderosa pine stock dif- 

 fered considerably between sites. Figure 4 compares the 

 yearly survival and height growth of bareroot and con- 

 tainerized stock for all five sites. The order is from best 

 overall performance (top graphs— Mammoth Cave site) to 

 the poorest (bottom graphs— Dave's Hollow site). 



After 5 years on the Mammoth Cave site where the 

 trees are the tallest (a = 0.01), there is no difference be- 

 tween the survival and height growth of bareroot com- 

 pared to containerized stock. But on harsher sites, seed- 

 ling performance is poorer and container-grown seedlings 

 survive and grow better than bareroot seedlings. Dave's 

 Hollow is the poorest site and the trees are shorter (a = 

 0.01). Even though the containerized stock at Dave's 

 Hollow did not grow as tall and suffered higher mortality 

 than on other sites, it still performed significantly better 

 than the bareroot stock. 



On the other sites seedling survival and growth fell 

 between Mammoth Cave and Dave's Hollow. Again, as 

 survival and height growth improve from site to site, the 

 difference between containerized and bareroot stock 

 diminishes. 



Seedling mortality on the best three sites (Mammoth 

 Cave, Allen's Canyon, Wilson Peak) leveled off between 

 the second and third years but has continued on the two 

 harshest sites (Mammoth Creek Road, Dave's Hollow) 

 through the fifth growing season. Survival should not still 

 be declining in the fifth year. Often this indicates an in- 

 adequate degree of site preparation. On dry sites in cen- 

 tral Idaho, extensive site preparation is needed to ensure 

 ponderosa pine plantation success (Sloan and Ryker 1986). 



Heights of container-grown seedlings have continued to 

 increase over the bareroot on the two harshest sites. On 

 the better sites, the margin between bareroot and con- 

 tainerized stock heights has stayed fairly constant. The 

 exception is at Mammoth Cave, where the bareroot trees 

 have caught up since falling behind in the second year 

 (fig- 4). 



5 



