Figure 11. This ponderosa pine plantation was planted by machine in previously pre- 

 pared furrows. 



The range of soil conditions across a terrace affects height growth as well as 

 survival of planted trees. Analyses of planting tests conducted over 5 years showed 

 that trees planted near the cutbank were significantly taller than trees near the out- 

 side of the terrace 10 years after planting (Hall and Curtis 1970). 



Towed planting machines have been used in Intermountain forests with good results 

 on prepared ground and on moderate slopes (fig- H) . A crew consists of three men: the 

 tractor operator, a planter on the machine, and a followup man who walks behind the 

 machine to inspect the planted trees and correct any faulty planting, especially incom- 

 plete tamping. The planter and the followup man alternate jobs. 



Survival of machine-planted ponderosa pine has been high for the few years that 

 this method has been used. It was compared with hand planting in one test in central 

 Idaho in 1960. Four 10-acre plots had been aerially sprayed with herbicides to elimi- 

 nate the brush competition. Half of each plot was hand planted without further site 

 preparation and half was furrowed and machine planted. Two-year survival on the machine- 

 planted plots averaged 77 percent on east aspects and 71 percent on west aspects. 

 Survival on hand-planted plots averaged 17 percent on east aspects and 6 percent on 

 west aspects. The poor survival on the hand-planted plots was attributed to a rapid 

 invasion of cheat grass (Bromus tectorum) after the brush was killed. Furrowing removed 

 the cheatgrass seeds from the machine-planted trees. Although the comparison was not 

 conclusive because of poor survival on the hand-planted plots, machine planting was 

 successful, and many acres elsewhere planted by machines have shown survival as good or 

 better than in this test. Since 1962, Drivate planting contractors have relied on hand 

 planting because it requires no investment for equipment and because machines are 

 restricted to gentler slopes. 



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