 | Lumbering Cost control. | (2) |
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 | Designing efficient logging systems for northern hardwoods using equipment production capabilities and costs / R.B. Gardner. Gardner, Rulon B. : North Central Forest Experiment Station, Forest Service, U.S. Dept. of Agriculture, 1966. | |
| Optimum economic layout of forest harvesting work roads / Michael R. Carter, R.B. Gardner and David B. Brown. Carter, Michael R. Ogden, Utah : Intermountain Forest & Range Experiment Station, Forest Service, U.S. Dept. of Agriculture, 1973. | |
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