A contract is being bid to clear and grub 600 acres. You are considering using two 460-hp dozers to do the job. The site is reasonably level and the machines will have no problem with bearing or traction. After clearing and grubbing, you will need to pile up the material in windrows for easy removal. About 80% of the trees are pines (softwood) and the rest are oak (hardwood). The total number of trees per acre is about 500, of that number: 180 trees per acre are 1 to 2 ft in diameter 40 trees per acre are 2 to 3 ft in diameter 30 tree per acre is 3 to 4 ft in diameter a. What is the estimated clearing and grubbing production rate