Monty's Christmas Tree Farm Ltd. grows pine, fir, and spruce trees. The farm cuts and sells trees during the Christmas season and exports most of the trees to the United States. The remaining trees are sold to local tree-lot operators. It normally takes 12 years for a tree to grow to a suitable size, and the average selling price of a tree is $28. The biggest costs to the business are pest control, fertilizer, and pruning trees over the 12-year period. These costs average $12 per tree (assume these are incurred evenly over the 12-year growing cycle).