\f3. The following graph shows the optimal time period for tree harvest based on the equation: Av = (v. - c)r + Sr Where Av = v -v. v's are value r = discount rate c = cost of harbest S = discounted present net benefit of harvesting the forest at a later date a. Show on the graph how an increase in the discount rate will impact the length of harvest (hint: It will shift one of the curves)