You own a 160 acre white spruce plantation. Based on current tree diameter, stocking levels, productivity rates, and timber markets, you estimate that commercial thinning can occur after 40 and 50 years, respectively, with a final harvest in 75 years. The estimated per acre returns at the time of the two thinnings (partial harvests) and final harvest are $300, $350, and $850, respectively. What is the present value of these three harvesting activities, assuming a 4% discount rate?