Just think if you were to expand that number out as in how many man hours of labor were saved in not having to plant the trees. How much money was saved by not having to pay people o plant those trees. 

Of course the down side is look at how much money the tree growers lost because he could not sell his trees to plant because to many people died so no one was interested any more in planting trees. Then how much tax revenue the governments lost because a whole product industry went bankrupt, but on the bright side the bankruptcy lawyers would make a killing.