In this graph, the prescribed fire occurred after the PRE-burn or first column. Notice how little change occurred the first year after the burn, above the "Post" or second column. In subsequent years, the trees began to reduce their density. Why do you think it took a couple of years for the pole-size trees to begin to disappear?
Codes
ACMA = Big-leaf Maple (pink)
PIPO = Ponderosa Pine (green)
PSME = Douglas-fir (blue)