An interesting observation made by the firefighters was that some parts of the forest seemed to escape the flames. the crown fire would drop down into a ground fire in these areas, and then jump back up into the canopy as the fire burned into adjacent areas. they observed that many of these areas had previously been thinned, which means that some of the trees were cut down and hauled away to be used as timber. in other areas, thinned forests burned with as much severity as the unthinned forest. your objective is to design an observational study to answer the question: what was the determining factor for areas that escaped the worst impacts of the fire, compared to areas that were severely burned?