I am currently working a project to determine the movement/migration of the pine beetle here in Colorado. What I have is data from each year from 1994-2013. I would like to show this in a map. I want to show the most recent migration over the last 3 years but other than just coloring the layers don't really know what to do. My Co-worker suggested that I erase 2012 from 2013 for example to show just the new growth. My problem with this is I will be deleting data. I thought of an elaborate select by location setup might do the trip but don't want to drop that much time into it.