That does sound like what I'm trying to achieve. Attached is a file with the circles I'm trying to convert. I have created them from the national tree survey data, which is below the circles.
I'm sure there are various scripts around, I'm just completely inept at writing them. If anyone could point me in the direction of one they know of that would be great, as I have been scouring the forums and can't find anything so far.
In an ideal world, those circles would be replaced with tree symbols that match the approximate size of each circle.
Thanks everyone!
Circle to Scaled Symbol Test File.vwx