I usually shoot for the flamethrower just to thin them out a bit before the construction bots and what not later on. Though some maps I generate have wonderful resources abound, but ridiculous amounts of trees blocking access. If the car is available early on, and the tank quite a bit further down, how about something in the middle that doesn't require as many resources like elec engines and red circuts. Say, 250x steel, 250x iron plate, 500x gears, 50x engines, and 100 green circuits. Have it be a 4x6 size (4 wide, 6 long) and a rather slow movement speed. But efficient enough to crush trees and not get the resources. Much the same way burning them might do.
It would be fun to mow down paths through some dense forest areas with something like this
