The DR TreeChopper will slice through tree trunks up to 4" thick. Let's take a closer look at how it's designed ... These front two blades straddle the tree trunk, and guide it into these two middle blades. You'll notice that the middle blades are round, and that they will rotate as they go through the tree trunk, with an action similar to a pipe cutter. The middle blades pretty much do all the work, but just to make sure no sharp stumps are left behind... ...the rear blade shears off any leftovers, so the stump is no more than a quarter inch high.