I found another reason it may have flown into the trees, and I feel like this one is a lot more plausible than the others. Here's a picture to aid the description, which shows the plane's flight path in the simulator.

The purple lines are the result of flying the plane in the simulator, and indicate what it is supposed to do. Starting at the labeled start position on the ground, the plane is switched into auto-landing mode. The plane takes off to the east, flying towards the center of the "1100" circle, which isn't exactly an intended feature, but rather I couldn't think of a good way to make it enter a circle from any random location, so it just flies until it reaches the center of the circle, then it begins following the circle. It follows the circle counter-clockwise until it is facing south, at which point it exits the circle to fly to the "1000" circle to the south.

The blue lines, also the result of flying in the simulator, show the same starting position, but with a feature enabled that tells the plane to avoid aileron turns if the altitude is too low, since rolling the plane can make the altitude even lower. Since the plane starts at the ground, it definitely thinks it's too low, so it makes rudder-only turns which aren't as effective, and so it isn't able to follow the circle. So it ends up flying away from the circle until, until at the north end of that gentle curve, it suddenly decides it has reached a high-enough altitude and enables aileron turns. At this point it immediately turns back towards the circle and eventually drops the circle from consideration and begins flying south.

So imagine if my real-life plane, which was also switched into auto-landing mode soon after take-off, were just a bit slower at climbing in altitude: It would have flown straight over to exactly where it landed in the trees.

Between this predicting the crash site rather well, and requiring the start conditions that the plane actually had (being switched into automatic mode immediately after launch), I think it's much more likely that this was the problem vs. my other theories.