The weakest tree IMHO is the sawmill.
The staff of the New Bugle disagree with you.
Lol. Yeah, they just might.
Anyway, from an aesthetic point, I kind of like to use some Robots modified from the Robot Workstation. Also have a mod with multiple paint jobs so my Protectrons can have authentic Industrial or construction paint. I know they can lower overall happiness, but a couple Central Park plots and Bars fix that easy enough.
I just really enjoy coming home and passing the local sawmill. (Which is usually placed near some trees, i mean a saw mill in the middle of a parking lot just dont look right to me) Standing there is a Robot with a Saw Blade or Axe on one arm and a Construction Claw on the other. It just fits so perfectly.
Or my Iron Mine with a Robot weilding a Hammer and a Drill.
I also have a Robots only settlement in the Glowing Sea, (Conquest). I built and since its Robots, i dont need to go back, just let the resources add up in the workshop. I plan to send any Ghoul settlers I get down there if I ever get any. For some reason, the only Ghoul I've gotten so far was a Synth and had to be banished, so what are ya gonna do...?
Except of course for one guy at Outpost Zimonja. I stepped out of my Power Armor for a second and the prick stole it. After I got it back, I sent him down there to die of Radiation. Huh,.. maybe I should go check on him....