I believe that model is very similar to the XLO's I had and retro fitted, these were fitted with single speed 230v 3ph spindle motors with Vari speed head, some versions of the Tree 310 were very similar.
I replaced the vari-speed head with direct drive and used a 240v 1ph for a VFD.
The control fed from 1ph 120v.
The one down side in using a VFD with the existing controller is that it may not be able to be configured for other that direct drive to the VFD, i.e. no variable VFD speed, just start/stop. If so you will need to keep the vari-speed.
Al.