I am in the forest industry up here in BC, more on the lumber end than chips but yes entire trees can be made into chips. We call them pulp logs. These are logs (or parts of logs) that have too much defect (rot, twist, wind shake, etc) to make lumber but the fiber is still OK for something, ie chips.
Up here we tend to transport them as whole logs, rather than cut up to the 8' lengths they do back east/down south.
A chip plant on its own can be very small, just an in-feed for the logs, the grinder mechanism, and some sort of output. We are seeing a lot of portable chippers right now trying to deal with all the dead pine we have.
Not sure this helps but I hope a bit of it does.
