When a chain saw is placed on the chain saw mounted and moved towards the trunk of the tree along the guide bars, the tree is cut to {HEAD ~ a position} determined by {TAIL ~ the stop mechanism} on the guide bars 
determined by
When a chain saw is placed on the chain saw mounted and moved towards the trunk of the tree along the guide bars , the tree is cut to { HEAD ~ a position } determined by { TAIL ~ the stop mechanism } on the guide bars
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH