trim back vs cut down

trim back and cut down both are verbs.

Word	Noun	Adjective	Verb	Adverb
trim back	No	No	Yes	No
cut down	No	No	Yes	No

As verbs, trim back and cut down are synonyms defined as:

Other synonyms of trim back include bring down, cut, cut back, reduce, trim, trim down.

trim back (verb)	cut down (verb)
cut down on; make a reduction in	cut down on; make a reduction in
	intercept (a player)
	cause to come or go down
	cut with a blade or mower
	cause to fall by or as if by delivering a blow
	cut with sweeping strokes; as with an ax or machete