Meaning

noun a tree with limbs cut back to promote a more bushy growth of foliage

noun a usually horned animal that has either shed its horns or had them removed

verb convert into a pollard

originFrom Middle English poll (“head”) + the pejorative suffix -ard (“person characterized by or associated with something, often in a negative way”). The suffix has the same meaning as in drunkard and coward. When used as a verb, it is often used to mean a cut head, which originates from the terms usage in cattle, where "pollarded" is used to mean "headed," as opposed to horned.

Etymology from Wiktionary, CC BY-SA 3.0