דברי הימים ב, פרק י״ד, פסוק ב׳

A decisive campaign to purify the land requires completely uprooting every symbol of foreign worship. This sweeping reform targeted four distinct types of idolatrous installations, each serving a unique purpose in the religious practices of the time.

The first to be removed were the altars dedicated to foreign gods [מצודת דוד]. These structures were built from many stones and served the general public for regular, ongoing sacrifices [מלבי״ם]. Alongside them, the high places were eliminated. There are different perspectives on the exact nature of these high places. Some explain that they were the actual buildings and houses that contained the altars [מצודת דוד]. Others suggest that they were also stone structures meant for sacrifice, but rather than serving the public, they were used by individuals for temporary worship [מלבי״ם].

The purification effort then moved to the monuments, which were pillars carved from a single stone [מצודת דוד, מלבי״ם]. Unlike the altars and high places, these monuments were not used for animal sacrifices; instead, worshippers would pour oil on their tops. Finally, the sacred cultic trees were chopped down. Both the stone monuments and the sacred trees were typically positioned directly in front of the altars [מלבי״ם]. The deliberate act of chopping down these trees was a practical fulfillment of the explicit commandment in the Torah to eradicate idolatry by destroying such trees [רלב״ג].