A more thorough explanation:

The Court of Attachments was an inferior forest court that had jurisdiction over trespasses in the royal forests. The judges of this court, known as verderers, would meet every 40 days to hear charges made by the royal foresters.

For example, if someone was caught hunting or cutting down trees in a royal forest without permission, they would be brought before the Court of Attachments to face charges. The verderers would then decide on a punishment, such as a fine or imprisonment.

Major trespass cases were heard by the justices in eyre, which was a higher court. The Court of Attachments was also known as the wood-mote or forty-days court.