This feminine noun appears to be a collective for trees, though BDB notes textual uncertainty. In Jeremiah 6:6 it occurs in the command to cut down trees against Jerusalem. Most manuscripts and versions suggest reading this as a third feminine singular suffix on the regular noun for tree/wood, yielding 'her trees' or 'its timber.' The form as it stands would be collective 'trees,' but emendation to a suffix form is widely accepted.