A vocabulary of landscape — a landscape of words 1467 entries

assart

uh-SART
To clear woodland by grubbing out the roots, and also the piece of ground that results. Under English forest law, it was the gravest trespass you could commit inside a royal forest — worse than waste, which meant felling trees that could grow back. Assarting took the wood away permanently. The Crown eventually stopped prosecuting it in favor of charging assart rents on the land already taken.
Etymology
Old French essarter, to grub out, from Vulgar Latin *exsarīre — Latin ex (out) plus sarīre, to hoe or weed. That root has a long reach: it is cousin to Latin sarpere, to prune, Greek harpagē, a hook or rake, and Sanskrit sṛṇī, a sickle. It is a word about a blade working in soil.
Notes
Assarting often leaves an assart hedge behind, built from the woodland species that happened to be standing at the edge of the clearing — small-leaved lime, wild service, hazel — which is not what anyone would plant. Botanists read those hedges as fragments of the original wood, still standing in the line where the axe stopped.