Definitions for "Motte"
An earthwork mound on which a castle was built. (Gies, Joseph and Francis. Life in a Medieval Castle, 226) Mound of earth supporting a tower and palisade. (Kenyon, John R. Medieval Fortifications, 211) Related terms: Castle
York, England (GillB) An artificial conical earth mound with a flat top which was reached by a sloping or stepped timber bridge. On top of this would be the keep. A wide circular ditch would be dug, and the earth and stone put in the middle to create the mound. The height varied from 10 feet to 100 feet and the base diameter from 100 to 300 feet. The slopes were covered with an outer layer of clay to prevent uneven settlement and slippage.
A mound on which a small castle might be built ( OED). The usage is puzzling. It might indicate a subtlety depicting a siege in miniature; or it might merely signify food in the form of a mound ('lump'). See also 'mangonel'.
Keywords:  clump, grove, prairie, trees, small
A clump of trees in a prairie.
Small grove or clump of trees.