Possible Clues:

• Tree seen in so-called harbour
• World War II Operation, as part of the D-Day landings
• Bush in nursery rhyme
• Tree whose leaves feed silkworms
• In cold weather, children go round this harbour
• Fruit of burry elm?
• Fruit for silkworm
• Fruit - artificial harbour
• Tree, its leaves fed to silkworms
• Upper-class learner beginning to bash into jolly tree