Possible Clues:

• Cafeterias for caterpillars
• Trees used for firewood
• Trees symbolizing strength
• Where squirrels go to get their acorn fix
• Thousand __, California
• Thousand __: Ventura County city
• London's ___ Park, near Epsom Downs
• Annual flat race run at Epsom for three-year-old fillies
• Durable wood sources
• They were once acorns