Possible Clues:

• Tree of Madagascar
• Gigantic tropical tree with very thick trunk
• With 25-Across, it has a huge trunk
• Tree that's home to Rafiki in 'The Lion King'
• Old British seaman joins another climbing tree
• Tree with a gourdlike fruit
• "Wisdom is like a ___ tree; no one person can embrace it" (African proverb)
• Boy devouring a slice of bread under a tree
• Monkey bread source
• Bob might leave the tree a sheepish sound