A treetop is the highest part of a tree, where the uppermost branches and leaves form a leafy crown. If you've ever looked up at a tall oak or maple, that bushy green area at the very top is the treetop.

Treetops are busy places. Birds build nests there, squirrels leap from branch to branch, and insects buzz around the leaves. Scientists who study forest ecosystems sometimes build platforms in the treetops or use special climbing gear to observe animals and plants that live high above the ground. This upper layer of the forest, called the canopy, gets the most sunlight, which is why leaves grow so thickly there.

When the wind blows hard, you'll notice treetops swaying back and forth while the thick trunk below stays relatively still. That's because the treetop catches the wind like a sail. People sometimes use “treetop” to describe something very high up: a treetop view means you can see far into the distance, as if you were perched at the top of a tall tree.