A chainsaw is a powerful cutting tool with a motor that spins a chain of sharp metal teeth around a long bar at incredible speed. When the spinning chain hits wood, the teeth rip through it like a hundred tiny axes working together. Chainsaws can cut through tree trunks in seconds, a job that might take an hour to saw by hand.

Loggers use chainsaws to fell trees in forests, and arborists use them to trim dangerous branches or remove trees that have died or grown too close to power lines. After a storm knocks down trees, utility crews use chainsaws to clear roads and restore electricity. Sculptors even use chainsaws to carve enormous bears, eagles, and other figures from tree trunks.

The chainsaw revolutionized forestry when it was invented in the 1920s. Before chainsaws, cutting down a large tree required two people working a long saw back and forth for hours. Now one person with a chainsaw can do the same work in minutes.

Chainsaws are extremely dangerous tools that require training, protective equipment, and careful attention. The spinning chain can cause terrible injuries in an instant, which is why only trained adults should operate them.