If you have a large tree in your yard, you could use it to hang a tire swing, a baby swing or regular swing. When you use the best way to hang a swing from a tree limb, you provide a safe place for a child or a young-at-heart individual to play. Done incorrectly, it's possible to damage both the person and the tree.
The most important consideration for a tree swing is to determine whether or not the limb can hold the wait. Roger Cook of This Old House recommends using a tree branch with at least an 8-inch diameter. If the limb has any signs of damage or weakness, find another one. In order to prevent a collision with the trunk, the closest support for the swing should be three feet from the trunk. If the limb sags when you attach the swing, you may be too far away from the trunk for the limb to support the weight.
While many people only use rope to hang swings from tree limbs, this isn't the best approach. As the tree grows, the rope cuts into the limb, which can cause damage. The same principle applies with chain. Instead, use stainless or galvanized steel 5/8-inch eye bolts. Look for bolts long enough to go through the limb and secure the bolt using nuts. The hole you drill to fit the bolt through won't damage the tree, and the living tissue of the limb will eventually grow around the bolt, creating a better hold. The eye of the bolt should be on the bottom of the tree limb. Tire swings only need one eye bolt, but most other types of swings need two; a baby swing may need three.
While a chain is strong enough to support the weight of a rider, it can pinch fingers. To avoid this, use a polypropylene rope. The rope should have a weight rating on the package, so you can determine how much weight the swing can hold. The rope connects to the eye of the bolt, which you can do by using a knot. A carabiner can prevent wear and tear on the rope by acting as the point that swings against the eye bolt. If you don't want to use a carabiner, you can use a thimble, which is a horseshoe-shaped piece of metal designed to separate the rope from the eye.
When you tie the rope to the connection point, you want to use a knot that won't come loose. Examples of knots used to secure a tree swing include a double square knot or a double running bowline. You'll want to equally measure the rope for each side of the swing to prevent the swing from hanging crooked.