Our range of wooden round pole swing sets are made from whole tree trunks trimmed to size. These natural tree trunks are very sensitive to atmospheric changes and moisture content.  Often naturally occurring splits will appear in the poles. In warm sunny weather the wood shrinks, in wet weather it expands. These physical changes cause the cracks. The overall thickness of the poles mean that the strength of the beam is very rarely affected by these cracks. For more information, learn about our wood. If you are still worried, please contact our technical team with photographs of the cracks and they will be happy to take a look.