Crown thinning is where crown density is reduced by the removal of selected branches from the whole crown, but the overall shape and size of the tree is maintained throughout the work.
This practice is often done to reduce damage that could result from crown resistance. Crown thinning improves the tree’s strength against adverse weather conditions so that the wind can pass through, resulting in less “load” being placed on the tree.
Another reason for crown thinning is in order to allow more light in through the tree. A densely canopied tree can cause loss of light and shading issues, particularly in small gardens or when in front of windows.