A well trained young tree usually grows into a well structured mature tree. Structure pruning is key! Structure Pruning is the practice of selective trimming to promote a strong framework within the tree which will support future growth. When the tree is around 5 years old, structure pruning should be performed annually on trees that become large at maturity as it encourages a single central trunk and regularly spaced branches that are horizontal. Structure pruning is important for saving maintenance costs in the future.