Home > Tree structure basics > Structural defects > Overview of structural issues > Branch protection zone
Branch protection zone
A branch protection zone forms at the base of branches that are small in comparison to the trunk (upper illustration). Codominant stems do not have a protection zone at their base so when one is removed there is only a small capacity to slow the spread of decay down into the trunk. This is another reason to keep branches small in relation to the trunk using appropriate structural pruning.