Pruning in April
Frost-damaged branches of the sweet gum can be cut back to the live wood after winter. The best time to do this is in April, when the leaves start to appear. You can then see which sections need to be removed, as no leaves will grow on the affected branches.
Pruning between June and August
In the summer months you can remove the low side branches of the sweet gum. This used to be done by cutting the branches as close to the trunk as possible, but studies have now shown that it is better to leave the branch collars intact.
When pruning thick branches, first make a cut on the underside before sawing through the branch from the top. Make sure you cut the branch a few inches from the trunk. You can shorten the stump after the branch has been removed, keeping sufficient distance from the trunk so that the branch collar is left intact.
Pruning in autumn and winter
This is a suitable time to remove any branches from the sweet gum that have become too big. The crown can be thinned out (see illustration) if the tree is too large or if the crown is too dense.
Thinning out the crown will encourage the development of new branches and leaves. Remove a few heavy branches evenly from all over the crown. The branches will not tear if you first make a cut a few centimetres deep on the underside of the branch. You can then saw through the branch from above. It is recommended to treat pruning cuts with a wound sealant, and you should never prune in freezing weather.