An orange tree is pruned by removing any overlapping, dead or diseased branches and cutting off any water sprouts, according to Garden Guides. Pruning is most important when the tree is young; older tress can be pruned every other year.
Trimming an orange tree keeps the tree healthy by ensuring proper air circulation and limiting the risk of disease. Trees with extremely dense branches have poor air flow and the upper branches block sunlight from getting to lower branches. These conditions conspire to limit the fruit the tree produces.
The best time to prune an orange tree is before it blooms. During this period, leaves are less dense, making it easier to identify branches that need pruning. Additionally, pruning before blooming begins ensures the tree receives the maximal benefit from the increased air flow and access to sunlight.
Lower branches are more amenable to heavy pruning; these branches are likely to be the densest and have the least access to sunlight. Upper branches should be pruned very selectively; these branches have the most access to sunlight, so they are typically very healthy. An effective pruning procedure focuses on lower branches for air flow and only eliminates broken or diseased branches in the canopy of the tree.