When to Trim the Lower Branches of a Pin Oak Tree

Pruning Time Frame

• The best time to prune away the low-hanging branches on a pin oak is late winter to early spring. The precise timing varies by region across its hardiness range -- U.S. Department of Agriculture plant hardiness zones 4 to 8a. Prune dead or broken branches away at any time. Time late winter to early spring trimming, February and March, to occur before the buds swell and unfurl to reveal new leaves.

Pest and Disease Issues

• If you live in a region where oak wilt disease or tree beetles are troublesome, do not prune the pin oaks anytime in spring when sap flows. The pruning wounds are a way for fungal spores and hungry beetles to infiltrate the vascular tissues of the tree. Alternatively, conduct the removal of lower branches -- called limbing up -- in late summer to early fall, or mid to late winter when the tree remains fully dormant. This timing coincides with drier conditions and the flow of sap out of the tree's wounds is much reduced or absent.

Tree Size Considerations

• Limbing up a pin oak is done for improved clearance over roads, driveways, sidewalks or lawns where people walk or lawn mowers pass. Do not arbitrarily limb up young pin oaks to establish the lowest limb to immediately be no lower than 6 to 10 feet above the ground. You deplete the canopy of foliage and slow the tree's growth rate. Only cut lowermost branches little by little over the course of several years. No more than 1/4 of the entire leafy canopy should be removed during one annual pruning event. Larger trees, such as those more than 25 feet tall, tolerate removal of three or four lower branches without detriment.

Equipment

• Use a hand or bypass pruners to cut branches that are less than 3/4 inch in diameter. This utensil is best when thinning out lower branches or trimming away any downward twigs from the bottom of the tree's canopy or sprouts off the trunk. Use a pruning saw for branches over an inch in thickness that emanate from the main tree trunk. Loppers are effective on branch junctions away from the trunk. Use loppers on branches with a diameter of 1/2 to 1- 1/2 inches.