Steve is fabulous and David & crew were great and hard working. ” - Robert F.

Summer: Time to Prune Your Oak Trees

Ever wonder why we avoid pruning oak trees in spring? Spring is prime time for oak wilt disease to infect your trees; pruning oak trees in spring significantly increases chances they'll become infected. With the heavy population of oak trees across Dallas and Fort Worth, the last thing we want to do is add to this growing problem. So, we typically stop pruning oaks in early February and wait until July to start back up.

Occasionally, there will be a situation where we have to do some emergency pruning on an oak tree during spring. In those situations we take special precautions to cut down on the chances of spreading the oak wilt infection.


An oak tree is infected with oak wilt disease.

What is Oak Wilt Disease?

Oak wilt disease is deadly and it can easily spread to nearby trees. The fungal disease is caused by the fungus
Bretziella fagacearum
. The spores are carried from tree to tree by sap-feeding beetles that feed on the fungus. It can also be spread by contaminated tools previously used on a tree with oak wilt disease. Because spring is the time when the beetle is most active, we avoid pruning oaks so as not to create open wounds where the fungus can more easily enter your tree. Once infected, the disease inhibits water and nutrients from spreading throughout the vascular system.

Did you know that many oaks are also infected underground? That’s right; roots of an infected tree can spread the disease to neighboring trees. How? Via root grafts. Roots of oak trees can graft together underground, creating a connected network of living root. The disease can spread via root grafts to trees growing as far as 50-feet apart. So if your neighbor’s tree has oak wilt, you’ll need to take immediate action to try and prevent the disease from also taking your oak trees.

FIREWOOD: Infected, unseasoned oak firewood can also spread oak wilt disease. Fresh firewood cut from infected oaks must be sealed to the ground with plastic and dried completely so as not to allow nearby beetles to spread the fungus.

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Oak wilt is so deadly, it can kill a large established tree in a single growing season.

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In the Dallas-Fort Worth area, live oaks and red oaks are most susceptible to oak wilt. This is why we suggest planting alternatives such as the Monterrey oak or other good urban trees in their place.

Signs your oaks could be infected.

Only an experienced certified arborist can truly diagnose whether or not your trees have oak wilt. Here at Preservation Tree, we take our training a step further and make sure that we always have Texas Oak Wilt Qualified arborsits on staff.

If you notice any of the following signs on your oak tree, give us a call immediately.

  • A rapid yellowing of the outer leaves near the top in mid-late spring
  • The yellowing will spread throughout the entire canopy.
  • Individual leaves become mottled yellow, tan and red.
  • Leaves suddenly drop en masse. More on leaf drop here.

Now is the time to call and schedule an appointment for a consultation or pruning work for your oak trees.

For more information on oak wilt management and how we handle this insidious disease, visit our page here.

Entry Info

Categories: Disease
Tags: Disease
Posted: June 22, 2015