Many people prune their trees in spring and summer. DEC recommends holding off on pruning oak trees until winter to protect them from oak wilt, a deadly tree disease.

The video, ‘Winter Pruning For Oak Wilt Prevention’ (2 minutes) highlights why it’s important to prune oak trees from October – February instead of during the spring and summer, if pruning is needed. Pruning during the winter can protect oaks from becoming infected because the beetles that spread the disease are dormant. These beetles are active in spring and summer and are attracted to freshly cut or injured healthy trees. Pruning in the spring and summer puts oaks at risk of contracting oak wilt. Oak wilt can kill trees in as little as 4-6 weeks and is one of the most destructive tree diseases.

What can I do to protect my oak trees?

1. Prune oaks between October and February – NOT during the growing season.
2. Follow existing regulations and quarantines meant to protect our trees and forests.
3. Don’t move firewood. Firewood can transport oak wilt and other deadly pests and diseases to new areas.
4. Learn to identify the symptoms of oak wilt which include discoloration around the entire leaf edge and sudden loss of a substantial portion of leaves during the summer.

For questions, contact the DEC Forest Health Office at 1-866-640-0652 or email us your photos of tree symptoms.

Visit the DEC website for more information on oak wilt.