November 16, 2020 - Oak wilt is one of the most destructive tree diseases in the United States, and has been killing oak trees in Central Texas at epidemic proportions. Texas A&M Forest Service urges all Texans, particularly hunters, to take preventative measures and be cautious when collecting and purchasing firewood this time of year to reduce the spread of oak wilt.
“We all have a responsibility when it comes to limiting the spread of oak wilt,” said Jonathan Motsinger, Texas A&M Forest Service Central Operations Department Head. “One simple thing is ensuring that we are not moving firewood and potentially introducing the disease to new areas. Hunters on a ranch need to leave any wood they find there. Don’t take it back home and be the one who starts a new disease center.”
Oak wilt fungus spreads in two ways - above ground and below ground. Above ground, a sap-feeding beetle carries fungal spores from infected trees to open wounds on new trees. Below ground, the fungus travels from tree to tree underground through interconnected roots.
Transporting and storing diseased wood spreads devastating oak wilt fungal spores to previously uninfected neighborhoods and properties. Because live oaks tend to grow in large, dense groups, oak wilt spreads quickly and one infected tree can lead to large patches of dead and dying trees.
By following these preventative steps, Texans can reduce the spread of oak wilt fungus:
- Select well-seasoned firewood. Well-seasoned wood is cut before the summer and is typically dry with loose bark and cracked ends. Avoid oak wood that appears unseasoned, which may have tight bark and cut ends which show no cracks or signs of aging. The extreme heat and dry conditions of a full Texas summer effectively destroy the fungus in cut firewood.
- Safely store unknown sources of firewood under plastic. If oak wood comes from an unknown source and is not well seasoned, cover the woodpile with a clear piece of plastic. Burying the edges of the plastic will prevent the entry or exit of insects that might have been attracted to diseased wood and fungal mats.
- Destroy diseased red oaks. A knowledgeable arborist or forester should diagnose red oaks (i.e., Texas red, blackjack or Shumard oak) that die rapidly (2-3 weeks) or in groups (2 or more trees over several years) for oak wilt. Trees suspected to have died recently from oak wilt should be destroyed by burning, burying or chipping. The heat of a fire destroys the fungus and the smoke emitted poses no threat to healthy trees. When planning to do any outdoor burning, be sure to check with local officials to see if an outdoor burn ban is in place for your county and take care not to burn on windy days with low humidity.
- Avoid wounding oaks during vulnerable seasons. The general recommendation is to avoid injuries to oaks from February through June. The best times to prune oaks are during the heat of the summer (minimal spore production) or the cold of winter (minimal insect activity).
- Paint all oak wounds including pruning cuts. Throughout the year, immediately apply a thin coat of latex or pruning paint to all fresh wounds and other injuries that expose the inner bark or sapwood of oaks. This prevents contaminated sap beetles from infecting the wound with oak wilt spores.
Oak firewood is an important commodity to Texans, whether it’s used for firing up the barbecue pit or warming up the home on a cold winter’s day. By selecting well-seasoned, disease-free firewood and by following these disease prevention guidelines, Texans are taking the correct steps to prevent a new oak wilt disease outbreak in their neighborhood.
Please visit www.texasoakwilt.org and www.dontmovefirewood.org for more information on this devastating tree disease. Find your local Texas A&M Forest Service Oak Wilt forester at https://texasoakwilt.org/find-my-forester/.