Firewood is an important commodity to Texans, whether it is used for firing up the barbecue pit or for warming up on a chilly winter morning. And with cooler temperatures arriving, now is the time to pay close attention to the firewood you are picking up and storing for use in winter. Transporting and storing diseased wood can actually spread the devastating oak wilt fungus.
By selecting well-seasoned, disease-free firewood and by following other disease prevention guidelines, homeowners can take the following steps to prevent a new oak wilt disease outbreak in their neighborhood.
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, that may have tight bark and cut ends, which show no cracks or signs of aging. The extreme heat and drying of a full Texas summer effectively destroys the fungus in cut firewood.
Safely store unknown sources of firewood. If the oak wood comes from an unknown source and it 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 (two–three weeks) or in groups (two 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 and check with local officials to see if an outdoor burning 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 for pruning of oaks are during the heat of 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.
Hunters, especially west of IH 35, should be especially careful in not transporting recently killed oak trees off of ranch land. The probability exists of moving red oaks that have died of oak wilt and having these trees produce disease spores while being stored. If in doubt, again always cover the wood with clear plastic and seal the edges with rocks or soil.
Oak wilt is one of the most destructive tree diseases in the United States, and has been known to kill oak trees in Central Texas at epidemic proportions.
For more information, visit http://texasoakwilt.org. Pictures and examples of oak wilt can be found at https://www.flickr.com/photos/texasforestservice/sets/72157648325640510/.