Acute Oak Decline, which causes oozing patches on the trunks of mature oak trees, is spreading across England, now affecting thousands of trees. According to the BBC, scientists believe a beetle may be responsible for spreading a bacterial infection from tree to tree.
"We know that it does affect both of our mature species-so that's the sessile oak and the pedunculate oak," the Forestry Commission's lead scientist Sandra Denman said on Radio 4's Farming Today. "But because our native oaks are native, they have a very broad genetic base and so we're hoping that there will be some trees that will have a natural resistance to this condition."
The main symptom of the disease is "stem bleeding," in which dark fluid seeps from splits in the bark. It is estimated to kill trees within four or five years. Ecologists are most concerned that it will affect the country's ancient trees that have survived other scourges.
