By Daniel Barringer, Preserve Manager
A disease of black walnut trees called “Thousand cankers disease” has been found in southern Chester County, so that means all of Chester County, along with Montgomery, Delaware, and Philadelphia Counties locally join Bucks County in a quarantine to prevent the spread of this disease.
The disease is a fungus carried by walnut twig beetles that burrow under the bark. It can take ten years for a tree to die after initial infestation. The beetles themselves are tiny, about the size of a poppy seed.
Pennsylvania Department of Agriculture has enacted a quarantine effective immediately upon the discovery August 4. The quarantine restricts the movement of all nursery stock, and all walnut material whether living or dead, include cut or fallen wood, stumps, roots, branches, mulch and composted and uncomposted chips. Nuts, processed lumber and finished wood products without bark are exempt from the quarantine.
The statement also reads, “Due to the difficulty in distinguishing between species of hardwood firewood, all hardwood firewood is considered quarantined.”
(We generate a lot of firewood when pruning trees and taking down hazard trees at Crow’s Nest Preserve, and give a lot of it away. None of it shall now leave the county—a tough but necessary restriction since we’re only a mile from the county line we share with an un-quarantined county. Meanwhile, black walnut is a major component of the woods in the north-central part of the preserve shown above, so enjoy the trees while they are here. There is no cure or treatment available for Thousand cankers disease.)
There are other forest pests that are spread by moving firewood, so it was already a good idea not to move firewood far from where it was cut to where it is being burned (think camping trips) but now it is also illegal here. They say, “Buy it where you burn it.”
For more information read the Pennsylvania Department of Agriculture press release here.