NYC Parks Director of Forestry for Brooklyn Andrew Ullman shares news of oak wilt containment efforts in that borough.
The image at left shows how oak wilt appears on the leaves of white oak (A) and on red oak (B). The leaves fall prematurely, with some green still present, from the affected trees.
To date, there has only been one confirmed case of oak wilt in NYC (Brooklyn) though there are several known outbreaks on Long Island. Oak wilt was first confirmed in Brooklyn in Green-Wood Cemetery during the fall of 2016. It should be noted, this tree was on private property and therefore not under the jurisdiction of NYC Department of Parks and Recreation (NYC Parks). NYC Parks has sampled about a dozen trees that are presenting possible oak wilt symptoms. We are currently awaiting the results from the lab and expect to have them within the next few weeks.
The potential impacts on NYC’s urban forest are significant. Citywide, there are nearly 90,000 street trees in the oak genus. Oaks make up roughly 13% of our street trees, and there are many more oaks growing in our parks and natural areas. Oak wilt, caused by Ceratocystis fagacearum, is a lethal vascular wilt fungi. Symptoms include wilting, defoliation, and ultimately death of the host tree. The disease is transmitted by root grafts or insects and affects host trees in a manner similar to Dutch elm disease.
After the confirmed case of oak wilt in Brooklyn, NYC Parks created a proactive inspection program to inspect trees within the boundary established around the confirmed infection site. Parks has inspected all of the oaks trees growing on the streets and in our parks within that boundary. Between NYC Parks inspectors and our friends at Trees New York, we looked at more than 3,000 oak trees as part of this program. We have also created a contract specifically for managing oak wilt. The work completed under this contract will aid us in our efforts to control the spread of oak wilt if we do find it has spread beyond the initial infection site.
Additionally, we are working closely with NYSDEC, Green-Wood Cemetery, and Cornell University’s Plant Pathology Lab to coordinate response and share information. Finally, we are also limiting non-emergency work on oak trees during the growing season to limit the likelihood of spreading the disease.
Please see as well a previous post about preventing the spread of oak wilt with DEC Oak Wilt Operations Coordinator Jennifer Kotary.