State rids parks of Japanese black pines to make room for native species

During World War II, the federal government planted an estimated 51,000 Japanese black pines in Fort Miles at the point of Cape Henlopen to camouflage military installations.

The trees were also planted in other areas along the Delaware coast to provide cover such as around the fire towers used to target enemy ships.

In subsequent years, more of the salt-tolerant species were planted to help forest the cape when it was taken over from the federal government to become Cape Henlopen State Park.
Now, however, the trees are considered a nonnative invasive species and are being systematically, and in some cases naturally, eliminated from state lands to allow native species to once again take hold. One area drawing the public’s attention is between the fishing pier and the point on the bay side of Cape Henlopen, where people have been noticing dying trees.

Rob Line, head of Delaware’s Environmental Stewardship program for the Division of Parks, said aerial surveys show Japanese black pines now dominate 30 percent to 40 percent of Delaware’s coastline. “They’re competing with beach heather and other native species like loblolly and pitch pines. We want to phase them out and allow natural succession to come back in,” said Line.

“There are North American nematodes starting to take their toll on the trees, so in this case we’re working with the pests. We’re also using a version of Round-Up to kill areas of mature trees and taking out seedlings so we can come at them from both ends of the candle.”

The species can sustain itself if the seedlings are not removed. “It will take a decade or two for us to get them all out of here and back to native species,” said Line. He said that in Japan and Korea the black pine is a much more majestic tree but one that is also now having trouble with nematodes. He said in some areas of the park the dead black pines may have to be cut out if they look too bad.