Treatment of Female Ginkgo Trees  Female Gingko Tree Injections The public space trees that are marked with a yellow dot are female Gingko biloba trees. The Urban Forestry Administration treats these trees to inhibit the fruit development with Pincher PGR. In the past the Urban Forestry Administration has sprayed these trees to provide the same effect. By injecting the trees, we reduce the amount of water used and that allows us to directly apply the chemical to the internal parts of the tree. See also Female Ginkgo Tree Removal Policy.