In the 20th century, chestnut blight and Dutch elm disease decimated billions of U.S. trees, in forests and along urban and suburban streets. The tree diseases, caused by invasive pests, effectively changed the face of one American city landscape after another—chestnut trees were virtually wiped out and elms diminished to but a few locations—and cost local governments and homeowners a fortune.
When cheap consumer goods arrive on American shores, they sometimes bring invasive parasites that go on to decimate forests and urban trees. A new study, out Tuesday in the journal Ecological Applications, synthesizes the information available on the true costs of these species and lays out the best available policy responses.
Last week, a group of researchers published saddening news about "sudden oak death," spread by an invasive water mold, that has killed over a million trees in coastal California. The pathogen, they found, simply cannot be stopped — though it can still be contained, and the harm mitigated. But it is too extensively established now in California to eradicate.
Efforts to prevent new pests are not keeping pace with escalating trade and must be strengthened if we are to slow the loss of our nation's trees. Dr. Gary Lovett describes the threat and the steps that can be taken to save our forests.
Growing reliance on both trees and trade makes imported forest pests the most pressing, and under-appreciated, forest health issue in the US today. Five high-priority policy actions that build on proven prevention measures can reduce the arrival and establishment of new forest pests.
Hemlock is a "foundation" tree species in eastern forests and its presence defines the properties of a unique ecosystem that is presently declining due to the introduction and spread of an invasive insect, the hemlock woolly adelgid.
Earthworms effect microbial nitrogen cycling and ecosystem nitrogen retention. Earthworm invasion of north temperate forests will have large consequences for nutrient retention and uptake in these ecosystems.