USDA. Blog.

Humans adores trees. But humans also migrate and trade, habits that led to the accidental introduction of insects and diseases that harm trees and alter the landscape. Examples are easy to find and may be outside your front door: American elms that once dotted streets across America succumbed to Dutch elm disease. Now all colors of ash species – black, green, white, pumpkin, and blue – are threatened by emerald ash borer. The already uncommon butternut tree, also known as white walnut, faces the possibility of extinction from a mysterious attacker. Many invasive insects and fungi come from regions where native trees have evolved to resist their attacks. When these species enter the United States, they find trees that lack this resistance. There's no immediate end to this dismal pipeline, but there is hope on the horizon.

USDA. FS. Northern Research Station.

The Alien Forest Pest Explorer (AFPE) is an interactive web tool which provides detailed spatial data describing pest distributions and host inventory estimates for damaging, non-indigenous forest insect and disease pathogens currently established in the U.S. The database is maintained as a joint effort of Purdue University, the U.S. Forest Service Northern Research Station, and the U.S. Forest Service Forest Health Protection.

Purdue University Extension. Forestry and Natural Resources (Indiana).

Publication FNR-421-W
See also: Forestry and Natural Resources publications

University of Georgia. Center for Invasive Species and Ecosystem Health.

Provides state, county, point and GIS data. Maps can be downloaded and shared.

Google. Youtube; Upper Thames River Conservation Authority (Ontario).

The Upper Thames River Conservation Authority (UTRCA) is working with the Forest Gene Conservation Association (FGCA) to preserve endangered native butternut trees. This species is threatened by butternut canker, a fungal disease, and protected under Ontario’s Endangered Species Act.