Department of Environmental Conservation

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Forest Health

Frontal close-up photo of an Asian longhorned beetle
Asian longhorned beetle
Photo: NYS Museum

DEC's Forest Health program is responsible for monitoring the ecological health and function of all of the forests of New York State. The program gathers, analyzes, and reports on tree pest and disease information for public and private landowners and land managers. The highest priority is placed on early detection of and rapid response to high-impact invasive species that may threaten the health of our forests.

Wondering what's wrong with your tree? Learn how to contact the Forest Health Diagnostic Lab for identification assistance.

Forest Health Issues

Pests that Can Harm New York State Trees

Learn about the biology, symptoms, hosts, and available control strategies of many of the harmful insects and diseases that threaten trees and forests in New York State. Damage can also be caused by environmental factors.

Forest tent caterpillar
Forest tent caterpillar

*Quarantine: when movement of certain articles is restricted in order to prevent the spread of a pest, disease or invasive plant.


More about Forest Health:

  • Oak Wilt - Oak wilt is an aggressive disease that affects many species of oak (Quercus spp.). It is a very serious tree disease in the eastern United States, killing thousands of oaks each year in forests, woodlots, and home landscapes.
  • Insect, Plant and Plant Disease Identification at the Diagnostic Lab - Identification of insects, plants and tree and plant diseases
  • Forest Health Aerial Survey Program - Each year DEC and the NYS Police Aviation Unit conduct a two-month aerial survey of the State's forests to detect possible threats by insects, diseases, human activity and major weather events.
  • Frost Damage - Freezing temperatures can kill new leaves.