Forest Health is a condition that sustains the structure, composition, processes, function, and productivity of forests over time and space. The condition is determined by a variety of factors, including human needs and land management objectives. It is a complex subject that can be viewed from an instrumental (economic) and an intrinsic (forest ecology) perspective.

The health of trees and forests is threatened by numerous environmental, social, and economic factors. These threats include invasive species, forest pests, and diseases, climate change, fire, and past land use practices.

Many tree pests and diseases cause damage to the vascular system of trees and shrubs, affecting their growth, development, and ability to produce essential products for human needs. In addition, phloem and wood-boring pests can cause damage to the roots of the trees they attack, which can reduce their ability to provide the necessary nutrients for other plants in the forest ecosystem. The emerald ash borer (Agrilus planipennis) and the mountain pine beetle (Dendroctonus ponderosae) are invasive species that threaten our native forests.

These pests are highly invasive and spread rapidly through the environment, and they can be difficult to control. The New York State Department of Environmental Conservation (DEC) has developed a comprehensive approach to forest health that involves collecting and reporting information about insect pests, diseases, and other damaging agents to landowners and managers.

This information is used to support the management of our forests and is also a contribution to international conventions and legal mandates regarding sustainable forest management. The information collected and reports are made available to all New York State forest owners, managers, and other interested parties.

Insect Pests and Diseases

One of the most important factors that affect forest health is the presence of insects, especially insect pests and pathogens. These pests and diseases can be categorized by the stage they are in during their life cycle and whether they are considered as “introduced” or “native.” The most common types of insect and pathogens that affect forests are phloem-boring beetles, aphids, bark beetles, fungi, and spruce budworms.

In addition to the direct effects of these pests and diseases, forest ecosystems are negatively affected by the resulting changes in soil fertility and hydrology as well as the impact of fire, climate change, and past land management. These changes can lead to a decline in biodiversity and the loss of ecosystem services.

Biodiversity is a critical component of healthy forests. It provides a wide array of ecological, sociocultural, and recreational benefits to the people who live in these environments.

The ecological functions that are most dependent on biodiversity in forest ecosystems include carbon sequestration, air and water quality, erosion control, pollination, and wildlife habitat. These functions are essential for human welfare.

Increasingly, however, we are experiencing a severe decline in the availability of these ecosystem services. This is a result of the effects of climate change, increasing urbanization, and overcrowding.

The negative impacts of these stressors on the health of our forests are often referred to as “nature deficit disorder” and are a major concern for forest managers. As such, it is important to recognize the benefits of forest ecosystems and encourage the active protection of our forest habitats.