Is the Forest Healthy? New England and New York

Production, graphic design, and writing:

Jennifer Stoyenoff, John Witter, & Bruce Leutscher

University of Michigan
School of Natural Resources & Environment

In cooperation with:
US Department of Agriculture Forest Service


State Forestry Agencies


A healthy forest gives us...

biodiversity, habitat and wildlife, timber, jobs, recreation, aesthetics, protection of environment

How much forest is there?

graph - forest in New England and New York

  • Human population levels in this region have increased sharply since the 1600s.
  • From the 1600s through the 1800s, forest area decreased as land was cleared for agriculture. However, some farms were later abandoned and trees grew back. This has caused a slight increase in the amount of forest area during the last 100 years.
  • In the future, human population levels will likely continue to increase, and the forests will be required to meet additional demands for resources as well as facing increasing levels of fragmentation as more land is used for housing and other purposes.

How many big trees are there?

Big Trees

  • Since 1980, the number of big trees has increased by 33%
  • Big trees are increasing in number because the forests are getting older.

Who owns the forest?

71% private, 7% public, 22% industry

  • Because of the large amount of non-industrial private forest land, it is very important for private landowners to practice good stewardship in order to safe-guard forest health.

1997 The fate of forest trees

There are 38 billion trees over 10 feet tall in the New England & New York Region. Let's look at the fate of 400 representative trees in a typical year during the last decade:


Trees are stressed by and die from a variety of causes. Some common reasons include:

  • Old age: Trees, like humans, eventually get old and die.
  • Competition: Trees compete for food, light, water, and space.
  • Fire: Arson and burning of debris are the leading causes of fire in this region. During the last 10 years, the region averaged 8,200 fires per year with 16,300 acres burned per year.
  • Weather: Drought, flooding, frost damage, ice damage, and strong winds all stress or kill trees.
  • Pests: There are numerous insects and diseases, both native and non-native, that stress and kill trees. Insects and diseases that are currently important problems in this region include hemlock wooly adelgid, butternut canker, gypsy moth, and hemlock looper.
  • Pollutants: Forests at high elevations that have contact with acid fogs experience stress from these events. Also, elevated concentration of ozone during the summer months is causing visible injury to plant leaves.

How do the trees look?

healthy tree image Most trees have no damage.
Some trees have wounds or damages on them. This does not mean that the damage is necessarily fatal. tree with wounds

On average, about 6% of the twigs and branches in a tree's crown are dead.

6% of the twigs and branches in a tree's crown are dead

This amount of dead branches and twigs is normal; 30% is considered serious for a tree.

Overall, the forest is in good condition.

Percent of trees over 10 feet tall that die annually from all causes in the New England & New York Region. 7% trees >10 ft tall die annually
7.5% new saplings annually Percent of trees that become new saplings annually in the New England & New York Region.

In a healthy forest you will see dead and dying trees. Trees die as a natural part of life in the forest. Dead and dying trees are more common in some places due to old age, poor soils, or weather extremes. In fact, having some dead trees is beneficial for wildlife habitat.

What about trees in the cities?

  • Size of urban forest in US: 93 million acres
  • Number of urban trees in US: 610 million
  • Value of urban trees in US: $250 billion
  • Most frequently planted urban trees in eastern US in rank order:
    • Norway maple
      flowering crab apple
      green ash
      honey locust
      red maple

  • Average life expectancy of urban trees in US:
  • 10 yrs - downtown, 30 yrs - city ave., 150 yrs - rural

  • Common stresses on urban trees:
    • pollution
      nutrient deficiencies
      drainage problems
      soil compaction

How do we know about the health of the forest?

No single measurement can summarize forest health. Instead, we need to look at a wide set of indicators which together serve as a reflection of existing conditions. Repeated monitoring of the forest over time allows us to identify trends in forest conditions and evaluate the effectiveness of our actions.

Information about forest health is obtained in a variety of ways. The USDA Forest Service conducts a program of Forest Inventory and Analysis, which provides information in each state on rates of tree growth and death, harvesting, and changes in forest types and tree species. The Forest Service and state agencies conduct regular ground and aerial surveys of forest damage and the causal agents, both in permanent plots and in other forest areas. Universities, private industry, and environmental groups cooperate with governmental agencies on a variety of forest research projects.

One major program aimed at understanding forest health is a joint federal/state program called the Forest Health Monitoring Program. This national program was developed in 1990 and is under the administration of the USDA Forest Service. It includes active participation of state foresters, other federal and state agencies, and universities. The program goal is to monitor, assess, and report on the status, changes, and long-term trends in the health of our nation's forests. The program involves a network of permanent plots and other off-plot areas that are regularly visited to monitor tree vigor, crown condition, and signs of damage. On a subset of the plots, plants are monitored for damage caused by ozone, a common gaseous pollutant. Structure of the plant communities and presence of lichens (pollution-sensitive life forms that are a combination of algae and fungi) also are evaluated on a subset of the plots. Currently, permanent plots are established in 19 states, with plans to expand the program to additional states in the future. In the New England & New York Region, participating states are Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont.

Want to know more?

USDA Forest Service
State & Private Forestry - Durham Field Office
Durham, NH (603) 868-7709

Connecticut Department of Environmental Protection
(860) 424-3540

Maine Department of Conservation
(207) 287-4986

Massachusetts State Forest and Parks
(617) 727-3180

New Hampshire Forest and Lands
(603) 271-2214

New York State Department of Environmental Conservation
(518) 457-1162

Rhode Island Department of Natural Resources
(401) 277-2771
Division of Forest Environment
(401) 647-3367

Vermont Department of Natural Resources
(802) 241-3600

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