Is the Forest Healthy?
How much forest is there?
- 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?
- Since 1980 the number of big trees has increased by 50%
- Big trees are increasing in number because the forests are getting older.
Who owns the forest?
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.
The fate of forest trees
There are 23 billion trees over 10 feet tall in the Mid-Atlantic Region. Let's look at the fate of 400 representative trees in a typical year during the last decade:
Trees are stressed and die from a number 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 ten years, the region averaged 7,000 fires per year with 133,000 acres burned per year. Over 80% of all acres burned in the Mid-Atlantic Region occurred in West Virginia.
- 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 gypsy moth, forest tent caterpillar, elm spanworm, hemlock woody adelgid, butternut canker, beech bark disease, and dogwood anthracnose. Deer browsing continues to have a severe impact on seedlings and young trees in many forest areas in Pennsylvania.
- Pollutants: Acid rain is contributing to problems with forest health in certain localized regions where trees are exposed to highly acidic fogs and cloud masses on a frequent basis. Also, elevated concentration of ozone during the summer months is causing visible injury to plant leaves.
How do the trees look?
On average, about 4% 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.
In a healthy forest you will still 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 in the forest is beneficial for wildlife habitat.
What about trees in the cities?
- Size of urban forest in the US: 93 million acres
- Number of urban trees in the US: 610 million
- Value of urban trees in US: $250 billion
- Most frequently planted urban trees in US in rank order
- Norway maple
- flowering pear
- green ash
- honey locust
- red maple
- Average life expectancy of urban trees in the US:
Common stress on urban trees:
- 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 forested areas. Universities, private industry, and environmental groups cooperate with governmental agencies on a variety of forest research projects.
One major problem 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 sub set 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 Mid-Atlantic Region, participating states are Delaware, Maryland, New Jersey, and West Virginia.
Want to know more?
USDA Forest Service
State & Private Forestry -- Field Office
Morgantown, WV (304)-285-1541
USDA Forest Service
Northeastern Forest Experiment Station
Radnor, PA (610)-975-4021
Delaware Dept. of Agriculture (302)-739-4811
Maryland Dept. of Natural Resources (410)-260-8531
New Jersey Forest Service (609)-292-2531
Ohio Dept. of Natural Resources (614)-265-6690
Pennsylvania Dept. of Conservation & Natural Resources (717)-787-2703
West Virginia Division of Forestry (304)-558-3446
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