What Challenges Do Our Forests Face?

Overall, the Maine forest is healthy. Still, natural and human induced disturbances pose challenges. These include land development, the introduction of exotic plant species that threaten native tree populations, insects and disease, and atmospheric threats like acid precipitation and climate change. Each of these disturbances has the potential to create a decline in biological diversity, or the decline in the total number of plant and animal species including small mammals, grasses, flowers, fungi and soil bacteria.

How Land is Used
Maine’s population increased 83% from 694,466 people in 1900 to 1,274,923 people in the year 2000. Most of the increase occurred in the first half of the 20th century. In the last 20 to 40 years some
people moved out of the state and others moved in, but the net population stayed about the same.
What has changed dramatically is where people choose to live. People left northern and Down- east Maine and moved to urban areas. Since the early 1980’s, the fastest growing towns are within 10 to 25 miles of metropolitan areas. Small towns have become suburbs. Between 1982 and 1997, the population of the greater Portland area grew 17% and continues to grow rapidly today. Housing is expensive and hard to find. Farms and forests are converted into residential and commercial development almost overnight; land use changes increased by 108% in the fifteen years between 1982 and 1997 when land was converted to house lots, roads and stores.



Housing developments break up forest habitat. While deer, chickadees, bluejays and raccoons thrive on patchy woods between houses, many wildlife -- like bobcat, some owls and hawks, and many songbirds -- need extensive stretches of undeveloped forest in order to successfully raise a family. Small patches of woods, or fragmented forest areas, don’t provide either enough food or enough protection from predators.

Land use planning that takes wildlife habitat into consideration can reduce the negative impacts of development without compromising economic value or the aesthetics of the property.

Example of Fragmentation:

Exotic Species
Non-native or exotic species can cause serious damage since they lack natural enemies - such as parasites, predators or disease – to keep their numbers in check. As a result, exotic species can spin out of control. Some are especially aggressive, however many, if not most exotics are not a threat to native ecosystems.

Gypsy moth caterpillars defoliate trees, bitter-sweet vines strangle native trees, and brown-tail moths pose threats both to trees and human health. Hemlock woolly adelgids, recent exotic insects that are a serious threat to eastern hemlock, are spreading through southern New England and have been found in nursery stock shipped into Maine. Quarantines of hemlock nursery stock and outright refusal to allow stock into the state may halt it before it gains a foothold in the state.

Atmospheric Threats
Acid rain, snow, fog, and other airborne pollutants such as low-level ozone and sulfur dioxide weaken trees, thus making forests more susceptible to insect infestation and disease. Acid precipitation appears to interfere with absorption of soil nutrients, resulting in stunted tree growth. Acid fog is a particular concern on some Downeast islands.

The effects of global climate change are difficult to measure, but increasing evidence suggests that warmer temperatures could change the mix of tree species in the state and introduce new insect pests and tree diseases.

Imagine you own 50 acres of forest in a neighboring town. It provides rich habitat to many plants and animals, including one of the only known populations of a rare salamander. You have just received a very attractive offer to sell the land for an upscale housing development. What do you do? Why?

Forest Fact
A French scientist brought the gypsy moth to Massachusetts in 1869 in an effort to develop a silkworm industry in the United States. Silkworms produce raw silk used in fabric making and he thought gypsy moths would be a good substitute. The plan backfired. The gypsy moth caterpillar became a serious leaf-eating pest and almost eliminated white oak in southern regions of Maine by eating all the leaves.

PLT Activity #56: We Can Work it Out
The decision on how to use a particular piece of land can involve and affect many people in many ways. Establishing processes for planning and resolving conflicts is essential for effective decision-making about land use. In this activity, students develop a plan to address a land use issue.

Resources/Web Sites:

CD-ROM: Using Remote Sensing to Address Coastal Management Issues – The Maine Project (Available from the Maine State Planning Office)

www.seec.scarborough.me.us/tour teachers, community members and research professionals work together designing investigations relevant to the community.