Managing Resilient Forests: Why Eastern National Park Forests Need Help

American beech forest. Credit: National Park Service.

Forests cover tens of thousands of acres in eastern national parks. They are complex and valuable — and, according to the Park Service's own monitoring, in need of help to last.

Richer than the forests around them

An analysis of more than a decade of data from five regional Inventory and Monitoring (I&M) networks found that park forests consistently had the more complex structure and dynamics typical of older forests:

• more large live trees, over 2 feet across — about 80% more than surrounding forests;
• more large standing dead trees, which wildlife use;
• more decaying wood on the forest floor, vital to many plants and animals — on average 135% of the volume in surrounding forests.

A huge white ash at Marsh-Billings-Rockefeller National Historical Park, Vermont, typical of the large canopy trees in eastern parks. More native canopy species are needed to sustain these forests. Credit: National Park Service.

But not enough young trees

The same data showed worrying, region-wide trends in regeneration. A healthy forest needs plenty of seedlings and saplings, of many sizes and of the same species as the canopy. Many parks lack the minimum needed to replace canopy trees as they die of age, fire, storms, or non-native pests and diseases, and non-native plants are increasing in most parks, suppressing regeneration further.

A forest without enough young trees, or with young trees that do not match its canopy, suffers "regeneration debt." Its most severe form — no regeneration at all — can eventually mean the loss of forest habitat.

The stressors

Park forests face many interacting pressures:

• too many white-tailed deer;
• invasive plants;
• new pests and pathogens;
• development of surrounding land;
• altered disturbance patterns;
• more frequent extreme weather;
• a changing climate.

At worst, native forest can be replaced by thickets of invasive shrubs that smother wildflowers and other native plants, block historic views and expose visitors to more disease-carrying ticks. The result would be higher costs for visitor safety and infrastructure — and parks that no longer look as generations of visitors have known them.

A call to act

Given these trends, I&M scientists believe eastern parks need active management to restore or sustain their forests. The I&M networks of the Northeast launched the Managing Resilient Forests Initiative to raise awareness of the threats and encourage collaboration across the region — because resilient forests are essential to ecosystem health, biodiversity, and the Park Service's mission to leave park resources unimpaired for future generations.

Sources

• National Park Service, "Managing Resilient Forests: A Regional Initiative," part of the series Managing Resilient Forests Initiative for Eastern National Parks; contact Stephanie Perles, vegetation ecologist, Eastern Rivers and Mountains Network. https://www.nps.gov/articles/000/managing-resilient-forests-initiative.htm
• The regeneration-debt concept is from Miller and McGill (2019).
• Rewritten in hubnx's own words.