Forests, Pests & Culturally Significant Species

When you look at the forests of the northeastern United States today, you can see that they are changing much faster than many expected. The climate is changing, pests are spreading farther north, and some tree species of great cultural importance to Indigenous peoples and local communities are becoming less resilient to these changes.

If you live in this region or are in any way connected to working in the forests, it is important to understand what is happening and why these changes matter.

How Climate Change Impacts Forests in the Northeast

The climate in the Northeast has been changing for many decades, as evidenced by changes in weather patterns. Winters have become noticeably warmer, heavy rains happen more often, and the usual rhythm of the seasons is becoming less predictable. Federal statistics confirm these changes. For example, climate data show that in Vermont, total precipitation from 1895 to 2011 increased by about 10%. Many states in the region have also seen fewer extremely cold days each new decade. Milder winters allow pests that were previously stopped by severe frosts to survive more easily. The Environmental Protection Agency's climate analysis of Pennsylvania also shows steady warming in winter and spring. This reduces cold stress in insects that damage trees, helping them survive in greater numbers.

If you work in forestry or land use, these changes directly affect your work. Trees grow best under certain conditions. Species that need long, cold winters are beginning to lose their advantages. And trees that tolerate heat or irregular rainfall better are, on the contrary, getting a chance to spread more widely. As a result, forest composition and species distribution are changing. Warmer winters also affect soil life, snowpack thickness, and the timing of spring plant growth. All of this is reflected in forests: dominant species shift, tree growth rates change, and their resilience to diseases or droughts is affected.

At the same time, it is important to understand that the climate affects different parts of the region differently. Coastal areas, mountains, river valleys, and uplands respond to changes in temperature and moisture in their own ways. For example, in northern mountain areas, cooler weather may persist longer, helping certain tree species survive. And in the lowlands, the air warms more quickly, creating favorable conditions for insect pests.

If you look at the region as a whole, it becomes clear that changes are occurring in several directions at once: winters are getting warmer, precipitation is increasing, the number of warm days is growing, and humidity levels are fluctuating more strongly. All of this makes forests more vulnerable to pests, such as the hemlock woolly adelgid or the emerald ash borer, especially when trees are already under stress.

Species With Cultural Significance in the Northeast

Some trees are important not only because they are part of the forest and nature. Their meaning is much deeper; they are connected to the culture, traditions, and history of the people who live next to them. For example, for Indigenous peoples of the Northeast and the Upper Midwest, black ash is not just a tree. It is used in basket weaving, in ceremonies, and in teaching young people traditional practices. These activities help preserve connections across generations. And when black ash begins to disappear, it becomes harder to pass these skills on.

Even if a person does not practice crafts themselves, the disappearance of a culturally important species always affects the community. Black ash cannot simply be replaced with something else. It grows in specific swampy areas and has a wood structure that can be split into strong, flexible strips, exactly the kind needed for weaving. Cultural masters know:

  • how to choose the right tree;
  • how to harvest the material properly;
  • how to work in a way that keeps the craft alive and sustainable.

Eastern hemlock is also important for many communities. It is easy to recognize by the kind of atmosphere it creates in the forest. Hemlock forests provide coolness, shade, and a feeling of special calm. People associate such places with the nature of the Northeast. But if the hemlock dies, these forests no longer look the same — they simply do not return to the familiar form of the region's residents.

Hemlock Decline and the Spread of Hemlock Woolly Adelgid

Eastern hemlock (Tsuga canadensis) is one of the key trees of the northeastern forests. It creates dense shade, retains coolness along streams, protects slopes from erosion, and supports a large number of wildlife species. But the stability of these forests is disrupted by the hemlock woolly adelgid (HWA), an invasive insect from East Asia. It was first discovered in the eastern United States in the mid-20th century and has since spread throughout the Northeast.

Researchers studying hemlock woolly adelgid climate relationships note that warming trends are allowing the insect to persist in areas where it could not survive historically. The survival of HWA is directly dependent on winter temperatures. Earlier, long periods of severe cold — below approximately -15 °C — prevented this pest from moving farther. But as winters become warmer, such natural barriers weaken.

When HWA infects a hemlock, the tree dies slowly but inevitably. The insect feeds on the nutrients stored in hemlock needles. Over time:

  • the needles become thinner and fewer;
  • the branches weaken;
  • the tree gradually loses its ability to recover;
  • after several years, an infected hemlock may die.

Because hemlock is one of the main species in the northeastern forests, its loss changes the entire ecosystem. Streams that once remained cold thanks to hemlock shade begin to warm. Brook trout and other species that require cold water lose habitat. The forest understory also changes when there is less shade; more light reaches the soil. Animals that depend on a cool microclimate may experience population declines.

To slow the spread of the pest, government agencies and researchers throughout the Northeast monitor hemlock health, treat valuable trees with insecticides, and use biological control methods, for example, predatory beetles and silver flies. These measures cannot eliminate HWA, but they help reduce damage and protect the most important stands. The U.S. Geological Survey also supports climate-oriented adaptation planning to help forest managers identify areas that may serve as safe zones for hemlock in the future.

Emerald Ash Borer and Accelerated Ash Mortality

The emerald ash borer (EAB) is another invasive pest that has significantly altered northeastern forests. It was first discovered in the United States in the early 2000s, and since then, it has destroyed millions of ash trees throughout North America. EAB larvae chew galleries under the bark, blocking the movement of nutrients. As a result, the tree gradually dies.

Warmer seasons and milder winters help the beetle survive in places that were previously too cold. Scientific studies show that climate change, combined with the spread of EAB, can affect forest ecosystems even more strongly than the pest itself. As the EAB population grows, ash mortality increases sharply. White, green, and black ash are all at risk.

The decrease in black ash is especially important because black ash has cultural significance. Indigenous communities use it in traditional basket weaving. When a mass die-off of black ash occurs in wetlands where it grows, groundwater levels rise, and the entire wetland ecosystem begins to change. Studies by the U.S. Forest Service confirm that the disappearance of black ash affects:

  • plant communities;
  • wildlife habitat;
  • the condition of watercourses;
  • the structure of wetland ecosystems as a whole.

Without intervention, these areas do not return to their original condition, resulting in long-term cultural consequences for communities that rely on the black ash decline.

To slow the spread of the pest, local communities, tribal forestry programs, and government agencies are joining efforts. They use different measures:

  • control over the movement of firewood and quarantines in infested zones;
  • removal of severely infested trees;
  • increased monitoring of forest areas;
  • experiments with planting alternative species to stabilize wetlands.

These measures cannot completely stop EAB, but they help slow its spread and protect important ecosystems. Restoration work requires time and close cooperation between cultural experts, foresters, and researchers.

How Climate Stress Amplifies Pest Damage

Climate stress makes trees much more vulnerable to pests. When trees face drought, very heavy rains, flooding, or sharp temperature swings, such as frequent freezes and thaws, they lose part of their natural protection. This gives pests an advantage.

Studies conducted in Minnesota show that trees are most vulnerable when water shortage is combined with insect activity. Forests with high tree competition are also more sensitive to climate stress. In years with low soil moisture, a tree that is usually resistant to insects and diseases becomes more vulnerable. If pests are already present, damage progresses faster.

Different climate factors weaken trees in different ways:

  • drought weakens the root system;
  • flooding reduces the amount of oxygen in the soil;
  • warmer winters increase pest survival;
  • early spring can create a mismatch between tree development and pest reproduction cycles, giving pests more opportunities to feed.

In the Northeast, climate change is favoring the spread of pests. The region has more warm days and fewer extremely cold nights. Heavy rainfall damages roots and soil layers. Mild winters allow insects such as caterpillars and other pests to maintain larger populations. As a result, forests weakened by climate stress decline more rapidly when exposed to invasive pests.

Understanding this connection helps land managers plan measures to improve resilience. Trees exposed to multiple stressors require closer monitoring, and forest management methods can be directed toward reducing competition, improving tree health, and creating conditions that slow pest spread.

Consequences for Forest Health and Biodiversity

The health of forests depends on how climate and pests interact. These processes occur at many levels and can be seen directly in the forest: the composition of tree species changes, some animal species disappear and others appear, water quality changes, and the overall appearance of forest areas shifts. For example, when hemlock dies, rivers and streams lose dense shade. The water warms more quickly, which is harmful to fish used to cold water. Plants in the understory that grow in low light can also begin to degrade.

The death of ash trees changes the situation in its own way. Ash trees often grow near rivers and in wet areas. If they disappear, invasive plants can quickly take their place. Wetland areas where black ash used to grow are experiencing rising groundwater levels, and as a result, the plants, amphibians, and birds living in this environment are changing.

When dominant tree species die, the forest's structure also changes. The places where hemlock once grew may gradually shift to deciduous species. The forest may become sparser or, conversely, too open. This leads to changes that are felt immediately:

  • the soil can break down more quickly;
  • the nutrient cycle changes;
  • the forest becomes worse at storing carbon.

Old trees that stored carbon for decades disappear, and young species are not always able to hold it as effectively.

The forest is closely connected with water systems. When the forest becomes thinner, wetter, or changes structure, the movement of water through the ecosystem also changes. This affects floods, soil moisture, and the speed at which water enters streams.

Biodiversity, like a mirror, reflects all these changes. Some species adapt, others disappear. Over time, the appearance of the northeastern forest, its functions, and the species within it change, forming a new ecosystem structure.

Cultural and Community Impacts of Species Loss

Forest change affects more than ecosystems. It affects people who rely on forests for cultural practices, recreation, local identity, and livelihood. Indigenous communities that weave baskets from black ash face shortages in suitable trees. The decline of black ash interrupts cultural education, reduces access to traditional materials, and threatens long-standing knowledge systems.

Residents notice changes in forests they have known for generations. Trails that once passed through cool hemlock stands feel different after hemlock decline. Streams that supported fishing traditions may warm. Wildlife patterns that hunters or naturalists rely on may shift.

Community groups, state agencies, and Tribal nations often work together to protect culturally significant species and the climate. Many projects involve monitoring black ash stands, collecting seeds for long-term conservation, and coordinating with forestry experts to find areas where black ash may survive. In hemlock forests, community volunteers help track HWA presence and report early signs of decline.

These collaborations help preserve both ecological and cultural resources. When communities see that forest change affects their traditions, identity, and future generations, they become more engaged in restoration and adaptation work.

Strategies to Protect Forests and Culturally Important Species

Protecting forests in the Northeast requires addressing multiple issues simultaneously. It is important to consider how the climate is changing, how pests are spreading, and the cultural needs of local communities. Because of this, different strategies are used in the region, complementing each other.

To help forests better withstand climate change, specialists work to increase trees' resilience. The main goal is to create conditions that allow trees to tolerate droughts, heavy rains, flooding, and warmer winters. Forest managers reduce competition among trees, preserve cool, shady areas, and protect areas where species have the best chance of survival. Special attention is given to climate refugia — areas where conditions remain more stable despite overall climate trends.

Pest management relies on several approaches:

  • treating valuable hemlock stands with insecticides;
  • using biological methods against the emerald ash borer;
  • removing heavily infested ash trees to limit the spread of the pest;
  • introducing quarantine measures that prohibit moving firewood from infested areas.

Restoration efforts aim to make ecosystems more resilient in the future. Specialists:

  • plant species that can tolerate warmer temperatures or higher soil moisture;
  • stabilize wetland areas that have been affected after the loss of black ash;
  • use native species to support wildlife habitat and maintain ecological balance.

An important part of this work is cooperation with tribal nations. This helps ensure that culturally significant species remain a priority in forest management decisions. Indigenous knowledge helps:

  • identify important forest areas;
  • collect seeds properly;
  • organize restoration work in ways that preserve traditional practices.

Such partnerships strengthen adaptation measures and better align them with the needs of the communities that live on this land and depend on its resources.

Conclusion

Forests in the Northeast face pressures from climate change and invasive pests that reshape ecosystems and cultural traditions. Eastern hemlock and black ash are two examples of species deeply affected by these conditions. The decline of these trees alters habitat, water systems, and cultural practices. Scientific monitoring, state management, and Tribal knowledge help guide adaptation. Protecting forests requires cooperation and a long-term commitment to ecological and cultural resilience.