If you reside in or near Eastern Pennsylvania or work in the forestry industry, you might be familiar with the Eastern Hemlock — an ancient tree species in Canada and the United States. This majestic tree provides protection, food, and shelter to many creatures. The species’ unique characteristics also make it effective at storing carbon.

Unfortunately, several factors have contributed to the tree’s population decline, and worsening climate conditions push invaders to move north. Below, we’ll explore the leading contributors to this population decrease and current conservation efforts to save the Eastern Hemlock.

The Decline of the Eastern Hemlock Tree

The hemlock was once at the forefront of innovation in the U.S. During industrialization; people could use hemlock wood to create cabin walls and bark as raw materials for tanneries. Along with aiding in reliable construction, the hemlock benefited many species by providing food and shelter for wildlife and songbirds. Now, what was once a helpful and beautiful species is a slowly dying population.

The Eastern Hemlock tree decline began in the 1950s, and by the early ’00s, the devastation was evident. National parks began monitoring significant declines. For example, Shenandoah National Park noted that 95% of their hemlocks died or succumbed to declining health.

The Effects of the Eastern Hemlock Tree Population Decline

This issue spans far beyond losing these trees’ natural elegance. A declining Eastern Hemlock tree population can lead to several adverse consequences that impact our economy and environment.

  • Loss of moisture: Hemlocks provide a dense canopy, which helps moderate stream and forest floor temperatures and maintain moisture. Without these trees, we could face increased water temperatures and algal growth, which would impact aquatic insects, crawfish, salamanders, and native fish.
  • Natural habitat disruption: These trees are also an excellent place for nesting, and their disappearance can disrupt native birds.
  • Economic challenges: The decline of these trees can also negatively impact the economy in several ways. Decreasing hemlock populations can affect the health of fisheries, terrestrial habitats, and watersheds, presenting unique challenges for several industries.
  • Reduced value: Hemlocks add aesthetic appeal to land, and their disappearance can decrease its value. Due to this decrease, businesses that rely on outdoor enthusiasts, fishers, or hikers may face lower income streams.
  • Fire risks: Dead trees can become wildfire hazards, posing a great threat to all life and property in the area. This threat could cause an additional decrease in land value and significant costs for remedying the property if a fire occurs.

Understanding the Factors Behind the Decline

The Eastern Hemlock tree growth rate is already slow, and two significant factors contribute to the tree’s premature decline — diseases and an invasive species. Understanding these contributors can help you determine when a hemlock tree is declining in health and how to tackle the issue to save the tree. Take a deeper look at these dangers below.

The Hemlock Woolly Adelgid Invasive Species

Virginia was the first state to observe a hemlock tree woolly adelgid. This small insect feeds on plant saps and is closely related to aphids. It is native to China and Japan but has spread to nearly 20 eastern states, where it attacks hemlock species.

This invader alone is responsible for extensive hemlock mortality and decline in the eastern U.S. When a woolly adelgid feeds from a tree. The process interferes with how the tree uses nutrients. Feeding hemlocks can cause branch dieback, needle drop, and tree mortality.

While some needle drops are normal for hemlocks during certain parts of the year, substantial ones often indicate a serious issue. Needles are essential for these trees because they contain nutrient transport cells.

When woolly adelgids feed on these trees, they pierce through the needles, directly impacting the tree’s ability to access and use vital nutrients. Additionally, these pests impact the growth of new needles, causing a vicious cycle that results in hemlock tree death within three to five years of infestation.

Eastern Hemlock Tree Diseases

Infection and disease are other dangers of hemlocks. Eastern Hemlocks can suffer from these diseases and symptoms:

  • Cytospora canker: This disease impacts shrubs and trees. It often begins when trees face stress from insect feeding, ice damage, or drought. Symptoms include dying or dead branches through the trees and purplish or brown needles on dying branches.
  • Fabrella needle blight: This fungal disease causes hemlocks to discolor and lose needles. Although this disease alone is often not fatal, stressed trees usually have a harder time overcoming it and eventually die.
  • Cone and twig rust: A disease affecting hemlock needles and twigs, cone and twig rust twists twigs until they die. It causes cones to develop yellowish spores and a dusty appearance.
  • Needle rust: This plant disease impacts needles and leaves. Rust fungi produce spores, typically reddish or orange in color, that coat infected tissue. Infected hemlocks often die in the summer, and you may see orange-yellow spores on popular leaves if the fungus overwinters.

Current Conservation Efforts

The growing concern for the declining hemlock population has sparked initiatives across the eastern U.S. People and businesses aim to forestall the loss of these trees and protect them from the woolly adelgid by implementing several practices. Current conservation efforts for the species include

  • Insecticides: Injecting insecticides into boles on trees or into the ground can kill woolly adelgid. This solution can prevent new infestations for up to five to seven years.
  • Tree breeding: A tree breeding program from several universities, states, and the USDA Forest Service aims to develop hemlock trees that are resistant to woolly adelgid and produce seedlings to restore hemlock sites.
  • Biological control: Biological control involves introducing predatory beetles to the hemlocks to feed on the woolly adelgid. These predators can reduce insect populations, thereby slowing their impact on the trees.
  • Silvicultural: Another conservation method is to replant native species in areas where woolly adelgids have already impacted hemlocks. Although this may help plant new trees, other methods will be necessary to ensure the new plants do not become infected.

Support Sustainability With Custom Truck One Source

Working in the forestry sector, you likely understand the significance of Eastern Hemlock wood and its many uses, including light framing, roofing, subflooring, boxes, crates, and pulpwood. Working with an equipment and tool provider that values its conservation as much as you do is important.

At Custom Truck One Source, we want to be the leading supplier of custom equipment for infrastructure, utility, rail, telecom, and forestry industries. We understand the value of using sustainable practices and trying to protect our environment.

As industry leaders, we set the precedent to take environmental responsibility across services and equipment. Contact our team to learn more about how we drive industry change and growth for businesses.