what eats or removes bark off trees in washington state

3 min read 22-01-2025

what eats or removes bark off trees in washington state

Washington State's diverse ecosystems support a variety of animals and insects that can damage or remove tree bark. Understanding the culprits is crucial for protecting your trees and managing forest health. This article explores the common bark-damaging organisms found in Washington, focusing on identification and mitigation strategies.

Common Culprits: Animals

Several animals in Washington State are known for their bark-stripping habits. These include:

1. Black Bears:

Identification: Large, black mammals with distinctive claws and powerful jaws. They often leave behind claw marks and ragged bark removal.
Damage: Bears frequently strip bark from trees, especially in search of insects or inner bark (cambium), a nutritious food source. Damage can range from minor stripping to complete girdling (removing a ring of bark around the tree trunk), which can kill the tree.
Mitigation: Protecting trees from bears often involves deterrents like electric fencing, bear-resistant containers for attractants (like garbage), and removing potential food sources near trees.

2. Deer:

Identification: Hooved mammals with varying coat colors depending on the species. They may leave behind browse lines (evenly-trimmed branches) or rubbing marks on trees.
Damage: Deer can rub their antlers against tree trunks, causing bark damage. This is more common during the rutting season (mating season). They also browse on twigs and buds, which can stress trees.
Mitigation: Repellents, fencing, and managing vegetation to reduce the deer's food sources are common mitigation strategies. Planting deer-resistant trees can also help.

3. Porcupines:

Identification: Rodents with quills, known for their nocturnal habits. They leave distinctive gnawing patterns on bark.
Damage: Porcupines feed on the inner bark (cambium) of trees. They often climb high up the trunk and branches, leaving characteristic gnawing marks.
Mitigation: Physical barriers, such as tree guards or netting, can deter porcupines. Repellents can also be effective, but application may require persistence.

4. Rodents (Squirrels, Rabbits, Voles):

Identification: Smaller mammals with varying gnawing patterns. Squirrels are larger and usually cause damage higher up the tree. Rabbits cause damage at the base. Voles work below the surface, damaging roots.
Damage: They gnaw on the bark, causing damage that can range from minor superficial stripping to more serious girdling.
Mitigation: Guards, repellents, and managing vegetation around the tree's base can help reduce damage.

Common Culprits: Insects

Insects play a significant role in bark damage in Washington State. Some key examples include:

1. Bark Beetles:

Identification: Small beetles that bore into the bark, creating galleries under the bark. Signs of infestation include pitch tubes (resinous material) on the bark and small holes.
Damage: Bark beetles can weaken or kill trees by disrupting the flow of water and nutrients. Certain species target specific tree species.
Mitigation: Early detection and removal of infested trees are crucial. Pheromone traps can help monitor beetle populations. Proper forest management practices can also help prevent large-scale infestations.

2. Wood Borers:

Identification: Larvae of various insects that tunnel into the wood beneath the bark. Signs of infestation include exit holes and sawdust-like frass around the base of the tree.
Damage: Wood borers can weaken trees, making them susceptible to breakage. They can also cause extensive damage to the wood itself.
Mitigation: Prevention is key. Maintaining tree health through proper watering and fertilization can help make them less susceptible to infestation. Removing and destroying infested wood is crucial.

Identifying the Cause of Bark Damage

Determining the specific cause of bark damage is important for effective mitigation. Consider the following:

Height of damage: High damage suggests animals that climb (bears, squirrels, porcupines). Lower damage points to rabbits, voles, or ground-dwelling insects.
Type of damage: Ragged tears suggest animals; smooth gnawing suggests rodents. Small, round holes point to insects.
Presence of other signs: Look for droppings, tracks, claw marks, pitch tubes, or sawdust.

If you are unsure of the cause, consulting an arborist or forestry expert can help diagnose the problem and recommend appropriate management strategies. They can also help you determine if the damage is severe enough to warrant professional intervention. Remember, early detection and intervention are key to protecting your trees.