Cohabitating with Bark Beetle

They aren't going anywhere soon.....

Bark beetle is not unfamiliar to the Pacific Northwest and is in fact native to North America. Bark beetles are a natural pest that has played an important role in our forests ecosystem. They target stressed trees that can not defend themselves properly. The trees are the perfect host for feeding and egg laying due to their protection from physical elements and the abundance of sugars in the phloem tissue. Bark beetles that affect pine trees specifically feed on the phloem tissue and do not affect the actual sap wood of the tree. They cause mortality in trees in two ways, either by introducing a fungi we commonly know as "blue stain" or by girdling the trees. In the PNW, we have several bark beetles that are vectors for the blue stain fungi, but not all  bark beetles are. Rapid decline that leads to tree mortality from bark beetle usually is identified from crown dieback and the sign of orange and yellow needles at the tip of the crown. The discoloration of the needles is the process of necrosis, dead tissue. The crown is dying from the top down due to the fact that water and nutrient transportation is being cut off or blocked. It is "cutoff" due to girdling or it is      " blocked" from blue stain fungi growing rapidly throughout the sapwood and blocking water transport. The effect of beetle damage is often times irreversible depending on the type of damage, the beetle that is identified and the size of the attack.

Due to an ever warming climate, bark beetle numbers are increasing. The research points to warmer and shorter winters, the larvae aren't battling extreme colds that can cause mortality. Also, with large fires, food is so readily available and trees are defenseless, populations are increasing. With this information, we understand attacks are inevitable and we look toward preventative measure to help our trees defend themselves.

The defense system of a tree is a process built through evolution in response to pressures and stresses. The resin pressure and flow of trees is the primary defense system to stop beetle attacks. This is the only natural defense and response of a tree.  Remember,  bark beetles are attracted to stressed trees or downed and dead tree material. So if trees are being attacked they are stressed! So our main concern is, how do we keep our trees from not being stressed?

Water.Space.Nutrients.

Water, trees need supplemental water when we have been experiencing years of drought. Space, trees need adequate space so they don't have to fight for water and nutrients. Also, they need space away from new construction, driveways, roads, sidewalks, things that cause compaction or loss of roots. However, there are efforts we can make to lessen stress in these scenarios. Nutrients, trees might need supplemental food or fertilization depending on site conditions and history. Often times, in the urban environment, the natural process for soil to obtain organic material and food is disrupted by our need or the requirements of having a clean yard or space.

These are efforts every homeowner can make to ensure their trees have the best chance for a healthy defense systems. It is vital that homeowners with high valued trees reach out to a certified arborist who can identify these conditions and create a plan for proper urban forest health. We also offer biological andchemical preventative measures, but the need should be assessed prior to application or installment. Our staff has two certified arborist that can asses tree health and develop plant health care needs. Call us today for a certified and free consultation.

Certified Arborist:

Boe Brodhun #PN-9329A

Todd Ebens #WI-0457A

More information can be found here:  https://www.fs.fed.us/research/invasive-species/insects/bark-beetle.php