Depending on what type of forest you live in, there are a number of native forest pests you should be aware of because of their involvement in tree deaths, which then create an abundance of fuel for possible fires. Understanding how pests are attracted to an area can inform the best way to mitigate your forest for fire danger.
In the Piñon/Juniper areas there are Ips beetle, Twig beetle, Juniper borer, and Pinon pitch mass borer among others. The Ponderosa forest has a variety of “bark beetles” which is actually a category that includes the Ips beetle, Engraver beetle, Mountain Pine Beetle, Turpentine beetle and others. And, in the Spruce and Fir areas, we have the Spruce Beetle. For more information on common beetles, read here.
The pests are native to this area and have a role in the complex cycle of our forests. Undeniably the delicate balance of nature has been affected more recently because of climate change, but also there is evidence of dramatic dieback written in the pollen records of thousands of years ago. Even though beetle dieback is a part of living in a forest and should be tolerated, there are certain human activities we do that exacerbate them. Let’s look at a few of these activities.
Firewood
Generally, seasoned wood is not going to house your forest pests. That is because it is dead and is now home to secondary decomposers like Sawyer Beetle. However, wood that was cut down this season or even two seasons ago may have pests in them from when they were still standing vertically. Poplar borer on cottonwood and Aspens can often be found deep in the heartwood. They can spend up to two years in the heartwood before they emerge. Your pine beetles however live just under the bark and cannot live more than a season in your firewood.
Beetle outbreaks are often associated with logging activity or blow downs in the forest. The logs left behind a logging operation are prime nesting grounds for beetles. They inhabit the freshly cut down trees as their cambiums are still alive and their defenses are down. Keeping this in mind, if you are bringing firewood to your property that is green, make sure it is of a different species than the living trees on your property.
Timing of pruning
Similarly, pests are drawn to fresh cut trees. Trees release chemicals called hydro-carbons, which is a fancy name for that pine-sol smell you get when you cut a pine down. Some insects have evolved to detect that smell as well as other “smells” that are undetectable to humans. These hydro-carbons are a signal to the forest pests that the trees are weakened and could be a target for successful infestation.
Therefore, pruning trees in your forest when forest pests are active can draw pests to your property. No, there is nothing you can put on the wound to mask the smell. If you have to work on your trees in the active pest season or have had damage to your trees caused by wind or snow, you may want to consider spraying them with a preventative pesticide.
Improper pruning
We unfortunately see this one too often. Trees do not have immune systems like humans. If they receive a wound they isolate the wound by putting up walls that prevent infection from spreading. These walls are infused with antimicrobial agents that are nearly impossible for wood decay fungi and bacteria to penetrate. Having said that, we have to take advantage of where these walls are strongest.
A branch connects with a main trunk through an intricate interlocking of wood fibers. These fibers are infused with hardened wood that is very difficult for pathogens to bypass. Chainsaws, however, can bypass them easily, resulting in what we call “flush cuts.” These are cuts made flush against the trunk. These cuts ignore the branch bark ridge and other physical clues that denote where the branch fibers stop and the trunk fibers start. Wounds made to the parent trunk not only have the potential for wood decay but are also challenging for the tree to heal over. Ripping wounds, where the saw cut directly down on the branch and allowed the fibers lower on the branch to rip down are also difficult for the branch to heal over.
Correct pruning cuts only affect the branch fibers, leaving the trunk fibers intact. Once the branch has been removed, the tree begins the process of walling off future pathogens and healing over the wound.
Knowing more about your trees’ health and susceptibility to pests along with proper pruning and care can help protect from fire dangers. Are you interested in a health checkup on your trees? Give us a call for a comprehensive assessment today.
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