More facts, logic, common sense, myths, fetishes, and hyperbole about the Ponderosa Pine Bark beetle
by Ron Jones
Actually, all information I offer I know to be factual. The above title is a sort of caveat. I wish not to assume the obligation of providing adequate bibliography, nor is it practical for me to employ scientific controls in a natural environment. What follows is a culmination of my experience, knowledge and observations from fighting beetle infestations since 1972. Clearly, allusions to cause-and-effect are only as accurate as my ability to remain objective as is humanly possible. However, the resulting method has always worked well for me on the East flank of Bighorn Point.
The beetles are bad this year and threaten to propagate infestations of epoch proportions. This is for those who care enough to want to effect some control over this situation.
WHY BOTHER?:
Good question. Many people don't care. Others think the beetles are part of the natural process, producing meadows where thick stands of trees once stood. Beetle control requires expense and hard labor. The infestations differ by area. In some places the trees are sparse and so are the beetles. Conversely, where trees are sparse, each one is all the more precious to some of us. Eradication of beetles can make them extinct in off-years.
Boulder is an area rife with statism and people with the "we gotta do something about this" collective attitude. Social pressures will probably produce the "legislative magic wand," and we shall once again have regulations on this problem. These codes only serve to burden private land owners and have little impact on the problem. Most of the beetles are on public land, the regulations are rarely enforced and are generally unenforceable. I don't think laws like this are a compelling reason to work beetle control, but others may have different ideas about "social order" and feel the need to comply.
To me, it is a matter of personal preferences regarding the aesthetics of the woods and matters of wildfire mitigation. If beetle control is important to you, do it.
BEETLE M.O.:
Know thy enemy. One cannot solve a problem without understanding the causal elements of the problem.
Beetle epidemics are cyclical and are usually found between 7,000 and 9,000 foot elevations in the front range. Beetles are semi-socialized annual insects. I say "semi-socialized" because they do not have the social structure of bees, ants or other hive or nest building insects. The structure is a swarm which attacks trees en masse. Individual beetles cannot strike off alone successfully. Propagation can involve the dividing of a strong swarm into two smaller swarms. Also, small swarms will unite with large ones to acquire strength. Small, weak swarms attack small, weak trees. Moderate sized, strong swarms attack majestic, old-growth trees. Epidemic sized swarms will attack every tree in an area.
Understanding the annual cycle is to remember grade-school science about metamorphosis, caterpillar and butterfly. Adult beetles can fly, and usually swarm in August/September with some variations. The pregnant females will bore into the bark of nearby healthy trees until they reach the cambium, or living layer between the bark and the wood. Then they tunnel upward in the cambium, sometimes for two meters or more. This injury causes pine tar which mixes with sawdust produced by the beetle resulting in a sticky mass. Beetles need to breathe and cannot turn around in the narrow tunnels. they go through a continual process of backing down the tunnel while kicking off debris with the hind legs. The entry point becomes a glob of this material called a "pitch tube." The tunnels are then lined with eggs which lie dormant over the Winter.
The Spring sap rise (March) stimulates the eggs to develop into larvae. These white worms work laterally into the cambium, consuming it entirely. The tree may still look green or just begin to look slightly yellow but it is now certainly dead. The worms dig small chambers which serve as chrysalises. They become pupae by Spring/Summer. The white pupae darken to a tan color and continue to darken to ebony adults by late July. They then swarm and the cycle repeats.
THE MOISTURE CYCLE:
All living things require moisture. Moisture is not the same as sap. Pine tar is the enemy of adult beetles, but moisture is always needed. Larvae and pupae are vulnerable to desiccation if the tree is too dry. The pupae lie between the wood and the bark in a layer of sawdust, dampened via capillarity, porous wood and moist soil. The bark is no longer attached but acts as a moisture retaining stocking. Cyclical beetle epidemics correlate with cyclical weather patterns called: "El Nina."
TOOLS:
Pealing the bark to observe the status of the beetles is essential. My favorite tool for this is a spokeshave, but a draw knife, draw shave or any similar such tool will do. A sharp hatchet can be used but is clumsy and can't produce the fine layers needed to observe pupae.
ALTERNATE METHODS:
Over the years I must have tried them all.
The forestry department first recommended Lindane. Trees needed to be felled, delimbed, bucked into four foot lengths, stacked and treated. A tarp was then needed as a cover. This method is effective but labor intensive.
Lindane, if you can still get it, can be applied directly to the infected tree. Simply climb the tree with a spray bottle. Done early enough, this will save the tree. I don't recommend this. I don't like the open use of pesticide poisons. Lindane contains petroleum distillates like diesel fuel which appear to be offensive enough to woodpecker olfactory to shun them, but it is still not a good idea.
The forestry department then turned to fumigation. Same as above but the tarp goes on first, the edges are buried in a trench and the gas is applied through a hose. Same problems as above. It is labor intensive and poisonous.
Removing infected trunks to a safe area (where there are no long needle pines for miles) is also effective. If the wood is useful on the plains, it can make up for all the labor.
My first few trees were felled, delimbed and debarked with the spokeshave. This was very effective. The larvae and pupae cannot tolerate exposure. It was also extremely labor intensive as I only had an axe and bow saw.
One tree I climbed and dug each adult beetle out with a screwdriver. This resulted in a quarter inch wide, meter long injury above each pitch tube. That tree lived, recovered and healed, but was probably never the same. About 20 years later wind blew the top half of it down.
Sometimes, doing nothing works best. The tree wins! Sometimes, the tree will just drown them all in sap. Also, the woodpeckers can be very helpful when the tree loses.
JONES' METHOD:
I discovered this by accident. I became overwhelmed with beetles in the mid '70s and had to start the process and finish at a later date. So, I felled 110 trees. When I returned in the Spring, my spokeshave revealed dying beetles.
First, you need to find them. It has no effect to work trees killed and vacated by beetles. In November the trees will look green and healthy except for the pitch tubes. Beetles don't migrate very far. Simply look for a cluster of dead trees. It is usually easy to discern the recent dead from the long dead trees. The beetles often follow a pattern and migrate in a certain direction, ever increasing in strength during bad years. Look at the bark on green trees near the recent dead.
From November to February, simply fell green, infected trees into a sunny area. Do not delimb. The tree will continue to "breathe" through the needles, drying the tree. The limbs will hold the trunk off the ground and out of snow drifts, allowing the sun to assist the drying. There will be no Spring sap rise for these. When the branches become crisp in the Spring/Summer you may delimb and buck these up as needed. Peal bark to monitor. Beetles may progress to the late pupa stage before dying.
The beauty of the above method is the bang for the buck. Saving labor is important in situations with a paucity of laborers and a plethora of work. In epidemics, this impacts the amount accomplished and overall effectiveness.
By late Spring, infected trees are easy to find by the yellowing needles. These are the new outbreaks which you missed in the Fall. These trees must be felled, delimbed and bucked up into firewood lengths. This will season the wood and desiccate the pupae. Do not remove any wood until after swarm season.
When the beetles look black in late July or later, forget it. You can't stop them without an alternative method. Wait for November. I have never noticed any truth to the rumor that wood cutting during swarm season attracts beetles from distances, however, it is certainly useless for beetle control.
As an added caveat I should assert that the above method is not always 100%. But, with the bang for the buck and avoiding poisons, it needn't be. Keep in mind that the goal is to reduce the swarm to relieve the epidemic. For example, the 110 trees I felled became only 6 newly infected trees the following year, and none the next. So much better than the exponential propagation of the prior years.
SUMMARY:
October-November: It is now safe to remove firewood previously felled and/or bucked up. It is also time to inspect the forest for newly infected trees.
November-February: Fell newly infected trees BEFORE the Spring sap rise. Leave them lie.
April-June: Trees having escaped prior detection become obvious. These need to be felled, delimbed and bucked up. Also, delimb and buck up trees felled in the fall if the spokeshave reveals the need, or if you expect to remove the wood.
July-September: Forget it. Alternatively, use some other, more drastic method.
For more information contact the Land Use Coalition at contactus@landusecoalition.org or call 303-666-7903.
Last updated October 27, 2003.
URL: http://landusecoalition.org/jones_beetle_paper.htm