I thought it would be a very long time before I would write about mountain pine beetles in the Black Hills. Our chief science officers have declared the mountain pine beetle epidemic over. Our governor took back over $700,000 of state money earmarked for the mountain pine beetle fight. We can all relax, they said.
Except that we can’t relax. I didn’t spray my trees last year, and I lost 12 medium-sized ponderosa pine as a reward for my faith in science. We have long held that more than one bug-killed tree per acre is the definition of an epidemic, that less than one hit per acre is endemic, normative, what we would expect.
The thing is, one hit per acre is an average. When all of the hits in a 100-acre area are focused on five or ten acres, it looks an awful lot like an epidemic. If it’s not an epidemic, it’ll do until an epidemic gets here. I had an epidemic in my yard. The bug-killed trees I cut down to process and kill the live insect larvae are still lying there, waiting.
I’m annoyed, chagrined, and sorry I didn’t take more care of trees I spent lots of money on over the past 10 years or more, spraying and protecting them so they would stay alive. At a cost of $15 per tree, spraying them would have been much cheaper, and a better investment, than leaving them to the whims of nature. I should have sprayed them, at least the ones that I really didn’t want to lose.
The problem with forest insects and disease is that those insects and disease don’t arrive suddenly from out of town and then leave the same way some years later. No. The insects and diseases that plague our pine forests are always here, usually in the background, rising suddenly when conditions are right and causing havoc, and then quieting down for a time before rising again.
The lesson I take away from this latest epidemic of bark beetles is bark beetles are always here, and they are always looking for the right conditions to break out and propagate their species by killing trees.
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That’s fine. I support natural cycles of growth and death. But I didn’t have to lose 12 of the trees I fought so hard to protect for so long. I bet against the come the beetles were done for now. They are not done.
I won’t spray the numbers of trees I sprayed in the past when the epidemic was at its height in 2005-2015. But I will spray the trees I absolutely don’t want to lose. The alternative is to keep losing several trees each year, including the big ones that weathered the past 400 years of bugs, fire, and people.
Of course, I understand the epidemic that so focused our attention across the Hills for the past 20 years or more is essentially done. I also understand the bark beetles are never done. As I create conditions that favor bark beetles, they will continue to exploit those conditions without regard to pronouncements about the scientific status of epidemics.
Conditions favoring bark beetles can be found in the wider forest in dense stands of unthinned trees, in areas where stress from soil impacts and vehicles or from other sources is present, and in areas and for reasons which we don’t understand. They can also occur in and around our homes and neighborhoods, and we may not, probably will not understand the dynamics. Yet, there they are.
The best defense is spraying the trees I don’t want to lose.