drought high in the northern Colorado mountains is the primary trigger of a massive spruce beetle outbreak that is tied to long-term changes in sea-surface temperatures

==>> bull-oney ...

its cyclical.. like it has been for eons ... what.. 14 billion years.. how old is the earth ... it has NEVER been a constant ... period ...

when the second sentence of any given article is political in nature..

then the rest of the article is nothing but politics ... after all.. who gave the money to the college.. to fund the biased study ????

plagues come and go over millions of years.. actually over decades...

another waste of my tax dollars ... crikey ..

ken

Thanks for the viewpoint from inside the ostrich hole, Ken!

OT, but Emerald Ash Borer was found in Boulder recently, too. Before the flood I noticed borer holes and sawdust at the base of a Patmore ash I planted 5 years ago. It could be lilac/ash borer or it could be EAB.

The Front Range of Colorado has seen it all this last year, drought, fire and floods. Add in pine bark beetle, IPS beetle, maybe the sky will fall next, lol!

Drought stressed trees are obviously more susceptible to insect and disease. I'm trying to view all this as an opportunity to add some diversity to my plantings. Most of the ash at my place are 60 plus years old and It seems daunting to try to save them with drenches or injections that may or may not work. None are threatening the house if they come down. I am hoping that my pines and spruce are young enough to be less threatened by beetles, we'll see.

I'm adding catalpa, honeylocust, oak, yellowwood, linden, sweet gum, horsechestnut and ginko to the mix in preparation for when the ash succumb.

Thanks for the article, love!

Barb

Ken immediately unplug your computer! That thing is nothing more than another waste of your tax dollars!

Ah, the certainty of the ignorant!

+oM

Only in America is climate change considered controversial and too political for polite company. (I guess there really is good reason for hanging that GOING OUT OF BUSINESS sign at the borders.)

Yes, we know, it's sun spots, cycles, and at one time there were dinosaurs running around in Antarctica, and palm trees growing in Alaska. The issue is RAPID ( and yes, man-made changes to the chemistry of the atmosphere) that will result in mass extinctions and the displacement of millions of people. So happens, that most of the Earth's present population lives near to rising sea coasts and may not be prepared to relocate to higher ground (though I am sure Denver is lovely this time of year).

No, maybe not the extinction of life on earth, and perhaps reminiscent of an ancient epoch, but still, a major inconvenience with political, environmental, and economic implications.

P.S., Ginkgo has been around forever so I guess it is a good choice but someone is gonna have to bring some females to that party.

Bark beetles always respond to drought. There is no new information here. As to ocean temps predicting drought - also well established for decades.

The funny, strange, or pitiful thing about freaking-out responses to this article is that the article wasn't even directly trying to make any point about global warming. From what I see, just the mention of the word temperature is enough to make some panic, refuse to listen or read further, and immediately start taking some sort of political defensive posture. These days, some are willing to totally abandon any objectivity with just the mention of a word.

Brandon, I wish you were wrong. You're not!

+oM

As salicaceae said, it's not at all surprising or new information that drought stress triggers outbreaks of conifer bark beetles.

What puzzles me is the statement that "The new study also puts to rest false claims that fire suppression in the West is the trigger for spruce beetle outbreaks." As far as I'm aware, fire suppression has never been claimed to be a "trigger" for these events, but rather results in conditions of forest structure and composition that are primed for large-scale outbreaks once they get started. I just skimmed through the paper, and as far as I can see, the study doesn't address those issues.

"What puzzles me..."

I can see what you mean about that choice of wording, but I can also see how the statement could address real issues of concern. It may also be helpful to note that the article above is a media presentation and not the actual study results. If I had been writing the article, I might have replaced "is the trigger for" with something like "encourages and exacerbates". To me, the possible slip in wording doesn't significantly change the overall relevance or importance of the article.

Even if it were just poor wording, it doesn't make sense. I've read the paper. The study design does not address fire suppression at all, nor the ecological variables (such as stand structure and composition) which may be relevant to fire suppression's effect on bark beetle susceptibility. Fire suppression isn't even mentioned in the paper. What they did was look at the association of climate variables with the initiation of spruce beetle outbreaks.

On first read, I don't see anything to complain about with the study itself. I certainly understand that the people writing the press release may not be the scientists involved, and they can sometimes state things poorly. But that statement in particular (which is attributed to one of the authors) is really out of left field, and not a conclusion that is made by or can be drawn from the paper.

The study looked at data for well over 300 years. Correlation was found between outbreaks and certain variables but not fire suppression. Fire suppression methods changed significantly over the period of study. For fire suppression to be responsible for the outbreaks, some unknown (or at least unexamined) variable would have to have occurred and skewed the data. Hart has mentioned and further elaborated on this extrapolation in other communications besides the article included above.

This study did not examine differences in scale or severity of outbreaks as part of the analysis, so it doesn't address whether fire suppression or anything else "encourages and exacerbates" spruce beetle outbreaks, as you suggested might actually be meant by the statement in the press release.

What they looked at was climate factors associated with the timing of the initiation of bark beetle outbreaks. So, the statement might make sense if people were claiming (as the press release statement indicates) that fire suppression were responsible for "triggering" bark beetle outbreaks. But I've never heard that claim made.

So, I still can't see any way that the statement makes sense.

Let's say I'm doing a study about how chopping a certain type of tree down at ground level effects tree death. I do this over a three year period. During the second year, I whistle every time I cut down a tree. I find that a large percentage of the trees I chop down end up completely dying, and I notice that that a similarly large percentage of chopped down trees also died during the second year. Can I conclude that whistling is not a likely variable in the amount of tree deaths? I didn't really chart tree deaths v. whistling, but the data still seems to suggest that the whistling didn't have much effect. Now, it is possible that the whistling did have an effect and that some other variable compensated for the results being similar to the other years. Still, I'd be tempted to greatly doubt the correlation between whistling and tree deaths.

This post was edited by brandon7 on Wed, Oct 16, 13 at 21:29

"I've never heard that claim made."

I've seen a number of reports from a variety of sources that contribute various beetle attacks, at least partially, to increased stand density (and therefore increased stress from nutrient and water competition) and lower average vigor (from a more mature stand) brought on by fire suppression efforts. I don't have anything on hand that contributes this particular outbreak phenomenon to fire suppression, but would be shocked if such a correlation hadn't been suggested (similar to so many other cases).

Sorry about the multiple posts, but I just realized there was another aspect I didn't cover...

The whole phenomenon is a matter of degree. It's not like the beetles are not present and then suddenly are introduced by some catalyst. If the sudden population growth of the beetles wasn't "encouraged and exacerbated" then the event wouldn't be "triggered". I prefer the "encouraged and exacerbated" terminology (or some other similar wording) because it seems clearer to me, but my phrase and the author's terminology is practically the same in meaning. Both wordings indicate a causal relationship, or lack thereof.

Brendon, I understand the concept, and if it were really the case that people were saying that fire suppression (whistling) was the primary trigger for the initiation of bark beetle outbreaks (tree death), then you might have a point. But no one says that, or at least it's not something that I've ever heard said or seen published among bark beetle specialists. And for that matter, the paper doesn't even report on whether there's a difference between the year without whistling (pre-fire-suppression) and the next. Based on their data sources, I doubt they had the statistical power to prove the negative.

Drought stress is commonly considered to be a main trigger for regional conifer bark beetle outbreaks. But even when regional outbreaks are occurring, the susceptibility of a given stand to infestation is affected by that stand's structure and composition. Fire history is a factor that affects stand structure and composition. These points are well-supported in the literature for many systems. Back to your analogy, the idea that fire suppression could affect bark beetle susceptibility is not nearly as unlikely as the idea that whistling could affect tree death. There is a mechanistic connection.

Also, these associations they're reporting are significant, but not absolute. For example, they find that 24% of the time that there was an AMO of at least 1.6, there was an outbreak in the study areas. Otherwise, when the AMO was

This post was edited by saccharum on Wed, Oct 16, 13 at 23:50

Brandon, I missed your last posts while I was writing mine. I disagree: there is a substantive difference between a "trigger" for outbreaks and something that "encourages and exacerbates" outbreaks.

I can show you many pine stands that are mature, overstocked and stagnant. They don't automatically suffer bark beetle outbreaks when they reach that state. But when outbreaks occur - which often happens during severe droughts - mature, overstocked and stagnant stands are much more likely to be severely affected. The drought is the trigger for the outbreak. The stand conditions encourage and exacerbate its effects.

Imagine you had an area where people tended to throw crumpled up pieces of paper. Every so often, someone comes by and throws in a lit cigarette, and sometimes this causes a fire. The cigarette is the "trigger" that ignites the fire, but the amount of paper that has accumulated plays a role in how much the fire is "encouraged and exacerbated," right?

This post was edited by saccharum on Thu, Oct 17, 13 at 7:43

Saccharum, my point in that last-of-three posts was that the "fire" (presence of beetles) is already burning. For the crumpled paper analogy to work, you'd have to have something that would keep the crumpled paper burning under control at some times (maybe a gentle rain). Until something allows the burning (beetle infestation) to grow more quickly (encourage and exacerbate it), the out of control burning (problematic infestation) isn't a problem (isn't "triggered"). That's why I'm not sure that trigger is the best word to use, because the lit cigarette isn't needed!

It's all just terminology, and I see the whole trigger wording issues as pretty much a non-issue anyway. But, I can kind of see both sides of this. The author does feel justified in extrapolating the stated position about fire suppression, AND you are correct that the study doesn't DIRECTLY address the issue (and therefore may not really PROVE the position beyond reasonable doubt). Maybe the author would have been more correct to say that the study suggested that control burning was at least not a primary contributor to the problem.

I see the study as one step along the path to the final answer and not as something meant to be the ultimate statement of fact. Maybe the authors are overstepping a bit, but they're excited about their study. There's always tomorrow and other studies to correct any oversteering.

It's not a perfect analogy, but few are. Between outbreaks, bark beetles are always present in the environment at endemic levels. What's being "triggered" is not the presence of bark beetles, but the switch from endemic to epidemic phase. And it's the timing of that switch, as associated with certain climate variables, that this research examined. Again, they don't present data on the size or intensity of the outbreaks.

I guess that coauthor felt justified in making the statement regarding fire suppression for the press release (unless he was misquoted), but apparently the authors did not feel that they could make that statement in the journal article. Like I said, the actual paper is fine. What bothers me is that many more people will read the media reports about the paper than the paper itself, and they'll think that it says or indicates something about fire suppression. It doesn't.

Well, we'll have to agree to disagree. I agree with the author that it does imply something about fire suppression. I don't buy the certainty that the media article seems to present (for reasons including some you mentioned above), but I can clearly see why the fire suppression topic would be brought up in conjunction with the study.

You're welcome to your opinion, of course, and so is Dr. Veblen. If he can support it with a relevant data analysis, I'd find that more convincing.