NOTE: The hijacking and spread of misinformation and slander by certain commenters has led to the closing of further comments on this article. I am however, very thankful to those many who made good points, asked good questions and provided further references, thus contributing to better public education. Jim.
Note: This is the first of two or more articles on the extensive tree mortality now being caused by bark beetles in western North America. The goal of this first post is simply to provide necessary background on the relevant biological/ecological processes involved, so that future articles discussing climatic and other possible influences, are more understandable.
__________________
It’s mid autumn in the northern hemisphere, whose deciduous forests annually provide one of earth’s great spectacles. When deciduous trees prepare for their seasonal cold dormancy they partially recycle important elemental components of chlorophyll and the associated photosynthetic machinery, such as nitrogen, phosphorous and magnesium. Other more minor leaf pigments, which vary in abundance and spectral properties from species to species, are then temporarily exposed on the tree before leaf drop. The timing of the chlorophyll loss varies between trees, and when combined with the presence of evergreen conifers, gives the flamboyant array witnessed, typically heavy in the yellow to red pigments.
New Hampshire, USA, in the autumn
If you’ve never seen it, consider putting it on your list of worthwhile things to do in your life, as did the guy from San Francisco I once met on the Appalachian Trail in Vermont. Never mind that he carried most of his gear in a plastic garbage bag slung over his shoulder and wondered why the bears were bothering him at night when he didn’t hang his food (mostly a large hunk of cheese in a paper bag). We were instantly friends when he told me he was on the trail just to see the colors, up close and personal for a few days, in response to a magazine article he’d read.
In western North America, true deciduous forests are strictly riparian and therefore limited. The vast majority of upland forests and woodlands are dominated by conifers, all but one of which are evergreen. However, one highly important deciduous species—quaking aspen (Populus tremuloides), which turns brilliant yellow—forms groves that range in size from a few trees to vast forested expanses, typically on mid to high elevation mountain slopes with decent groundwater supply through the summer. [The largest known organism in the world is a large aspen stand in the West Elk Mountains of Colorado, USA (aspen is highly clonal, connected by rhizomes).] The greens and yellows provide a poor man’s version of fall color compared to an eastern hemlock-hardwood forest perhaps, but when combined with often colorful rock exposures, blue skies and rivers, and montane topography, the sight usually has its own magnificence.
Red foliage however, is one thing you’re not supposed to see a lot of in western North America, any time of year.
In many places in the west–particularly through the central and northern Rocky Mountains and British Columbia–there is now a lot of red foliage, but unfortunately, it’s not just in autumn, and is occurring on non-deciduous species. The proximate causes of this are (1) Dendroctonus spp. (literally, “tree killer”), the most destructive of several destructive bark beetle genera, and (2) tree physiological stress. God’s “inordinate fondness for beetles”*, combined with certain human activities, is now causing some serious problems indeed. Here I’ll try to give background on the issues related to bark beetle outbreaks, working from proximate to ultimate causes, and focusing on the one beetle species currently doing by far the most damage, the mountain pine beetle (MPB), Dendroctonus ponderosae. The MPB is attacking a set of highly important pine species (Pinus spp.) over a very large area of western North America, especially lodgepole pine (Pinus contorta), ponderosa pine (Pinus ponderosa) and whitebark pine (Pinus albicaulis), but also some of the other five needle pines (esp. limber pine). Other species of beetles in the genera Dendroctonus and Ips are also doing some serious damage to these and other species, albeit at smaller spatial scales and/or less intensively, and represent so many variations on the theme illustrated by the MPB.
Not New Hampshire in autumn. MPB mortality on whitebark pine in western Wyoming’s Bridger-Teton National Forest. (Fig. 4 of Bentz et al, 2010)
Theological considerations aside, there are many hundreds of species of bark beetles worldwide, and the Curculionidae, or weevil family, of which bark beetles are a member, contains the largest number of species of any animal family. However, only a very small percentage of “aggressive” bark beetle species has the potential to cause extensive tree death during population outbreaks (“irruptions”). These species kill by overwhelming, with coordinated aggression and sheer numbers, a tree’s defenses, followed by a complete destruction of the tree’s ability to transport the products of photosynthesis (e.g. sucrose, amino acids, hormones, etc.) through its transport tissue, the phloem or inner bark. This is usually accompanied by an impaired ability to transport water to the leaves via the outer xylem (the sapwood), courtesy of blue stain fungi (e.g. Grosmannia or Ceratocystis spp.) carried and introduced by the beetles. As ecological systems go it’s very well studied, and contains the interesting wrinkles, non-linearities and feedbacks so typical of ecological systems, even relatively simple ones like this. Plant physiology and demography, insect population dynamics, insect-fungal symbioses, land management practices, and climate dynamics all play important roles in the overall outbreak process. Simplistic explanations of the causes of these dynamics are, as usual, to be avoided.
Whether or not an individual tree will survive a beetle attack is determined by its pre-attack nutritional and hydration states, and the number and timing of beetles that attack it. Conifers defend themselves with both pre-existing (“constitutive”) and de-novo (inducible) defense systems. In pines, resins–a large class of complex plant chemicals that function as antimicrobials, fungicides and insect toxins –are delivered primarily via a constitutive production/delivery system consisting of resin canals lined with resin-producing epithelial cells. Resins typically have strong and interesting odors (familiar to many in products like turpentine, a commercial resin derivative), and they cause the distinctive smell of a pine forest in the summer when they vaporize from leaves and bark. They are produced and delivered in solution, flowing through the ramifying canals in the outer sapwood (the mostly live, water conducting part of the wood) and phloem, which exist solely for that purpose. These solutions are typically highly viscous and sticky, not unlike the consistency of molasses or honey.
Adult mountain pine beetle, about 6 mm long.
Beetles attack by chewing straight through the outer bark into the phloem. If they sever a resin canal of a healthy, hydrated tree, there is an immediate and forceful flow of resin solution under hydrostatic pressure that often kills the beetle. This action represents a cost to the tree however, in both water and resin, the latter being metabolically highly expensive material. If the tree’s carbon balance has been suffering and/or the tree is not well hydrated–due to things such as drought stress, an extended beetle attack or low light levels–its ability to maintain resin solution pressure and/or chemical toxicity, is accordingly reduced. Inducible defenses are also important and involve gene activated cell death and a subsequent “walling off” of living cells/tissues via induced biochemical processes, to slow the beetles’ and fungus’ physical progress in the tree. Although many beetles will thus typically be killed or isolated during an attack, even a perfectly healthy tree can eventually have its defenses overcome by sheer beetle numbers. These trees then become breeding grounds for a repeat of the process on other, nearby trees. This leads directly to issues in beetle population dynamics, which are arguably the most critical element in the system’s dynamics.
Bark beetle population growth potential depends on forest structure and composition, tree vigor, and weather/climate. A key reason for the destructive potential of aggressive species like the MPB is plasticity in the number of generations produced per year, which correlates well with mean annual temperature. There are (at least) two direct temperature effects (and likely several other indirect ones) on beetle population processes. In the warm season, warmer temperatures accelerate development through several larval stages and pupation, and in the cold season they can reduce the kill of over-wintering larvae. In the MPB, two (or more) generations can be produced per year in warmer climates (“multivoltine” reproduction) while only one half generation per year may occur in more northerly or higher elevation populations. For equivalent food supply and fecundity rates, this variability in generation time will obviously have a very strong effect on the number of adult beetles emerging per unit time to attack new host trees (although the thermal requirements for the full developmental cycle can mitigate this somewhat). As a generalization, winter temperature controls are relatively more important in colder climates than in warm ones, so the thermal controls on population growth will vary with geography and physiography. Also, generation time has important implications for the potential rate of evolutionary adaptation to changing growth constraints (such as host defenses or climatic tolerances), via the total possible number of genetic recombination chances per unit time. Plants and their insect herbivores have been involved in this evolutionary battle for tens of millions of years, and have developed some fascinating defense and attack mechanisms in the process. It’s not at all easy being green.
Life cycle timing of the mountain pine beetle in British Columbia
Because a tree can recover from some limited number of beetle attacks–by restoring its carbon balance and/or hydration over time–aggressive species like the MPB do not allow this to happen. They do so by emerging from trees within a narrow window of time, roughly 2-3 weeks (also temperature dependent) and then coordinating their attacks using chemical communication (i.e. pheromones). For the MPB in southeast Wyoming’s Snowy Range for example, where there is currently one generation per year, emergence from lodgepole pine is typically in high summer (late July to early August) when trees are feeling the effects of summer water stress. The pheromones released by inititial colonizers signal to newly emerging beetles in flight that an attack is underway, drawing a critical mass of beetles into a coordinated attack on certain trees exceeding a minimum basal diameter. (Beetles reproduce far more effectively in larger trees and near the tree base, because the phloem food source is thicker there.) This creates an attack that would otherwise be far more diffuse and less effective, were beetles to just land randomly on potential hosts. Once tree defenses have been overwhelmed and the tree is certain to die, other pheromones are then produced which drive in-flight beetles away, thereby maximizing the food resource for the colonizing beetles and their coming offspring.
A tree under attack, with vigorous defense of resin exudate from entrance holes. This tree will not likely survive.
Tree physiological stress also plays a critical, climate-dependent role, especially in getting an outbreak started. A central tradeoff in all vascular plants is the unavoidable loss of water for a given gain of carbon dioxide, since both exchanges occur via stomatal pores on leaf surfaces. When plant water status drops below minimum levels required for cell functioning, stomates quickly close and carbon fixation thus stops. When light levels are low, carbon fixation also slows (albeit for different biochemical reasons). High tree densities can thus limit per-tree water and/or light availability, leading to lowered photosynthesis and consequent carbon balance problems that directly affect trees’ abilities to defend themselves from predation. An MPB population can very quickly irrupt in, and destroy, a stand of physiologically weakened trees. Healthy forest stands and landscapes, and mixed species and/or mixed size forests, stand a much better chance of at least slowing an outbreak down, especially at as the spatial scale increases. However, even then, large forested areas can eventually be overwhelmed by sheer beetle numbers, as is now happening in many places.
Much of western North America has elevated tree densities, relative to pre-settlement times, either for all trees, the largest tree classes thereof, or both. This is primarily due to active fire reduction/suppression policies over the last century or more by federal and state land managers, and/or timber harvesting practices. The resulting increased competition, without any increased climate stresses, would by itself increase tree physiological stress and affect beetle outbreak dynamics. The addition of warmer and/or dryer conditions simply magnifies this problem. Similarly, increased climatic stress unaccompanied by increased competition would also favor the beetles. Because natural fire regimes varied widely historically, and are complicated in many places by similar variability in logging practices and intensities, the effect of fire reductions on bark beetle outbreaks varies considerably and involves several issues of spatial and temporal scale variability. This makes the topic both interesting and difficult, and requires good information on past land management practices and forest stand dynamics. That topic however is fodder for another post.
*A famous quote, sometimes attributed to Charles Darwin, but formally attributed to evolutionary biologist J.B.S. Haldane (in: Hutchinson, G.E. (1959). Homage to Santa Rosalia, or why are there so many kinds of animals. American Naturalist 93 (870): 145-159): “There is a story, possibly apocryphal, of the distinguished British biologist, J.B.S. Haldane, who found himself in the company of a group of theologians. On being asked what one could conclude as to the nature of the Creator from a study of his creation, Haldane is said to have answered, “An inordinate fondness for beetles.””
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The next article will discuss the geography and dynamics of the beetle outbreaks in relation to likely causative factors, including climate. I encourage those interested to read the following recent paper:
General References:
Raffa, K.F. 1988. The mountain pine beetle in western North America, pp. 505-530 in: Dynamics of Forest Insect Populations., A.A. Berryman ed. Plenum Press, New York.
Gibson et al., 2009. Mountain Pine Beetle. USDA Forest Insect and Disease Leaflet 2
Leatherman et al., 2010. Mountain Pine Beetle (Colorado State University Extension Fact Sheet)
49 Gail Zawacki,
Perhaps we both should be kind to the realclimate folks, who mostly try hard to support discussion. I appreciate that very much.
If it is consolation to you, I differ with your opinion about degree of urgency and doom; though not about need for a serious solution. But I also contend that I think outside the box about solutions. And I am an old codger. The consolation you should note is that I asked about insecticides repeatedly; many of these being summarily deleted. Finally, we got some real discussion. And I learned some stuff.
Re #50 (Richard Pauli): I don’t see the point of allowing the rants of Gail Zawacki through moderation. Claiming such things as that that RC is propaganda for the fossil fuel industry is (as another Pauli would put it) not even wrong.
Gail,
Science is frustrating, but it works, and it works because it is conservative and systematic. What is more, I think that deep down, most people know it works. So it is extremely important in the case of climate change that science be seen to be working in the normal fashion. Otherwise, we will not convince our fellow citizens that action is essential.
The scientists have been fighting this battle a long time. Arrayed against them are lying SOBs who will stop at nothing to protect their entrenched interests. The only weapon scientists have is the truth, and it is essential that we not overstate the risks and not even appear to overstate the risks. Truth is the one weapon our opponents will never have in their arsenal.
http://www.google.com/search?q=autumn+color+tracker
Pick your state, province, or country; many are represented.
New England: http://www.newenglandtimes.com/new-england-fall-foliage/ne-fall-foliage-tracker.shtml
Jim, may I bother you for a bit of off topic, but sorta on topic advice? The Blue collar, as I call it, that is revealed when the pine is sawn open, is as I understand it the remnants of the blue stain fungi. Now some enterprising ladies in the interior of B.C. have been making a good living selling this processed wood to the East, especially Japan, calling it “Denim Pine”. And i have also been transporting this pine to Vancouver as firewood. i am only using standing dead so i am under the impression that it is not a concern. But could it be? I have not been able to find a ban on transportation on the B.C. Gov. website.
thanx.
Now the last post leads to this post. Jim, again, from what I have been told, if the beetle did not carry this fungus, more then likely most trees would survive. The gent that I was talking too, though not Forestry, has spent most of his life in the forest business. He was saying that in fact it was the fungus that actually kills the trees by basically starving them to death by filling their trnsport cells full of this fungus.
And from my experience on our small plot, it seems that this may hold some water. It appears that the trees do not really start showing signs of problems until a year or so after the beetles leave.
Do you know if there are any efforts to maybe “help” the beetle, i.e. genetically modifying them, so that they become a less hospitable host for said fungus?
Jim Bullis,
Re: insecticides. My conversations indicate (again with a single source, our city forester) that carbaryl is the only insecticide which is effective against the MPB. The drawback is that it is toxic to just about all fauna, including H. Sapiens. See this. This makes it, to put it mildly, quite unsuitable for the ecosystem scale application which would be necessary for controlling the MPB infestation in western forests. The most effective means of applying it is directly to the trunks of trees early in the lifecycle of the MPB. Too early and it has no effect. Too late and it has no effect, the tree is already doomed.
Pheromone packets work well but are very expensive and labor intensive to apply on a large scale, but they are effective in controlling the infestation. Once again not suitable for ecosystem level application since about every third tree needs to have one nailed to it and they need to be renewed periodically. There are two things that do work: once every tree in a stand is dead they go away (lack of suitable habitat) or an early freeze. It looks like both are at work here in SW Montana, last year we had an epic cold snap in early October and large numbers of favored species have already been killed. These conditions has slowed it down a bit out here. The funny thing is that the MPB generates it’s own antifreeze, but only after a certain point in the life cycle.
I second the request for an “official” statement on whether it is temperature or ozone. I thought it was climate [ winter temperature] only.
[Response: Edward, what in the world? Please people, I’m seriously, very quickly losing my desire to contribute any more articles on the topic. In fact I think I already have–Jim]
Jim (both of you), re: use of pheromone-baited traps,
Any Scandinavian biologists who actually know this stuff are welcome to chime in, but here goes: At the height of the ’70s outbreak, Norwegian entomologists and chemists isolated spruce bark beetle pheromones, and a domestic firm started synthetic production. A trap design was cobbled together from plastic drain pipe, a funnel and a collection flask (fuzzy picture here; this one’s fallen down, they’re supposed to be vertical). Pheromone dispensers were placed inside the long black pipes, which had entry holes; the beetles sniffed the perfume, entered the pipe and fell into the flask. This approach was preferred to an alternative strategy of baiting logs laced with insecticide. I think over a million traps were produced. The idea was exported to other European countries.
Systematic trapping has continued since 1979 to keep track of the beetle population, with a network of some 400 traps around south and middle Norway. Here’s a picture of the flask being emptied.
There’s no doubt that the things trap beetles, some 10-15,000 each at the height of the outbreak. They also trap some of their natural enemies (checkered beetles). Along with other factors, the traps helped end the ’70s outbreak, and were hailed as a success, but I’m not sure their contribution was all that critically assessed. (Homegrown technology success stories often aren’t.)
There’s scientific debate over how trapping affects population dynamics, and policy debate over how cost-effectively (the traps cost money and, not least, manpower). But this is very much not my field, and I’m not very familiar with the literature, so your Google scholar search for “spruce bark beetle pheromone trap” or similar is likely to be as good as mine.
Thank you Edward Greisch. In another thread, it was said by the moderator, that I don’t know what I’m talking about. Nowhere has the substance been addressed. Even the USDA and EPA say that crop yield losses due to ozone are in the BILLIONS of dollars annually – and they’re trying to hide the real implications!
[Response: End of acceptance of any more of your comments. Your continual, unsubstantiated conspiracy claims regarding agencies and/or scientists’ suppression of information constitutes libel and your aggressive, uninformed attitude is completely counter-productive to real progress.–Jim]
[edit]
Jim, thanks for the posting on the pine bark beetle part of the great tree die-off. In NE Georgia we experienced our infestation and maximum die-off perhaps ten years ago. Some trees survive, so maybe here at least the trees are somehow immune to the effects of the fungus.
But pines are just a part of the great tree die-off here. Perhaps you or some other expert can explain why the oaks and sweetgums are also dying? And why lichen is suddenly growing so profusely? Why vegetation in the under-story has very little chance of lasting more than a year?
Statistical based science has a limitation: the assumption that ALL variables NOT modeled will remain linear over the range of the model. In the real world, they never all do. That certainly keeps a scientist’s job interesting: finding that non-linear variable and explaining why it changed.
Witsend seems to be suggesting that ground level ozone is not a linear variable in its effects on plant and tree damage and that length of exposure also plays a role. Each species will have it’s own ozone damage threshold which would also be variable because of factors like temperature, CO2 level, moisture availability and nutrient availability. But we crossed some ozone level threshold just a few years ago.
Five years ago climate change was a hush-hush subject in America. We now know who funded the climate change deniers and why. Those same people are interested in preventing research about damage to plants caused by exposure to ground-level ozone in the real world. It’s in their financial interests.
Sadly, seeing the ‘big picture’ of our natural wold has become ‘thinking outside the box’.
Jim, thank you. A truly great article. When I am in California, I live in Big Bear Lake, which sometimes I think is a Pine Beetle breeding capital.
[Response: Thanks John. I fear for SoCal. For that matter, I fear for NorCal.–Jim]
I thought I’d share this excerpted from an article done in 2006. I biased the excerpts to the material revolving around myself because there is a certain humor factor.
I actually did not realize he was interviewing me. I thought he was only there to take pictures because the view from my place stared directly at a mountain full of dead trees.
By Alex Roth
UNION-TRIBUNE STAFF WRITER
July 15, 2006
BIG BEAR – Maybe the massive Sawtooth fire will overrun this popular resort village three hours north of San Diego, and maybe it won’t.
But this much is indisputable: The forest surrounding Big Bear Lake is choked with so many dead trees that a catastrophic wildfire is a very real possibility. Perhaps not today or this week, but eventually.
“How many times can we dodge the bullet?” said John Reisman, 43, an inventor who has lived in Big Bear for 24 years.
In the past five years, beetles have done enormous damage to the Douglas firs and piñon, Jeffrey and sugar pines that grow in the San Bernardino National Forest, which surrounds the town. Anywhere from 10 percent to 40 percent of the trees are dead, said Bob Sommer, a vegetation specia-list with the U.S. Forest Service.
By late afternoon, a huge brown cloud of smoke had spread over the entire valley. But still, people continued fishing off the docks and launching their sailboats on Big Bear Lake. Fire officials said the wind was blowing in the opposite direction and, for the time being at least, the town was safe.
Reisman, the inventor, was cautiously optimistic that the village would be spared. Every few hours, he’d go on the Internet to check wind conditions.
He was hardly relaxed, however. Standing on the porch of his cabin overlooking the Big Bear ski lodge, he pointed at swaths of dead trees on a mountain ridge in the distance.
“The last four or five years they’ve started dying real fast,” he said.
Making matters more combustible, Reisman lives in a log cabin built by hand. Asked what type of wood his house is made of, he replied, “Flammable.”
Source Article:
http://legacy.signonsandiego.com/news/state/20060715-9999-1n15bear.html
Discussion Balancing Economies (commenting fixed)
October Leading Edge: The Cuccinelli ‘Witch Hunt”
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Fee & Dividend: Our best chance – Learn the Issue – Sign the Petition
A Climate Minute: Natural Cycle – Greenhouse Effect – Climate Science History – Arctic Ice Melt
Gail, of course you know I’m sympathetic and recommend your blog to everybody. RC is a science site, and it’s reasonable for the mods to shepherd us within the fairly narrow valley of reproducible, peer-reviewed, published science. Hopefully, we can keep the discussion collegial.
[Response: It will never be collegial when certain uniformed individuals rant about their favorite topic, hijack threads and accuse scientists of conspiracy and incompetence. Never.–Jim]
That said, I strongly agree that research into the interaction between atmospheric chemistry and vegetation should be accelerated. The rapidly changing composition of the atmosphere could have various deleterious effects on plant life, well beyond ozone pollution.
[Response: There’s a lot of research that should be accelerated. And there is a LOT of research, past and present, on the effects of air pollutants on ecosystems. Ozone effects are well studied and well known, and are but a minor component of change at the global scale compared to land cover changes, climate change and invasive species.–Jim]
O3 is a major threat. Just read the many studies Gail and I have gathered. Ozone is like plant AIDS. Trees may not be directly dying from o3 but the o3 has made them vulnerable to fungus and disease. O3 also reduces the plants sequestering of CO2. If you care about climate change you should care about O3.
[Response: People care about ozone pollution, and know a lot about it I assure you.–Jim]
Jim, my apologies for wandering OT, but as you know I have long believed that RC should spend a lot more time on forests as sinks, and am happy that you have opened this topic. There is much evidence that logging and beetles reinforce each other, however, and I’d like to see this topic explored.
w kensit, #41, I was in Tweedsmuir Park in 2002, and logging was going on then, though maybe they’ve stopped since. Unlike US parks, BC government land has been degraded by either clearcutting or high grading.
Jim Bullis, it matters little where the wood ends up. Studies show that only about 15% of site carbon at a site logged for structural wood ends up in lumber, since most carbon is emitted short term as slash, soil dehydration, mill waste, branches, and nonmerchantable species. Even the 15% begins to decay immediately, and the original Kyoto protocols didn’t even allow that- on the grounds that the lumber was replacing decayed products.
For Leo G — just because you can’t find a ban on transporting wood with beetle larva doesn’t mean it’s a good idea to be hauling it into your area, whether you’re selling it or using it yourself. How did you look for info?
http://www.google.com/search?q=bark+beetle+firewood+transportation
finds for example
http://www.ext.colostate.edu/pubs/insect/05563.html
or
“Some bark beetles in firewood, such as the mountain pine beetle and elm bark beetle, can infest nearby healthy trees.”
” 8. Do not bring into the Cheyenne area any firewood or store firewood from beetle killed forest trees or local trees during the growing season, April – October.”
http://www.cheyennetrees.com/mountainpinebeetle.html
or
Health of the Urban Forest: The best defense to impede the beetle infestation is to disallow the transport of infested firewood into the community. …
http://www.ci.laramie.wy.us/…/BarkBeetleMitigationPlanfinal2-25-10_000.pdf
There are hundreds of pages about handling wood with beetles in it.
Jim Galasyn – thnx for the comment about blogs. Each blog seems to have a singular purpose. RC is hosting a very healthy science debate with two opposing attitudes that need not be polarizing: science with a civil purpose and pure scientific investigation.
And people should know that you have a superb blog that aggregates climate hard news from various sources. http://www.desdemonadespair.net/
Question for the knowledgeable folks here: Is there a type of tree that is naturally resistant to these beetles?
64 Mike Roddy,
Two interesting things there: First, the 15% number does not reckon in the root structure, which was said to be 80% of the stored carbon. I am looking for verification of that 80%, but I know it is a substantial number. I am looking to the biochar folks to help out with some of the scrap that you mention. Even so, the use of wood at harvest time is not the main objective of the standing forest. That is just one part of the whole picture.
Second, I suggest that the Kyoto folks are wrong when they don’t count the lumber. Yes, of course it replaces decaying wood or burned down houses or whatever. But this misses the point about the net standing wood mass. Of course that net standing wood mass has to continually expand to match coal usage. But this does not prohibit a cycling action, where mature forests are maintained as a stable and balanced system. Think of it as a large, full water tank, with a leak at the bottom, but with a fill pipe dumping water in at the top at a rate equal to the leak rate. The full tank is continuously maintained this way. Thus, the mature forest is maintained. If the maintenance process can include lumber harvesting, analogous to the water coming out of the leak in the tank, that represents expansion of carbon storage. And remember, the storage in the root structure goes on in spite of the leak. That is like another tank buried under the first, so that the leak does not affect the contents of this buried tank.
The same story of the tank applies to a village made of lumber. Sure, some rots and is replaced. But a village still stands. And that functions like another storage tank, again with a leak and a fill pipe. If the village expands, that is not bad either.
The Kyoto folks would be right if they were talking about crops that are harvested on a yearly basis, where the whole agricultural system is emptied each year of its stored carbon content.
But while we are at it, let’s also note that permanent standing orchards are also beneficial as standing wood mass. These are not like the giant redwoods as to magnitude of wood mass, but there is still might be potential in this system. Yes, the orchards are cycled on varying bases, but as long as there is a collective net wood mass in existence, that represents a carbon storage mass of importance.
(David B. Benson) Please hang in here as I momentarily stray into a socio-economic arena, but this suggests an organization of an agricultural system, where orchard operators would be allowed cheap leased land, which they would keep as long as they met the standing wood requirement, for their entire holding.
Now, back to beetles: The same goal with beetle ridden forests should be kept in site. As long as there is a cycling of wood, in and out, we could be ok. And of course, this would entail maximizing forest health as experts in that subject would tell us to do.
How hard is it to train someone to put up pheronome traps in a forest? I get it that there are a lot of trees. But notice, there are a lot of people doing nothing.
> naturally resistant
It’s a pattern involving many species, not an individual defense trait
E.g.
Ecological Consequences of Alternative Fuel Reduction Treatments in
Seasonally Dry Forests: The National Fire and Fire Surrogate Study
http://ddr.nal.usda.gov/dspace/bitstream/10113/40378/1/IND44340794.pdf
“… The effects of these treatments were measured on a wide variety of response variables, including the structure and composition of trees and understory vegetation, fuel beds and coarse woody debris, soils, bark beetle activity, and small mammal and avian species abundance. For a complete description of the FFS study, we refer the reader to our website (NBII 2009). The 11 contributions in this special issue include a lead-off article that describes the history, development, and organization of the FFS study; three articles that document treatment responses on stand structure, fuels, or fire behavior; two articles on the abundance and impacts of bark beetles; and five articles on vertebrate and invertebrate responses to the FFS treatments.
The FFS is one of the largest and most comprehensive forestry research projects ever undertaken ….”
71 Hank Roberts,
Thanks for the reference.
However, I don’t find anything about different tree types. Generalization to coniferous forests seems to the assumption in the reference. But what I was looking for is whether redwoods, cedar or such that are resistant to decay might also be unfriendly to beetles. But then, how about deciduous forests and beetles? What are eucalyptus trees in this respect? (Not that I am campaigning for eucalyptus – – but I am searching for hardy tree options) Or maybe we have to go back to trapping beetles etc.