Cherry Blossom Festival and Baby's Chocolate Diet

It's Cherry Blossom Festival time in Washington, DC.  Here's a photo of this year's display.  Notice the appalling condition of the trees - the amputated limbs to force new growth, the paltry crowns, and sparse blossoms, and the many tumors protruding on the twisted, corroded trunks.  Given the deterioration of trees in general, I would not expect anything else.  There's something really pathetic about all the people eagerly photographing the annual display, totally unaware of the decline that surrounds them.  The ground has prominent bare patches, which is true here around Wit's End - and not in places with foot traffic, either.

Yesterday morning these trucks arrived to take down the maples in front of the Peapack Gladstone Bank, in neighboring Pottersville.  The village center will look bare without them, but that is true everywhere, as the dying of the trees escalates almost exponentially.  I was told the battered companion below was next in line for the axe chain saw and chipper.  How neatly these machines eradicate the evidence that glorious, full, verdant trees once sheltered our homes with sturdy limbs.

I was googling "Waldsterben," the German term for forest death, and came across  an article in the Seattle Times from back in 1996, with the headline:  "Fears of Black Forest's Death Apparently Were Exaggerated"....following dire predictions in the '80's, when "A lethal assault by pollutants and climatic changes were said to be creating an 'evergreen cemetery,' in the arresting phrase of one popular book published in 1984." (For convenience all quoted passages will be so designated in lavender.)

The Black Forest's startling growth - tree stands show 20 to 30 percent more wood volume than similar plots a few decades ago - probably reflects nitrogen increases in tree diets, foresters say. But whether that is good, bad or indifferent for ecosystem balance in the long run remains uncertain.

"My colleagues say that a baby who stuffs himself with chocolate may look healthy, but that doesn't necessarily mean the baby is healthy," said Werner Schumacher, director of the Forest Experiment and Research Institute for the state of Baden-Wuerttemberg. "It's been suggested that the forest could grow itself to death."

Then again, this photo taken in May 2010, is titled "Waldsterben 2010?  It would appear trees are still, in fact, dying off.

How I love that quote about the chocolate-consuming baby!  I have been asking scientists why increasing levels of CO2, which make plants grow faster, should be any better for their ultimate health than would increasing levels of calories for people, causing them to get fatter.  This is the only instance when I have seen a scientist pose the same concern.

As it happens, over the weekend I had to take youngest daughter's cocker spaniel, Tasha, to the emergency clinic because she had lost all ability to navigate.  I thought maybe she had a brain tumor, or else maybe those HAARP conspiracists were on to something after all - but it turns out, she has a deep inner ear infection, making her vertiginous.

Anyway, I don't have teevee anymore but there was one in the exam room, silently tuned to a cooking show on the food channel - so I watched it through an interminable wait for the vet.  It was astonishingly surreal.  The "chef" was cooking  (boiling frozen corn!) in a kitchen and presenting it to a row of eaters.  I don't want to be mean but the truth is, they were all enormously fat.  I'm not kidding!  I had to wonder who on earth the audience for such a farcical show could be, but the ads told me all I needed to know about who is tuning in - garbage candy like Almond Joy...oh, and "Starkist Seasations" which are frozen entrees made of..."Atlantic white fish fillets in restaurant-inspired sauses."  Okay...unspecified "white fish" that are rectangular blocks of pulverized, regurgitated, and then solidified glop.  Stay tuned for an ad for Soylent Green...

Further googling Waldsterben resulted in a link to a more recent 2010 report, from the Institute for World Forestry, "Forest Condition in Europe."  Their mission has been to monitor the effects of pollution on the health of European forests since 1986, when the big scare began, and as far as I can tell the authors are engaged in the same frantic denial that American foresters have been ever since it became apparent decades ago that we are killing our forests with pollution, when they invented the euphemism "decline."

Regarding ground vegetation, the summary states:  "...in contrast to earlier evaluations based on less comprehensive data sets, there were in addition clearly significant effects of nitrogen deposition on present vegetation species composition. Based on Ellenberg indicator values, a significant change over time towards nitrophytic species could be shown as well and could be linked to nitrogen deposition."


This tendency to focus on a change in species composition due to pollution, which is common, seems to me to be merely a way to avoid saying the inconvenient but inescapable fact that "some species are disappearing due to pollution" by emphasizing their replacement by some other, more pollution resistant plant - by definition an invasive, and eventually, doomed anyway.

In determining defoliation trends, there was an effort made to exclude countries that had only recently begun to participate, or were missing data, and so forth, which seems reasonable, but this...

Studies of previous years show that the fluctuation of trees in this sample due to the exclusion of dead and felled trees as well as due to inclusion of replacement trees does not cause distortions of the results over the years.

Say what?  This seems ridiculous of the face of it.

It reminds me of the report from the Smithsonian Institute, which stated that trees are growing faster, and the researcher wrote me:  I'm afraid I don't quite understand this 'dieoff' you're talking about. I see no evidence of massive die-offs in eastern forests...and then I went to their forest to see for myself and guess what?  There was PLENTY of evidence of widespread decline, dead and dying trees in every direction!  You can see the pictures here.

Its ironic that although this extensive monitoring program was initially designed to track the effects of air pollution, meanwhile, the analysis avoids the topic as much as possible.

Natural factors strongly influence crown condition. As also stated by many participating countries, air pollution is thought to interact with natural stressors as a predisposing or accompanying factor, particularly in areas where deposition may exceed critical loads for acidification (CHAPPELKA and FREER-SMITH, 1995, CRONAN and GRIGAL, 1995, FREER-SMITH, 1998). p. 19
It's dense with data and graphs and charts, and that's where the unfiltered information is to be found.  At least from what I can tell, these particular pie charts are indicating that at best only slightly better than 50% of tree crowns aren't compromised (the dark green slice) - and that ought to be regarded as a very bad thing indeed, in my estimation.

These graphs are downright scary - far fewer than half of all trees are in the 0 - 10% defoliated class.

Poland is abysmal!

The variation of crown condition is mainly the result of intrinsic factors, age and site conditions. Moreover, defoliation may be caused by a number of biotic and abiotic stressors. Defoliation assessment attempts to quantify foliage missing as an effect of stressors including air pollutants and not as an effect of long lasting site conditions. In order to compensate for site conditions, local reference trees are used, defined as the best tree with full foliage that could grow at the particular site. p. 16

In 2009 crown condition was assessed on 7 193 plots (Table 2.1.3.1-2) comprising 136 778 (Table 2.2.1-1) sample trees with defoliation scores. Of the assessed trees a share of 20.2% was scored as damaged, i.e. had a defoliation of more than 25% (Table 2.2.1-1). The share of damaged broadleaves exceeded with 22.4% the share of damaged conifers with 18.3%. p. 21

Maybe I don't know how to read graphs but the impression I get from the data is far worse than as presented in the text.

Here are some more graphs, these taken from "Tropospheric Ozone:  A Growing Threat," published by the Acid Deposition and Oxident Research Center in Japan back in 2006 - before they had more immediate disasters to contend with.

Back then they obviously thought air pollution is killing trees, because the picture on the cover of the report depicts just that.  It's a really excellent assessment of impacts on trees and agriculture that is certainly a worth-while read - but I will confine this post to just some fun graphs, because...why not?

Yesterday there was a horrible story of a series of violent storms that blasted through the South, knocking down trees, which felled power lines.  But what was unusual was the number of injuries and deaths of people from falling trees and branches:

An enormous tree limb that crashed through a Georgia family's bedroom killed a father and the young son he was holding in his arms Tuesday as a fast-moving storm system pounded the South with tornadoes, hail and spectacular lightning. At least nine people were killed around the region, including several who died on roads made treacherous by downed trees and power lines.

 One of the victims was killed by a tree that fell after the storm, while he was cleaning up the debris.  This all seems very bizarre.  Trees didn't used to be lethal weapons that I recall, and I don't think it's only because winds are stronger.

What follows are pictures I took last Saturday.  The first set are from a home in Bernardsville that maintains a dog kennel in the back of the property, which used to be invisible from the road behind a dense screen of evergreens.  Most of them have died off and been removed - the few remaining are on their way out.

This giant is standing dead.  The kennels are to the right.  It's very expensive to remove large trees!

There is another article about trees dying off in England, blaming it on the sudden oak fungus - even though it skipped oaks and is attacking other trees...and then there are various other pathogens blamed for what is actually a general trend, not a set of unrelated, isolated incidents.

Sudden oak death arrived in Britain from America, where it decimated the oak population, just under a decade ago via imported plants.

This is what is left of the treeline that screened the yard.  The pine in the center is thinning - on either side of it are pines with no needles left at all.

In Britain the disease, officially known as phytophthora ramorum, spared oaks and jumped to rhododendrons and Japanese larch trees. In the last year it has taken hold along the west of the country in larch plantations, including more than 120 Forestry Commission sites, 20 National Trust properties and two Woodland Trust reserves.

Already 4 million trees have been felled or marked for destruction.

More are expected to be chopped down in the coming years because the warmer, wetter conditions expected with climate change encourage the spread of the disease.

More bare pines along the fence.

In the latest cull, a landowner in the Quantock Hills in Somerset was forced to cut down 50,000 trees, while the National Trust chopped down 10,000 larch trees in the area. Landowners face crippling costs for felling sick trees, while walkers are urged to disinfect boots to stop P. ramorum, which is a fungal disease, spreading on their feet.

Experts from the Forestry Commission are carrying out inspections across Britain and will order a cull wherever the disease is found.

It takes hold quickly, causing bleeding lesions, blackened or wilted leaves and, ultimately, death. It can also affect garden shrubs, such as rhododendron and camellia.

Charlton Clark, of the commission, said landowners could be offered a small grant to pay for the culls. "The equivalent of 4,400 football pitches of Japanese larch have so far been confirmed as infected with ramorum disease in the UK, and either have been or will be felled to prevent the disease from spreading," he said.

There is no known cure for the disease and Mr Clark warned that Japanese larch could be wiped out in the South West.

The outbreak is one of a number of threats to Britain's ancient trees.

A separate disease, acute oak decline, is killing oaks, while chestnut trees have been felled across the country because of infections spread by moths.

These large old trees are shedding bark - click to enlarge.

In Ireland it's the same trend - Already, two government forests and a private woodland have been confirmed as having the disease and more than 100,000 Japanese larch trees are in the process of being felled.

The scale of dying trees is unimaginably huge.

In this idiotic report, it's claimed trees aren't actually dying, they're just losing their leaves temporarily! Read more drivel from the Ohio Division of Forestry.

COLUMBUS, OH - A cool, moist spring has led to an increase in sycamore anthracnose and oak anthracnose, diseases affecting the foliage of sycamore and white oak trees, according to the Ohio Department of Natural Resources (ODNR).

“The diseases appear to some extent each spring, but symptoms are unusually severe this year,” said Dan Balser, forest health administrator of the ODNR Division of Forestry. “Diseased trees will be stressed, but should survive with little permanent damage.”

These leaf and twig diseases are caused by a family of closely related fungi and are responsible for the widespread defoliation observed on sycamore and white oak trees in recent weeks. These diseases prevail as the leaves begin to emerge from the bud and expand. By early summer, re-growth will be underway. New shoots will arise from buds that would have remained dormant. Summer heat and dryness will prevent the new shoots from being attacked by the fungi and the trees will once again leaf out.

However, property owners should be aware that weakened trees may be subject to branch dieback and insect attack. Disease resistant varieties of sycamores and white oaks may be obtained from local nurseries for home and landscape plantings.

Other hardwood trees such as ash and maple are also subject to anthracnose diseases. However, sycamore and white oak appear those most affected this spring.

Meanwhile the city manager of Jacksonville, NC wonders if a waste water plant is responsible for dying trees and bemoans the loss of timber sales in this video.  He really should go check other areas not in the watershed of the plant and compare.  I'd wager anything they will look just as bad.

Morroco Bama posted a link to this article, from Steamboat Today, from August 2008, Titled "How the West was Lost," naturally blaming the spread of the bark beetle on warming temperatures.

This reminded me that Wall Street Journal ran a story in 2009 about Sudden Aspen Decline, which interests me because unlike the bark beetle, there is no convenient insect to blame and researchers aren't sure what is killing the aspen.  So I decided to see if they have since made any progress in figuring it out.  Following are excerpts from that 2009 article, and pictures I took Saturday of a mixed forest, where nobody has bothered to clear up the fallen trees and so it's pretty obvious that a preponderance of both conifers and hard wood trees, of all ages, are dying or already dead.  All the photos were taken from an area of less than two of acres in size.

What is killing the aspen is unclear.

The western aspen forest depicted in the report.

In 2002, the U.S. Forest Service began investigating reports that entire stands of aspen were dying in the San Juan Mountains in southwest Colorado, and in an odd way. Usually when mature aspen fail, they send out hundreds of new shoots, called suckers, through their root systems. Those shoots sprout quickly, and the grove regenerates.

But in the San Juans, the shoots were dying, too, or were failing to sprout. That phenomenon was named Sudden Aspen Decline, or SAD, but scientists say they don't fully understand it.

These are mostly pines, with no needles.  There should be almost no sky visible.

The U.S. Forest Service conducted an aerial survey in Colorado in 2005 and spotted about 30,000 acres of dying aspen. Last year, that figure climbed to 540,000 acres, or about 15% of the state's aspen forest, according to the Forest Service's Rocky Mountain Research Station.

"We're still trying to figure out this puzzle," said Paul Rogers, an ecologist at Utah State University who runs the Western Aspen Alliance, a coalition of forest scientists studying the problem.

It could get worse. "SAD is progressing at an exponential rate," said Wayne Shepperd, who led research into aspen decline at the U.S. Forest Service before retiring to teach at Colorado State University.

And it has left many locals reeling. "My God, it was a sad year," said landscape photographer Richard Voninski.

Some of his colleagues photograph the stark skeletons of dying trees, but Mr. Voninski said he could not bring himself to do that.

"I know what it's supposed to look like," he said.

I noticed that one of the foresters interviewed in that article, Wayne Shepperd of Colorado State, just gave a talk last February about aspen decline - am I ever sorry I missed that, since the series of public lectures is for the following purpose:
The theme of the 2011 Lyceum Series is "Trying To See The Forest For The Trees: Forest Health In The Rocky Mountains." The forests in and around Rocky Mountain National Park provide wonderful benefits such as water, recreation, wildlife habitat, timber, and other forest products. They are, however, vulnerable to a wide variety of stressors. RMNP will invite regional experts to answer visitor questions on insects, diseases, exotics, invasives, wildfire, prescribed burns, ozone/pollutants, wildlife/biodiversity, watersheds, soils, and forests as indicators of climate change.
Yes they did!  They actually included "ozone/pollutants!"
I couldn't reach Wayne Shepperd, so I called Paul Rogers, who had also been quoted in that article.  He implied that the problem had initially been overblown, and there is some question as to whether SAD even exists, or is just part of a spotty problem from drought exacerbated by grazing from elk and other animals which prevent the aspen from regenerating.  He said some of the proponents of SAD have since realized it's "not as bad as they thought" because it's "...not widespread...not consistent.  Not really a big die-off" and then he mentioned "natural cycles."
Does that mean scientists are backpedaling Sudden Aspen Decline, too, just like the Europeans with Waldsterben?  And if so, why?  Has the overall health of the forest really improved?

Maybe this quote attributed to him on his Utah State University webpage is revealing:

"Discussion of the problem, he says, quickly leads to economic, political and social issues beyond traditional natural resource sciences."
Parse that sentence carefully!  He sums up in a nutshell exactly why scientists are reticent.  They are reluctant to delve into a public discussion of "the problem" because then they inevitably risk becoming embroiled in "economic, political and social issues" which are "beyond traditional natural resource sciences."  And who can blame them?  They don't want to be attacked for making policy.
I asked if he could send me papers indicative of a reconsideration of the severity and extent of SAD, and he obligingly forwarded two links.   The first titled "Effects and etiology of sudden aspen decline in Southwestern Colorado, USA," was published in January 2010.

The abstract:  Sudden aspen decline (SAD), affecting Populus tremuloides, was first observed in Colorado in 2004. By 2008 it affected at least 220,000 ha, an estimated 17% of the aspen cover type in the state. In southwestern Colorado, we examined site and stand features in paired healthy and damaged plots to assess the effects of SAD on aspen and to identify factors associated with decline. Root mortality increased significantly with recent crown loss.

Consequently, density of regeneration did not increase as the overstory deteriorated, and regeneration that originated since 2002 decreased significantly in stands with moderate to severe SAD. However, mortality of regeneration did not increase with that of the overstory. Remeasurement of a subset of plots after 1–2 yrs showed significant increases in severity. Contrary to expectations, overstory age and diameter were not related to SAD severity as measured by recent crown loss or mortality. Severity of SAD was inversely, but weakly, related to basal area, stem slenderness, and site index, and positively related to upper slope positions. This is consistent with moisture stress as an underlying factor. To test the role of climate as an inciting factor for SAD, a landscape-scale climate model was used to compare moisture status of declining and healthy aspen at the height of the warm drought in water year 2002. Polygons identified as damaged aspen in the 2008 aerial survey had greater moisture deficits than healthy aspen in the 2002 water year. SAD has led to loss of aspen cover in some stands, and is occurring in areas where early loss of aspen due to climate change has been predicted. Further warm, dry growing seasons will likely lead to recurrence of SAD.

Before the needles fall off they turn yellow.

The pines along New Hampshire roads have the same yellowing, as depicted in this photo sent by Susan Shamel from  the Global Warming Education Network.

Rapidly increasing branch dieback and mortality of trembling aspen (Populus tremuloides) was first noted in southwestern Col- orado in 2004 (Worrall et al., 2008). By 2006 it was observed by aerial survey on 56,091 ha of Colorado. Because the disease appears to be a decline in the strict sense, has appeared suddenly and progressed rapidly, and to distinguish it from what has been widely termed “aspen decline,” we named it “sudden aspen decline” (SAD).

SAD is characterized by rapid, synchronous branch dieback, crown thinning and mortality of aspen stems on a landscape scale, without the involvement of aggressive, primary pathogens and insects. Preliminary evidence suggested that affected stands may fail to produce suckers in response to the crown loss and mortality (Worrall et al., 2008). Similar damage to aspen apparently began several years earlier in Arizona (Fairweather et al., 2008) and southern Utah (Ohms, 2003; Bartos, 2008). Branch dieback, growth loss and mortality of aspen in the aspen parkland and southern boreal forest of Alberta and Saskatchewan increased following a severe drought in 2001–2002 (Hogg et al., 2008).

Etiology of decline diseases is often complex and can be considered in three categories (Manion, 1991; Manion and LaChance, 1992). Predisposing factors are long-term, static or slowly changing factors such as site or stand conditions. Inciting factors are short- term physiological or biological factors that cause acute stress. Trees affected by inciting factors alone may recover quickly, but recovery is much slower if the damage is exacerbated by predisposing factors. Finally, contributing factors, or proximate causes, kill trees that have been debilitated by predisposing and inciting factors. We proposed a decline disease model for SAD as follows (Worrall et al., 2008). Predisposing factors included low elevations, south/southwestern aspects, physiological maturity, and low stand density. 

Inciting factors were acute drought with high temperatures during the growing season. Contributing factors were insects and pathogens that tend to invade and kill stressed trees, as opposed to those capable of attacking otherwise healthy, vigorous stems. 

In previous work, we provided direct evidence for several predisposing factors and reported putative contributing agents commonly found in affected stands, including Cytospora canker (usually caused by Valsa sordida), aspen bark beetles (espe-cially Trypophloeus populi), poplar borer (Saperda calcarata), and bronze poplar borer (Agrilus liragus). Here, we provide additional evidence for predisposing and inciting factors and better characterize the impacts on aspen stands.

Our objectives were to: (a) determine the effects of SAD on aspen stands, their regeneration, and their roots; (b) better characterize the etiology of SAD by identifying associated fine-scale site and stand factors; and (c) test the hypothesis that SAD was incited by a severe, hot drought.

The BALDing syndrom is ubiquitous.  Bark Atrophy Lichen Decline, often accompanied by bleeding.

It boggles the mind that they don't even mention ozone, let alone the fact that exposure to ozone predisposes trees to suffer more from drought, as they allocate more energy to shoot and leaf production, and less to roots.

Holes at the base of trunks indicating interior rot are commonplace.

The other link is to a paper of which he is the lead author, published in 2009, titled "Landscape assessment of a stable aspen community in southern Utah, USA."

I'm not sure what produced this curious growth.

The abstract:  Recent reports of rapid die-off of aspen (Populus tremuloides), coupled with vigorous debate over long- term reduction of aspen cover in western North America, has prompted considerable research given the importance of this forest type for economic and non-economic interests. Despite this interest, indicators of aspen conditions are poorly understood, and there is a lack of systematic monitoring of stable aspen landscapes. Principal findings include: (1) a relatively uniform age of adults within the study area; (2) approximately 10% crown dieback on half of the plots sampled; (3) roughly 50% of the study plots had greater than 50% of the trees with damage to the bole; (4) about 25% of the adult basal area was dead; and (5) over half the plots had few sub-canopy individuals and/or limited regeneration. Physiographic variables including elevation, slope, and aspect were generally not strong indicators of aspen condition, typically explaining less than 15% of the variation in basal area, mortality, dieback, or damage.  Healthy stands were rarely observed in the most drought prone locations, though the inverse was not necessarily true; healthy and unhealthy stands were found in more mesic settings. Principal components analysis identified two clusters of plots that differed considerably in regeneration; however, no other variables differed between these groupings. We suggest exogenous factors such as land-use history or altered disturbance regimes and endogenous factors such as soils and geology influence aspen condition on this landscape. Further research is necessary to test these hypotheses.

Conclusions and implications:  We examined a large aspen-dominated landscape using the general metric of ‘sudden aspen decline’ (Worrall et al., 2008). This phenomenon is characterized by rapid die-off of mature overstorey in aspen coupled with an absence, or unsustainable level, of regeneration. While few stands measured here on the Colorado Plateau in Utah have experienced stand-wide mortality, a majority of these stable aspen forests appear to have limited regeneration. Thus, while not meeting the criteria of a ‘sudden aspen decline’ on the landscape, there is cause for concern where much of an aging cohort does not appear to possess enough recruits to regenerate the stand. Further, our initial assessment of stand structure and aspen health indicates generally good conditions, with the exception of an apparent lack of the vertical diversity expected in stable aspen stands (Mueggler, 1985; Kashian et al., 2007; Kurzel et al., 2007). Though long-term wild and domestic ungulate grazing is anecdotally implicated in this lack of regeneration, we were unable to present conclusive evidence to support that hypothesis with the current dataset.

Since I didn't detect much to give me confidence that SAD is history - or conclusively explained - in either of those two papers, I pestered him again, this time specifically asking about the possible influence of ozone - and was amazed when he sent me this as-yet unpublished paper, which he had written himself in 2005...The title of which is "Effects of Tropospheric Ozone on Aspen!"  So, with Dr. Roger's kind permission, readers at Wit's End have the opportunity to examine the world debut of just about the best summation I have seen to date of what ozone does to trees.  Thank you Dr. Rogers and I hope you publish this excellent review.

While many disturbances have evolved with aspen forests for millennia, others such as the accumulation of tropospheric ozone and increased greenhouse gasses, present unprecedented challenges for maintaining healthy aspen trees and forests (Karnosky et al. 1999; Logan et al. 2006).

Ozone is the most widespread air pollutant in North America at concentrations known to be phytotoxic (Berrang et al. 1989). This review focuses on the effects of tropospheric ozone on aspen ecophysiology. Ozone in the troposphere is caused by a photochemical reaction of sunlight with nitrogen oxides and organic compounds from anthropogenic sources such as auto emissions and industrial pollution (Matyssek and Sandermann 2003).

Interestingly, in some areas of the country such as the Northeast, ozone appears to be having equal or greater effect on tree health in rural areas as in urban corridors (Gregg et al. 2003). On a global scale, tropospheric ozone concentrations have increased by 2-5 times in the northern hemisphere since industrialization began (Matyssek and Sandermann 2003). How have these increases in phytotoxic ozone concentrations impacted vegetation generally, and aspen specifically?

Before looking at aspen it will be instructional to review physiological mechanisms and symptoms of ozone damage to plants more generally. Ozone concentrations are typically most damaging in northern temperate zones during summer’s warm dry weather. This period coincides with the highest levels of plant photosynthesis. Ozone enters a plant through the stomates, so those factors regulating stomatal opening play an important role in the amount of damage done to plants. The high light environment of mid-summer, therefore, provides the prime mechanism not only for ozone formation in the troposphere, but for ozone entry into frequently open stomates (Treshow 1970).

Influx of ozone via plant stomates touches off a series of reactions leading to widespread tissue damage, reduction in photosynthetic capacity, and potential die-off of limbs or entire trees over a period of multiple growing seasons.

After ozone passes through the stomata it enters mesophyll cells, specifically in the appoplasts and plamalemma. The plant may attempt to repel this invasion by detoxifying the ozone with increased apoplastic ascorbate in the cytoplasm (Matyssek and Sandermann 2003). With continued exposure, however, the plant cell growth may cease as ozone damage spreads from the site of influx (substomatal cavities) through the apoplast of the entire leaf. It is thought that ozone will eventually compromise cell membrane integrity leading to loss of fluid (decreased turgidity) and collapse of mesophyll cells as visible damage begins to advance across the leaf surface (Treshow 1970; Matyssek and Sandermann 2003). These structural changes will also cause a decrease in gas exchange reducing Rubisco activity, carboxylation efficiency, and photosynthetic production (Clark et al. 1996; Matyssek and Sandermann 2003; Karnosky et al. 2005). With reduction in photosynthesis CO2 fixation is limited which negatively affects chlorophyll fluorescence, leading to visible chlorotic (yellowing) spotting of leaves (Matyssek and Sandermann 2003).

It is important to note that although discrete plant reactions occur with short-term incidence, chronic long-term exposure to phytotoxic ozone levels are more significant ecologically (Matyssek and Sandermann 2003). Plants may repair themselves only if exposed to limited dosages. Ozone damage appears to mimic other pathogens setting off both chemical and physical responses in the plant. Early research focused on acute chemical reactions to high ozone doses (Miller et al. 1963; Treshow 1970), while more recent work has been directed toward physiologic changes within plants, such as gene transcription, plant defense systems, and systematic acquired resistance (Matyssek and Sandermann 2003). Matyssek and Sandermann (2003) believe strongly that enzymatic “signals” controlling plant growth, photosynthates, susceptibility to pathogens, and reaction to herbivores drive long-term reactions to ozone exposure, although they have yet to prove these assertions.

Several researchers have noted that older leaves, presumably exposed to longer/larger doses of ozone, show the most prominent signs of injury (Treshow 1970; Harward and Treshow 1975; Clark et al. 1996; Matyssek and Sandermann 2003; Karnosky et al. 2005). More precisely, Clark et al. (1996) found that in aspen maximum ozone sensitivity takes place just after leaf maturation, as the leaves transition from sinks to sources of plant energy. The most widely reported symptom of ozone damage, in addition to chlorosis mentioned above, is leaf “stipple” or “flecking.” Necrotic flecks are the culmination of cellular breakdown in the mesophyll palisade cells (Treshow 1970). Apparently these cells are the most sensitive to ozone damage. On the leaf, flecking is apparent first on the upper side of the leaf between the smallest veins.

Continued ozone damage may lead to visible necrosis on the leaf’s underside and, in combination with advancing chlorosis, early leaf abscission (Treshow 1970; Clark et al. 1996). These outward signs and symptoms on ozone-affected leaves are the basis for damage detection work in the United States (1998). Other common symptoms reported beyond the leaf- level include leaf die-off and crown thinning, reduced top and root growth, reduce number of blossoms, reduced number and weight of seeds, loss in total leaf area and biomass (Harward and Treshow 1975; Coleman et al. 1995).

Previous researchers have discussed the interactive affects of disturbance agents on trees in general and aspen in particular (Hinds 1976; Hinds 1985; Rogers 1996; Rogers 2002). It appears that ozone similarly effects a predisposition to pathogens such as aspen leaf rust (Melampsora medusae f.sp. tremuloidae) (Karnosky et al. 2002; Percy et al. 2002). These authors showed that aspen leaf rust was attracted to the roughened leaf surface and weakened defense mechanisms wrought by ozone. Their results show a 3-5 times increase in rust infection to sites exposed to either ozone or combined O3 and CO2 (Karnosky et al. 2002). Similarly, aspen herbivores, such as tent caterpillar (Malacosoma disstria) and leaf aphids (Chaitophorus spp.) appear to be attracted to leaf surfaces with increased epicuticular wax buildup (Percy et al. 2002; Kopper and Lindroth 2003).

This tree trunk is a typical example of maples turning black.  It's perfectly hideous.

Just as I was about to wrap this up Wayne Shepperd returned my call and was nice enough to take quite a bit of time to answer my questions on a range of topics relating to various threats to ecosystems, from invasives to climate change.  I asked him if there had been progress in determining the cause of SAD and this (more or less verbatim, as best I could transcribe) is part of his response:

"We have a better understanding," he told me, and said it was associated with the severe drought in 2002.  "There is a pattern on south-facing slopes, where the root system dies as well as the overstory."  He said in comparisons of aerial survey data with results from a climate change model a remarkably strong correlation was detected, but that there had been recovery in recent years with closer to normal precipitation.  "Since 2009, 2010, aerial surveys show a striking drop off in the number of acres affected.  In some cases mortality has stopped...harvesting has led to regeneration...it appears SAD has run it's course.  That's the good news.  The bad news is we will see more of it in the future with warming temperatures."

Then I specifically asked him if impacts of ozone are factored into determining the cause of SAD (keep in mind that exposure to ozone increases the effects of drought!)

"The short answer is No," he replied.  "Ozone concentrations have not been factored in because there is no monitoring of ozone nearby any of these locations.  It's the same as with climate data - so you have to extrapolate.  To have data you would require a network of weather stations on a scale that would be extremely expensive.  Aspen is sensitive to ozone.  I think what we've learrned is that mortality seems to be related to stress, such as insects attacking dying aspen.  Insects are all associated with stressed trees - they don't attack healthy trees.  Those are the pile-on factors."

He concluded that there has been a 20% depletion in the aspen population, which is quite similar to many species shown in the graphs of the European report above.

So I guess, we're never going to find out if ozone is the primary underlying factor in the drought sensitivity and insect and disease attacks, because nobody is going to fund a study to determine what the levels of ozone are and what those levels do to trees.  Because who wants to know?

It's fascinating that he recounted as an example of unintended consequences from ecosystem disturbance the history of an invasive saltcedar originally imported as an ornamental, a plant which gobbles up water and creates salt deposits.  At last an insect was imported to attack and destroy it, but unfortunately there is nothing replacing it...so the birds have nowhere to nest.  The fact that nothing is replacing it is exactly what I would predict, however - since any kind of vegetation has to photosynthesize, and that is exactly what ozone interferes with.  I don't worry about invasives around Wit's End any more.  They're all going to die along with the desirable imports, and the natives.

Oh well.

I had planned to finish up with comments on a Climate Progress post from last week, which referred to the "hide the decline" controversy of "Climategate", where Joy asked:  "Why do the tree rings diverge after 1960? Does that have something to do with CO2?"

I posted my usual answer, and that led to an exchange mostly with someone named Frank, who sounds like a parrot of a certain person at Real Climate, and Tamino.  It's reproduced below, for my amusement:

It appears that the bark is seeping fluid and staining the surface, perhaps from a fungus growing in the wetness.

Wit's End says:


Joy #29: excerpt from this post:http://witsendnj.blogspot.com/2011_03_01_archive.html
Imagine, not one scientist has ever replied to my many letters and comments about the “hide the decline” scandal. The reason researchers had to discard the anomalous data in tree rings of the last few decades when constructing temperature records, is because the accelerated growth from warming was diminished from rising levels of background tropospheric ozone, even in remote areas. Briffa himself conjectured in one of his early publications that “anthropogenic” causes could explain the decline, without specifying what those causes might be. Considering how damaging that episode was to efforts to cap carbon emissions – and still is, the deniers continue to repeat it – it’s amazing that neither Briffa nor Mann is willing to consider the evidence that ozone is the cause of the decline they had to “hide.”
…maybe, scientists frightened by positive amplifying feedbacks leading to a runaway Venus syndrome prefer to be oblivious to ozone, because the last-ditch hope they secretly cling to is that catastrophic warming might be slowed with geo-engineering technology…and geo-egineering won’t do a d*** thing to stop trees from going extinct, taking most other life-forms with them. Now, that’s a seriously disheartening notion.

Interestingly, it is blacker on the side facing south, with a clear divide to a mossy green growth on the northern side.

Frank says:

Joy, Wit’s End:
With all due respect, Wit’s End, you’re getting the totally wrong idea.
To begin: we call a physical measurement a ‘proxy’ for temperature if it is known to agree (closely enough) with temperature. Let’s say the measurement increases with temperature: then if the temperature rises, then the physical measurement should rise; if the temperature drops, then the physical measurement should drop. (If, however, the measurement decreases with temperature, then a rise in temperature should result in a drop in the measurement.)
By saying “tree-ring densities are a good proxy for temperature”, we’re saying that increases and decreases tree-ring densities correlate with increases and decreases in temperature in some way, and we can thus infer changes in climate stretching back hundreds or even thousands of years by studying spaces between tree rings.
So we’re talking about two totally separate questions:
(1) whether temperatures have warmed or cooled, and
(2) why tree-ring measurements no longer correspond with temperature.
Repeat, these are two totally separate questions. Your ‘reasoning’ is that

Tree-ring measurements are diverging from actual temperature because actual temperatures have fallen.

which is illogical and not even an explanation in the first place! You’re trying to answer a question about (2) by referring to (1).
It’s like saying

My watch is becoming less and less accurate. I think it’s because I’m taking less time to prepare breakfast.

when what you should be looking for is an explanation like

My watch is becoming less and less accurate. I think it’s because its battery is running out.

(I see Sime’s Skeptical Science link does point to some proposed explanations for the tree-ring divergence phenomenon.)

The center tree with the dark trunk is a needle-less conifer with bark peeling off the high branches.

Wit's End says:


Frank, you interpreted my comment as:
“Tree-ring measurements are diverging from actual temperature because actual temperatures have fallen.”
What?
I think exactly this:
Tree-ring measurements are diverging from actual temperature BECAUSE OZONE IS STUNTING GROWTH AND INCREMENTALLY KILLING TREES.
Hope that clears things up for you.

Frank says:

Wit’s End:
My bad… I stand corrected.
Nevertheless, what you should be looking for is not only a possible explanation of the reason behind the divergence phenomenon, but — as far as possible — the correct explanation that agrees with all the known existing clues, and agrees better than competing explanations.
As Joe points out, the divergence problem crops up mainly in trees in the high latitudes. Does your proposed mechanism (ozone pollution) operate more strongly in the high latitudes?
Furthermore, Does it operate more strongly than other proposed mechanisms, such as sulphur dioxide pollution, or the drop in stratospheric ozone, and so on?
That’s an awful lot of analysis that needs to be done before you can begin to accuse climate scientists of loving ground level ozone.

Wit's End says:


Frank, the sheer staggering wealth of published, peer-reviewed scientific research detailing the tree growth-stunting, and crop-yield impairing effects of ozone – and the dearth of research on any other conceivable source – represents an awful lot of analysis indicating ozone is the primary cause.
There are two lists with links to such research at the top of my blog.
Here’s a nice one:
http://people.oregonstate.edu/~muirp/ozeffect.htm, college course notes which state:
“Plants are generally more sensitive to O3 than are humans, with damage to some sensitive species occurring at concentrations as low as 0.04 ppm.

Ozone injury can take several forms:
1. Alterations in physiology, particularly decreased rates of photosynthesis in some species and altered carbohydrate allocation patterns. A common alteration is decreased allocation to roots and increased allocation to shoots, which makes the plant more vulnerable to drought.
2. Injury to membranes. Once inside the plant, ozone causes the production of secondary products, such as OH- radicals, organic free radicals, H2O2, and singlet O. All of these are oxidizing agents which appear to be responsible for its toxic effects.
Secondary consequences of ozone exposure then result somehow from #1 or 2, above. These secondary consequences include:
reduced growth and yield of fruits, vegetables, trees
increased vulnerability to insects and pathogens”
And I never said climate scientists love ground level ozone. I said they ignore it, because most of them do.

Frank says:

Wit’s End:
You still don’t get the picture. Ground level ozone may cause a lot of bad things, but there’s no indication that it caused the tree ring divergence problem specifically.
Again, two questions:
1. Does ozone injury operate more strongly in the high latitudes? (Again, as Joe pointed out, the divergence problem is more prominent at high latitudes.)
2. Does it operate more strongly than other proposed mechanisms, such as sulphur dioxide pollution, or the drop in stratospheric ozone, and so on?
Make an effort to look at these questions, otherwise you’re not doing science, you’re just pushing a pet theory.

Wit's End says:

Frank, I never said I was “doing science.” I’m not a scientist, and I don’t pretend to be. Having said that, the divergence problem is probably more prominent in the high latitudes not because ozone “operates more strongly there”, but because it is warming faster there than elsewhere, hence a greater divergence.
As to the relative destructive capabilities of ozone, sulphur dioxide, and a drop in stratospheric ozone, I don’t know of any studies comparing them. What I DO know is that air pollution damages vegetation, causing stunted growth – and that is not a theory, pet or otherwise. It’s a well-established fact.
Make an effort to consider that fact, otherwise you’re not contributing to understanding the threat to trees and crops, you’re just pushing a pet non-theory.

Frank says:

Wit’s End:
Ozone pollution is not itself a climate change problem, any more than tobacco smoke or oil spills are climate change problems. Both are environmental problems. Neither ground level ozone nor tobacco smoke nor oil in the sea directly affects rain, or clouds, or winds, or sea level, or the intensity or frequency of hurricanes, etc. — the stuff that climate is made of.

Frank, I never said I was “doing science.” I’m not a scientist, and I don’t pretend to be.

You see, that’s the problem. You don’t “do science”, yet you demand that scientists do the things you want them to do, without making much effort to understand what theyare currently doing. Climate scientists study things that actually have some direct impact on the climate, and they’re interested in ground level ozone only insofar as it relates to climate.
So, how about this: Talk to scientists other than climatologists who do study ozone and/or tree rings. (Dendrochronology is a pretty wide field.) And instead of prefacing each message withh a long rambling commentary about the ills of ozone pollution, ask clear, concise questions so that people know what you’re asking about, e.g. “How do you think the presence of ozone pollution might affect the use of tree rings for paleoecology? Is there any research on this?” Someone might be able to give you a clear, concise answer on the state of the art.

Wit's End says:

Frank, I started out over two years ago doing exactly what you suggest: asking questions. At first I thought that trees were dying from decreased precipitation due to climate change. That is how I got interested in the topic of climate change: dying trees.
It was quite a while before I realized that the reason there has been a recent escalation in tree mortality isn’t climate change induced drought, it’s the composition of the atmosphere.
Ozone is pertinent to climate change in two ways. One, it is the 3rd most important greenhouse gas. See this paper by Shindell, et al (including Hansen): http://meteo.lcd.lu/globalwarming/ Shindell/ role_of_tropospheric_ozone_increases.pdf
Furthermore, if (when) the trees all die, one of the most important sinks for CO2 will disappear.
Climate science and the study of ozone are inextricably linked, and furthermore, the processes that create CO2 are the identical processes that result in the creation of ozone.
“…without making much effort to understand what they are currently doing.”
How on earth would you know how much effort I expend trying to understand what climate scientists are doing? And why do you make personal insults? I thought that was a tactic reserved for deniers who can’t argue the facts.
The reason I write to climate scientists is they are the ones who understand how atmospheric physics works, how precursors are transported, etc. and they are the ones with the funding to operate satellites, for example. And in many cases, that funding comes from my taxes.

Mark says:

Wit, why would the amazon be dying so much more than many other forests (check the two recent stories in sciencedaily.com)? I mean, wouldn’t you expect there to be a much worse tree death problem in, say, eastern europe where there is, presumably more ground level ozone than in the Amazon?
Meanwhile, how do you explain the bark beetle explosion in the American and Canadian west? Again, there’s recent stories at sciencedaily. I suppose you could try to argue that beetles population lags tree death, in the same way some say CO2 lags temp. But most folks seem to think the winters are not cold enough to kill off breeding adults, who then are able to get a jump start on the next years population of the bugs. Combined with drought stress, its party time for the bugs. And why would that species be hurting so badly in the borderline arid west and northwestern canada, with its much clearer skies and lower pollution, than, for example, the mixed forest of Michigan being downwind from major pollution sources almost any direction the wind blows?
I’m all for studying ground level ozone, but I think you’re dead wrong blaming these forest issues on pollution instead of shifting habitat parameters as a result of climate change.

Wit's End says:

Mark:
Trees are dying everywhere, not just the Amazon or the American west. They ARE dying in Eastern Europe and have been for decades. The Germans call it waldsterben – forest death. It’s a global pattern. And trees that are being watered in nurseries have the identical symptoms of foliar damage as trees growing in the wild.
Trees that are exposed to ozone allocate more energy to shoots and less to roots, making them more vulnerable to drought. Trees that are exposed to ozone are more susceptible to insects, disease and fungus. This has been proven in open air tests – one scientist called the insects, disease and fungus the “sharks circling in the water.”
Here’s a snippet from the National Park Service:
“Ozone enters plants through leaf openings called stomata and oxidizes plant tissue, causing changes in biochemical and physiological processes. Both visible foliar injury (e.g., stipple and chlorosis) and growth effects (e.g., premature leaf loss, reduced photosynthesis, and reduced leaf, root, and total dry weights) can occur in sensitive plant species In a natural ecosystem, many other factors can ameliorate or magnify the extent of ozone injury at various times and places such as soil moisture, presence of other air pollutants, insects or diseases, and other environmental stresses. Ozone effects on natural vegetation have been documented throughout the country, particularly in many areas of the eastern U.S. and in California.”
NASA: “An increasing number of reports have appeared during the past 25 years regarding ozone-induced injury to plant leaves in many countries.”
Links and more excerpts here:
http://witsendnj.blogspot.com/ 2011/ 02/ shattered-illusions.html
In 2010, the United Nations Environment Programme published a book, “Air Pollution, promoting Regional Cooperation” which stated:
“The impact of air pollution on agricultural crops and quality of produce and ensuing food security has hitherto been largely ignored by policy makers. The ubiquitously rising ambient ozone levels are a matter of serious concern in a world with growing food shortages and increasing food prices. Some 75% of the world’s cereal is grown in areas which are exposed to damaging ozone concentrations.
Studies in Europe, Africa and Asia suggest that agricultural output may be dramatically reduced by air pollution, above all ozone (formed by chemical reactions with nitrogen oxides and volatile organic compounds in the presence of sunlight).
The Sida funded programme on Regional Air Pollution in Developing Countries (RAPIDC) includes studies in e.g. India, Pakistan and Bangladesh, as well as in southern Africa, which indicate that the crop yield of wheat may be reduced by some 30% due to air pollution (based on European dose response functions). Investigations in these countries and in Sri Lanka suggest a potential yield loss of 50-80% for mung beans, spinach and potatoes. It has been indicated that rice yield in Japan has been reduced due to the influence of long- range transport of air pollution.
Some years ago air pollution was treated as a local problem, particularly in urban areas. While urban problems tend to be continuously exacerbated in most big cities of the world, air pollution is today recognized as a global issue with transboundary consequences.”
Please keep in mind that long-lived species such as trees get exposed season after season, and so the damage, unlike that to annual crops (unless you’re counting the damage to soil and microbes which is another component), is cumulative.
And while I’m at it, I would like to add to Frank, who said:
“Ozone pollution is not itself a climate change problem, any more than tobacco smoke or oil spills are climate change problems. Both are environmental problems. Neither ground level ozone nor tobacco smoke nor oil in the sea directly affects rain, or clouds, or winds, or sea level, or the intensity or frequency of hurricanes, etc. — the stuff that climate is made of.”
This climate blog and many others frequently include posts about the Gulf oil spill, other oil spills, the Fukushima nuclear accident, the bark beetle epidemic, and a range of other tangential issues. Ozone is at least as pertinent to climate if not more than those topics – since it IS a greenhouse gas – I would aver that they are all connected and relevant to the science climate change.

Sycamores have multiple cankers...lethal tumors created by opportunistic fungus.

Frank says:

Wit’s End:

Frank, I started out over two years ago doing exactly what you suggest: asking questions.

You’re not asking enough questions, and of those questions you do ask, you’re not asking them clearly enough, and you decide too quickly on an answer you like, instead of trying to find the correct answer.
Jeez, look, I’m not trying to stop you, I’m not trying to belittle you, I’m trying to help you by showing you a way forward. In the time you spent writing your diatribe about how those darn ignorant scientists are living on your tax money, you could’ve sought out for some experts in dendrochronological techniques and asked them some clear concise questions! Why aren’t you doing this? You’re not helping yourself!
That’s it. None of us are obliged to answer your points about why your theory on everything is so obviously correct that you can’t be half-bothered to seek out a practising dendrochronologist and actually ask him what he thinks. You can either take a way forward, or you can continue your campaign of yelling at a cul-de-sac.

Notice, these younger trees have splitting bark as well.

Wit's End says:

None of “us”?
That’s cute, Frank.
Diatribe? Hardly!
And I’m getting rather tired of conjectures about what questions I’m asking of whom and whether they are sufficiently clear. You can’t possibly know of all the letters I have sent to all sorts of scientists asking them questions.
Why don’t you address the facts I bring up instead of making slurs against me? Why did you abandon your question about the divergence? When you said ozone has no place on a climate blog and lumped it in with oil spills, why did you ignore my response, which is that CP and many other climate blogs report on oil spills and other environmental issues like Fukushima?
Instead you resort to mischaracterizations such as this:
“…darn ignorant scientists are living on your tax money.”
which is one of several distortions of what I have said. Specifically, I referred to “funding to operate satellites” and not funding the salaries salaries of scientists, nor did I refer to scientists in any derogatory manner, let alone characterize them as ignorant.
You owe me an apology for that one.

That was the last comment as of today so, I guess, I'm not going to get one!

This arresting stump is my favorite of the set.

It fascinated me, because it provides a view of the inside the hollowed decaying trunk, and in this perspective the remnants of branches  - conical spikes and holes - seem to make a face.

A tragically sad face, I might add...the image of an inner spirit, trapped, perplexed and mournful, that mirrors my own.

These few remaining shots are from Susan.

She and husband Roger are pictured here next to an historic tree, which was standing in the year our Constitution was signed...a reminder that, absent human intervention, trees should live for centuries.

Unfortunately, the bark is discolored, corroded, and breaking off.

Perhaps it is better to focus on more durable, less vulnerable things than trees...like stone sculptures! Thank you Susan for these photographs from New Hampshire.