“'Your basic street tree has about a 35-year . . . life expectancy in today’s urban forest,' said Peter Wild, owner of Boston Tree Preservation in Woburn. 'That might mean that some of them might live to be 70. Some of them might live to be 15.'"
"One tree that many towns and cities hoped would be hardy, the Bradford pear, has proven disappointing, Wild said. Although the trees grow densely, ideal for urban and suburban streets, the angles of their branches, and their tendency to keep their leaves into late fall, make them susceptible to damage during winter storms, he said."
"'That’s an example of a tree that was heavily overplanted two decades ago and even recently,’’ Wild said, “and it hasn’t proven to be the tree that we thought it was.'’’
Luckily for readers at Wit's End, I have no other new pictures of trees dying from air pollution, with depressing broken branches, peeling bark, cankers and weeping holes. Instead today I'm going to post colorful photos from a wonderful gallery, of birds. My favorite is the flamingo image above, because there is a tanker lurking ominously in the background. The rest are just pretty.Before we get to those voluminous Forest Service reports though, here's a link to a wonderful website called Environmental History Resources, which is maintained by a professor who, I think, is Dutch. Among other essays, he wrote one called "The Role of Wood in World History". It surprised me to learn, although it shouldn't have, that civilizations have over and again relied upon and then ruthlessly depleted their supply of forests, being then forced to forage elsewhere, conquering other societies to import their supplies...or collapsed. I have always regarded forests as essential for all they provide - fruit and nuts, wildlife habitat, and most of all for their primeval beauty. But in this broader perspective, their foundational role as a prerequisite for civilization to grow and prosper is made apparent:
"Today it is hard to believe that in antiquity vast forests were growing in the Middle East. However, during the early part of the third millennium BCE, the mountain slopes of this region were covered with massive cedar forests. These forests disappeared in the millennia before Christ's birth about two thousand years ago. The destruction of the cedar forests of the Middle East is told in the oldest known, surviving written story in the world: The epic of Gilgamesh. The epic was written in Mesopotamia sometime during in the 3rd millennium BCE. The second episode of the epic is known as 'The Forest Journey' and is the story of deforestation in the Middle East2...."
"The destruction of the world's forests is a major concern in our age. According to the UN about 40 percent of Central America's forests were destroyed between 1950 and 1980 and during the same period Africa lost about 23 percent of its forests. A whole range of environmental problems is associated with deforestation, among them severe flooding, accelerated loss of soil, encroaching deserts and declining soil productivity1. Sometimes we get the impression that these problems are unique to our time, but vast areas of surface of the earth were stripped of their tree cover well before the modern period."
"Now that we have explored the importance of wood and forests of antiquity, we make a big jump forward in time to examine the importance of wood in the rise of the West. Without the abundant availability of wood, Europe would never have been able to undertake the exploration of the world’s oceans that led to the great geographic discoveries. This development had become very difficult in the Middle East, where the ancient forests were had largely disappeared during antiquity."
I won't post the entire thing - but the site is worth a visit if you want to follow through the Greeks and Romans, to the era of coal in England, and also he has some more references to scholarly works on the topic. It's amazing at how many forests humans have demolished, although of course in the past they did it the old-fashioned way, by chopping them down. We moderns are chocking them from the excrement of our insatiable desire for energy.
In yet another under-appreciated aspect of forests are the findings of two Russian scientists, who connect the lack of evapotranspiration when deforestation occurs to a consequent lack of rainfall, impacting even distant places:
"Two Russian scientists, Victor Gorshkov and Anastassia Makarieva of the St. Petersburg Nuclear Physics, have published a revolutionary theory that turns modern meteorology on its head, positing that forests—and their capacity for condensation—are actually the main driver of winds rather than temperature. While this model has widespread implications for numerous sciences, none of them are larger than the importance of conserving forests, which are shown to be crucial to 'pumping' precipitation from one place to another. The theory explains, among other mysteries, why deforestation around coastal regions tends to lead to drying in the interior."
"Although the theory has garnered a wide contrast of reactions—from dismissal to accolades—it has so far been mostly ignored by the greater scientific community since first published in a small journal in 2007. A new paper in Bioscience by Douglas Sheil and Daniel Murdiyarso attempts to remedy this by introducing (or re-introducing) the theory to scientists of all fields, many of whom have probably never heard of the theory despite its radical and widespread implications.""...it has so far been mostly ignored by the greater scientific community..." Sound familiar? There are gargantuan forces at play transforming the ecosphere right in front of our eyes, and meanwhile, the greater scientific community, immersed in their meticulous research, is either preoccupied, or sanctimoniously in denial.
A perfect example are the three aforementioned US government publications. First up, the National Report on Sustainable Forests 2010. They are excerpted out of order, because the 2010 Report is based on the other two earlier drafts, but bear with me - we will discern some disturbing trends. Everything that follows will be direct quotes, that I won't muddle up by including the extensive references to original research (which can of course be found by clicking the link) or adding quotation marks. Instead any comments of mine will be highlighted. Tommy Tidwell, the head of the USDA (which is the umbrella organization for the Forest Service), states in the introduction:
One of the report’s key findings is the fact that the United States is richly endowed with forests, 751 million acres to be exact. That area has remained remarkably stable over the last 50 years, and the amount of wood in these forests is increasing. Ha, does he mean the amount of living trees is increasing? Or the amount of dead wood is increasing? This may seem silly, but don't laugh. Further on, they have declared standing dead trees to be "assets" because 1) they provide habitat and 2) they store carbon. That's right, even as they actually are releasing carbon while they decay, as long as any part is intact carbon is sequestered...so let us not quibble when there is a potential for international carbon offsets to be had. That's our clever Forest Service at work, never one to waste our tax dollars!
At the same time, however, forests in the United States face a number of threats, ranging from fragmentation and loss of forest integrity due to development to an alarming increase in the area and severity of forest disturbances. The report finds, for example, that the incidence of insect-induced tree mortality has increased three-fold in the last decade. In the coming years, climate change could substantially increase the damages and uncertainties associated with these threats. Not coincidentally, forests have a major role to play in helping to mitigate climate change, a fact that is well documented in the report. Even he used that word "alarming". That insect-induced tree mortality has "increased three-fold" is very important, especially considering (as should be kept in mind throughout) that this is all based on old data, and the trends are continuing and accelerating...Yet nowhere in this report is it mentioned that from controlled fumigation experiments it has repeatedly been demonstrated that plants and trees exposed to ozone are more likely to be attacked by insects, disease, and fungus cited as threats. Nowhere is there evident the plain speaking to be found in this textbook about European forests, which describes some stands as being "all but obliterated" by air pollution.
Second, this report is the United States’ contribution to the set of reports produced by the 12 countries that are members of the Montréal Process Working Group (MPWG) on the Conservation and Sustainable Management of Temperate and Boreal Forests. The MPWG is a voluntary, nonlegally binding group of countries that have agreed to use a common set of criteria and indicators for tracking each country’s progress toward their shared vision of sustainable forests. Visit http://mpci.org formore information about the MPWG.
Right. No need to rush over to that link. Their latest news? Circa 2009. They did have a meeting in Canada last October...but Annex E and F (Summary, and Joint Draft Statement) are still "under preparation". This is consistent with a disturbing lack of up-to-date information.
Right. Don't rush over there either, because all it says is: Page Not Found.
Third, this report is just one component of the reporting process that the United States is using to report on forest conditions and trends and the progress being made toward sustainability. Supporting this document are a number of more detailed subsidiary reports on the individual indicators that provide a great deal of additional information in more detail than could be included here. These supporting technical documents are available at http://www.fs.fed.us/research/sustainability.
This report identifies seven major driving forces affecting forest sustainability:
1. Climate change.
3. Biomass energy demand.
4. Urbanization and related shifts in land use patterns.
5. Forest fragmentation and parcelization.
6. Loss of working forests.
7. Altered disturbance patterns.Note: not even a glancing reference to acid rain, the Nitrogen Cascade, or ozone!
Population growth is a major determinant in total consumption. Choices about desired standard of living and lifestyle—both of which are dependent on disposable income—determine per-capita consumption. When both of these factors are combined—increased consumption per-capita and increased overallpopulation growth—stresses on sustainability can be magnified. Policymakers concerned with sustainability should track trends in per-capita consumption and use available population projections to evaluate future prospects for sustainability. The MP C&I have indicators of per-capita consumption, but leave population projections to others. With one paragraph they dispense with arguably the greatest threat to forests of all. No surprise there.
p. I-13 Despite notable reversals in the population declines of some forest animals (wolves in the intermountain West, for example), important components of the overall diversity of forest flora and
fauna remain threatened. Seventy-seven forest-associated plants and animals that were present in our forests when our Nation was founded are now presumed to be extinct. An additional 4,005species, or 27 percent of the total number of forest-associated species, are at risk of extinction. Horrible numbers...but if all the trees die from ozone, closer to 100 percent are at risk of extinction.
The data presented for the two indicators comprising Criterion 3 clearly show that the Nation’s forests are subject to increasing levels of disturbance, such as insect infestation and fire. These disturbances result from processes we often cannot control and may not always fully understand. In particular, the incidence of insect-induced tree mortality has increased three-fold in the past decade. This fact is backed by substantial anecdotal experience and is undoubtedly the clearest red flag emerging from this report.Do you suppose that's why they leave out air pollution - because insects and fire are disturbances we cannot control. We CAN control air pollution of course. But we don't want to.
p. I-16 In this regard, the increases in insect infestations, drought, and fire registered in Indicators 3.15 and 3.16 may be the partial result of climate change, but we cannot say so with any degree of certainty.
p. I-17 Moreover, forests in close proximity to heavy emission areas, such as in and around cities, can help alleviate air pollution and reduce temperature variation by providing shade in the summer and shelter from wind in the winter. WHERE is the essential question - what happens to the forests when they "alleviate" air pollution; i.e. absorb it?? We know what happens when humans absorb it - they get cancer, emphysema, allergies, respiratory illness, heart disease, Alzheimer's, ADHD, autism, and diabetes.
p. I-25 North Carolina Report Card: Several issues threaten western North Carolina’s forest ecosystems. These include, but are not limited to, loss of native species and natural communities; spread of invasive
species; insect and disease infestations; air pollution; landslides: and the loss of contiguous forest land.Wow, North Carolina recognized air pollution as a threat to forest ecosystems. Where is it in the synthesis? The report doesn't even list ozone in their glossary, or nitrogen. Following is their one acknowledgment in the glossary:
air pollutants - Gases, particles, or aerosols generated from management or combustion activities (industry, transportation, agriculture, management, etc.) that are released into the atmosphere,transported, and deposited in human and natural ecosystems. Air pollutants may be absorbed by forest ecosystems without effects (sink) or exceed the absorption capacity and have a deleterious effect on processes or components. They manage to avoid any elaboration on exactly what those "deleterious effects on processes or components" might be. Purely Orwellian.
Following are excerpts from the Draft Forest Health Monitoring 2009 National Technical Report upon which the National Report was based. The FS has been monitoring forest health, by extensive and sophisticated means, utilizing ground inventories, aerial surveys and satellite imaging. This they do because there is a very large timber industry with vast amounts of money at stake. Think Georgia-Pacific, acquired by Koch Brothers in 2005 - a company which has paid tens of millions in fines for illegally polluting. Just a minor cost of doing business in the USA.
This chart measuring mortality only goes through 2008, which was the year I first noticed that every single tree had symptoms of decline. So had they included more recent data from the last three years, when symptoms have multiplied in number and severity, that mortality would have to be incredibly worse. Even so, this 2009 draft report has fairly extensive discussions about mortality and the link to pollution - a connection which was almost completely dropped from the next draft in 2010, as shall be seen - and the 2010 National Report from the USDA, which was quoted above. WHY??????
on mortality, p. 41: While the percentage of affected forest land in the United States may appear relatively low, the rate at which acreage is being impacted is alarming. As predicted by risk modeling, and confirmed by site-specific observations, actual impacts at local or regional levels are often extreme.
Overall, the indicator shows a continuing trend in forest decline. Arguably, and considering the potential for certain outbreak events to be cyclical in nature (such as mountain pine beetle in pure, unmanaged lodgepole pine stands), many affected areas will likely regenerate; however, the resulting single-species/single-age-class regeneration will not provide a sustainable forest.Right, "will not provide a sustainable forest", because, all of the co-dependent interrelationships of various species that contribute to the complex web of life will have been irreversibly disrupted. This is evolution 101 and government agencies who skirt this fundamental aspect of genetic adaptation are doing so deliberately. You won't see this come up again in the USDA final summation!
Spikes in mortality during the reporting period are largely due to a combination of high stand density in unmanaged forests and drought. Cumulative impacts are occurring within previously surveyed areas and expanding into new areas. The total area with mortality and defoliation has quadrupled over recent years for select indicators (table 3.2). Regardless of whether the cause of impacts is overstocking, climate, invasive pests or a combination of all three, intervention may be necessary to restore ecosystem to health, vigor and productivity.Intervention? That is delusional, but still, contrast the above assessment - total area with mortality and defoliation has quadrupled - with all the happy talk in the introduction of the National Report about our "remarkably stable" 751 million acres of forest. Below is a case study of Hawaii. I'm including it because it's remarkable to see how comprehensive is the tragic end of paradise, where even the Forest Service uses a word like "decimating".
Hawaii is also negatively affected by invasive pathogen, plant and insect pests. Impacts of invasive species, including animals, have been profound in Hawaii and are at the root of Hawaii's biodiversity crisis (fig. 3.13). Guava rust is currently defoliating non-native forests at low elevation; there is a potential threat to native ohia, which dominates 80 percent of Hawaii’s native forests. The erythrina gall wasp threatens widespread mortality of native wili trees, a component of much of Hawaii's remaining dry forests, and has almost eliminated the introduced coral tree.
As far as I can tell, since this was written, the Forest Service has ceased to have interest in "detecting mortality patterns that reflect fundamental ecosystem processes due to such large-scale factors as air pollution"!
Criterion 3, Indicator 16 of the Montreal Process Criteria and Indicators for the Conservation and Sustainable Management of Temperate and Boreal Forests was designed to assess the impact of abiotic agents upon forests (Montréal Process Working Group 2007). Various abiotic agents, both natural and human-induced, can change forest structure and species composition. Where such change goes beyond some critical threshold, forest ecosystem health and vitality may be significantly altered and its ability to recover from disturbance reduced or lost, often meaning a reduction or loss of benefits associated with that forest ecosystem. Monitoring the area and percent of forests affected by abiotic agents beyond reference conditions may provide information needed in the formulation of management strategies to mitigate risk. The summary of this analysis is reported in the National Report on Sustainable Forests 2010 Report (Robertson and others 2010) while the purpose of this document is to provide the detailed evidence to support the reported data. "The summary of this analysis is reported in the National Report on Sustainable Forests 2010 Report"...oh, really??
The original National Report on Sustainable Forests 2003 (Guldin and others 2004) and the Montréal Process Working Group (2007) identified several abiotic agents: fire, storm, land clearance, permanent flooding, salinization, specific air pollutants (e.g. sulfates, nitrate, ozone), ultraviolet B, and soil nutrient cycling. These were addressed in three separate indicators. In the National Report on Sustainable Forests 2010, these were re-organized and addressed as one indicator (Criterion 3, Indicator 16) and were grouped into five sub-indicators that have the greatest impact on forest health. These abiotic sub-indicators are: fire, weather-related damage, pollution, land use, and climate. Specific air pollutants - nitrate, ozone...where is that again in the National Report?? here it comes, watch for the sleight of hand on p. II-45:
What has changed since 2003?
The data––The indicators in this criterion have benefited from data improvements resulting from ongoing survey efforts undertaken by the Forest Service’s Forest Health Protection program.
The indicator––The following table summarizes the revisions. Indicator reference numbers for 2003 and 2010 are provided to assist in comparisons with the previous report. A more detailed rationale for the revisions may be found at http://www.rinya.maff.go.jp/mpci/meetings/18_e.htm.
Note: Below is a portion of where that link with the "more detailed rationale for revisions" leads - it's all in Japanese with the exception of the copyright line, and when you try to translate, it responds with an error message:
Copyright:2007 Ministry of Agriculture, Forestry and Fisheries〒100－8952 東京都千代田区霞が関1-2-1 電話：03-3502-8111（代表）
Next is the chart, from the National Report, showing the revisions. 2003 Reference 16 indicator "area and percent of forest land subjected to levels of specific air pollutants..." has been "
merged" purged to be "area and percent of forest affected by abiotic agents (eg fire, storm, land clearance). It's the incredibly disappearing pollution!!
Following is the only other sections that reference pollution I could find in the National Report, which is buried by the volume of references to fire, weather, insects and disease - and then dismissed:
What does the indicator show?
Of the abiotic agents that affect forested ecosystems, five were selected that have a dominant impact—fire, weather, pollution, land development, and climate change. Given the breadth of disturbance agents, it was not possible to treat any one of them in detail. Extended details are available in the supporting data report.
Pollution effects on forests are indicated by Critical Acid Loading (CAL), which incorporates SO4 and NO3 and their relationship with soil properties. From 1994 to 2000, 74 million acres, or 17 percent of U.S. forest soils exceeded their CAL by more than 98.4 equivalents per acre per year. These areas are predominately located in the Northeastern United States. Surface ozone (O3) is also an important air pollutant that affects vegetation. No evidence exists linking Forest Health Monitoring ozone bioindicator response data to a specific tree health problem or regional decline. Nevertheless, mapped data demonstrate that concentrations of plant damaging ozone air pollution are widespread in parts of the United States.
That's it, folks! Is that any way to report on the Nitrogen Cascade, which leads to eutrophication??
The 2009 Draft has more about pollution that was subsequently forgotten in 2010:
The Forest Health Monitoring ozone (O3) biomonitoring program uses ozone-sensitive plants to monitor air quality and the potential impacts of tropospheric O3 (smog) on forestlands. These data include both tabular regional synopses and a raster surface model using the biomonitoring site point data. The surface ozone-injured indicator plants regional summary and graph were obtained from Smith (2008).
A Critical Acid Loading (CAL) surface raster model obtained from McNulty (2007) and the forest mask were applied to create a CAL grid layer for forested areas. The data were summarized and graphed.
Surface ozone (O3) is an important air pollutant that affects vegetation (US EPA 1996). Ozone is routinely monitored throughout the world and data are mostly recorded as hourly or half-hourly averages. Over the last 30 years, hourly averaged data have been summarized in different ways for the purpose of assessing vegetation effects.
There is "not yet any evidence linking...ozone...to a specific tree health problems or regional declines?? They have got to be kidding. How about all the trees that are dying from no other apparent cause?
Just TRY to get more recent biomonitoring data - this chart stops at 2006! When I called the northeastern station this year, I was told they had stopped collecting due to "anticipated budget constraints" and when I asked what they were doing with their time (they are still being paid!) I was laughingly told they are pushing a lot of paper around their desks.
I believe the emphasis on soils is a distraction. Certainly acid rain depletes soils of nutrients and that has killed many trees, BUT, plants and trees being grown in pots with enriched soils (and being watered) have no more or less symptoms of ozone injury than plants or trees growing in the ground. The only thing they share in common is the atmosphere.
When Charles Little wrote "The Dying of the Trees" (for which he was widely
p. 144: Results – Approximately 80 percent of dead trees had confirmed D. destructiva infections. As of 2006, 245 of the 294 (85 percent) flowering dogwoods in the permanent plots had died. Of the dead trees 67 percent (196 trees) died after being confirmed as positive for infection. However, of the 43 trees still alive as of 2006, 79 percent had also been confirmed as positively infected by anthracnose. Since 2000, mean crown rating for living trees has remained relatively constant. Prior to 2000 mean crown rating had declined steadily from a high of 5.0 in 1989 to a low of 2.3 in 2002. As of 2000, no trees were rated “healthy,” or a crown rating equal to five. Of surviving trees, those infected during the secondary peak infection year of 1999 were in the poorest health.
Notice, NONE of the trees were rated as healthy, even though not all of them had anthracnose. Above graph, live dogwoods per acre in 1983-1985, below, 2000-2004.
Lately there have been a bevy of studies claiming that long-term climate change drought is causing trees to die off, now that foresters are reluctantly coming to the realization that in fact, trees ARE dying off. It's coming up on 3.5 years since Mother Nature smacked me upside the head and shrieked with unmistakable ferocity that all the trees are dying. I didn't know then about the terminology of PWP (Permanent Wilt Point) but as a devoted gardener I recognized that the extent to which leaves of deciduous trees in August were hanging straight down meant that they would never really recover, ever. They will limp along until all of their stored energy is used up, or a biotic agent moves in for the kill.
"The concept was introduced in the early 1910s. Lyman Briggs and Homer LeRoy Shantz (1912) proposed the wilting coefficient, which is defined as the percentage water content of a soil when the plants growing in that soil are first reduced to a wilted condition from which they cannot recover in approximately saturated atmosphere without the addition of water to the soil."
Initially I also attributed the leaf wilt, and then the coniferous needle drops to long term drought from climate change - what else could have such universal ramifications? That was before I realized that just because ozone is invisible, it doesn't mean the air is clean. Not at all. And look at the Forest Service maps. There can certainly be made a case that areas of the US have suffered more than mild soil moisture deficit - but not the Eastern Seaboard. In fact, that is more closely aligned to climate change predictions - dry areas will get drier, and wet areas will get wetter. This map is moisture deficit 98-02.
Actually, since 2003, according to the map below, much of the Eastern Seaboard has had a surplus of moisture. So why would young trees that have been planted in the last five to eight years exhibit the same symptoms of stress - singed foliage, yellowing needles, thinning crowns, oozing bark, excessive lichen cover, etc - as older trees? Why are some of the worst impacts attributed to climate change occurring, for instance, among maple trees in New England and Canada?
The Draft 2010 has already abandoned any specific mention of ozone.
p. vii Executive Summary:
Mortality is a natural process in all forested ecosystems, but high levels of mortality at large scales may indicate that the health of forests is declining...An analysis of FIA plots from 27 states found that the highest ratios of annual mortality to gross growth occurred in ecoregion sections of the Plains States. Mortality was also high in parts of southeastern Texas and New York. Even in areas of relatively high mortality relative to growth, no mortality occurred on most sample plots. However, on the plots with mortality, larger-diameter trees exhibited higher mortality trends as compared to remaining smaller-diameter classes of surviving trees, suggesting the mortality is related to either senescence of older stands or some insect or disease issue.
Or else it's suggesting mortality of older trees is because they have been exposed to toxic pollution longer! Senescence is just a lie, most trees can live for centuries. This article lists 10 famous ancient trees, the oldest of which is 4,800 years old, located in Nevada! And again, rigorous scientific studies show that trees stressed by pollution are more likely to be attacked by and succumb to insects and disease.
The first paragraph of the introduction, with its "long list of threats" doesn't mention pollution either:
Forests cover a vast area of the United States, 303.1 million hectares (749 million acres) or approximately one-third of the nation’s land area (Smith and others 2004). These forests possess substantial ecological and socioeconomic importance. Both their ecological integrity and their continued capacity to provide goods and services are of concern in the face of a long list of threats, including insect and disease infestation, fragmentation, catastrophic fire, invasive species, and the effects of climate change.
The mission of FHM is to monitor, assess, and report on the status, changes, and long-term trends in forest ecosystem health in the U.S. (U.S. Dept. of Agriculture, Forest Health Monitoring 1994). Thus, the aim of this mortality analysis contrasts with how mortality might be approached in other reports, such as FIA State reports or State Forest Health Highlights. The approach to mortality presented here seeks to detect non-specific or multiple host mortality patterns that might reflect subtle changes to fundamental ecosystem processes (due to such large-scale factors as air pollution, global climate change, or fire-regime change) that transcend individual tree species pest/pathogen interactions or direct concern over forest resource production and availability.
At this point a mortality baseline is still being established for most of the U.S. using the first two cycles of annualized data (i.e., the first two measurements of each plot). To discern trends in mortality rates, a minimum of three cycles of FIA data are required*6. With at most two cycles of data currently available, it is only possible to do a spatial comparison of ecoregions and identify regions of higher than average mortality (relative to growth) for
Always, further study. Wait, why can't they present a trend in mortality that might "reflect subtle changes to fundamental ecosystem processes - due to such large-scale factors as air pollution??? Oh, they "choose not to do so":
The MRATIO can be large if an over-mature forest is senescing and losing a cohort of older trees. If forests are not naturally senescing, a high MRATIO (> 0.6) may indicate high mortality due to some acute cause (insects or pathogens) or due to generally deteriorating forest health conditions. An MRATIO value greater than 1 indicates that mortality exceeds growth and live standing biomass is actually decreasing.
This is frightening because it is so out of date considering the dramatic and rapid deterioration of tree health since 2008:
On Page 35 is a chart broken down into which species are dying. p. 36 says:
Green ash also represented a large portion of the mortality in ecoregions 332A-Northeastern Glaciated Great Plains (17.43 percent), 332C-Nebraska Sand Hills (10.22 percent), and 332E-South Central Great Plains (12.25 percent). The cause of this mortality is not immediately apparent. One might be tempted to suspect the invasive insect, the emerald ash borer. However, this pest has not yet been reported in or near these regions (USDA Forest Service and others, N.d.). In ecoregion 332A-Northeastern Glaciated Great Plains, the age of the dead trees (table 4.2) suggests that older, senescent stands may be dying.
I love it! They are "tempted" to blame an insect that doesn't exist!! So again it's older, senescent stands, since they can't find a biotic agent. The fact is that aside from a few isolated, protected specimens located in places that have been preserved for historical or cultural reasons - like churchyards, battlefields, Colonial estates, and Ivy-league campuses - there are virtually NO senescent stands in the Eastern US, they have ALL been clearcut, some more than once (unfortunately). The new growth is too young to be dying of natural causes.
Further study is "probably warranted?" I should think so since the causes of trees experiencing high mortality "are not immediately apparent" which is probably because they refuse to factor in the rising level of background ozone, or the disruption to the nitrogen cycle. It's interesting that "The areas of highest mortality occur in the mostly riparian forests..." What is riparian?? Let's check with our trusty Wikipedia:
"Wiki: The word "riparian" is derived from Latin ripa, meaning river bank. The riparian is an important feature of a wetland because it allows characterization of the wetland's overall health...Research shows riparian zones are instrumental in water quality improvement for both surface runoff and water flowing into streams through subsurface or groundwater flow. Particularly the attenuation of nitrate or denitrification of the nitrates from fertilizer in this buffer zone is important. Riparian zones can play a role in lowering nitrate contamination in surface runoff from agricultural fields, which runoff would otherwise damage ecosystems and human health. The use of wetland riparian zones shows a particularly high rate of removal of nitrate entering a stream and thus has a place in agricultural management."
As usual, the emphasis is on the benefit received by having trees in riparian areas soak up nitrate contamination - and not on what happens to trees when they absorb it. Is is any wonder that these areas have the highest mortality rate? They are getting a double whammy from absorbing ozone in their foliage and nitrates from their roots.
Introduction to Chapter 8 p. 71
Airborne nitrogen (N) and sulfur (S) from industrial pollution and automobile exhausts have been deposited across Europe and the Northeastern US for over 70 years in the form of acid rain. Heavily polluted areas can receive over 50 kg N ha-1each year. The environmental impacts of air pollutants have been studied since N and S were first suspected to cause forest damage and decline across the region in the mid-1980s. High pollutant levels and forest mortality can lead to mobilization of soil aluminum (Al3+) and nitrate (NO3-) and subsequent increases in stream Al and NO3 concentrations. Increased Al and NO3 stream concentrations can have negative health impacts on fish populations and human water supplies. High forest soil acidity can also cause aluminum toxicity in roots, foliar nutrient imbalances, reduced tree cold tolerance, and tree freezing injury. Each of these stressors can lead to tree mortality.
"Each of these stressors can lead to tree mortality" - (never mind what they do together) and yet the National Report neglects to mention any single one of them as a cause of tree mortality??
...Acidic deposition in excess of the critical acid load is termed the acidic exceedance, and the larger the acidic exceedance, the greater the risk of ecosystem damage. This definition of critical acid load applies to a single, long-term pollutant exposure. However, a static critical acid load level may not accurately assess ecosystem risk to damage when an ecosystem is subjected to multiple, episodic environmental stresses. If multiple stress impacts (e.g., drought, insects, wildfire) are included in critical acid load assessments, the critical acid load may need to be lowered in many areas to maintain long-term ecosystem health.
Climate change is a generic term used to define a host of changing environmental conditions associated with the atmospheric increase of greenhouse gases and global warming. Climate change is characterized by both climatic shifts and increased climate variability. Both inter-decadal shifts in climate and inter-annual climate variability can influence the critical acid load of forest soils. Each of these impacts is examined below.
Short- and Long-Term Droughts
Water is one of the principle determinants of ecosystem type. Average annual precipitation in temperate forests ranges from 50 to 250 cm per year. Deserts, scrubland, and woodlands receive between 0 and 125 cm of precipitation per year. Millennia of plant competition have favored vegetative species that best adapt to limited resources (including water). Short-term (i.e., less than two years) drought can reduce ecosystem productivity, leaf longevity in deciduous species, and leaf area. These factors reduce biological demand for nitrogen which can alter soil critical acid loads. Under short-term (i.e., less than two years) extreme drought, reduced soil moisture can cause reduced nitrogen mineralization and nitrification that then result in reduced ammonium and nitrate availability. These conditions would not impact critical acid load in the short term if both nitrogen demand and supply are reduced. However,
nitrogen will continue to accumulate in the ecosystem during the drought. A nitrate pulse could occur following a drought if nitrogen mineralization and nitrification rates respond to available water before plant demand for nitrogen increases.
A large nitrate pulse?? This looks intriguing. It also looks like a positive amplifying feedback - trees die back (or are cut), meaning they take up less nitrogen, so there is even more nitrogen supplied to the remaining trees, overfertilizing them.
Climate change is expected to negatively impact forest ecosystems in several ways during this century. However, the exacerbation of forest soils affected by acidic deposition may not be among those negative impacts. The results of this SMBE suggest that those soils most likely to be in exceedance of their critical acid load levels (e.g., New England forests) may also be the most likely to benefit from the warming associated with climate change. Increases in both nitrogen uptake and base cation weathering are predicted in this region of the country. The increase in weathering rates would be particularly important for increasing the region’s critical acid load capacity. This study suggests that a major reduction in the area representing the most seriously impacted forest soils could occur. While this is potentially good news for ecosystem management, other aspects of climate change are not accounted for by the simple mass balance equation approach to critical acid load determination. Potential increases
in insect outbreaks, hurricane intensity, wildfires, and changing patterns of ice storms could all reduce forest productivity and therefore nitrogen uptake. These conditions would the reduce buffering capacity of the ecosystem and make it more likely that the ecosystem would be in exceedance of its critical acid load, so caution should be used when interpreting these results.
I'm sorry, but if you parse it, this incoherent, self-contradictory paragraph reads like double-speak! Increasing the critical load capacity?? This is so out of step with current science about disruption of the nitrogen cycle, it's just staggeringly ignorant.
Given the ecological importance of whitebark pine as a keystone species in these ecosystems, it is imperative that genetic materials, such as seed and/or scion, are collected from these populations and placed in genetic archives for their potential use in ecosystem restoration in the future. Furthermore, the populations should be monitored regularly to determine the trajectories of their health status over time and action taken as appropriate. All options intended to reverse the decline of these populations should be considered, including the dissemination of genetically resistant materials, restoration of natural fire regimes, and maintaining and archiving the gene pools of current populations.
This prognosis is stunningly bleak. Whitebark pine - a keystone species - is in such imminent danger of extinction that they want to collect and archive genetic materials? Sadly, I think this is true for ALL species if we keep on filling the atmosphere with poisonous gases. Next, check out the graph of the increase in wildfire incidents and keep in mind, it only goes to 2009. Wait till the wildfires start tearing through the suburbs, lapping at the fringes of major cities. It's coming.
|Forest Fire Occurrences measure by MODIS|
"The US Forest Service administers a long-term, nationwide ozone biomonitoring program in partnership with other state and federal agencies to address national concerns about ozone impacts on forest health. Biomonitoring surveys begun in 1994 in the East and 1998 in the West provide important regional information on ozone air quality and a field-based record of ozone injury unavailable from any other data source. Surveys in the Northeast and North Central subregions cover 450 field sites in 24 states where ozone-sensitive plants are evaluated for ozone-induced foliar injury every year. Sites are typically large, undisturbed openings (>3 acres in size) close to forested areas where >3 bioindicator species are available for evaluation.
Over the 16-year sampling period, injury indices have fluctuated annually in response to seasonal ozone concentrations and site moisture conditions. Sites with and without injury occur at all ozone exposures but when ambient concentrations are relatively low, the percentage of uninjured sites is much greater than the percentage of injured sites; and regardless of ozone exposure, when drought conditions prevail, the percentage of uninjured sites is much greater than the percentage of injured sites. Results indicate a declining trend in foliar injury especially after 2002 when peak ozone concentrations declined across the entire region."
Below is a random picture I took in July of 2009 of maple leaves with marginal leaf burn. This is utterly typical of trees the past three summers - and the biomonitoring program supposedly reveals a declining trend in foliar injury?? I. Don't. Think. So.
Notice, the abstract states that PEAK ozone concentrations declined...but neglects to mention that the background levels are inexorably increasing. Personally, I think it's not just possible but likely that it is worse - perhaps far, far worse - for plants to absorb lower but constant levels of ozone all of the time without respite - including nighttime - than to be exposed to occasional transient high doses during daylight when there is UV radiation...because they never get a change to recover. I called Smith a couple of years ago to ask her whether she wasn't alarmed at what the data showed, and perhaps ought to communicate that alarm to public policy makers. She seemed to get rather irritated and responded that partly due to her work in the ozone biomonitoring program, the EPA was going to tighten ozone standards. Well, we know how well that worked out!
I think we should get rid of power tools like mowers, hedge clippers and leaf blowers...for starters. Also, ridiculous trips like the one filmed in this Youtube, a movie which although very cool, is unintentionally revealing of how absurd overpopulation and overconsumption have become...no matter how the Forest Service tries to define current practices sustainable.