President's Address

President’s Talk, delivered at ASEH conference, Tallahassee, February
2009
Nancy Langston, president of ASEH, is professor in the
Nelson Institute for Environmental Studies and the Department
of Forest and Wildlife Ecology at the University of Wisconsin-Madison.
She has recently completed an environmental history of endocrine
disruptors, titled Toxic Bodies: Endocrine Disruptors
and the Lessons of History, which is forthcoming from Yale.
Citation: Nancy Langston, “Paradise Lost: Climate Change, Boreal
Forests, and Environmental History,” Environmental History 14
(October 2009): 641-650.
Nancy Langston
Paradise Lost:
Climate Change, Boreal Forests, and Environmental History
JUST BELOW THE ARCTIC lies the boreal forest, 16 million square kilometers
of conifers that stretches across North America, Scandinavia, and Russia.
The boreal forest makes up one of the world’s largest terrestrial ecosystems,
yet few scholars have explored its interconnected human and ecological
histories. In Smithsonian magazine, the artist Robert Bateman calls
the boreal forest the “completely forgotten” ecosystem.1 While boreal
forests have largely escaped the scholarly gaze, they haven’t escaped
the attentions of commercial forestry concessions, eager to find new
sources of pulp to satisfy the world’s growing appetite for paper. And
now, as concerns about global warming capture public attention, they
are becoming key sites of conflict.
Ecologically, boreal forests share certain important constraints.
They exist in places with extremely cold winter climates and short
growing seasons, and they tend to grow on nutrient-deprived, poorly
drained soils. These are disturbance-prone ecosystems; wind, fire, and
insect activity have historically played roles in shaping these forests.
The scales of these disturbances, however, are changing. Fire intensities
are increasing, insect epidemics are intensifying, and toxic chemicals
are saturating the aquatic ecosystems that make up such an important
part of boreal landscapes.2
For much of the twentieth century, during the development of scientific
forest management, foresters had portrayed boreal forests as naturally
unhealthy forests, impoverished by their particular climates,
soils, and disturbance regimes. Intensive management, foresters
believed, might be able to rescue these forests from their own native
unhealthiness, bringing them into a more modern and vigorous condition.
In the past two decades, ecologists and environmentalists have challenged
these views of boreal forest health, while introducing new metaphors
of health and vulnerability into the conversation. Portrayals of the
boreal forest have changed from a place of sickness, unhealthy cold,
and dangerous airs, to the lungs of a world imperiled by global warming.3
Ecologists now argue that boreal forests are worth protecting because
they make up one of the world’s significant carbon reservoirs.
Boreal regions contain just under 15 percent of the global land surface,
but they contain over 30 percent of all terrestrial carbon, stored largely
in the soil. Low soil temperatures promoted the formation of permafrost
and peat, and low decomposition rates in the cold temperature
meant high rates of carbon sequestration. Yet these boreal carbon stores
turn out to be quite vulnerable to climate change. As temperatures rise,
carbon decomposes faster, and peat and permafrost release their
carbon.4 One of the great carbon sinks of the
world may tip into becoming one of the great carbon sources of the world,
a positive feedback loop that could affect the health of human and natural
communities throughout the globe.
In its introduction to a proposed planning process for the boreal
forest, the Ontario government writes: “Ontario’s Far North Boreal
Forest is one of the last, great, undeveloped spaces on the planet
and a vital carbon sink. ... It is also one of the world’s largest intact
ecosystems. ... The Far North Boreal Forest has remained virtually
undisturbed by humans since the glaciers retreated. But as pressure
for new resources and new places to live increases, that will likely
change. ... Scientists have said that in order to preserve a healthy
ecosystem in the Far North, a minimum of half of the land be protected.”5 The
modern rhetoric of conservation planning, in other words, posits the
forest’s natural condition as a paradise about to be lost. An “essentially
untouched” landscape is about to be sickened by development, unless
planners step in to protect it and restore it for climate change mitigation.
But is forest management really changing in the region? What are
the legacies of history that we need to consider before embarking
on ambitious new plans to manage boreal forests for climate change
mitigation? Will the new management regimes really look any different
from the old management—or will they only be more of the same,
with new language to justify them? Looking at changing rhetorics of
disturbance can help us approach these questions.
Disturbances have always been part of boreal forest ecology. Eastern
spruce budworm moths lay their eggs during the summer on conifer
needles, particularly balsam fir (Abies balsamea) and white spruce
(Picea glauca). Caterpillars overwinter and in the spring feed
upon the trees, killing the trees if enough budworm are present.
Large-scale infestations of the eastern boreal forest occur in cycles
of roughly thirty-five years. The timing and extent of those infestations
depends on many things: spring weather (the caterpillars particularly
like warm dry springs); host populations (large expanses of mature
balsam fir provides an excellent food source for an exploding caterpillar
population).
While these insect cycles are natural, after World War II, they began
to complicate commercial efforts to “fully utilize” the boreal
forest for pulp and paper production. Dead trees and massive fires signaled
an unhealthy forest that required the presence of scientific foresters
who could step in and restore the forests to health. When the
spruce budworm populations exploded in the late 1940s, foresters were
armed with new technologies made possible by the war. DDT could be sprayed
over millions of acres from planes released from military service.
Aerial spraying of DDT did indeed suppress budworm populations, but
only temporarily. By killing off 95 percent to 98 percent of the spruce
budworm in an area, DDT spraying kept the budworms from killing off
all the local spruce and fir. But for the 2 to 5 percent of budworms
that had managed to escape each DDT spraying, those surviving trees
offered a super-abundant food source that stimulated insect reproduction.
Budworm epidemics had, historically, collapsed quickly, when budworm
killed off their own food supply. But now DDT actually prolonged the
budworm cycles, leading to ever more defoliation and ever more spraying
of DDT in an attempt to control the outbreaks.6
When foresters tried to manage the boreal forests by removing small-scale
natural disturbances, they appear to have increased the intensity
and frequency of large-scale disturbances. Clear-cutting, replanting
with susceptible species such as white spruce, fire suppression, and
pesticides may have only led to bigger budworm outbreaks. For example,
the infestation of 1910–1920 defoliated 10 million hectares. The infestation
of 1945–1955, when DDT was first used heavily, defoliated more than
twice the earlier infestation: 25 million hectares. And the infestation
of 1968–1985 defoliated even more: 55 million hectares. As a comparison,
the combined area of New York, Pennsylvania, Maryland, West Virginia,
Virginia, and North Carolina is about 57 million hectares.7
DDT spraying didn’t stop the budworm, but it did ignite concerns
about the environmental effects of massive spray campaigns in
the boreal forests. In Silent Spring, Rachel Carson wrote of the
“rivers of death” created by the intense DDT spraying in the boreal
forests of New Brunswick that began in 1952. The Miramichi River,
once the most abundant Atlantic salmon run in the world, became what
Carson called “a picture of death and destruction.”8 She
described the spraying: “So in 1954, in the month of June, the planes
visited the forests of the Northwest Miramichi and white clouds of settling
mist marked the crisscross pattern of their flight. The spray—one
half pound of DDT to the acre in a solution of oil—filtered down through
the balsam forests and some of it finally reached the ground and
the flowing streams. ... Soon after the spraying had ended there were
unmistakable signs that all was not well. Within two days dead and dying
fish, including many young salmon, were found along the banks of the
stream. ... All the life of the stream was stilled. Before the spraying
there had been a rich assortment of the water life that forms the food
of salmon and trout. ... But now the stream insects were dead, killed
by the DDT, and there was nothing for a young salmon to eat.”9
After
Silent Spring was published in 1962, another five years would pass
before aerial spraying of DDT ended in New Brunswick. In those five years,
12.5 million pounds of DDT were sprayed each year over the boreal forests
of that one province alone. Not until 1985 did the Canadian government
completely ban the use of DDT in forestry (although existing stocks could
be used until 1990).
In the chapter “Rivers of Death,” Carson focused on DDT’s acute poisoning
of fish and insects, while noting that DDT and other pesticides might possess
the potential to alter sexual development and reproduction. In Carson’s era,
no one understood how pesticides might be affecting sexual reproduction, but
we now know that DDT is one of many endocrine-disrupting chemicals that can
unravel the networks that weave together hormone systems and fetal development.
DDT was only the first of many endocrine-disrupting pesticides sprayed in the
boreal forest. In New Brunswick alone, some 220 million pounds of pesticide
were sprayed between 1952 and 1990 in the effort to combat spruce budworm.
Other synthetic chemicals continue to leach into Carson’s Miramichi River.
As the biologist Inka Milewski notes, “effluent from the pulp and paper mill,
plywood mill, groundwood mill, leachate from former and current industrial
chemical dumps, and sewage outfalls create a formidable soup of chemicals through
which fish must pass on their way up the river or out to sea. In addition,
while the magnitude of pesticide spraying has declined, herbicides are still
sprayed to control “nuisance” vegetation in upper reaches of the Miramichi
watershed.”10 Many, if not all, of these chemicals are endocrine
disruptors, so while they may not directly kill fish, they can compromise their
immune systems and change reproduction.
DDT clearly affected wildlife within the boreal forest, but it also had profound
effects on creatures living continents away. In the 1950s, George Woodwell
was a young botany professor at the University of Maine, when the forests he
was studying in northern Maine were doused with DDT. Woodwell grew concerned,
and his investigations showed that only half the DDT sprayed from the planes
actually landed in the forests below. The rest seemed to vanish, and Woodwell
set out to figure where it went. He learned that the DDT solution dried into
tiny crystals that could be easily dispersed on air currents, and eventually
be deposited tens of thousands of miles away. DDT residues, Woodwell learned,
were appearing not just in boreal lakes, but also in the tissues of seals as
far away as Antarctica.11
Much of the DDT used in the 1950s and 1960s within the boreal forests quickly
made its way into the bodies of fish and people. Some of it, however, landed
on the snows of Antarctica and the Arctic, where the crystals froze into the
ice sheets and were immobilized, unable to cause harm. Until recently, that
is. Global warming is now releasing those legacies of history back into the
flesh of polar wildlife and from there into people. The scientist Heidi N.
Geisz and her colleagues estimate that up to 2 to 8.8 pounds of DDT are released
into coastal waters annually along the Western Antarctic Ice Sheet from glacial
meltwater—a discovery with potentially profound consequences for ecosystem
health.12
Even when toxic chemicals such as DDT are banned, their legacies persist.
DDT is not the only example. In the 1990s, Canadian biologists were startled
to find that levels of the pesticide toxaphene were increasing in the
bodies of lake trout that swam in the cold clear lakes of the boreal forest—and
also in the bodies of people who ate those fish. Toxaphene is a potent
endocrine disruptor that can upset reproduction of both the fish and the
wildlife and the people who eat that fish.
High toxaphene levels were puzzling because levels of other persistent organic
pollutants had been steadily decreasing in Lake Superior and other boreal lakes
since the 1980s, after bans on their use had been instituted in North America.
Toxaphene had also been banned in Canada in the early 1980s, but levels of
the chemical were for some reason extraordinarily high—far higher than levels
of PCBs, and other better-known chemicals such as DDT. Lake Superior is cold,
vast, and isolated from industrial centers. Of all the Great Lakes, it is easily
the cleanest, and in many ways it seems almost pristine. So why would toxaphene
be highest in this particular lake, in a region where the chemical had never
been produced and had hardly even been used? And what might that contamination
mean for one of the great recovery stories of modern conservation: the restoration
of Lake Superior fisheries?
Decades earlier, in the 1950s, lake trout in the Great Lakes had been driven
to the verge of extinction. With intensive fishing harvests, invasion by sea
lampreys and alewives, and accumulation of persistent organic pollutants that
affected reproductive health, the cumulative effects had led to a collapse
of lake trout populations, with economic, cultural, and health consequences
for Native peoples and for whites alike. But, in one of the great recovery
stories of conservation, commercial fishing restrictions and the banning of
many persistent organic pollutants led to a substantial recovery. By the late
1980s, breeding populations appeared to have recovered in Lake Superior. Finding
a decade later that lake trout were newly contaminated with toxaphene unsettled
fisheries biologists deeply. Where was that toxaphene coming from?
Researchers initially suspected the culprit was pulp mills lining the Canadian
shores of Lake Superior near Thunder Bay, where deforestation of regional boreal
forests had begun in the 1980s. The harvests supplied a growing paper industry,
which dumped pulp mill wastes directly into Lake Superior. Those wastes contained
chlorine and pine oils, which could combine under certain natural conditions
to form toxaphene. But even after those waste products were regulated, contamination
continued. Researchers soon suspected that the chemical was coming, not from
local, contemporary sources, but instead from sources much more distant in
time and place. The remote boreal forest was not nearly as remote as researchers
had perceived.
Researchers now believe that the chemical continues to be volatized from
old cotton fields in the American South, and that global wind currents may
also be transporting toxaphene still used in Africa into Lake Superior and
other boreal lakes—where it finds its way into fish, and eventually into the
people eating that fish.13 Among those most concerned are indigenous
communities who live along the shores of Lake Superior. Fish is particularly
important for the health of fetuses and young children, and eating fish is
of great cultural significance. But its potential contamination forces communities
to make trade-offs between their beliefs and possible harm to themselves. How
much fish do you eat when it’s culturally important? How much do you eat when
you’re pregnant? These are difficult dilemmas posed by changes in ecosystem
health. Contaminants transform more than the health of lakes, fish, and forests;
they also transform cultural identities as well.
Global warming, like toxic burdens, is transforming ecological relationships
within boreal ecosystems. Insect epidemics are worsening, as increasing temperatures
reduce the frequency of late spring frosts, which means that budworm may have
more time to reproduce in a given year. Changing climates also appear to be
decoupling budworm population cycles from those of its predators, both parasites
and birds. For example, three of the warbler species that feed on budworms
may be shifting north at faster rates than are the budworms, making the birds
less likely to control outbreaks. Rising temperatures, drought conditions,
and insect damage is likely to increase fire frequency and intensity. Changes
in fire frequency not only decrease carbon storage, but they can lead to major
ecosystem shifts: namely, a shift to grassland or grass/shrubland in areas
currently dominated by the southern boreal forests. Current research suggests
that boreal forest in Saskatchewan may well be replaced by grassland vegetation
by the end of the century.14
In Canada, conservationists now warn that less than 8 percent of the boreal
forest is protected from development, while more than half has been opened
for harvests by logging companies, usually by clear cutting. In June of 2003
the Standing Senate Committee on Agriculture and Forestry called for action
to conserve Canada’s boreal forest because it is “increasingly under siege.”15 Even
as environmental groups and Canadian senate committees call for protection
of the boreal forest, commercial ventures are moving quickly to utilize its
resources, as new technologies make previously non-commercial forests accessible
for harvest. Nearly 2 million acres of boreal forest in Canada are now harvested
each year, and 65 percent of that goes to pulp and paper.16
The Canadians have offered protections to some boreal forests, but those
have been largely focused on the northernmost reaches of the boreal forest,
where logging has less commercial viability. The southern boreal forest is
still slated for logging, but that’s where the highest diversity of birds and
other wildlife is found. And that’s also where models predict the boreal forest
will be most stressed by climate change.
Some paper companies are quite explicit about their goals for the boreal
forest: get what’s left before it’s gone. Why let perfectly good fiber go to
waste, especially if the forest is going to die anyway as the climate warms?
Provincial forest managers, however, have adopted the rhetoric of natural disturbance.
In Ontario, for example, outside the provincial parks, most of Ontario’s southern
boreal is slated to be harvested within the century. The Ministry of Natural
Resources argues that they need to open these forests to commercial logging
in order to “renew the forest.” The Ministry’s forestry webpage reassures the
public: “The Ministry of Natural Resources has developed forest policy and
management approaches to emulate natural disturbance. Emulating natural disturbances
includes regenerating Ontario’s forests in natural patterns, ensuring that
the needs of wildlife species are met and healthy, diverse ecosystems are sustained.
... Clear-cuts are a critical component of emulating natural disturbances.”
In this vision, clear-cuts no longer level the forest. They “create desirable
habitat for wildlife species. ... Wildlife species of the boreal forest have
evolved in forest patterns that have largely been shaped by wildfire. Existing
wildlife species will benefit from forest management practices that emulate
natural disturbance patterns.”17
What does this actually mean in practice? In Ontario, the provincial ministry
approves clear-cuts that range up to 12,483 hectares in size—a massive clearcut—justified
by the rhetoric of natural conditions. Other forestry publications urge planners
to shift species composition of the boreal forest from white spruce to rapidly
growing species less vulnerable to climate change and budworm. Genetically
modified trees are particularly promising, one government document suggests.18 As
the document argues, “under conditions of climate change, maintaining species
and ecosystem diversity in the western boreal forest may require increasingly
intensive management policies.”19 So, as the environmental historian
Brian Donahue suggests, “while scientific and cultural understanding of the
forest may be turning in a new direction, actual management may be running
more strongly than ever in the same old direction.”20
Disturbances, like climate change, are indeed part of the natural processes
that have shaped boreal forests since the retreat of the glaciers, and emulating
natural disturbances is indeed a worthy goal for foresters. Much as we might
long for a paradise lost, we know that there’s no past state of perfect health,
stability, and balance to which we can return. Scale, however, matters. Even
though disturbance and extinctions are perfectly natural, we are now facing
a different magnitude of change. The ecologist Sarah Wright writes: “Assemblages
of species are continually cycling, as some forms wink out and others better
suited to a changed environment emerge. As the Earth’s climate warmed following
the retreat of the glaciers, species migrated northward to colonize areas newly
hospitable to them, just as they do today; probably, some species were locally
extirpated from their southernmost extremes as conditions became too warm there.
But the critical difference today is that these changes are happening at break-neck
speed. They are slow on our human time scale, but on Earth’s time scale they
are as sudden and violent... leaving little time for species to adapt and
to maintain their relationships with one another.”21
In a seminar this fall on the past and future of the Great Lakes forests,
we closed with a discussion of global warming. One of our seminar members was
a forest planner from the Wisconsin Department of Natural Resources, whose
job involves trying to plan future forest conditions for the state. She expressed
her frustration at how difficult it was to manage forests given the growing
uncertainties of global warming. “Our forest plans are based on history,” she
argued. “All our desired future conditions, all our allowable cuts, all our
silvicultural treatments—they’re all based on trying to restore forest types
from the past, forest types that we now know are ghosts. We live in ghost forests.
They’ll never exist again. But if we give up on trying to restore historic
conditions, then how can we manage forests? Ecologists tell us to focus on
restoring processes, not historic patterns, but global warming is also changing
those ecological processes. Do we just give up on the southern range of the
boreal forests? On balsam fir, birch, and white spruce in the north woods of
Wisconsin?”22
What’s threatened by global warming is not only the earth, but also ourselves.
What won’t persist is our sense of place and time—our own human histories on
this earth. It’s the places we love, the relationships we cherish with the
species that make their homes in those particular places, that help to make
us human. The naturalist and artist Mary Burns asks, “What will our woodlands
be like without the ethereal call of the hermit thrush or the “zee-zee-zee-zu-zee”
of the black-throated green warbler tumbling down through the hemlocks? Who
will usher in spring when the white throated sparrow’s “Oh, sweet Canada, Canada,
Canada” no longer wakes us?”23
The atmosphere ties us to our planet’s past and to its precarious future.
Each molecule of air that we breathe has circulated through the biosphere time
and again. Those molecules cross scales, moving inwards through our lungs,
and outwards into atmospheric currents that moderate the planet’s temperature
and protect us from the sun’s radiation. Scientists with spare time on their
hands have estimated that one to ten molecules breathed by the Buddha in his
last breath are making their ways through our lungs right now. The carbon taken
up by spruce in the boreal forests may once have moved through your ancestors’
bodies; the carbon in the atmosphere that threatens our shared futures on earth
come from the coal once taken up by plants in ancient forests.24 Across
time and space, the atmosphere connects us all, and it is those connections
that environmental historians are uniquely qualified to illuminate.
Without reference to an ecological past that may no longer resemble our ecological
futures, how will we learn to live responsibly in place? Global warming challenges
us to re-examine what history means to us when we are changing the earth so
quickly that our shared environmental histories are vanishing, possibly never
to be witnessed again.
NOTES
1. Robert Bateman, Quoted in Katy June-Friesen, “Art for Nature’s Sake,” Smithsonian,
December 2006, 29-30. For a useful essay on Canada’s forest historiography,
see Graeme Wynn, review of Ken Drushka, Canada’s Forests, a History, Richard
A. Rajala, Feds, Forests, and Fire: A Century of Canadian Forestry Innovation,
and Richard A. Rajala, “Up-Coast: Forests and Industry on British Columbia’s
North Coast, 1870–2005,” Environmental History 12 (October 2007): 1,016-21.
This October 2007 special issue of Environmental History on Canada provides
a valuable entry into the literature.
2. For example, see Ben Bond-Lamberty, et al., “Fire as the Dominant Driver
of Central Canadian Boreal Forest Carbon Balance,” Nature (2007): 89-92; and
Stephen Pyne, Awful Splendour: A Fire History of Canada (Vancouver and Toronto:
UBC Press, 2008).
3. For insights on the links between landscapes and health, I am indebted
to Conevery Bolton Valencius, The Health of the Country: How American Settlers
Understood Themselves and Their Land (Basic Books, NY: 2002); Gregg Mitman,
“In Search of Health: Landscape and Disease in American Environmental History,”
Environmental History 10 (April 2005): 184-210; and Linda Nash, “Inescapable
Ecologies: A History of Environment, Disease, and Knowledge (Berkeley and Los
Angeles: University of California Press, 2006). For insights on science and
northern environments, Stephen Bocking’s work is invaluable, particularly “Science
and Spaces in the Northern Environment,” Environmental History 2007 (October
12): 867-94, and Nature’s Experts: Science, Politics, and the Environment (Rutgers
University Press, 2004).
4. Eric S. Kasischke, “Boreal Ecosystems in the Global Carbon Cycle,” in
Fire, Climate Change, and Carbon Cycling in the Boreal Forest, ed. Eric S.
Kasischke and Brian J. Stocks (New York: Springer, 2000), 19-30.
5. Office of the Premier, “Protecting a Northern Boreal Region One-and-a-half
Times the Size of the Maritimes,” http://www.premier.gov.on.ca/news/Product.
asp?ProductID=2358 (last accessed 4/25/09).
6. As the botanist George Woodwell noted: “spraying half a pound of DDT in
oil per acre could reduce that year’s budworm population by 95 to 98%, but
next year the remaining population would explode. Spraying only prolonged the
outbreak, in fact, because while it kept the trees from dying, that meant the
few remaining insects had unlimited food, and their populations could explode”:
see “Toxic Food Web,” in Life Stories: World-Renowed Scientists Reflect on
their Lives and the Future of Life on Earth, ed. Heather Newbold (Berkeley
and Los Angeles: University of California Press, 2000), 74.
7. Nicholas Bolgiano, “Cause and Effect: Changes in Boreal Bird Irruptions
in Eastern North America Relative to the 1970s Infestation,” “Spruce Budworm
and the 1970s,” American Birds 58 (2005): 26-33. Online at http://www.audubon.org/bird/cbc/
pdf/104_026-33BUDWORMfeature.pdf.
8. Rachel Carson, Silent Spring (New York: Houghton Mifflin, 1962), 131.
9. Ibid.
10. Inka Milewski, “Rivers of Death Revisited: A Tribute to Rachel Carson,”
online at http:// www.elements.nb.ca/theme/artists/inka/milewski.htm.
11. Woodwell, “Toxic Food Web,” 77; G. M. Woodwell and F. T. Martin, “Persistence
of DDT in Soils of Heavily Sprayed Forest Stands,” Science 145 (1964): 481-83.
12. Heidi N. Geisz, et al., “Melting Glaciers: A Probable Source of DDT to
the Antarctic Marine Ecosystem,” Environmental Science & Technology 42
(2008): 3958-62.
13. Melvin Visser, Cold Clear and Deadly: Unravelling a Toxic Legacy (East
Lansing: Michigan State University Press, 2007).
14. Saskatchewan Environmental Society, “Climate Change and Saskatchewan’s
Boreal Forest: A Saskatchewan Environmental Society Fact Sheet,” Dec. 2003.
Online at http:// www.environmentalsociety.ca/issues/forests/climate-change-boreal.pdf.
15. Ibid.
16. T. Edward Nickens, “Paper Chase,” Audubon, January-February 2009. Online
at http:// audubonmagazine.org/features0901/habitat.html.
17. Ontario’s State of the Forest Report 2006, “Indicators of
Forest Sustainability,” http:// www.mnr.gov.on.ca/MNR_E005239.pdf (last accessed
4/25/09). For other Ontario forestry ministry publications that discuss emulating
natural disturbances, see: http:// www.mnr.gov.on.ca/en/Business/Forests/2ColumnSubPage/241068.html
and http://www.mnr.gov.on.ca/en/Business/Forests/2ColumnSubPage/STEL02_166047.html.
18. J. Thorpe, N. Henderson, and J. Vandall, Ecological and
Policy Implications of Introducing Exotic Trees for Adaptation to Climate Change
in the Western Boreal Forest (Saskatchewan Research Council Publication 11776-1E06,
Saskatoon, Saskatchewan, 2006), 3. A summary is available at http://www.parc.ca/pdf/research_publications/
renamed/SD2008_03.pdf.
19. Ibid.
20. Personal communication, Brian Donahue.
21. Sarah Wright, Paradise Lost? Climate Change in the North
Woods (Madison: University of Wisconsin, Center for Biology Education, 2007),
16; http://www.wisc.edu/cbe/assets/ docs/pdf/paradiselost/paradise_lost.pdf).
22. Anonymous, personal communication, December 2008.
23. Mary Burns, Paradise Lost?, 35.
24. James Rodger Fleming, Vladimir Jankovic, and Deborah R. Coen, Introduction
to Intimate Universality: Local and Global Themes in the History of Weather
and Climate (Sagamore Beach, MA: Science History Publications, 2006), ix-x.