United States
Department of
Agriculture
Forest Service
General Technical Report
FPL–GTR–182
Experimental Forests and Ranges
100 Years of Research Success Stories
Experimental Forests and Ranges
100 Years of Research Success Stories
Gail Wells
Gail Wells Communication
Contributors
Washington Office
Deborah Hayes, Katrina Krause, Ann Bartuska
Forest Products Laboratory
Susan LeVan-Green (Editor-in-Chief), Jim Anderson, Tivoli Gough
Northern Research Station
Mary Beth Adams, Thomas M. Schuler, Randy Kolka, Steve Sebestyen,
Laura S. Kenefic, John C. Brissette, Susan Stout, Keith Kanoti (Maine Forest Service)
Pacific Northwest Research Station
Fred Swanson, Sarah Greene, Margaret Herring (Oregon State University)
Experimental forests and ranges
across the nation
Pacific Southwest Research Station
Martin Ritchie, Carl Skinner, Tom Lisle, Elizabeth Keppeler, Leslie Reid,
Peter M. Wohlegemuth
Rocky Mountain Research Station
Stanley G. Kitchen, Ward McCaughey
Southern Research Station
Jim Guldin, Don C. Bragg, Michael G. Shelton, David Loftis, Cathryn Greenberg,
Julia Murphy
“….and all those selfless souls who kept conducting excellent research on Experimental
Forests and Ranges throughout the years.”
Foreword
Long-term research is the foundation of Forest Service Research and Development. I am pleased to introduce some of the scenery behind this research story—a historic network of experimental forest and ranges.
Experimental Forests and Ranges: 100 Years of Research Success Stories overviews a century of research
by dedicated Forest Service scientists, research that forms the scientific basis for much of present and future
forest management.
The 14 vignettes in this publication are only part of the larger story. The USDA Forest Service maintains
81 Experimental Forests and Ranges across the United States and in Puerto Rico. These valuable scientific
resources incorporate a broad range of climates, forest types, research emphases, and history. They serve as
living laboratories where Forest Service scientists not only learn but also share results with cooperators and
stakeholders. Long-term records on many of these lands date back to the 1930s, when 29 of the 81 experimental forests and ranges were established. They provide an opportunity to conduct the bold, imaginative research
required for a future with natural resources issues such as global climate change, watershed function, invasive
plants, recovery after natural disturbances, among others.
As an ecologist and biogeochemist, I have often reflected on the contributions to watershed research coming
from the experimental forests that I have more personal experience with, namely Coweeta, H.J. Andrews,
and Hubbard Brook. This publication does not cover all, the oldest, or the most famous of our historic forests
and ranges. It offers a few snapshots of research—old and new—on land areas that will continue to provide
knowledge to address new questions and needs of society. We present these stories to illustrate something of
the scientific resource and public benefit represented by this special segment of public lands.
I acknowledge the many contributors to this publication along with the scientists, technicians, and staff who
are bringing this research to fruition. Their dedication, enthusiasm, and passion for these experimental forests
and ranges are the real stories behind these living laboratories. This publication touches on some of their
historic achievements and the pathways they opened for today’s work. In the next century, today’s scientists
will continue this important and exciting work to solve some of the most vexing natural resource problems
that we face.
Deputy Chief of Research and Development
The land cannot speak, but it
can communicate. A change
in the flow of a stream, the timing of bud break on a sycamore
tree, the rate at which shrubs
come in after a wildfire—all these
are messages people can read if
they know the language. That
language is science.
Contents
Introduction ...............................................................................................................................................1
Silviculture
Crossett Experimental Forest, Arkansas—Loblolly Pine, the Miracle Tree .....................................2
Penobscot Experimental Forest, Maine—Leaving Something to Grow On ......................................4
Wind River Experimental Forest, Washington—A Counterweight to Hubris ..................................6
Water
H.J. Andrews Experimental Forest, Oregon—Out of the Comfort Zone ..........................................8
Casper Creek Experimental Watershed, California—The Effects Go On and On ........................10
Fernow Experimental Forest, West Virginia—Tracing the Effects of Nitrogen..............................12
Fire
Blacks Mountain Experimental Forest, California—Trial by Fire ................................................14
Tenderfoot Creek Experimental Forest, Montana—Changing Flows from Forested
Watersheds ...........................................................................................................................................16
Grasslands
Desert Experimental Range, Utah—Old Research Sheds Light on New Questions ........................18
Soil Erosion
San Dimas Experimental Forest, California—A Giant Outdoor Hydrologic Lab ..........................20
Climate Change
Marcell Experimental Forest, Minnesota—The Breathing of Peatlands ........................................22
Hardwood Regeneration
Bent Creek Experimental Forest, North Carolina—Bringing the Oak Forest Back ......................24
Learning from the Past
Blacks Mountain, California; Coram, Montana; H.J. Andrews, Oregon—A New
Look at Old Growth .............................................................................................................................26
Connecting to the Future
Fernow, West Virginia; Kane, Pennsylvania; Bent Creek, North Carolina—Getting the
Science Out ..........................................................................................................................................28
Introduction
100 Years of Success Stories from Experimental Forests and Ranges—Reading the Language of the Land
For a century, scientists of the USDA Forest Service have been reading the language of
the land on a comprehensive network of experimental forests and ranges. These 81 sites
encompass a rich variety of forest and grassland ecosystems across the United States
and Puerto Rico. They range from boreal forest to tropical forest to peat-bog deciduous
forest (Marcell Experimental Forest in Minnesota) to semi-arid chaparral (San Dimas
Experimental Forest in California) to dry desert (Desert Experimental Range in Utah).
In 2008, Forest Service Research and Development celebrated the Centennial Anniversary of these Experimental Forests and Ranges. This publication celebrates the many
scientists who over the course of decades conducted the long-term studies that began
and are continuing to shed light on important natural resource issues. Story suggestions were solicited from the Experimental Forest and Range Working Group and were
selected to demonstrate the array of research issues being addressed on these living
laboratories. Gathering a wealth of information from her interviews with scientists,
Gail Wells proceeded to write these “…wonderful success stories from 100 years of
research.”
Studies established decades ago on many of these sites are still going strong. Experimental forests and ranges provide a valuable, long-term stream of information about the
land and its resources. Over the years, researchers have built an impressive body of science to support good land management and further understanding of natural processes.
Their research sheds light on many important questions. These experimental forests
serve as living laboratories that help us connect the future to the past.
Silviculture: Many Forest Service management regimes have been based on knowledge gained from experimental forests. Much of what is known about old-growth
structure and function came from studies on the H.J. Andrews Experimental Forest
in Oregon and the Wind River Experimental Forest in Washington. Current research
is conveying knowledge of old growth into management of young forests, including plantations. Loblolly pine management techniques were pioneered on the Crosset
Experimental Forest in Arkansas; and impacts of diameter-limit cuts were developed on
the Penobscot Experimental Forest in Maine.
Water: Forests play a critical role in their relationship with watersheds, and many
watershed management strategies came from research on the experimental forests. The
H.J. Andrews Experimental Forest was one of the first to examine the relationship between forest ecology and watershed function. The Caspar Creek Experimental Forest in
California has yielded key information on how logging on steep slopes and riparian
areas can impact sediment flows on watersheds. Research from the Fernow Experimental Forest in West Virginia demonstrated the effects of acid rain on forest soils,
streams, and vegetation and ways to mitigate acid rain.
Fire: A 2002 wildfire on the Blacks Mountain Experimental Forest helped researchers see the true effects of forest thinning—the fire dropped to the ground when it
reached research plots that had previously been thinned. Research conducted on the
Tenderfoot Creek Experimental Forest helped increase understanding of the relationship between fire, water, and forest ecology.
Grasslands: Early trials to rehabilitate ranges on the Desert Experimental Range in
Utah helped pioneer the discipline of range management.
Soil Erosion: Long-term studies on the San Dimas Experimental Forest helped to
answer important questions such as what people can and cannot do about landslides,
floods, and wildfires that characterize chaparral watersheds in California.
Climate Change: The Marcell Experimental Forest in Minnesota has helped
demonstrate the role of forests in mitigating climate change through measurements of
carbon flux into and out of peatland forests.
Hardwood Regeneration: The Bent Creek Experimental Forest in North Carolina was the site of some of the earliest experiments on regeneration of hardwood
species on degraded land after extensive logging. Many other experimental forests
have contributed to a rich body of knowledge about regenerating forests.
Like the land itself, scientific capacity is a resource that needs stewardship. Over the
past century, the Forest Service’s experimental forest and range network has been
utilized to deepen our understanding of problems confronting society and the natural
world—global climate change, species extinction, water quality and quantity, ecosystem degradation, invasive plants and animals. To be good stewards of the land, we
need to understand the language of the land. The following success stories describe
some lessons learned from interpreting the language of the land from this network
of experimental forests and ranges. As the Forest Service celebrates the centennial
of this outstanding network, the emphasis is on continuing this stewardship into its
second century.
1
Crossett Experimental Forest, Arkansas
Loblolly Pine, the Miracle Tree
If it weren’t for the chiggers, ticks, and poisonous snakes, the teeming lushness of a loblolly–shortleaf pine forest might be considered almost Edenic.
These forests cover 10 million hectares (25 million acres) of western Gulf
coastal plain, a rough carpet of lifeforms jostling for light, space, and
moisture.
The most enthusiastic jostler of the bunch is the loblolly pine itself, thrusting its crown above a shoulder-high tangle of understory that includes
poison ivy, honeysuckle, Jessamine, muscadine grape, rattan, and assorted
prickly shrubs and vines.
“Loblolly is a miracle tree,” declares Jim Guldin, project leader at Crossett
Experimental Forest. Guldin has near-evangelical enthusiasm for the qualities of this sturdy conifer. Loblolly pine is a prolific cone producer, a reliable seeder, a fast grower, a generous wood producer, and a hardy dominator
of practically any site it’s growing on.
Silviculture
Most remarkable of all, says Guldin, is the way loblolly can bounce back
from a near-death experience. A stand of loblolly reduced to a bare one-third
of its former abundance of trees—“that’s a stand that looks like a tornado
has hit it, which is often the case”—can be restored to its full glory in
15 years with the right silviculture.
2
“These forests have a tremendous innate fruitfulness, which makes using a
variety of reproduction cutting methods very easy to do,” Guldin says. “It’s
nice to be working in a silvicultural laboratory where the major species is so
productive.”
Because most of the forestland in the South is held by private non-industrial
owners, sustainable and profitable timber management is important not only
to landowners but to the Southern economy. Seventy-five years of Crossett
research have proved that an owner can harvest a continuous flow of timber
from a small tract of loblolly–shortleaf pines, all the while keeping the land
forested, beautiful, and hospitable to wildlife.
Timber has been the economic heartbeat of much of the rural South for
more than 100 years. The Crossett Experimental Forest was formally established in 1934 when the Crossett Lumber Company, owner of thousands of
hectares (thousands of acres) of timber in southern Arkansas and northern
Louisiana, leased 680 hectares (1,680 acres) of its cutover timberland to
the Forest Service for a research station. The company needed scientific
Scientist Guldin points to stand condition in the uneven age “Poor Forty” in
2008, after 72 years of continuous management.
support for managing the second-growth timber that was springing up on
its logged lands.
The Crossett Lumber Company was one of the largest of many that flourished
in the South toward the end of the 19th century, logging the old-growth longleaf, loblolly, and shortleaf pine forests that covered hundreds of thousands
of hectares (thousands of square miles) from the Ouachita and Ozark mountains to the flatlands of the Atlantic and Gulf coastal plains. By the 1930s, the
old-growth forest was almost gone, and most companies had either folded or
moved to richer pickings on the West Coast.
The Crossett Lumber Company was one of the few that stayed. It sold what
land it could, tried unsuccessfully to convert some to ranchland, and finally
resolved to learn how to manage its second-growth timber—a forwardlooking idea at the time, considering that second-growth logs were
considered low-quality material hardly worth milling.
In 1912, a Yale forestry professor, H.H. Chapman, came down to Crossett
with some of his students. They inventoried the Crossett lands and assessed
their regrowth potential. Chapman proposed the foundations of Crossett’s
forestry program, and the company took his suggestions to heart—extending
its logging railroad into second-growth stands, hiring a forester, and adopting
a policy of leaving seed trees on logged sites.
In 1933, the Forest Service assigned Russ Reynolds, a recent graduate of
the University of Michigan’s School of Forestry, to work with the Crossett
In 1937 Reynolds began Crossett’s Farm Forestry study in uneven-aged
forestry, choosing two 16-hectare (40-acre) plots that became known as the
Good Forty and the Poor Forty. Both these parcels had been heavily logged
about 1920 without any thought toward regeneration and had recovered at different rates. “The Good Forty had good stocking of about 5,000 board feet of
pine timber to the acre in 1937,” says Guldin, whereas the Poor Forty had less
than half that amount. But trees still grew on the cutover land, and loblolly
seedlings sprouted like mushrooms each spring. (“God bless loblolly pine,”
Guldin says fervently. “There’s always more regeneration than we know what
to do with.”)
Reynolds set up his trials of group and single-tree selection silviculture on
both parcels, aggressively controlling the competing trees and shrubs and
cultivating the prolific natural regeneration. “By 1951,” says Guldin, “after
15 years of management, both the Good Forty and the Poor Forty were producing between 350 and 400 board feet per acre per year” in harvests every
5 years.
The Good and Poor Forty findings have been confirmed with statistical rigor
in replicated experiments that Reynolds set up a few years later. They’ve also
been confirmed with the record of time through seven decades of repeated
measurements.
The Farm Forestry research showed conclusively that owners of small tracts
of loblolly and shortleaf pine could manage their land profitably without
clearcutting it—even if the forest is damaged from overcutting, ice storms,
high winds, or pine beetles.
For instance, a 16-hectare (40-acre) loblolly stand, managed with any of several variants of selection harvesting, and logged every five years, can yield
2.5 m3 per hectare (400 board feet per acre) of pine timber per year. That’s
about 40 m3 (16,000 board feet) off the parcel every year, “or, put another
way, five really big piles of timber,” says Guldin. As a photo opportunity and
graphic demonstration, Russ Reynolds liked to pile a year’s yield of timber
from the Crossett’s Good Forty in the yard behind the headquarters and invite
visitors in to admire it.
Logs in 1956 photo
show one year of
harvest, which is
equivalent to the annual growth from the
16- hectare “Good
Forty” (seen in the
background).
The message of the Farm Forestry study, in keeping with its Depression-era
roots, is that conservative forest management can pay off. “By cutting less
than what’s possible,” says Guldin, “you can recover those stands to highquality sawlog production quicker than if you clearcut.” Most landowners
can’t afford a big up-front investment in replanting anyway, and with loblolly’s spectacular regeneration potential, they don’t need to, says Guldin.
“Why look a gift horse in the mouth?”
Crossett’s research legacy has not always been appreciated. When Russ
Reynolds retired in 1969, the experimental forest was closed because many
believed that plantation-type silviculture was the wave of the future and
uneven-aged methods belonged in history’s dustbin.
The shutdown might have been permanent but for a clause in Crossett’s
lease: the land had to be used for research or the company would take it
back. Crossett Lumber Company had been absorbed by Georgia-Pacific in
1962, and G-P announced that it would take the land back unless research
resumed. The Forest Service reversed its decision, and Crossett Experimental Forest was back in business by 1979.
The miracle trees kept on growing through the hiatus, and today Crossett
has the most complete long-term data on growth and yield of naturally
regenerated loblolly–shortleaf pine stands in the South. Crossett’s work
continues to be relevant to managed forests throughout the South—not only
on private lands, but also on public lands such as national forests, where
values such as wildlife and aesthetics are often as important as timber.
Silviculture
Lumber Company. One of Reynolds’s first studies demonstrated that smaller
second-growth logs could be profitably yarded with horses and hauled with
trucks—truck hauling was just then becoming practical as local roads improved. The success of these initial efforts eventually led to the establishment
of the Crossett Experimental Forest, which became home to Reynolds and his
family in 1936.
3
Penobscot Experimental Forest, Maine
Leaving Something to Grow On
Imagine a pretty forest tract owned by two brothers in Maine. It’s a mixed forest
of red spruce, balsam fir, eastern hemlock, and eastern white pine, interspersed
with red maples, birches, and aspens. This composition is typical of the Acadian
Forest (the name comes from the early French settlers), a transitional eastern
broadleaf/northern boreal forest that is widespread across the region.
Selection cutting
has maintained
complex forest
structures
and compositions
while improving
tree growth and
regeneration.
Now imagine that the two brothers divide the tract between them and prepare
to do a selection harvest. Each brother wants to leave some of the forest on the
ground. One brother goes into his half and takes all the biggest trees.
The other brother takes his time and thinks about his objectives. He may take a
few big trees and a few more medium-sized ones, paying attention to spacing.
He may remove patches of aspen or birch so that spruce and hemlock seedlings can get established. He may remove the low-vigor or poor-quality trees,
whether large or small.
In short, the first brother focuses on what to take, while the second focuses on
what to leave.
Silviculture
After the brothers are done, their woods don’t look much different to the neighbors. But these forests have been set on diverging pathways, and after 50 years
and a few more harvests, even a casual observer will notice that Brother #1’s
forest doesn’t look so good, while Brother #2’s forest is healthy and vigorous.
4
It all comes down to harvest method, says Laura Kenefic, research forester
and principal silviculturist at the Penobscot Experimental Forest in Maine.
Brother #1’s method, termed diameter-limit cutting or “logger’s choice,” has
been standard practice in the forests of the Northeast for 300 years, ever since
colonists began harvesting masts for the British navy. Diameter-limit cutting
(DLC) is considered a form of high-grading, which means taking the best and
most valuable trees first.
“As a harvesting method, it’s appealing,” Kenefic says, “because it’s so
simple—if a tree is bigger than a certain size, you cut it.” It is also appealing
because it yields immediate revenue.
And initially, at least, it doesn’t seem to do any harm. “From a landowner
perspective, a long-term vision is about one human life span,” says Penobscot
project leader John Brissette. “So people don’t realize what they’re doing.
There’s a tendency to say, ‘We cut over this thousand acres; we’ll just move
on and let the forest heal on its own.’” The problem is that the forest doesn’t
heal itself, because the diameter-limit harvests systematically strip it of its
best trees.
Poor-quality and low-vigor trees, non-commercial species, and clumps
and voids of vegetation are common occurrences in the diameter-limit
cut stands after three harvests.
Kenefic and Brissette have documented startling results from a 56-year-old
experiment, a side-by-side comparison of DLC with various levels of selection and shelterwood harvesting based on silvicultural principles.
The selection cuts (an uneven-aged management method) were done with the aim
of maintaining a wide distribution of tree sizes and improving the quality of the merchantable trees. The shelterwood harvests (an even-aged method), scheduled for a
100-year rotation, involved taking some of the trees, leaving others behind to shelter
the new seedlings, and then removing the rest of the big trees. Some plots were left
alone as a control.
After 56 years and three harvests, the silviculturally managed plots have the most
diverse and productive forests, with thick canopies and an abundance of vigorously
growing conifer trees with good age and size distributions. The DLC plots have
smaller trees overall, slower-growing trees, many small unmerchantable and damaged trees, more gaps and patches on the ground, and a thinner canopy.
Not only are the well-managed forests prettier after 56 years, they’re also more valuable, because the harvest was designed to keep high-quality trees growing all the
time. By contrast, in the DLC plots, Kenefic says, “we found that value per harvested tree got lower over time.” That’s because the most valuable trees were gone
after the first cut, so subsequent harvests have to take more small, low-value trees to
get the same volume.
Kenefic and Brissette are currently studying ways to rehabilitate a stand degraded by
repeated diameter-limit cuts. “But management options are limited,” says Kenefic.
None of this is really surprising. Anecdotal evidence has long held that high-grading
is bad for forests. But the Penobscot experiment, which is both long-term and statistically rigorous, is the first to make a conclusive case. Says Kenefic, “Now we have
data to persuade people to apply sustainable forestry practices instead of diameterlimit cutting.”
The Penobscot findings, says Kanoti, should interest two kinds of landowners in
particular: those who want to make money right away, and those who don’t want to
harvest at all for fear of losing their forest’s scenic value. The study, he says, is “a
powerful tool to inform landowners that there are options that can generate revenue
for them quickly, yet leave a good forest legacy for their children.”
Researchers in the 1950s
initiated a variety of
treatments, resulting in
greatly differing forest
conditions today.
Silviculture
For many landowners, seeing is believing, says Keith Kanoti, landowner assistance
forester for the Maine Forest Service. “When they look at the pictures, they’re
amazed that the 10-year selection [one of the selection-harvest trials] looks as beautiful as it does—with multiple layers, light filtering through small canopy openings,
vigorous healthy trees—because trees have been harvested there every 10 years for
the last 50 years.” The contrast with the degraded DLC stands “allows them to see
that there really are a lot of different ways to do things in the woods.”
5
Wind River Experimental Forest, Washington
A Counterweight to Hubris
Munger using
calipers to remeasure
a permanent plot.
Three generations of scientists have left their mark on the Wind River
Experimental Forest. Each was striving to answer the important questions
of the day, and each left behind a wealth of data, a legacy for those who
followed.
Thornton T. Munger installed the first studies at Wind River nearly
100 years ago. His work on the basic ecology and management of Douglasfir led to techniques for managing it profitably through a replanting and
second rotation. His work helped prove that the timber business could profit
by turning from destructive, cut-out-and-get-out ways and embracing longterm land stewardship.
The second generation at Wind River took the early, basic silvicultural work
into the technological age. To help meet the booming post-World War II
demand for lumber, Leo Isaac, Roy Silen, Robert Tarrant, George Staebler,
and others developed management techniques for growing trees quickly and
efficiently.
Silviculture
The third generation of scientists faced a different social imperative—
concern about overuse and degradation of forests, especially old-growth
forests. For Jerry Franklin, Dean DeBell, Tom Spies, and others working
from the 1970s through the end of the century, the task was to find ways to
manage forests more the way nature does.
6
Now a fourth generation is coming on, and a new concern has emerged:
global climate change. Today’s researchers are taking measurements of carbon from the air and soil, and they’re studying the canopies of old-growth
forests from a basket dangling from Wind River’s famous canopy crane.
The one constant amid the shifting social questions and research agendas
has been the forest itself. Not that things have stayed the same there—the
forest has grown and changed through time too. But the knowledge gained
through these long-term investigations has become a priceless resource.
“This is a place that is protected in space and through time,” says Peg Herring. “That gives us the opportunity to learn things we could never learn
without it.”
Herring, a science writer, is coauthor, with Sarah Greene, of Forest of Time,
a 2007 history of the Wind River Experimental Forest. “The research questions don’t remain constant,” says Greene, a forest ecologist and the recently
retired manager of Wind River, “and so there’s an ebb and flow to how
much [a single experimental forest] is contributing at any given moment to
the important topics of the day. But you still have the place, and you still have
the long-term data sets.”
Thornton T. Munger clearly had longevity in mind when he installed the first
permanent Douglas-fir study plots at Wind River in 1910. Munger, a young
New Englander who had come west to study ponderosa pine, quickly realized
that Douglas-fir was the commercial species of greatest importance west of
the Cascades. He saw, too, that wildfires and destructive logging were making
a sustainable timber industry impossible.
Munger began his work in a hilly, fire-scarred, multi-aged forest near the
Wind River in south-central Washington. He located stands of successive
ages—40, 50, 60, 70, 80 years—and began measuring them to determine their
pattern of growth decade by decade. He found that Douglas-firs not only grow
fast, but add wood in a predictable pattern through time. That meant it was
possible to calculate rates of return from an investment in reforestation.
To document his hypothesis, Munger established 0.4-hectare (1-acre) permanent growth plots in young forests at Wind River and elsewhere in western
Washington and Oregon. He measured every tree larger than 64 millimeters
(2.5 inches) in every plot and set up a study plan to continue the measurements in perpetuity. Although some of Munger’s plots have succumbed to logging or blowdown over the years, the remaining ones are still being measured
by Wind River scientists.
Munger and colleagues Julius Hofmann, Leo Isaac, and other early researchers conducted studies on every aspect of Douglas-fir management: tree
heredity, matching of seed sources to the planting site, spacing of seedlings,
thinning, pruning, fertilization, weed control, and cultivation of nursery
seedlings. Leo Isaac in particular made significant advances in knowledge
of natural reproduction in Douglas-fir, and his work is still being used
today.
Munger also established an arboretum for testing the growth of exotic tree
species. He also set aside a 480-hectare (1,180-acre) patch of old-growth
forest as a research natural area, so scientists could observe how Douglas-fir
forests grow in the absence of management.
In the process of doing their science, these researchers amassed a large
body of data about Douglas-fir—knowledge that is now so common it is
taken for granted. “Lots of things seem obvious now that weren’t obvious
then,” says Greene.
The second generation of scientists built on the findings of Munger, Isaac,
and the others. Working during the boom times between the end of World
War II and the mid-1970s, they developed silvicultural and harvesting techniques to grow timber as quickly and efficiently as possible, which was the
priority of the day.
That legacy has not always been appreciated. In the mid-1980s, Wind River
scientists were directed to pull the plug on Munger’s permanent plots. They
were too expensive and time-consuming to maintain, the rationale was, and
surely there was nothing more to learn from them. But the scientists went
on taking the readings anyway, “and that was good,” says Herring, “because
those data were needed later.”
The longevity of an experimental forest, she says, provides a bracing perspective amid short-term jolts such as a booming housing market or a spate
of environmental lawsuits. “It’s always tempting to assume we’ve found the
answer and don’t need the data any more,” she says. “But an experimental forest is a counterweight to hubris. The questions may change, and the
social setting may change, but we’re never done learning.”
Herring, Margaret; Greene, Sarah. 2007. Forest of Time: A Century of Science at the Wind River Experimental Forest. Oregon State University Press,
Corvallis, OR.
Researchers taking twig
samples in the upper canopy
of an old-growth western
redcedar.
Silviculture
The third generation, concerned with the ecological functioning of the forest, also drew on Wind River’s growing legacy of data for their studies of
wildlife habitat characteristics, the roles of fungi and mites and spiders, and
the effects of canopy gaps, among many others.
7
H. J. Andrews Experimental Forest, Oregon
Out of the Comfort Zone
It took a perfect storm of distinctive geography, a politically fraught research
agenda, and proximity to a research university (Oregon State University, in
Corvallis) to turn the H.J. Andrews Experimental Forest away from a narrow
focus on commercially logged watersheds and toward an interdisciplinary
program of ecosystem science.
The Andrews Forest is part of the vast, productive Douglas-fir region of
the Pacific Northwest, where forests have shaped the region’s economy and
way of life. In recent decades, forests have been a battleground in a cultural
war over environmental protection. It’s been observed that forest management in Douglas-fir country can be a combat sport, and the Andrews Forest’s
research on old growth, stream ecology, and wood decay has exposed its
scientists to both public acclaim and public wrath.
In their recent histories of the Andrews Forest, Max Geier (Necessary Work,
2007) and Jon Luoma (The Hidden Forest, 2006) portray it as a crossroads
where experts on forest ecology, silviculture, soils, wildlife, fish, streams,
and landscape dynamics push themselves out of their disciplinary comfort
zones. The forest has become a natural and human environment that links
“people, place, and community with an emerging vision of ecosystem management,” in Geier’s words.
Water
This vision, says Fred Swanson, might seem inevitable in hindsight, but it
was mostly the product of a succession of rewarding accidents. Swanson, a
research geologist who recently stepped down as Andrews Forest lead scientist, joined the International Biological Programme at the Andrews Forest in
1972, as ecosystem science was just beginning there.
8
The coniferous forests of the western United States have three (at least)
distinctive native features: big, old trees; cold, fast streams; and lots of dead
wood. These are topics that lend themselves to interdisciplinary research
anywhere. It happened that, in western Oregon in the 1970s, they also were
harbingers of a brewing environmental war. “We didn’t set out to study
old growth,” Swanson says. “We studied old growth because that’s what
was here.”
When the Andrews Forest was dedicated in 1948, the main purpose of its
research was to quantify the effects of commercial logging on watersheds
and find ways to mitigate its environmental impacts, especially on stream
flow and water quality. It was a time when enlightened management philosophy called for liquidation of “decadent” old-growth forests to make room for
fast-growing, “thrifty” plantations.
A snowy winter
day at the Mack
Creek gauging
station within the
Andrews forest.
Then, in the mid-1960s, that philosophy began to shift. Andrews Forest researchers, led by forest scientist Jerry Franklin and soil scientist Ted Dyrness,
questioned the assumption that old-growth forest was nothing but overripe
timber. (This story has been told in colorful detail in Geier, Luoma, and elsewhere.) The work of these scientists began to reveal old forests for what they
are: complex ecosystems with processes of living and dying going on all the
way from soil microorganisms to lichens at the tops of the tallest trees.
The Andrews “Stream Team,” first led by aquatic ecologist Jim Sedell and
later by Stan Gregory, began probing the function of wood jams commonly
found in old-growth forest streams. Common wisdom, backed by the latest
fisheries research, said dead wood choked the stream and blocked passage for
the fish. So loggers were routinely (and expensively) hauling all wood out of
streams after a logging operation, even the pieces that had been there before.
The Stream Team turned common wisdom on its head. Their studies showed
that dead wood provides calm pools where fish can rest, gravel bars for
spawning, and cover from predators. And it harbors insects fish need for food.
The Stream Team’s work was first featured at a major 1975 conference that
brought together scientists, forest managers, loggers, and timberland owners.
There followed a rapid about-face in standard forest practices. This marked
one of many translations of Andrews research into policy.
If dead wood is ecologically valuable in the water, shouldn’t it be just as valuable on land? Mark Harmon, a forest ecologist at Oregon State University,
began a remarkable experiment in 1985 to look at decomposition processes in
dead logs at the Andrews—more than 500 of them, carefully chosen to be free
of defects and to represent a broad range of decay rates.
Harmon designed his research to last 200 years, which garnered him skepticism and even derision from some colleagues. There was also hostility from
the neighboring town of Blue River, which, like many Oregon timber towns
at the time, was suffering economically. It galled some people to see perfectly
good logs rotting on the ground.
But Harmon’s careful study design won the respect of colleagues, and his
gentle explanations to the forest workers—the loggers who felled the trees
and the equipment operators who placed the logs—smoothed the waters with
the neighbors. The study prompted Harmon to coin a whimsical new term,
“morticulture.” The word, says Swanson, “crystallizes the importance of a
science for management of dead wood to parallel the science of silviculture
for managing the living parts of a forest.” Two decades in, Harmon’s study
has begun to yield important findings about the role of dead wood in wildlife
habitat, carbon dynamics, and nutrient cycling.
Andrews Forest research has continued to influence public policy. A major
example is the ecosystem science that went into the conservation plan for
the northern spotted owl, listed as threatened in 1990, and eventually into
the Northwest Forest Plan. Another is the 1990 paper (Harmon was the lead
author) showing that cutting old forests and replacing them with new ones
would raise carbon output into the atmosphere, not lower it as some political
leaders were claiming.
The Andrews Forest is collaborating with sister experimental forests to function more as a true research network. “Surprisingly, there’s been very limited
networking among experimental forests until now,” says Sherri Johnson, a
stream ecologist and the Andrews’s lead Forest Service scientist. “We are beginning collaborations that build on research findings from individual sites.”
None of these accomplishments would have been possible, says Fred Swanson, without a long-term relationship with the land. “We can carry out planned
learning through hypothesis testing with experiments, but totally surprising
discoveries are tremendously important, too. Because of this long-term relationship with place and one another, we can look back and say, ‘Wow! Look
at all those serendipitous lessons we learned!’”
Geier, Max. 2007. Necessary Work: Discovering Old Forests, New Outlooks,
and Community on the H. J. Andrews Experimental Forest, 1948-2000. USDA
Forest Service Pacific Northwest Research Station, General Technical Report
PNW–GTR–687, Portland, OR.
Luoma, Jon. 2006. The Hidden Forest: Biography of an Ecosystem. Oregon
State University Press, Corvallis, OR.
Lookout Creek flowing past oldgrowth Douglas-fir and western
redcedar in the Andrews forest.
Water
The Andrews Forest is also the base of a close research-management partnership with the Willamette National Forest, within which it is situated. The
partnership carries out communications programs and studies of landscapescale management and management of young plantations. For these reasons
the site was designated the Central Cascades Adaptive Management Area in
the 1994 Northwest Forest Plan to function as a testing ground for a range of
management strategies.
9
Caspar Creek Experimental Watershed, California
The Effects Go On and On
Between 1963 and 1967, researchers at Caspar Creek Experimental Watershed made preliminary measurements for a paired-watershed logging
study on California’s redwood coast. The effects of logging would be
identified by comparing flow and sediment measurements from a logged
watershed with those from a similar, unlogged watershed.
Stream gage
and sediment
sampling station
in a tributary
of North Fork
Casper Creek.
The study site was a wet coastal forest that had been logged around the
end of the 19th century and was now covered with fast-growing 90-yearold redwoods. The study would document the effects of a tractor-yarded
selection harvest on the South Fork of Caspar Creek that would take out
about two-thirds of the timber. (In tractor yarding, the logs are dragged
out of the woods by a bulldozer.) The operation would start with extensive
road-building.
Researchers expected that the South Fork operation would have a substantial effect on the landscape of the 400-hectare (1,000-acre) watershed. And
when the operation took place between 1967 and 1972, indeed, it hit the
watershed pretty hard. Sediment more than tripled from the road-building
in 1968, and then doubled again when the site was tractor-logged from
1970 to 1973. Major post-logging landslides occurred, peak streamflows
increased, and numbers of coho salmon in the South Fork declined.
Water
The magnitude of the effects was not a surprise to those early researchers, says Liz Keppeler, a hydrologist who oversees the research at Caspar
Creek. In the 1960s and early 1970s, logging operations were mostly
unconstrained by the kinds of protective rules taken for granted today.
“There were no requirements to leave a buffer along the stream, for example,” she says. “You could even drive a bulldozer in the streambed, and
they did.”
10
The researchers did expect peak streamflows and sediment to settle back
to pre-logging levels relatively quickly. These expectations also seemed
reasonable, and after a few years they seemed to be coming to pass:
streamflows and sediment levels in the South Fork were declining,
and salmon numbers seemed to be rebounding.
In 1985, with recovery from the South Fork logging well underway, the
scientists moved on to a second watershed-scale experiment, planning a
cable-yarded clearcut harvest in the North Fork watershed. This operation
too produced a pulse of sediment and higher peak flows, but the sediment input was not as extreme as it had been in the South Fork. The cable
yarding was much lighter on the land because it required fewer roads,
and skid trails were constructed only in the few low-gradient areas that
were yarded with tractors.
The simple conclusion—and a correct one—would be that logging with
bulldozers in such steep, wet country is hard on the environment. And
indeed, the California Forest Practice Act, passed in the early 1970s, sets
forth forest-practice rules that, among other things, restrict where bulldozers can operate (not through a stream, for instance), limit the size of a
logging operation, and require that trees be left along streams to protect
the channel and its riparian environment.
Caspar Creek scientists can’t claim credit for the whole forest practice
law, says Tom Lisle, research hydrologist and program leader at
Caspar Creek, “but our work has helped make and refine the rules.”
Thanks in part to Caspar Creek research, the days of unregulated
logging are forever past. And that, says Lisle, is the beauty of hard
data: “You can always deny there is an effect, until somebody actually measures it.”
Yet the Caspar Creek story does not end here. In the early 1990s,
the sediment levels in the South Fork—thought to have recovered
from the logging—started creeping higher. Lisle and Keppeler attribute this to the gradual failure of roads and culverts constructed
during the logging. This hypothesis is in keeping with other findings on logging and roads in steep, moist coastal forests.
“The point,” says Liz Keppeler, “is that the effects go on and on.”
Indeed, she notes, the watershed was surely greatly altered by the
original, turn-of-the-century old-growth logging, although it is
impossible to know how much because there are no baseline prelogging data.
The California Division of Forestry and Forest
Service have worked together to maintain a
continuous record of stream flow and sediment
transport in Casper Creek since 1962.
Water
“But if we’d walked away from the forest in 1985 after measuring
the effects of the South Fork selection cuts,” says Keppeler, “we
would have a very different story from what we have now. This underscores the value of these long-term experiments, this long-term
data set. If we walk away from here tomorrow, we will never know
what long-term effects we failed to discover.”
11
Fernow Experimental Forest, West Virginia
Tracing the Effects of Nitrogen
Workshops
on the
Fernow.
Fernow Experimental Forest lies squarely in the path of windborne air pollution from the Ohio Valley. It’s not hard to understand why scientists there
have a longstanding interest in acid rain. Recently, acid-rain research at Fernow has moved from the greenhouse level to encompass entire watersheds. It
is yielding new findings about nitrogen, one of the chief culprits in acid rain.
For decades, acid rain—the common name for the deposition of air pollution
containing sulfur, nitrogen, and other acidifying agents—has brought stress
and damage to forests all along the eastern seaboard. Among the hardest hit
have been those of the Allegheny Mountains of West Virginia, whose diverse
and high-value forests collect smokestack emissions and auto exhaust from
Pittsburgh and other heavily populated industrial areas to the west.
Long-term research at Fernow and other experimental forests (notably Hubbard Brook in New Hampshire) supported amendments to the 1970 Clear Air
Act mandating cars that burn fuel more efficiently and cleanly and reductions in sulfur emissions from factory smokestacks. These laws are mostly
concerned with sulfur, the main damaging agent in acid rain. But no clean-air
legislation has yet addressed nitrogen, a common pollutant that comes from
car exhaust, fossil-fueled factories, and agricultural fertilizers.
Water
“I grew up in Indiana,” says Mary Beth Adams, forester and soil scientist at
Fernow, “and one of the smells of spring was ammonia [a nitrogen compound]. The farmers would apply it to their fields, and it would volatilize
and escape and come down later somewhere else.”
12
Nitrogen is, of course, necessary for life on earth. It is the most abundant
component of air and an essential nutrient for plants. But too much can disrupt the workings of streams, lakes, and wetlands. Adams and her colleagues
are looking into nitrogen’s effects on upland plant communities, including
forests. They want to know whether excess nitrogen is causing hard-to-detect
but potentially serious long-term problems.
Excess nitrogen lowers the pH in soils, making them more acidic. Along
with sulfur, it can rob the soil of essential nutrients, particularly calcium and
magnesium. In some plant communities, this alteration of soil chemistry
leads to a host of destabilizing effects: reduced soil fertility, changes in plant
and wildlife communities, increased susceptibility to invasive exotic plants,
and in some tree species, increased susceptibility to wood-attacking insects.
“For reasons we don’t fully understand,” says Adams, “invasive species seem
to be more efficient at using nitrogen than native plants.” The nitrogen may
be boosting the invaders’ growth and making them more competitive. Forest
trees can absorb some extra nitrogen, but it seems to make them more attractive to insects and perhaps to browsing deer, too.
If more nitrogen enters a watershed than the trees and other plants can absorb,
it runs off into streams, contaminating downstream drinking water with nitrate
and causing algal blooms that deplete dissolved oxygen. Or it vaporizes into
the air and becomes a greenhouse gas.
Adams and her colleagues at Fernow are studying the effects of introduced
nitrogen, using watersheds of approximately 40 hectares (100 acres). They
aerially apply ammonium sulfate fertilizer at double the rate that nitrogen and
sulfur are found in rainfall, and then measure how the nitrogen makes its way
through the system.
Because the watersheds are equipped with gauges to measure precipitation
and streamflow, “we know what’s coming in and what’s going out,” Adams
says. The scientists calculate how much nitrogen remains in the watershed
and measure where it goes—how much to the soil, how much to the plants,
how much to the stream environment. “We’re mainly looking at the flow of
nutrients over time,” says Adams. “And we measure repeatedly, so we get an
idea of the trends.”
The Fernow’s watershed acidification study is one of only two in the
United States. “The reason this kind of work is rare,” says Adams, “is that
it’s hard to find watersheds that can be dedicated to long-term manipulative research, such as those we have here.”
Not much is yet known about how excess nitrogen might affect the animal
life in the Fernow watersheds, but preliminary work on salamanders offers
a clue. Researchers are looking into the stomachs of salamanders to see
what they’re eating. They’ve found more ants in the stomachs of salamanders in the nitrogen-dosed watershed than in those from salamanders in
untreated watersheds.
Ants are a low-quality food for salamanders because their crusty carapaces make them hard to digest. Could the nitrogen have altered the insect
community in a way that affected the salamanders’ food supply? The
nitrogen treatment made the environment more acidic, and salamanders do
not thrive in high-acid environments. The degree to which the nitrogen is
responsible for difference in the salamanders’ diet is not yet documented,
says Adams. “But it’s an intriguing idea that we’ll follow up on.”
So far, the effects of excess nitrogen are most noticeable at the smaller
scale: changes in water chemistry, soil nutrients, fungi, and some insects.
The forest as a whole has not changed perceptibly. “The trees don’t seem
to care about the nitrogen,” says Adams. “They’re still growing well; there
are no major signs of decline, no holes in the tree canopy, no trees falling
over dead.”
This may be a testament to the resiliency of forest ecosystems. But in
forests, as in humans, chronic, low-level stress can have severe consequences later on. The Fernow scientists are trying to determine whether
nitrogen poses that kind of stress to the Allegheny’s forests. If it does, “we
don’t know what the tipping point might be,” says Adams, “so continued
vigilance is important.”
Entrance to the Fernow
Experimental Forest on an
autumn day.
Water
In fact, only a few incidents of damage to forests from acid deposition in
rain are well documented: high-elevation red spruce in the northern Appalachians and Adirondacks, pine in the Los Angeles basin, and sugar maple
in Quebec and a few areas in northwestern Pennsylvania.
13
Blacks Mountain Experimental Forest, California
Trial by Fire
When Martin Ritchie and his colleagues at Blacks Mountain Experimental Forest
installed a research project in 1996, they were hoping to better understand the role
that stand structure and fire play in the interior ponderosa pine forests type. They
also hoped to gain insight into the use of fire and thinning to make stands more
resilient to fire and other disturbances.
Prescribed fire
in an unthinned
research area
at Blacks
Mountain
Experimental
Forest.
They didn’t count on getting results quite so soon, but wildfires happen on their
own schedule. A fire that swept down from nearby Blacks Mountain in the dry
autumn of 2002 gave the experiment a rigorous real-world test.
The fire roared through the crowns of the untreated parts of the forest, killing
all the vegetation in its path. But when it reached plots that had been thinned, it
dropped to the ground immediately. In plots where researchers had followed the
thinning with prescribed burning, the fire was halted even more dramatically—
in one instance expiring before it reached a firebreak.
The Cone Fire burned about 600 hectares (about 1,500 acres) of Blacks
Mountain Experimental Forest, about one-sixth of the total area, including 3 of
the 12 treatment units. Fire behavior experts estimated that if none of the forest
had been treated, the fire might have burned closer to 3,200 hectares (8,000 acres).
“So we lost some of our treatments,” says project leader Ritchie, “but we learned
some interesting things.”
Fire
Blacks Mountain Experimental Forest lies in a gently rolling basin northeast of
Mount Lassen at an elevation of about 1,645 meters (5,400 feet). The forests are
dominated by ponderosa and Jeffrey pine, intermixed at higher elevations with
white fir and incense-cedar. The lower-lying areas have an understory of bitterbrush, sagebrush, and grass. It is a dry landscape, receiving a little over 460 mm
(18 inches) of precipitation yearly, most of it as snow between October and May.
14
Studies on commercial logging of ponderosa pine began at Blacks Mountain in the
mid-1930s. In 1933 and 1934, after it received its official research designation, the
whole forest was inventoried and each tree larger than 100 mm (4 inches) in diameter was mapped, giving later researchers an invaluable baseline for comparison.
Even after the early logging studies, quite a bit of old-growth ponderosa pine remains on the forest. Recently the research at Blacks Mountain has focused on fire,
both wild and prescribed. Scientists are particularly interested in the ways in which
wildfire has shaped this forest over time, and also possible methods for using fire
as a tool to reduce wildfire risk in both managed and reserved forests.
Before European-American settlement, ponderosa pine forests of the interior
West tended to experience frequent wildfires, although the pattern of frequency
and severity varied widely from place to place. From evidence at Blacks Mountain, including rings from living and dead trees (which can reveal not only the
year but the season a fire occurred), fire ecologist Carl Skinner and his colleagues are developing the most comprehensive picture yet of early fire patterns.
“We’ve detected evidence of fire on 70% of the plots across Blacks Mountain
every 14 years,” says Skinner. “We’ve also looked at scarring of the trees in
sequential fires, and we’ve found that you rarely get scarring of the same tree in
successive fires.” This suggests a pattern of frequent, extensive fires that left a
mosaic of burned and unburned patches across a wide landscape.
Because the fires burned so widely, says Skinner, the summer air was likely
full of smoke. “Today’s visitors wouldn’t appreciate the vistas,” he says with
a smile. “I tell people that that’s what pristine air was like back then.”
The fire pattern is different today, of course, because fires have been systematically excluded from most forested areas for over a century. Until the 2002 Cone
Fire, Blacks Mountain had experienced no fire at all for 70 years. Its forests
have responded by packing more vegetation into their understory—in particular,
young ponderosa pine at lower elevations and white fir higher up, which get a
toehold in the absence of fire. The densely packed young trees grow to compete
with the older, dominant pines for scarce water.
The result, says Martin Ritchie, is that “the old-growth component in these
stands is falling apart.” The large, old pines are dying, and the younger ones
can’t grow fast enough to replace them. Left to itself, the forest will not
recover the character that most people associate with old-growth pine forests: the
stately, golden-sided pines reigning over an open, parklike understory.
“There is a thought among some people that if you just stand back these forests will
recover on their own,” says Ritchie. “But they will never recover in the absence of fire.
They’ll just be dense stands of smaller ponderosa pine and fir, until some catastrophic
event, resulting from fire or bark beetles, sets them back to the beginning of the cycle.”
Or unless human management—thinning or burning or both—can effectively mimic
natural fire. In the 1996 thinning and burning experiment, researchers created two different forest structures on plots within the old forest. In one treatment, called “Hi-D”
(high-diversity), the areas within the drip lines of mature trees were cleared and the
rest of the forest was thinned, leaving snags and some dense clumps of smaller live
trees. Overall, more biomass was left standing in this treatment, which was similar to
a non-commercial thinning that might be done to enhance ecosystem values and
reduce ladder fuels.
In the “Lo-D” (low-diversity) treatment, all the mature trees were logged and much
of the understory was thinned heavily, leaving a middle canopy layer of younger pine
and fir. Overall, less biomass was left behind in this treatment, which was similar to
an overstory removal. Half the plots in each structure were treated with prescribed fire
after the thinning, to remove even more potential fuel.
More importantly for the future, the thinning and burning treatments seem to be jumpstarting the growth of the pines. In the Lo-D treatments, says Ritchie, researchers
expected to see more growth out of the individual trees but less out of the stand as a
whole, because so many of the smaller trees had been thinned out. “But not only was
tree growth higher, stand-level growth was higher.”
Even the older trees in the Hi-D plots have responded with greater growth. “We’ve
wondered if it was too late to treat these older stands for maintaining high structural
diversity,” Ritchie says. “The answer we found is, no, it’s not too late. At least in the
short term, we’ve maintained the health and vitality of these old-growth stands by thinning. It will be interesting to see what happens in the long haul, but for now it seems to
be working.”
High-diversity treatment
unit 10 years after thinning
at Blacks Mountain
Experimental Forest.
Fire
The research team at Blacks Mountain is evaluating the ongoing effects of the two
treatments, in both the areas hit by the Cone Fire and the areas spared. Among the preliminary findings: the low-diversity treatment with fire seems to be the most effective
in making the forest wildfire-resilient. Nearly all the trees in the Lo-D plots survived
where prescribed fire was used before the wildfire. But even the Lo-D plots that had not
had prescribed fire fared better in the wildfire than the untreated plots. The old-growth
trees in the Hi-D treatment area generally fared well, although a few along the edge
were weakened by the wildfire and died over the next couple of years from scorch or
attacks by bark beetles.
15
Tenderfoot Creek Experimental Forest, Montana
Changing Flows from Forested Watersheds
In the far-distant past, when wildfires visited the rugged ridges and plateaus
of Tenderfoot Creek Experimental Forest, they tended to burn extensively.
In recent decades, however, fires that have come have been more contained,
burning less of the landscape. This shift in wildfire patterns has produced a
cascade of effects, altering the age and composition of the forests and potentially changing the amount and timing of the water that flows into the rivers
and reservoirs below.
Designated in 1961 as a hydrologic laboratory, Tenderfoot Creek EF occupies 3,726 hectares (about 9,200 acres) of forests, wet meadows, and
drier grasslands in the Little Belt Mountains of north-central Montana, just
east of the Continental Divide. Its dense stands of lodgepole pine and pine/
Engelmann spruce are typical of about 6 million hectares (almost 15 million
acres) of fire-influenced mid- to high-elevation forests across the Rockies.
Mountain forests like these are important for human communities downstream because they collect water as snow and disburse it in the spring for
drinking, hydroelectric power, irrigation, and recreation. Watersheds on
the dry east side, such as the Tenderfoot Creek EF, are particularly worthy
of study because they are greatly influenced by year-to-year variability
in precipitation. Experimental Forest manager Ward McCaughey and his
colleagues are studying precipitation and runoff patterns, trying to quantify
how water from snow makes its way into the ground through a forest community that is changing in response to changing fire patterns.
Fire
The higher reaches of the forest at the Tenderfoot Creek EF are dominated
by stands of pure lodgepole pine, with a few stands of mixed pine, fir, and
spruce. This forest is the very definition of “doghair”—tall, skinny trees in
crowded stands with dead boles fallen every which way, like jackstraws.
The forest floor is thickly carpeted with grouse whortleberry, a huckleberry
relative. Spread across the lower slopes of Tenderfoot Creek are broad
“parks,” or meadows, with ribbons of aspen nestling in their moist creases.
16
The slenderness of the standing pines—they are 30–36 cm (12–14 inches)
in diameter—can deceive a person trying to guess their age, McCaughey
says. Unlike ponderosa pines, which are thinned to open stands by frequent,
low-intensity fires, lodgepole pine typically grows from adolescence to old
age as a cohort. “This type of forest is generally shaped by low-frequency,
high-severity stand-replacement fire,” says McCaughey. “These stands can
Gail Wells (author)
standing next to
entrance sign for the
Tenderfoot in early
June 2008. Snow
can occur in any
month of the year in
most high-elevation,
subalpine forests
of the Northern
Rockies.
get to be 200 years old, if another fire doesn’t come along first, although we are
finding that occasional low-intensity fires are creating some two-aged stands.”
The oldest stands on the forest date from a big fire in 1580, which burned more
than half the area now falling within Tenderfoot Creek’s boundaries. The last fire
of any size was in 1873, burning more than a third of the experimental forest. By
the beginning of the 20th century, these big fires had ceased. A 1902 fire burned
about 6% of the forest, and three subsequent fires burned less than 1% each.
“So we’re far outside the historical range of fire frequency and extent,” says
McCaughey. As a result, the forest has grown older, and there are fewer open or
early-successional stands. To find out how these changes in forest composition
and canopy coverage might be affecting runoff, McCaughey and his colleagues
started with nearly 20 years of hydrological data collected at Tenderfoot Creek,
along with 50 years of measurements of nearby streams.
Using data from several Montana watersheds, McCaughey and his team estimated the amount of runoff that would be produced by a given forested watershed if
the land were bare. Then they analyzed 5-year snow and rainfall data from nearby weather stations and SNOTEL (snow telemetry) sites. The SNOTEL system
is a federally operated snow-measuring network with installations throughout the
United States, including two at Tenderfoot Creek.
The researchers correlated the precipitation data with measurements of runoff from the Tenderfoot Creek drainage. Then they compared the accumulation of snow in open areas of the forest with that in closed-canopy areas.
They found that most of the snow that fell directly on the ground in the
open areas became part of the watershed’s runoff when it melted. In contrast, a substantial fraction of the snow that fell on the trees in the closed
areas either evaporated or was sublimated (converted from a solid to a
gaseous state without passing through the liquid phase) before it reached
the ground.
In other words, bare areas collected more water from the snow than did
forested areas. This was not too surprising, but in addition, the researchers found that the thickness of the forest canopy makes a difference in how
much snow is intercepted and kept from melting into groundwater. In the
thickest-canopied stands, about one-fourth of the water in the snow never
reached the ground as liquid water.
The researchers refined their results by calculating the snow-water equivalent (SWE, meaning how much water is contained in a given amount of
snow) for a range of forest vegetation types and cover densities. Then they
categorized the stands according to how old they were, based on known fire
history.
Implications for management are still being refined, says McCaughey. If
the objective is increased runoff, the older, climax-forest stands, such as
those that result from less-extensive fires, will keep water production at a
minimum, while a younger forest, whether created by natural fire or management, is likely to have more open or early-successional areas where the
water can get into the ground.
The hydrological work at Tenderfoot Creek promises to help managers
understand not only how runoff is affected by natural forest dynamics, but
how different management treatments are likely to influence the amount of
runoff in a particular watershed. It will also give managers a way to judge
the effects on water yield as forest composition changes with a changing
climate.
The majority of forest communities on the
Tenderfoot Creek Experimental Forest are
pure stands of lodgepole pine. Sparse and
dense understories and overstories of subalpine fir and Englemann spruce can be found
in a number of smaller stands scattered across
the Experimental Forest.
Fire
They observed that, after a lodgepole stand passes middle age, mortality
tends to increase, and shade-tolerant spruce and fir begin to invade the open
gaps in the stand. Even though lodgepole pine is no longer the dominant
forest canopy, thick spruce and fir crowns begin to hold large amounts of
snow, letting less water reach the forest floor.
17
Desert Experimental Range, Utah
Old Research Sheds Light on New Questions
Grasslands
Situated as it is in the sparsely populated Great Basin, the Desert
Experimental Range (or DER) does not register very high on the public
radar screen. “For a lot of folks it’s the Great Empty Quarter,” says
Stan Kitchen. “Most people don’t pay it much attention.”
18
long-term look at plant succession in response to grazing,” says Kitchen,
“and also a look at year-to-year variations in response to climate.”
Kitchen is a research botanist and manager of the DER, located 260 km
(160 miles) southwest of Provo, Utah. Despite its low public profile, the
DER is a significant spot on the map for range ecologists, being a place
where past ecological research is paying off in future-focused science.
Data from long-established grazing studies are helping scientists come
to grips with two of today’s pressing challenges: invasive weeds and
climate change.
A key discovery at the DER was that, from the standpoint of environmental impact, season of use matters more than grazing intensity. “You
can graze at a low to moderate level without significant impact if grazing occurs during the cold part of the year, when the plants are dormant,”
Kitchen says. “That’s because the livestock are not eating the growing
points on the plants, and when [the plants] break dormancy, there’s moisture in the soil, and they are able to recover.” In contrast, when the animals
overgraze in the spring, the most important period for active plant growth,
plants are damaged and recovery is slow.
Composed of 22,500 hectares (about 55,600 acres) of mostly treeless
salt-desert shrubland, the DER is the largest of all the Forest Service’s
experimental forests and ranges. Its sparse vegetation and minimal
precipitation make it typical of an ecosystem that is widespread across
the vast Great Basin, an internally drained region covering about
55 million hectares (135 million acres) of the intermountain West.
Thanks to these findings and others, it became possible to manage grazing to minimize damage and allow the recovery of degraded landscapes.
Management practices that emerged from this work call for restricting
most grazing to winter months and for imposing rest periods after spring
grazing. “The vegetation can be grazed in the spring,” says Kitchen, “but
you should do it only every third or fourth year.”
More than half the land in the Great Basin is administered by the USDI
Bureau of Land Management, and most of that is divided into grazing allotments for domestic sheep and cattle. Grazing has been a dominant land
use since European-American settlers arrived in the mid-19th century.
Historically, ranchers paid little attention to management or protection of
the resource, and by the early 20th century the range had lost much of its
ecosystem function and its capacity to support livestock.
Another management recommendation developed at the DER was that
ranchers should haul water to the animals and move watering locations frequently, to distribute the impacts of grazing and limit soil erosion caused
by herds moving between fixed watering locations and areas of unused
forage. Frequently moving watering stations not only mitigates the environmental impact of grazing, but also increases ranchers’ profits, because
animals that travel less gain weight faster.
The DER was set aside in 1933 as a place to investigate the economic
and ecological impacts of grazing. In 1934 and 1935, the first researchers
established 20 paddocks of 100–130 hectares (240–320 acres) each, of
which 16 had two 4,000-m2 (1-acre) fenced “exclosures,” or control areas
where the animals couldn’t graze. Grazing treatments in these paddocks
have been used to test the long-term effects of various combinations of
grazing intensity and season.
For many years DER researchers held regular field days to show local
ranchers and land managers how to apply the results of their studies. “Over
time these practices were learned and incorporated pretty successfully,”
says Kitchen. “If you spend any time on BLM lands like those of the DER,
you can find allotments that follow practices recommended by the Experimental Range, and they’re in pretty good condition. Unfortunately, you
can still find allotments that ignore the recommendations, and it shows.”
Changes in vegetation are still being monitored today on permanent plots
in these paddocks and their associated exclosures. “They’ve given us a
Eventually demand for on-site demonstrations dwindled, and the regular
field days ceased. “That too is a success story,” says Kitchen, “because it
meant the techniques developed at the DER were becoming widely known
and more commonly practiced. The fact that many of these concepts
seem obvious today attests to the strong impact of the work.” Kitchen still
conducts tours for visiting scientists, ranchers, university students, and
government officials.
The headquarters facility of the DER was closed down between 1984 and
1992 because of budget cuts. (Quite a few of the experimental forests
have faced shutdowns or cutbacks at some point in their histories.) “The
Forest Service offered to transfer the land to the BLM, but apparently
the BLM was not interested,” Kitchen says. Then in 1992, responding to
growing university and agency demand, “and recognizing that there were
a lot of questions that still needed answers,” the Forest Service reopened
the headquarters facility and recommitted to a full research program.
“Ultimately, we’re interested in looking at how resilient this community
is to climate change,” Kitchen says. The salt-desert-shrubland ecosystem
is a good place to study that question, because it is a relatively simple
ecosystem that can function as a model for more complex systems.
The importance of DER was affirmed in 1976 when it was designated a
Biosphere Reserve by UNESCO’s Man and the Biosphere program. It is
the only reserve of its type in the western hemisphere.
Symbolic of the wealth of
knowledge generated from
monitoring cold deserts,
the Headquarters for the
Desert Experimental Range
is the “pot of gold” at the
end of the rainbow.
Grasslands
Kitchen joined the DER at that time. Today’s research is focused on
mechanisms of ecosystem stability in response to various sources of
disturbance. The goal is to learn how the whole ecosystem responds to the
combined effects of invasive weeds and climate change in the presence of
livestock grazing.
19
San Dimas Experimental Forest, California
A Giant Outdoor Hydrologic Lab
A visitor to the San Dimas Experimental Forest might be forgiven for wondering where the trees are. It’s not that San Dimas doesn’t have trees; the
native chaparral that furs the canyonsides has a lot of scrub oak—technically
a tree—amid chamise, ceanothus, and toyon. Moister riparian grottos support
laurel, sycamore, and alder. And clinging to the edges of roads are a few
specimens of incense-cedar and Coulter pine, exotics brought in by early
foresters.
Unlike most other experimental forests, San Dimas was not established to
support the commercial management of timber. Instead, it is a giant outdoor
hydrologic laboratory where scientists study how water circulates through
the arid, shrubby landscape, how extreme rainfall and runoff events shape
the land from ridgetop to valley floor, and how wildfires affect the system’s
hydrology and hasten erosion.
Soil Erosion
When San Dimas was established in 1933, the pressing research question
was how to squeeze more water out of the mountain ecosystem. Leaders
in the rapidly developing Los Angeles basin below wanted more water for
drinking and irrigating crops.
20
One important early study at San Dimas yielded a rough baseline of how
much water was being consumed by the various plant communities. With
the help of inmate laborers, researchers sank 26 large concrete containers
into the hillside at the research station at Tanbark Flats. They planted each of
these lysimeters, as they are called, with different grasses, shrubs, and trees.
Special plumbing made it possible to measure the water coming in and
going out.
Although a flawed design made precise measurements impossible, scientists
found that, in general, trees and shrubs used water “extravagantly” (in the
words of a later report), while grass “saved water if kept clear of weeds.”
In the decades that followed, researchers experimented with a variety of
methods for getting rid of the woody vegetation and increasing the grass.
These trials involved herbicides, defoliant gases, bulldozers, and other tools
that today’s researchers might regard as heavy-handed. Results were mostly
unsuccessful—it turned out that extracting more water from these mountains
proved impractical, costly, environmentally damaging, or all three.
Nevertheless, these studies and others have yielded a wealth of long-term
data that are helping to answer today’s important questions, such as what
In the foreground are
unburned chaparral and
converted grass watersheds in the San Dimas
Experimental Forest.
In the background is
3,050-meter (10,000-foot)
Mt. Baldy, highest peak
in the San Gabriel
Mountains.
people can and cannot do about landslides, floods, and wildfires that characterize the restless ecosystem of the San Gabriel Mountains.
“We have upland areas that burn frequently and with great enthusiasm,” says
Pete Wohlgemuth, research hydrologist and program manager at San Dimas.
“We have lowland areas filled with people and property and infrastructure.
Every time it burns, big erosion events happen. Part of my job is to try to
understand these events for planning and risk assessment. And the other part
is to determine whether we can do anything to offset some of the negative
consequences in a cost-effective, environmentally sensitive way.”
The geologically active San Gabriel Mountains (along with neighboring
mountains), are being upthrust as two of the Earth’s crustal plates grind
against each other. The mountains are rising faster than erosion is wearing
them down, and over the past few million years, gravity and running water
have been sloughing soil and rocks down into the valleys below.
The Los Angeles coastal plain owes its existence to fires and debris slides,
says Wohlgemuth: “If we didn’t have these processes, we would have a lot
more ocean.” A pulse of erosion is typically triggered by a wildfire, especially
if the fire season is followed by a wet winter.
Wildfire has struck the San Dimas on an average of every 40 years since its
establishment in 1933 (there is evidence that the presettlement fire interval
was longer). The largest and most intense of these fires occurred in 1960,
when “the whole forest burned to the ground,” says Wohlgemuth.
The bare hills left by the 1960 fire seemed to reinforce the wisdom of converting the landscape into something tamer and more tractable. Between 1958
and the mid-1960s, researchers used herbicides and bulldozers on the chaparral in an attempt to “type-convert” the thirsty shrub community to grass. The
theory was that the quick-growing grass would stabilize the hillside better
than chaparral. As it turned out, it doesn’t—steepness of slope and intensity of
rainfall make more of a difference in whether a slide will occur than the type of
vegetation growing on the ground.
Other erosion-control experiments from that era included building concrete
check dams along tributary streams, digging wide contour terraces across the
slope with a bulldozer, and planting barley in horizontal strips.
Results of these trials were inconclusive, says Wohlgemuth. The 1960s produced several dry years in a row followed by wetter years and culminating in
the storm of the century in 1969. So it was hard to tell if the weather or the
treatments made more of a difference.
In the 1970s, many of the water-flow monitoring stations at the San Dimas
were mothballed (“under the illusion that we’d learned all we could from that
study,” Wohlgemuth says), and ultimately the ideal of large-scale manipulation
of the landscape fell out of favor for both environmental and practical reasons.
“Most people would not use those treatments today. But that’s why we have
experimental forests—so you can try this outlandish stuff and see if it works.”
A few years before the fire, Wohlgemuth and his colleagues had reactivated
the mothballed monitoring stations. They had been keeping track of water flow
for eight years by the time the 2002 fire occurred, so they were prepared to
evaluate any change that occurred as a result of the chemical. A few years of
measurements revealed that the spray didn’t work well enough in the shallow,
coarse San Gabriel soils to warrant the expense of applying it.
A more promising treatment is stream-channel barriers made of prefabricated
log sections placed every 9–15 meters (30–50 feet) along a channel. “We found
they worked great,” says Wohlgemuth. “They reduced erosion down at the
debris basin tremendously, and eventually they’ll biodegrade.”
Whether or not it has paid off in practical tools, all the research at San Dimas
has yielded useful information. “Experiments like these are the only way we
can learn how the natural system works,” says Wohlgemuth. “If we don’t know
how to understand and quantify products like water, or sediment that is poised
to come down into somebody’s living room, there’s no way we can develop
cost-effective mitigation that will still be environmentally benign.”
The 2002 Williams Fire produced
floods and massive erosion on the
San Dimas Experimental Forest.
Soil Erosion
Another fire in 2002 offered an opportunity to try other ways of slowing erosion. One test concerned a chemical called polyacrylamide, which is used in
agriculture as a flocculant—it binds soil particles together. The manufacturing
company offered to aerially spray its product on the San Dimas as a field test.
Aggregating the soil into larger particles, it was thought, would encourage
water to infiltrate rather than sweep downhill and carry the soil with it.
21
Marcell Experimental Forest, Minnesota
The Breathing of Peatlands
Forests have been called the lungs of the planet, but peatlands—those
swampy areas in northerly climates where soil is mostly organic and
slow to decompose—equally deserve the title.
Climate Change
Peatlands occupy a huge swath of territory north of the 45th parallel in
North America, Europe, and Russia. If you started in St. Cloud, Minnesota, and drew a line east across Lakes Michigan and Huron and through
Ottawa, northern Vermont, and Maine, and then a line west through
South Dakota and along the Wyoming-Montana border, you’d be drawing the rough southern boundary of the North American peatland zone.
22
Peatlands are carbon sinks, and highly efficient ones, because they pack
away a disproportionately large amount of CO2 relative to the land area
they occupy. The reason they’re so good at storing carbon is that their
cold, waterlogged, oxygen-poor environment inhibits decomposition of
the organic matter that makes up peat soil.
Thus far, the peatlands of the world have been helping to put the brakes
on global warming. That may be changing, says Randy Kolka, soil
scientist and team leader at the Marcell Experimental Forest, which sits
squarely in the peatland zone of northern Minnesota. A warming climate
could hasten the decomposition of peat, eroding the capacity of these
lands to absorb CO2 from the atmosphere. Research in Britain, says
Kolka, suggests that some peatlands there have already flipped from being a carbon sink to a source—they’re now releasing more than they’re
storing.
Kolka and his research team are measuring gases flowing into and out of
the peatlands at the Marcell, trying to find out what is happening there.
“We want to know three things,” he says. “If [the peatland] is still storing carbon, how much is it storing? If it’s become a source, how much
of a source is it? If it’s not a source, has its ability to sequester CO2
lessened over time?”
Research at the Marcell, begun in 1960, historically focused on timber
harvesting and its effects on water quality and quantity in upland and
peatland watersheds. Scientists have also been investigating mercury, a
toxic pollutant that accumulates in living matter up the food chain.
These studies have produced long-term data on streamflow and water
Measuring snow
amount at the
Marcell Experimental Forest
to help predict
the spring flows
resulting from
snowmelt.
chemistry that have proven valuable for assessing ecosystem carbon
storage and climate change. (The harvesting and mercury studies continue, and their findings have served as the scientific basis for widely
used land-management policies and guidelines.)
Research on peatlands and CO2 began in 1988, as global climate change
was catching public attention. A group of scientists led by Shashi Verma, from the University of Nebraska, and Sandy Verry, from the Forest
Service, used an array of high-tech instrumentation called an eddy
covariance system to monitor the “carbon flux”—the amount of CO2
flowing into and out of peatlands. “This was one of the first places on
the planet where scientists were looking at how the peatlands ‘breathe,’
if you will,” says Kolka.
Those experiments ended in the early 1990s, and for a time no more
measurements were taken. Kolka and his colleagues resumed the study
in 2006. In 2007 they had their first full year’s worth of data. After another couple of years they’ll be able to compare their data set with that
of Verma and Verry, and see what has changed over two decades.
The researchers are also looking at the flux of methane, picking up
where the studies left off in the early 1990s. Although less methane than
CO2 is present in the atmosphere, methane produces a stronger atmospheric greenhouse effect.
In addition, they are analyzing the Marcell’s collected data on dissolved
organic carbon (DOC). DOC is a measure of carbon dissolved in the
water flowing out of the peatlands. It is a relatively small influence on
overall balance of carbon in a watershed, Kolka says, but a change
in the amount over time could be a signal of a climate-change
effect on carbon balance. “If the climate is warming, we would
expect to see more gases coming out of the peatland, and more
carbon dissolved in the water coming out,” he says. “If these levels
are increasing over the past 15 years, it may indicate that climate
change is affecting the peatlands.”
Better large-scale measures of carbon flux would improve the
reliability of the computer models that monitor global climate.
“These models are only as good as the data going in,” says Kolka.
“Our research is an attempt not only to understand carbon flux and
storage at our scale, but to add to the database that allows us to
measure these at larger scales.”
An important goal of research at the Marcell is to show policymakers how to utilize the land in mitigating the warming of the
planet. (The average temperature at the Marcell, notes Kolka, has
risen about 2°C since 1960.) Some policies that might flow from
the Marcell’s findings are measures to protect peatlands from
development, fire, or other disturbances. “Right now, peatlands are
mitigating a warming atmosphere. If things are flipping the other
way, or even if they’re becoming less of a sink than they were
before, that matters a lot.”
Current eddy convariance system at the
Marcell Experimental Forest measures
the net exchange of carbon dioxide between the atmosphere and the peatland.
Climate Change
With the help of funding from NASA, Marcell scientists are comparing their data with those from other research sites in the Rocky
Mountains and the northeastern United States, trying to get a
picture of carbon flux across the landscape. The goal is to combine
plot-scale measurements and extrapolate them accurately up to
larger areas—states, regions, even the whole world.
23
Bent Creek Experimental Forest, North Carolina
Hardwood Regeneration
Bringing the Oak Forest Back
24
By the time the Forest Service took it over in 1914, the Pisgah Forest—
which would later become part of the Pisgah National Forest—was in
rough shape. It had once been part of the famous Biltmore Estate, where the
wealthy George W. Vanderbilt had pioneered scientific forest management
by employing European-trained silviculturists Gifford Pinchot and later Carl
A. Schenck. Before Vanderbilt’s time, the land had been worked over for
100 years by homesteading farmers and by timber companies that stripped
out the best of the valuable hardwoods. The trees that remained were stunted
and deformed. Furthermore, American chestnut, once a dominate tree in the
East, was being decimated by the chestnut blight, an introduced fungus.
The Pisgah National Forest became the first national forest east of the Mississippi. Like many others across the nation, it was assembled from “the
lands nobody wanted,” says David Loftis, research forester and former project leader at the Bent Creek Experimental Forest. “By the 1920s, virtually
everything had been cut over, burned, and largely abused, with no provision
made for regeneration.”
In 1925, Bent Creek Experimental Forest was set aside on the newly established Pisgah National Forest. (Its campus, near Asheville, is on the National
Register of Historic Places.) The first research priority for Bent Creek was to
conduct silvicultural experiments with the goal of bringing the degraded
forest back to something resembling its pre-logging, pre-homesteading
condition.
The forest at Bent Creek is typical of the oak-dominated forests of the lowto mid-elevation southern Appalachian Mountains—a complicated landscape, topographically and ecologically. The climate is mild and moist, and
forests of many species of trees and shrubs range over the ridges and coves.
The development of these forests may follow any of several successional
pathways, with disturbances such as ice, wind, fire, and insects playing a
poorly understood role.
Of the dozens of hardwood species, oaks are of high economic and ecological interest. They dominate the forest on dry sites and are an important
component in mixed stands on moist sites. Their wood is valuable for timber,
and their acorns are important food for many wildlife species.
The Buell regeneration study began in
1931 with the first
clearcut created for
the sole purpose of
studying natural
stand regeneration
dynamics on the
Bent Creek Experimental Forest.
Because the climate in these parts is mild, the forest vegetation was growing
back just fine, says forester Julia Murphy, Bent Creek’s technology transfer
specialist. “The forest was regenerating but not with the same tree species that
were present before the disturbances.”
An early study at Bent Creek, established in the 1930s, was a clearcutting
experiment directed at naturally regenerating the forest. Clearcutting may
have seemed an odd thing to try. The forest had been laid waste, after all, by
a sequence of clearing, burning, and logging that had nearly denuded the landscape. And indeed, says Loftis, the timber managers on the Pisgah National
Forest at the time favored selection harvesting (in which trees are harvested
singly rather than in large blocks), partly because of concerns about the damaging effects of past unregulated cutting.
Before beginning the study, silviculturist Jesse Buell drew on the earlier
observations of E.H. Frothingham, the first director of the Appalachian Forest
Experiment Station, that heavy cutting seemed to promote better regeneration
than lighter, partial cutting did. More practically, Buell had little choice: there
was almost no forest left to work with. “So he inventoried the stand and then
clearcut it, and started observing, measuring, and recording what happened,”
says Julia Murphy. There was no need to plant seedlings because in contrast
to tulip-poplar, most tree species in these forests regenerate from seedlings or
saplings that exist prior to cutting, and also by sprouting from the stumps of
harvested trees.
Findings from Bent Creek’s ongoing studies show that harvest methods
that remove most of or all the overstory in one or more removal cuts—in
either a small lot or an entire 16-hectare (40-acre) stand—are the most
appropriate for regenerating the forests of the southern Appalachians. For
these methods to be effective, large seedlings or saplings of many species,
including oaks, need to be present when the overstory is removed. Otherwise, light-loving species, such as tulip-poplar, will win the “race” by
growing faster and overtopping other species. Therefore, managers need
to control the light reaching the understory for several years in advance of
overstory removal so that this regeneration of more shade-tolerant species
can develop.
The research at Bent Creek took a while to get noticed, says Loftis. “But
eventually people began to see that the kind of silviculture the Forest
Service was practicing in the southern Appalachians was not leading to
adequate regeneration.” By the mid-1950s, results from the Buell study
were beginning to guide the shift toward even-aged silviculture. “That was
one of [Bent Creek’s] very first impacts of silvicultural research on the
practice of silviculture,” Loftis says.
Like most other experimental forest research, the Buell study illustrates
the value of keeping long-term studies going. It takes years to get definitive results, and what becomes common practice in one generation may be
challenged in the next. The Buell plots are still being measured, and so are
those in a later study, begun in the 1940s, of uneven-aged methods. The
various treatments are displayed in side-by-side plots for the education of
managers and other visitors. This is in keeping with Bent Creek’s other
key mission, demonstration and delivery of scientific results to managers
and the public.
Researcher takes measurements on
oak regeneration on the Bent
Creek Experimental Forest.
Hardwood Regeneration
What happened was that the moist, lower slope was dominated by the
light-loving tulip poplar along with a few oaks and other species, while
the drier middle and upper slopes regenerated primarily to oaks. Buell and
researchers who followed experimented with a variety of harvest methods, including even-aged (such as clearcut and shelterwood harvesting),
uneven-aged (such as selection harvesting), and two-aged methods. They
tried various levels of cutting and other management strategies to control
light prior to heavier cutting in the overstory.
25
Blacks Mountain, California
Coram, Montana
H. J. Andrews, Oregon
A New Look at Old Growth
Learning from the Past
Back in the 1930s and 1940s, when many experimental forests were starting their
research, old-growth forests were typically not on the agenda. The main focus
was either timber management (mostly in the West) or land restoration (mostly
in the East), depending on the condition of the landscape in question.
26
Over the decades, however, values shifted. Old-growth forest, in its variety of
forest types, ages, ecosystems, and desired conditions, has become socially and
scientifically important in terms other than timber. This has prompted researchers
to view some of their old findings through new eyes.
For example, long-term studies at Blacks Mountain, in northern California’s
ponderosa pine country, initiated in the 1930s and carried forward to the present, have demonstrated that the ecological conditions in these forests are much
changed from those of presettlement times, when fires typically occurred every
8 to 10 years. A new long-term study begun in the mid-1990s is shedding light on
the resilience of these older-forest ecosystems and their response to management
manipulation.
The study suggests that conditions common in presettlement forests—notably
the big, vigorous older pine trees (between 250 and 800 years old) and the open
understory—will not come back as long as fire is excluded. In fact, these forests
are at considerable risk of high-severity fire because of the proliferation of understory vegetation that has come in over more than a century of fire exclusion and
grazing.
However, active management, such as thinning and prescribed burning, shows
promise for restoring these desirable old-growth features. These treatments,
which remove understory vegetation to varying degrees, seem to be enhancing
growth in the older pines at Blacks Mountain and lowering their mortality rates.
Properly carried out, the practices have the added benefit of making the forest
more resilient to wildfire and insect damage.
When the Coram Experimental Forest was established in western Montana in
1933, nearly all its western larch forests were old growth, typical of vast areas
of pre-settlement mid- to high-elevation forestlands across the northern Rockies.
Part of the Coram was set aside as a Research Natural Area (RNA) in 1937; the
intent was to keep it undisturbed so it could provide baseline information. Active research on the rest of the Coram Experimental Forest began in 1948, with
studies focused mainly on natural regeneration after various methods of logging,
including clearcutting.
In the 1960s and 1970s, researchers at Coram began new tree-spacing studies
and studies of harvesting methods other than clearcutting, testing the effects
of these treatments on growth of the remaining trees and the overall stand, as
well as on wildlife, soil, and water. They also started studies on old-growth
dynamics within the Coram RNA. In 1976, Coram, together with Glacier and
Waterton Lakes National Parks, was designated a “Crown of the Continent”
Biosphere Reserve by the U.N. Man and the Biosphere program.
Scientists at the H. J. Andrews Experimental Forest in western Oregon began
to look closely at old-growth forests in the 1970s, building on two decades
of more conventional research on the effects of various forestry practices and
harvest patterns on watersheds. Work at the Andrews Forest was thrust into the
public eye in the 1990s, after the northern spotted owl was declared threatened
under the Endangered Species Act. Federal land managers drew heavily on
Andrews old-growth research in developing a conservation strategy for the
owl, and Andrews research informed the Northwest Forest Plan of 1994, under
which federal forests in the Pacific Northwest are now managed.
In addition, Andrews scientists have done path-breaking work on the ecological roles of dead wood, a major component of old-growth forests. Once
considered waste, fit only to be hauled away and burned, dead wood is now
known to be crucial in the functioning of forest and stream ecosystems. Dead
wood stores carbon and keeps it out of the atmosphere; it breaks down to
become fertile organic soil; it is the growing medium for many plants and
essential habitat for microorganisms and larger creatures; and it is a medium
for nitrogen fixation, which enhances soil productivity. Because of Andrews
Forest research, ecological roles of dead wood are now widely recognized.
Thanks to the longevity of research throughout the experimental forest network, studies begun in one era can shed light on problems arising in the next.
Today’s research promises to prove useful in solving tomorrow’s problems,
which we can now hardly imagine.
Spies, T.A., Duncan, S.L. (eds). 2008. Old Growth in a New World: a Pacific
Northwest Icon Reexamined. Island Press, Washington DC.
Learning from the Past
Mature, interior ponderosa pine
old growth on Blacks Mountain
Experimental Forest.
27
Fernow, West Virginia Kane, Pennsylvania Bent Creek, North Carolina
Connecting to the Future
Getting The Science Out
28
One of the most important missions of experimental forests is to get the
science out to the people who need it. “If we want an informed public,” says
Mary Beth Adams, project leader at the Fernow Experimental Forest, “it’s
vital to connect people with their environment and to demonstrate how various management options affect that environment.”
Fernow’s Timber and Watershed Laboratory in West Virginia is a landmark
for teaching, training, and demonstration. Fernow’s scientists lead interpretive tours showcasing the forest’s half-century of research on hydrology, silviculture, and wildlife ecology. “Our audience for these show-me trips runs
the whole gamut, from grade school children to college students to professional foresters to scientists from other nations,” says Adams. The Fernow
is also a beautiful place to visit, and self-guided walking and driving tours
are popular with tourists.
Fernow’s scientists are also reaching out to their counterparts on the other
watershed-focused experimental forests, including some of those profiled in
this publication: Marcell, Tenderfoot Creek, San Dimas, and H. J. Andrews,
as well as Coweeta in North Carolina, Hubbard Brook in New Hampshire,
and Fraser in Colorado. “When we bring our data together,” says Adams,
“we can start to interpret watershed processes at a regional or even national
scale and find answers to bigger questions. That’s one of the cool things
about watershed science—it’s distinctive to the Forest Service. Nobody has
as many long-term watershed studies as we do.”
A long-standing and popular outreach program at Kane Experimental Forest
in western Pennsylvania grew out of a regeneration crisis in black cherry
forests in the mid-1960s. Kane researchers launched an intensive effort
to figure out why stands of black cherry, a valuable commercial species
whose range is centered in western Pennsylvania, were not regrowing after
harvesting.
It turned out there were two related regeneration problems: First, in this
forest, seedlings needed to be well-established and abundant before the
harvest. And second, deer were eating the seedlings after the disturbance
(or harvest).
Excluding the deer solves most of the problem, says Susan Stout, a silviculturist and project manager in charge of the workshops. But in addition,
Bent Creek
Experimental Forest
provides opportunities to showcase
research results.
Kane researchers developed a technique for inventorying the smaller seedlings and designing site-specific techniques for cultivating them, thereby
boosting regeneration success even more.
When managers began excluding deer and using the new inventory technique, regeneration success shot up to over 90%. In the early 1970s, Kane
began holding an annual week-long workshop to teach the new technique.
The workshop has become an institution in Pennsylvania, “something like a
rite of passage,” says Stout. “When you’re hired any place in Pennsylvania as
a forester, you go to a training session in your first year.” Over the years some
2,500 people have attended, many more than once—the program’s curriculum is refreshed each year as new research results become available. In recent
years Kane has extended the sessions to Ohio and West Virginia.
For participants, the workshop rekindles the spark that led them to their life’s
work in the first place. “We get to think about the forest again, as a whole,
and in a passionate way,” says Stout. “We have a steak fry on Wednesday
night, and we stand around the bonfire and talk till the wee hours of the
morning. We are immersed in what we really love.”
Because of its ties to the famous Biltmore Estate, the acknowledged birthplace of scientific forestry, Bent Creek Experimental Forest has been in the
spotlight right from the start. Bent Creek was on the rail line from Washington, D.C., which made it a convenient showcase of early Forest Service
research, regularly toured by visiting dignitaries and scientists. “Theodore
Roosevelt came here, and Gifford Pinchot, too,” says Julia Murphy, technology transfer specialist for Bent Creek.
A rising demand for recreation on the Bent Creek Experimental Forest
is both a challenge and an outreach opportunity. “We’re 10 minutes
away from Asheville, and we are being overrun by recreation—mountain biking, horseback riding, running—and a lot of people don’t know
or value what we do,” says Julia Murphy, Technology Transfer Specialist. She’s plunged into an interpretive program that combines friendly
tips about proper recreational behavior with information about Bent
Creek’s science and its contribution to environmental values.
Forest Service workshops on
experimental forests are popular
training events for young
and old alike.
Connecting to the Future
After 83 years the visitors are still coming by car, horse, mountain
bike, and on foot. Among Bent Creek’s regular outreach programs is a
two-week training for managers of national forests working in upland
hardwood forests throughout the eastern United States. Bent Creek
also conducts a one-week lecture and field training for state and private
forest managers. Instructors use the demonstration forest and many
active field studies within the Bent Creek Experimental Forest to teach
about sustainable timber management and wildlife considerations in
an upland hardwood ecosystem. Bent Creek hosts hundreds of visitors
annually for individually tailored field tours of its demonstration plots.
Visitors include university classes in forestry and environmental studies, research scientists, natural resource managers, private landowners,
state and private foresters, middle school students, and the general
public.
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The USDA prohibits discrimination in all its programs and activities on the basis of race, color,
national origin, age, disability, and where applicable, sex, marital status, familial status, parental
status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because
all or a part of an individual’s income is derived from any public assistance program. (Not
all prohibited bases apply to all programs.) Persons with disabilities who require alternative
means for communication of program information (Braille, large print, audiotape, etc.) should
contact USDA’s TARGET Center at (202) 720–2600 (voice and TDD). To file a complaint of
discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue,
S.W., Washington, D.C. 20250–9410, or call (800) 795–3272 (voice) or (202) 720–6382 (TDD).
USDA is an equal opportunity provider and employer.