(gentle music) (solemn music) - [Peter] Forests have been
a part of human culture for our whole history. - [Lincoln] Over the course
of Colorado's history, humans have changed the
forest in all sorts of ways. - [Mike] We're
seeing larger fires. We're seeing more bark beetle. - The unforeseen outcome
and unintended consequences. - To understand what's
happening today, having historical context
is really important. - History can really open
our eyes to the intricacy of these ecosystems. The changes are really daunting. (gentle music) - But forests are
changing and adapting and experiencing
disturbances all the time. - [Thomas] It's really
important to emphasize how dynamic our forests are, how dynamic they
always have been, and how dynamic
they always will be. - [Announcer] This
program was made possible by the History Colorado
State Historical Fund. - [Announcer] Supporting
projects throughout the state to preserve, protect
and interpret
Colorado's architectural and archeological treasures. History Colorado
State Historical Fund, create the future,
honor the past. - [Announcer] With
additional funding provided in memory of Deanna
E. La Camera, The Benedict Family Foundation and members like you. With special thanks to the Denver Public
Library, History Colorado, the Colorado Office of
Film, Television & Media and to these organizations. (solemn music) (gentle music) - [Lincoln] Human relationships
with forests go back to the dawn of time. - We evolved in forests. Our ancestors came
down out of the trees. We are children of
the forest, literally. - Throughout human history,
people have made all sorts of meanings of
forests and of trees. - People have revered
trees in many cultures. The tree of life symbol
is pretty much ubiquitous in every culture that represents
the interconnectedness of all things. - Robin Hood with
Sherwood Forest, his band's place of
refuge, at the same time, "Grimms' Fairy Tales," the
forests were dark, scary places where bad things happened, both good and bad,
cultural connotations. - Political meanings,
from the great Charter Oak in Connecticut, which
played an important role in colonial and in
early national history, up through the
Great Council Tree, out on Chief Ouray's
place, near Montrose. - [Laurie] We've depended on
trees for food, fuel, clothing, shelter, for pretty much
our entire existence. - [Peter] Watershed
values, in particular. - Forests capture water. The rivers are basically
born in the forests. - [Mike] They provide
stability to the soil, so the soil doesn't
erode into our rivers. - A greater amount
of carbon is stored by forests than the atmosphere. That's a pretty
staggering number. - [Peter] So when
we think of forests, we think of the trees, but it's the entire
ecosystem that's there. - About 80% of the species
that live on land use forests for habitat, in some way. So in addition to all the
benefits provided by forests to us, we also have the
benefits to biodiversity, which is probably more important than all those other things. We're all surrounded by
forests, in Colorado. Roughly 56% of the Southern
Rocky Mountains is forested. Colorado forests, in particular,
ecologically speaking, are really interesting,
because we're in the edge of many different
species ranges. - That doesn't mean that
there are sharp edges, or sharp boundaries. - [Thomas] When we think
about the United States, southwestern species tend
to have northern boundaries. In the Colorado area, species from the
Northern Rockies meets
its southern extent, just around the southern
border of Colorado, and they overlap in
the Colorado area. - Trees, somewhat like people
have different tolerances. Some of us like the cold
and the same with the trees, and that's what makes
our forests so unique, is that we have such a
huge elevation gradient. - The gradient of different
forest types that we have in about 50 linear miles,
but thousands of feet of elevation is the
equivalent to if you drove from the plains of
Texas all the way up to the Arctic Circle in Canada. - And you just see all these
different types of forests, and it's all based
on the elevation, the precipitation,
the temperature. Forest can have different
species composition, dependent on the aspect, at which way it's
facing towards the sun. So southern aspects get more
sunlight, and they're drier. Northern aspects are
more cool and moist. - [Laurie] Literally, when
you step across a ridge, you're stepping into a
completely different ecosystem. - [Narrator]
Colorado's unique blend of landscapes create
the most complex forests of any in the west,
lending to the diverse and iconic sights of the state. - [Mike] Skiing through
spruce fir and lodgepole, mountain bikin' in
the ponderosa pine. - [Kyle] Kenosha Pass,
Kebler Pass, San Juan's. - Have you been to Maroon Bells? These are places that are recognized the
world over, nowadays. Pike's Peak, which inspired
"America the Beautiful." Not a lot of forests
and landscapes can make that claim, but it's something that Colorado's forests
can definitely claim. - [Mike] The beauty
is unmatched. - [Laurie] What we're
seeing in our forests now, particularly in the
last 20 or 30 years, is a lot of change. - Initially, when I
look at the forest, I see a lot of dead trees. There's a lot of beetle kill. There's a lot of areas
that have burned. - [Laurie] In the last 20 years, we've had a lot of
really large wildfires that have burned
really intensely, and it's slow to regenerate. We have had this mountain
pine beetle outbreak that coincided with
the early 2000s drought that killed acres
and acres of trees. How big a change is this really? - To understand whether what's happenin' now is
unprecedented we look into the past to understand
how forests developed. - [Laurie] What were the
processes that defined them and perpetuated them? - Colorado's forests grow
slower than a lot of places, so in many ways,
we see the evidence of historical events
even more strongly here. Those dynamics from
things that happened 100 and 150 years ago are still
playing themselves out, in our slow-growing forests. - We have to find ways to reconstruct what was
going on in forests. - [Mike] How do you
recreate a forest? - [Laurie] You have
to talk to the trees. - One of the nice things about
trees is they don't move. They live their entire
lifetime in one location. (bright music) That whole lifetime,
they're influenced by whatever happens
to come along and affect the
growth of that tree. We can find out what
affected those trees for any particular year. - One way is to core a live
tree with an increment borer. It doesn't hurt the tree. So what I'll do is-- - [Peter] Trees
grow once per year, at least the trees that
grow here in Colorado and other temperate
areas of the world. They only grow in
the summertime. They quit growth. Next year, they do the same
thing, so one ring per year. We can look at past climate
from the tree rings. Climate is controlling
the growth of the trees, so all of the trees in an
area are gonna show more or less the same
pattern of growth. Because climate's controlling
the growth of the trees, the ring patterns
are going to match. If it's a dry year for
that tree over there, it's a dry year for
this tree over here. Both of 'em are gonna
show a small ring for that particular year. This way, we can get a
record of the tree rings without having to cut the tree. - Then you can look
at the tree rings and determine how old it
was when it germinated and started growing. - We start with living trees. We work our way backwards. Again, to be a good
dendrochronologist, you just have to know how
to count backwards from 10. We put a dot on every decade. So we work our way backwards. We put a dot on 2010,
2000, 1990 and so on. - If the tree is dead,
take a sample of the stump or the log, and we would
then cross-date that to determine when
that tree was born and then when it died. And then we can reconstruct
how big the trees were, what kind of tree
species were there, and then we map those
to determine what that spatial arrangement of
those trees were, as well, how many trees were
around a piece of land, the size of those trees,
what type of tree was it. - In addition to
using tree rings to reconstruct forest history, we've also used
historical photographs. - Historical photographs supply
a unique historical dataset to track longterm trends, to
see how forests have changed. Aerial photos give
us the ability to really zoom
into the landscape. Right here would
be one single shot. And to actually
create this mosaic and be able to say anything
about the whole area, we had to use lots and
lots of individual photos and stitch it all together. You can actually pick
out individual trees. There's a lot of detail
in that landscape. - Using historical
landscape photographs, we go out and match the scene, take a modern photograph
and show the changes that have occurred
over 100 or more years. Often, we would go
into those scenes that were photographed, core
trees, determine the history so that we can put together
an overall interpretation of the changes that you
see in the photographs. - [Narrator] These
Colorado researchers have each worked
years to decades to get a better understanding
of the dynamics at play. And they have unearthed
a wide variety of changes in our forests. - Using dendrochronology,
we found that, in our ponderosa pine forests, tree density has increased
two to three times. So there's two to three
times more trees out on the landscape
than there were. Most of those trees
are in small diameter, and we're seeing a shift in
not only the number of trees but also a shift in the
species composition. We also found that
fire has been excluded from these forests for
over a century now. - Using air photos, we
identified the areas that either gained
or lost forests. A lot of the change
that we've seen in the 20th century has
been lower elevation forests and higher elevation forests. We saw a lot of forest gain. The middle elevation sites
didn't actually change as much. - Using repeat photography, you can see some areas
have really increased in stand density. Some areas have
recovered after a fire. Some areas have not
recovered after a fire. - [Narrator] A variety
of pressures have shaped these changes that we
see in our forests, some natural, but many
due to human activities. (solemn music) To understand these
changing forest dynamics, we first need to understand how human dynamics have
changed across landscapes. In relatively recent history, the most significant
transformations took root with the settlers. - When Europeans started
populating and arriving in North America, you saw
this real conflicted idea about forests and their use,
when they got over here. Imagine coming over from
Europe, in the 17th century, and landing in a pretty
much solid deciduous forest that's two or three
times the size of the entire continent
you came from. It was immense and overwhelming. It was a tremendous natural
wealth that they landed into, but also it was kind of
obstacle, at the same time, to what they really wanted
to do with the land. Trees were valuable,
but they were valuable when you cleared
them out of the way. It's not an overstatement to say the United States
was built on wood. Up until the middle
of the 19th century, 90% of our energy
needs came from wood. Today, oil provides roughly
30% of US energy use, so it was extremely
important for people, and a lot of settlement across
the United States followed where those resources were. - If settlers came
into Colorado, they
brought a whole range of different ideas
about forests. - [Lincoln] What really
brought the first mass of people was the Gold Rush. That started in 1859. - Initially, the mountains
didn't much concern gold miners. They were interested in the
gold that was in the streams along the Front Range. Very, very quickly, though,
they became frustrated with how meager the
findings were in their pans, and so they looked
to the mountains. They started heading up in
search of the mother lode. - You can't overstate
the rush of activity and the pace and scale
of that activity. I've heard it described
as things not changing on a daily basis
but an hourly basis. Basic land law at the time
was first come, first served. So there were mad
scrambles of people trying to make their fortune
and stake their claims. Towns would pop up overnight and could be
depopulated overnight. - When we're talking
about mining, it is very natural to
talk about the mineral. Mining involves timber
in every dimension. - For the production
of the mining itself, building a a sluice or a flume
to channel your water into, to sort for your precious metal. Think about where
the miners lived. First, it was tents. Then, it was log cabins. Then, it was kind of
rough-hewn wood structures to milled-wood structures. Think of an old
mining frontier town, with its main street
and the facades. And wood is the energy source they're heating
these buildings with and cooking their food with. - They set fire to forests
to expose outcroppings. This is a key technique
of prospectors. Miners tended to not be very
careful with their campfires, and so they introduced all
sorts of accidental fires. Here, it's really important to realize what
mining was about. - [Patty] If you were
gonna go underground, if you're gonna dig underground, then you have to support
that underground space. If you don't support the
walls and roof of a mine, that's just a deathtrap. - And so they had to use
timbers to support the mines. The mines consumed massive
quantities of lumber. Basically, every successful
mining camp was surrounded by a widening circle
of forest decimation. It's pretty striking if
you look at historic photos of mining towns,
anywhere in Colorado. You'll see pretty bare hills around any of the
mining settlements. - Many areas are not affected
by the mining business, but that is a huge, enormous
campaign of deforestation, localized around mining areas, because it's not an
easy thing, in that era, to transport wood
over long distances. - The arrival of
railroads, in 1870, really changed
Coloradans relationship to the forest in the state. Coloradans now had
access to lumber from other parts of the country. - Colorado did see
commercial timber harvest, but not on the scale
that you think of, the massive timber
industry that moved across the United States,
starting in the Northeast, moving out to the
Pacific Northwest. Colorado was much more
isolated than these places. The railroad came somewhat late, and it wasn't
extremely economical to ship milled lumber
out of the state, but it was being used at
a pretty voracious clip, within the state itself. That's not to say the forests
in Colorado were spared, during the settlement
period, but generally, it wasn't being used for
a commercial purpose, to ship out of state. - Over time, the forests
of the Pacific Northwest, the Upper South, Northern
California started coming into Colorado, and
after about 1870, virtually all of the lumber
used to construct Denver came from outside of Colorado. After the arrival of
railroads and the development of new mining and
smelting methods, over the course of
the 1870s, as well as new mineral discoveries
in places like Leadville, Colorado really
began to take off. - [Lincoln] And it was an
explosive growth of people that came into the state, in
a fairly short amount of time. - [Patty] The degree to which
mining thrives and disperses, that's the degree to which
forests really take a hit. - Many miners never
found gold, of course, and so they started turning
into farmers, ranchers. These are occupations that
they generally knew well, from where they
originally came from. - For most of its history, the United States'
official land policy was to dispose of land, not
throw it away but give it to states and private
individuals and
private corporations. So think the railroad grants,
think the Homestead Acts. And the idea was we're trying
to encourage settlement of this continent. The Homestead Act really allowed
you to claim federal land, and generally it meant
ranching and farming. - [Thomas] And this was
initially unregulated. And it was basically
a free-for-all. - When you're giving
all that land away, and different groups are
using these natural resources at such an astounding rate,
it was creating problems for the people that remained in areas that had
been deforested. They already understood,
at that time, if you clearcut a mountainside, it was gonna release a lot
of sediment, the next year, when the snows and the
rains and runoff came, and it would clog up
the irrigation projects. There was real talk
of a wood famine. - [Patty] There was concern
about what will happen to the watersheds if
they don't have forest. - We'd explored all the
way to the Pacific Ocean, by this time, and realized,
well, there's an endpoint. There is a finite resource
that we might use up. - There was fear of what
would happen if the treatment of forests in the Rockies
followed the pattern of the treatment of forests
in the Upper Midwest and in many parts of the South. - And this was part of
the conservation movement with the idea of let's
have trained experts solve these natural resource
issues that we're having. How do you keep from overusing
these natural resources and wealth that we have? And, for them, the
answer was conservation. - [Narrator] For the first
time since Europeans set foot on this continent, a large
area of land was set aside to remain preserved forever. Yellowstone, the first national
park, was created in 1872. At the same time, this
seed of an idea began to germinate in Colorado. - [Lincoln] Part of their
Constitutional Convention had a section on forests
and management issues of deforestation
and overgrazing. - A pretty large area
of the mountains, in particular in Colorado, was
never gonna be homesteaded. And areas that didn't
include paying quantities of minerals were not
gonna be privatized through mining law. So in the 1870s and
1880s, Coloradans active in forestry issues really wanted to protect Colorado's forests. We see people like
Frederick Ebert of Denver, Colonel Ensign of
Colorado Springs, William J. Palmer, also
of Colorado Springs, really taking active
measures and they were part of a larger movement
that resulted in the Forest
Reserve Act of 1891. And that act is
really a landmark in American
environmental history. - Congress gave
the president power to reserve forested landscapes
out of the public domain. It was just one sentence, and it was a pretty
inauspicious start. But this was the very first
change in federal policy from giving land away,
full-time, all the time. Now there was this one
little opening that said, okay, land can be reserved? And that was an entirely
new concept, at the time. President Benjamin Harrison,
within a couple years of this law being
passed, he reserves about three million
acres in Colorado as some of the first forest
reserves in the country, and it wasn't because he was
a Coloradoan who had his eye on some favorite landscapes
he'd like to go to. He had actually been receiving
letters and petitions from local Colorado residents. So that was kind of the genesis of Colorado's first
forest reserves, actually local lobbying the
president of the United States. This was a really radical
idea, at the time. There was no other
country on earth that was creating public
lands for the public to use. So we were operating
without a script. - The challenge of
figuring out how to actually govern them,
it really took a couple of decades to work out. Initially, there
were very few boots on the ground, as it were. These were huge swathes of
land with very few rangers. The rangers were often locals. And so for the first couple
of decades, grazing, logging, other uses of these forests
were essentially unregulated, with some exceptions. Early in the 20th century,
the federal government started to take a more active role. - During Theodore
Roosevelt's presidency, he adds about another
150 million acres of national forests
to that system, and in 1905, he signs a law
called the Transfer Act, that actually took
the forest reserves and formally transferred them to the Department of Agriculture and a new agency called
the Forest Service, to actually manage these lands. Theodore Roosevelt appoints
Gifford Pinchot the first chief of this new agency,
the US Forest Service. Their idea of conservation was, "For the greatest amount of
good, for the largest number, for the longest amount of time." They wanted not only
you to use the land, but they wanted your
grandchildren to use
that land as well. And this applied to grazing. Very quickly, in 1906,
Gifford Pinchot issues national forest-wide
grazing regulations. Basically, you had
to obtain a permit to run sheep or cattle
on national forests. And they were trying
to figure out a formula where there was gonna be
a finite number of animals that would be allowed
on the landscapes so that the landscape would
survive grazing, year to year. Right at the beginning
of this grazing period, they issued roughly
230,000 permits for cattle and about 539,000
permits for sheep. This was at a time when the population was
roughly just over 500,000. So there was actually more
sheep and cattle in 1907 than there were people. So it's not an insignificant
industry, at the time. It's pretty large. - And of course, this
generated a lot of tension. A lot of Coloradans
were not happy about federal conservation. We see a real sort of
rural-urban divide. Federal conservation was
very popular among urbanites, among business and in
Front Range communities. It was quite popular among
Eastern Plains farmers as well. All these people realized that the forests were
important for tourism. They were important for
protecting irrigation. But folks in Western Colorado
often took a dimmer view of federal efforts to
control how they interacted with the forest
that surrounded them and that they'd become
accustomed to using. (gentle music) - [Narrator] Both
Gifford Pinchot and Theodore Roosevelt
traveled to Colorado, to argue for the new
permitting system. While ranchers initially
resisted regulation, in the end, they actually
endorsed the policy, understanding the
benefits down the road. - They saw there might be
some restrictions, at first, but it's for stability of our
entire industry over time. So in 1910, the Forest Service opens the
Office of Grazing Studies, and this was to do
reconnaissance of rangeland so that we actually
had scientific data of what the landscape
could handle, what it's carrying capacity
would be for livestock. - [Narrator] During
the early 1900s, several more national
parks were created within the newly established
National Parks System. But overgrazing sheep and cattle still threatened
Colorado's forested landscapes. The federal
government intervened, passing the Taylor
Grazing Act of 1934, to regulate grazing on all
remaining federal lands. - There hasn't been major
legislation regarding grazing, since 1960, when
Congress passed in law what the national forests
were supposed to be used for and what the Forest Service was
supposed to manage them for. Grazing, timber production,
wildlife, recreation and fire. (fire crackling) American views about wildfire
predate the Forest Service and go back into the
19th century where
there's an old adage that fire follows people. As people move out into any
kind of natural landscape, outside of the towns, people
accidentally cause fires. People cause fires on purpose,
and back in the 19th century, there was a series of extremely
deadly disaster fires. The 1825 Miramichi Fire in
Maine and Canada, hundreds died, where a large fire
burns over a town that's surrounded by forest. Same thing happens in
Peshtigo, Wisconsin, in 1871, where up to, they estimate, somewhere around
1,500 people died. More would've died if fleeing
residents hadn't made it to a couple of
rivers in Green Bay, literally running into the bay. More people died on that fire than the Great Chicago
Fire, the same year. Fast-forward just a few
years later, to 1910, and the same type of
disaster fire strikes, but now it strikes out west, and it strikes a
national forest. (solemn music) The 1910 Great
Northern Rockies fires, burning about three million
acres in about 48 hours, overran the city of Wallace,
Idaho, overran firefighters and people trying to
contain the blazes. The US Army had to be called
out to help restore order and help clean up
after these fires. And 1910 is just five
years into the existence of the US Forest Service. And the reaction was swift. We need to stop these fires. There's great loss of
life, but trees were money. This is what you could
build your community out of. - [Patty] So fire suppression,
by the early 20th century, is becoming a version of wisdom. The notion that
you would waste all of this wonderful resource, that idea is just
becoming intolerable. - And so the consensus
view, it was fight fire. And literally, after
the 1910 fires, the federal government doubled
the Forest Service budget with the express direction
to go put fires out. It's very, very hard to
find, in the historic record, times where Congress doubles
a federal agency's budget. - And you don't have to
persuade people who are living in proximity to
public lands, forests, because it's their
towns, their residences, their farmlands that are
gonna be burned over. - But the question was, what could they
actually do about it? (solemn music) Early on, they didn't have
very many actual rangers. Their firefighting techniques
were pretty haphazard. They didn't even have
very good ways of knowing when fires had broke out. - Everything was a hand tool. Transportation's extremely
difficult, in the backcountry. And this was the
early 20th century, where 30-plus million acres
was average, burned per year. Today, it's normally
less than 10. - [Narrator] For
over two decades, the goal of fighting fires
was a slow and painful task, only made more so by the
burgeoning Great Depression. - [Reporter] Discouragement,
fear, failure. - [Narrator] But this
dark era brought fortune to the forested land
across the United States, through President
Franklin D. Roosevelt's Works Progress administration, which gifted jobless men
and the Forest Service with a mutually
beneficial program, (fanfare music) the Civilian Conservation Corps. - [Reporter] Today,
depression is a fading memory. - The Civilian Conservation
Corps gave the Forest Service really the manpower to
actually start to be able to achieve this goal of
controlling wildfire. So in 1935, the Forest
Service issues a new policy called the 10 a.m. policy. And the idea was to control
every wildfire by 10 a.m. the morning after
its first report. And that really becomes policy
for the next 50 years-plus for the Forest Service. I would refer to it
as total suppression. And we start being more
successful in that goal. The Civilian Conservation
Corps also helped to accelerate building
of fire towers, which aided in
reporting wildfires. They also string miles
and miles and miles of telephone wire, which aids
in the reporting of wildfires. And also during this period is when CCC builds a
tremendous amount of roads throughout the national
forests in the west, which can get
firefighters quicker to a small fire
before it grows big. (gentle music) And we start being more
successful in that goal from the 1930s on. During World War II, the
Wartime Advertising Council started the Smokey
Bear campaign. - So remember only you
can prevent forest fires. - Wood was a vital resource,
even in World War II, and people sometimes
don't think of that. They think, well, didn't we
have metal planes and tanks that were fighting World War II? Yes, but how did you get all
the war material overseas, that we fought with? You shipped them in
wooden containers. And so wood was actually
a very vital resource to the war effort. The Ad Council found
that, at one point, Smokey Bear was the
most recognizable figure after Santa Claus,
in the United States. - [Narrator] With the
marketing help of Smokey and advances in technology,
the goal after World War II of controlling wildfires
became more and more successful with yearly fire
averages dropping from 53 million acres
to three million. But then post-World War II, the modern conservation
movement was born, and many researchers began to understand how integral fires
are to forested landscapes. - But it takes decades for
the scientific consensus of, hey, fire does a lot
of good for the forest to actually translate into
policy, at a national level. The National Park Service
officially changed its policy, in 1968, to give fire
managers more options in letting, particularly
backcountry fires, do some good ecological work,
if conditions were right, and it's not until 1978, when the US Forest Service
officially changes its policy to allow the same thing. - [Narrator] From fire
to mining and grazing, researchers have increasingly
pursued the question, how exactly have we
impacted our forests? Now scientists have begun to
uncover the many mysteries of our changing forests. (energetic music) The root of much of this
change lies in the industry that developed
our state, mining. Beginning in the middle
of the 19th century, miners cut and logged
forests and caused fires, intentionally and
unintentionally. Although most forests
would recover over time as new trees seeded
into the landscape, the synchronization of this
growth would have consequences over a century later. - In the late 1990s, trees,
such as lodgepole pine, were of a size that
were highly susceptible to attack by
mountain pine beetle. So the fire events that
occurred in the second half of the 19th century really
set up the landscape for the extensive bark
beetle outbreaks that began in the 1990s and continued
for mountain pine beetle up until very recently, about 2012. - [Narrator] But the
mining industry's influence on the landscape did not
end with its dissipation. At middle-elevation sites,
mining was heaviest, and prospering towns grew. In and around the
industry's destruction, people continued to build
their homes, shops and roads, limiting the amount forests
could recover in these areas. - Places that were
mined really heavily, these middle-elevation sites, we actually didn't
see much forest gain, across the 20th century. We have these really
extreme hotspots. Like the Fourmile Canyon
area, west of Boulder, was mined really,
really heavily. Central City and Black
Hawk, similar story. - [Narrator] Where
mining did not flourish, trees filled the landscape. - Places that had sort of
a low-to-moderate amount of mining, the
low-elevation sites and the high-elevation sites,
we saw a lot of forest gain. - [Narrator] Whether
forests have gained or lost tree cover,
it is apparent that our mining activities
have had an influence. While mining has left some
extremely visible scars across the landscape, other activities have
left more subtle imprints. - It wasn't the miners
who made all the money. It was the people who supplied
those miners, the ranchers. So those ranchers
brought in lots of sheep and cattle grazing. - [Narrator] For most
of Colorado's history, livestock were allowed to
graze on forested lands, depleting them of grasses. These grasses,
however, were essential to maintaining
frequent, healthy fires, in our lower-elevation forests. - The ecological role of those
fires was to kill baby trees. These fires would come along
before they had a chance to reach overstory
status, kill 99.9% of 'em. - [Narrator] With most young
trees allowed to mature, these forests have
become denser. And this density has
been reinforced in areas, due to our accomplished
history of fire suppression. (solemn music) But while fire suppression and
grazing have both contributed to density, they have
had opposing influences on the forest floor. Grazing has reduced grassy
fuels, but other fuels, like needle litter and branches, have collected, for decades,
without the occurrence of fire to clear them away. Together, more dense forests rooted in thick floors of fuel, have changed forest dynamics
at lower elevations. - Instead of havin'
surface fires that just kill
the smaller trees, we're havin' larger fires
with higher severity that are killin' even
the larger trees. (dramatic music) - [Narrator] But this may not
be the case for all forests. Those at higher elevations
typically experience less frequent fires. - [Peter] They're much cooler. They're much wetter. And so those forests
don't burn quite as often. - [Tom] Typically,
you'd have at least 100 and sometimes
several hundred years between fires affecting
the same areas. - [Narrator] With such
long fire cycles compared to our relatively short history
of modern human influence, researchers are uncertain
how much fire suppression and overgrazing have
exactly affected these high-elevation forests. (gentle music) It's clear Colorado's
forests have changed in a variety of ways. But how much is due to
our recent activities or management practices? And how much is due
to a changing climate? (solemn music) - Large fires were
very uncommon, within human memory,
in the Front Range. The Buffalo Creek fire
started on May 18th, 1996. It was human-caused. It was an escaped campfire. There was an extreme wind event, and the fire burned
10,000 acres in a day. And nobody living had
seen a fire like that in the Front Range, and
then two months later, there was an extreme
thunderstorm event,
on top of the burn, that caused massive
flooding, lots of damage. - [Reporter] The
firehouse is demolished. The community center
is carried downstream. Trees are uprooted. Homes are damaged, and
cars are swept away. In the end, two
people are found dead. - Then in 2002 was
the Hayman Fire. And that was, at that
time, the largest fire that had happened in Colorado. It burned 138,000
acres, 133 homes. It started on June 8th, 2002. It was also human-caused. And it burned under
extreme conditions. It made a run on June 9th,
where it burned 60,000 acres, including trees that had
clearly survived a lot of fires. (solemn music) We had an almost 1,000-year
tree ring chronology there, and it burned hot, in one day. - [Narrator] Across 60 to
70% of the total fire area, all of the trees are gone. - That's pretty astounding,
when you walk around in a big place like that. It just feels very,
very different. I was living here. We woke up in the morning
with a half an inch of ash on our car, a couple days. When you experience a thing,
and you see it change, it's much different than
just experiencing it after it changed. This idea of shifting baselines, where we talk about
the environment that
you're raised in, indicating how you think
about a certain issue, change on the landscape
is a similar thing. If people are born into an
area, and they see it start in a certain way, that's
what they think of as normal. People that tend to
recognize the fact that Colorado has changed
quite a bit are older folks, 'cause they've experienced a
lot of the changes firsthand. - The Hayman Fire itself
occurred in the same year as fires all across Colorado. (solemn music) - All of Colorado
is burning today. - The 2002 fire year
was in conjunction with the most extreme
drought that we've had in the modern climate record. About the same time, late 1990s, we had the beginning
of the massive outbreak of mountain pine beetle,
especially on the western slope. That was driven by drought. So that was kind of a
turning point, in the sense that a lot of people who
might've had some uncertainty about the reality of climate
change, the effects of warming, they started to think and to
say, yeah, okay, we get it. We're seeing some
impacts of warming. We expect that we're
going to have increases in fire, increases
in bark beetle, and that's already
initiated, since the 1980s. We've seen more than
a 2 1/2-fold increase in the annual rate
of tree mortality. - Humans have very
short memories, and even within
our own lifetimes, we tend not to think of the
entire temporal spectrum. - We need a longer
window of understanding of climate variation. There's a record of
climate in the tree rings. - When you're dealing
with trees, you're dealing with organisms that
live for centuries. And when you're dealing
with ecosystems, you're dealing with communities that have existed for millennia. Forests have legacies. Forests have memory. And when you get organisms
that live 600, 700 years, you have these legacies. I have a couple of
chronologies that go back into the early 1,000s, and
it's just the bare root end of a ponderosa pine that
has been dead for centuries. It dates to 980. So Vikings were going to
Iceland, at that time. And we can read that
code back into time. If you go back 1,000 years, If you go back 1,000 years, you're in a very
different climatic era. You're in what has been called
the Medieval Warm Period, which was, on average,
about three degrees warmer than the 20th century. I've found pieces
of ponderosa pine, which is now the
lower-elevation dominant, up as high as 10,700 feet, miles from the nearest
living ponderosa pine, thousands of feet higher than the current
living ponderosa pine. They were livin' up there,
during the Medieval Warm Period, because it was warmer
at higher elevations. If you age trees up
at upper treeline, it's pretty clear that upper
treeline advanced up-slope, during that warmer
period of time. What we could be staring at
now, with climate change, as temperatures get warmer,
as droughts get longer, is the whole
elevational gradient of forest is gonna
walk back up the slope. Where the concern is, is that this change is
happening more quickly than ones we have
observed in the past. And trees migrate
very slowly by seeding into their next environment, and they may not be able
to keep up with that pace. So some of the
lower-elevation areas that have burned really hot
may not regenerate to trees. It may be too hot
and dry for them. (solemn music) - We're seein' snow melt
occurin' very early. That increases the
growin' season. That's great for the plants, until it gets late summer,
and there's no water. Then they get drought stressed. But what also happens when you
increase the growin' season is you increase you fire season. - There are projections
that with an increase of one degree Celsius warming,
you see more than doubling of the fire activity
in the Western US. - Our winters are
gettin' warmer. And winter temperatures
that were really cold serve as a mechanism to reduce
bark beetle population, and so since we're not
gettin' as cold in the winter, those bark beetles are
survivin' over the winter, and so there's more of them
that emerge in the summer, and then there's more of
them that can kill trees, and we're seeing that already
with the mountain pine beetle, in our lodgepole pine forests,
but now we're seeing it in our spruce forest, with
the spruce bark beetle. - [Narrator] Predicting the
future of our forests is based on climate projections,
assumptions about
how well we will or will not limit the
emissions of greenhouse gases. - Really low emission
scenarios are saying that things will change relative to the historical
period but not too much. At this point, a
lot of people think that those are pretty
unrealistic expectations. Modern emission scenarios
seem to indicate that we'll see a
fair bit of warming across the Southern Rocky
Mountains, high emissions. Basically, the human
population's gonna explode over the next century. We're gonna continue
emitting carbon emissions at an unprecedented rate. Those sorts of assumptions
indicate pretty dire scenarios in the Southern Rockies. The average drought stress across the Southern Rockies
could more than double over the next century under
those extreme scenarios. And that is a pretty
terrifying thought. Under substantial
warming, that could mean that the Southern Rockies
could be like Northern Mexico, climatically, in
some ways (laughs). - The altitudinal zones
that'll be suitable for the forest we recognize,
those are shifting upwards, at rates that are faster than
those forests can colonize. But there's ecosystems
that are predicted to disappear entirely. The tundra will just be kind
of spaced off the mountains. (solemn music) - We are losing some
of our forest cover. Areas are not recovering to
dense forest, but instead, will transition to
grasslands and to shrublands. Is that a big deal? It is, in terms
of carbon storage. If we have a reduction
in the forest area, that carbon, that otherwise
would be stored in the trees, would be emitted
to the atmosphere. That's an example of one of
these positive feedbacks, where it's worse than
what we thought it was, when we start understanding
the feedback that results from burning forests
and a lack of recovery. - [Narrator] Forests
protect reservoirs from over-sedimentation. As fires continue to escalate, fewer trees could
mean less clean water. - Clean water is
usually important. It's probably our most important
resource in the Western US. - [Peter] The cities
in the Front Range, we actually live in the desert. We don't get a lot of water. So all of our water comes
from those watersheds above us that are all
surrounded by forests. - A fire leaves such
a disrupted landscape and so much sediment and
ash waiting to be picked up by any rainstorm
that comes along. So what happens if we are
depending for close to 80% of our supply on an area
that is so susceptible? (solemn music) - [Thomas] The
recreational value as well as the general tourist
dollars brought in by our forest resources
is highly significant to the economy of Colorado. - [Lincoln] Recreation,
it's the largest use of national forests, today. Recreation contributes
about 11.2 billion to the gross national product and adds about 145,000
jobs to the US economy. (solemn music) - At this point, we're not
making significant progress on limiting greenhouse gases. We're going exactly in
the opposite direction. So this should be
a source of alarm. - We're starting to see
those kinds of patterns. At the same time, this is
building on this legacy of fire exclusion,
of timber harvest, all these other impacts that
we've had in the forest. - When you pull on something, you find out it's hitched
to everything else. Climate and topography
and forest type and human activity, all of
these things are interrelated, and (laughs) kind of
timing is everything. - To actually know a place, you have to understand
a lot about it. You really have to understand
the historical context and the way things work in
that particular location, because very place on the
landscape is different. - So managers have to
have an understanding of what the past of
their forest was like. - Has this stand
been cut before? What species composition
do we want to have as a desired condition
when we're done? What was the past fire
history of this stand? That will make a different
in terms of what you might do and when you would
do that activity. And you would do different
types of treatments and different types of forest
types that are appropriate. - There is no value in a
one-size-fits-all approach. You have to recognize
that, not only over space but over time, conditions
are going to change. - [Narrator] As more and more
human structures encroach on forest lands, however,
the more difficult it is to manage them. These points of ever-increasing
intersection are known to scientists and historians as the wildland-urban interface. - [Patty] This has
been a great trend of the last 50 or 60 years. - Particularly
after World War II, the suburbanization rise
of a lifestyle economy in Colorado, we see people
really wanting to live in the mountains, near trees. This is a problem, of course,
'cause these forests burn. It's also a problem, because
some human activities at least were increasing
the likelihood and the intensity
of those fires. - The more people that move
here, the greater the impact from humans in natural systems. - 3.5% of Colorado's
land mass is categorized as wildland-urban interface. However, 42% of Colorado's
population lives in that 3.5% land mass. We're talking 2.2
million-ish people live in what we consider the
wildland-urban interface. That makes it much
harder for fire managers and firefighters on the
ground to let a fire go. Even if it's doing
good ecological work, if there's homes
up on that ridge, their first priority
has to be those homes and those lives up there. - [Mike] And so every time a
fire starts, we put it out, but that just kicks the can down for the next time a fire starts. - [Lincoln] It makes
fire management much more of a challenge. - And that means
that, unfortunately, we're probably
gonna have to move towards more strict zoning laws. We're gonna have to move towards
more strict public policy, more strict management
of national parks, more strict management
of national forests, regulating the amount of
recreational use in places. (solemn music) - [Thomas] Forests in Colorado
simultaneously divide people and bring them together. When we look at the
management of these forests, it's a really Balkanized world. - [Kyle] Colorado is a
really fragmented place, because of its complex history. Homesteads, mining
claims, a lot of things that split up land in Colorado. - In some ways, then, forested
lands are really fragmented, and that's further
fragmented those ecosystems. On the other hand, though, nature doesn't really respect
those property boundaries. The forest transcend borders. Key dynamics of those ecosystems
transcend those borders, whether we're talking
about mountain pine beetle or wildland fire, and I think
this has really been a spur to collaboration and
to collective action. - Historians really have
such interesting case studies of when troubles or
even calamities cause
human communities to come together
and when calamities, tragedies cause human
communities just to fracture and fall apart. And both things can happen. I know which one I prefer, but what's gonna
be the response, cooperation, collaboration, or contention and
blame and conflict? - And so there's really
an opportunity here for people to come together
and to work together, despite those boundaries
that divide them. - To actually do things in
the management of forest, you have to focus on all
land management categories, and that involves a
lot of collaboration. If you live in these
local communities, you actually have a lot of say in the things that
happen around you. Go to public forums,
go to public meetings. - Look into the local
grassroot organizations around, to volunteer or to
provide comments. Some of these collaboratives do have a citizen
science portion, that the citizens are out
there collecting the data. - Even if you aren't
physically able and able to go out there and actually
do the things yourself, you can interact with the
people that are making decisions and deciding what's
gonna happen, because you do have
a say in what goes on in the forests around us. (gentle music) Humans are really good at
making changes when we see that there's a problem. We're retrospective (laughs). We're not as good at doing these preventative
solutions to problems. But there's some evidence
that we've been able to do that, in the past. So I have hopes that humanity
will be able to recognize that there's a problem
and start to address it. We haven't taken
tremendous steps over the past couple decades. But I would say I'm
kind of an optimist. I think that the moderate
emission scenarios could be realistic,
as long as we start to take some pretty big steps,
in the next two decades. - I'm pretty optimistic that we'll still have
forests into the future. They may look different. They might not look
like the forests that you saw when
you were a kid. But trees have been around
a lot longer than humans. And I think they'll
continue to be around. They're pretty resilient. (solemn music) The snapshot that we're
seein' is just a small portion of what is happenin' in
the lifespan of a tree. - We're gonna have less forest in the future than in the past. I'm very optimistic that under
future climate conditions, we will have some
form of species that are adapted to
those conditions. We may have to walk to a
little bit higher elevation to recreate in those forests. - Understand that we're
gonna see trees die on the landscape. (solemn music) There are areas we can
prioritize with some management to maintain the integrity
of the ecosystem. Lookin' into different
research that we can do so that our grandkids
still have some forest to look at, in the future. - We may be heading
into conditions that haven't existed
within the period of time that we've been able to
study and understand. We don't know how ecosystems
are going to adapt, although we're trying
to figure that out, but one thing I do know
is that people are going to have to learn to adapt. We can't keep doing things
the way we've been doing them. (solemn music) - [Kyle] A lot of the decisions
that we make are driven by the things that
we want as a society. More than science,
more than economics, it's what society
actually wants out of the landscapes we live in. - We have to decide that. Do we want forests? Do we like forests? And do we want to
maintain our forests? If we decide that
all those answers to the questions are yes, then we need to figure out
how best to manage 'em, now and certainly
for the near future. - [Lincoln] What would Colorado
be without its forests? It's such a part of living here. It would be an immense tragedy if we let our complacence
get the better of us. (gentle music) (solemn music)
