- This next talk is from William Keeton
with the Rubenstein School of Environment
and Natural Resources at the University of Vermont
in the Gunn Institute of Environment presenting,
and now for something completely different,
Climate Change Effects on Forest Fire Hazards
in the Wildland-Urban-Interface of Bhutan.
- And thanks for attending.
The title of my talk this morning
is Climate Change Effects on Forest Fire Hazards
in the Wildland-Urban-Interface of Bhutan.
And this is gonna be a little bit different
from other talks I've given for this conference
over the years, but I'm really excited to share with you
this project that we've been working on
for a number of years.
It's been a collaboration between UVM
and a team of scientists from Austria, Germany,
Spain, and Bhutan.
So I'm gonna take you to a very different place in a minute,
but let's start off with just a little bit of context.
I'm sure everyone is aware
of the increasing forest fire problems,
both in the United States
and in many other parts of the world.
And I'm sure you're aware
of some of the particular concerns around risks
that that poses for the willdland-urban-interface
where risks to human lives, and property, and infrastructure
are the greatest.
And there are really no lack of examples
of these types of disasters from recent years,
you know, such as the Paradise Fire in Northern California
just two years ago.
Other parts of the world are beginning to experience
similar phenomena.
We've seen similar catastrophic fires
in the wildland-urban-interface in Greece, in Spain,
in Indonesia, and Australia, in many parts of the world.
And one place that people don't typically think of as much
as having these types of fire hazards
is the Himalayan Mountains.
And yet there are forest types there
that are highly fire prone
and increasingly pose these types of risks
to urban areas and suburban areas
like the capital city of Bhutan
that you're seeing here in this picture called Thimphu.
No, we see this phenomena
in many of these Himalayan countries
of out-migration from rural areas
and in-migration into the the few urban areas
that there are in a country like Bhutan
and that leads to sprawl into the fire-prone vegetation
just like we see in California and other parts of the west.
So I'm gonna talk a little bit today about these hazards
and models that we can use to try to predict
where these fire hazards might be the greatest in the future
with climate change.
And even though this is an example from far, far away,
I think there's relevance to our own region
in terms of models, and methodologies, and other approaches
that we might use here
to think about fire risks in the future,
especially in some of our more fire prone forest systems.
So that's really the connection to New England.
Okay, So I'll be reporting on this paper
that was just published last spring.
The lead author, Lena Vila-Vilardell
was a Master's student with me.
And I'd also like to thank specifically Choki Gyletshen,
who was another Master's student with me
who contributed to another component of this project.
Okay, so this is where we're headed.
We're headed to the kingdom of Bhutan,
which is a mountain kingdom in the Himalayan Mountains
just north of India, just south of China,
a place that was closed off to the Western world
until fairly recently, until the 1970s and 80s.
There's now some degree of tourism there,
but it's highly regulated.
It's a constitutional monarchy,
but the King still holds great sway over the society.
It's a fascinating place to work.
I thought I would just show you
a couple of pictures quickly to get you in the mood.
So these are the high Himalayas,
the peaks there are no less tall than the more famous ones
not too far away in Nepal.
Fascinating culturally, it's a majority Buddhist country.
There's a Hindu minority,
even a Baptist and some Christian minority groups,
Animist religions, a fascinating place culturally.
The national sport is archery,
and these folks are just tremendous archers.
So again, back to the point about most people
not thinking of Himalayan forests as having fire.
Well, that's because, of course,
these are high elevation mountains,
so highly mountainous terrain,
and the higher elevation forest there
are wet tempered forests, or boreal forests
that don't have much fire,
but there's a thin band of forest and mid elevations
that tends to surround settlements in urban areas.
It's dominated by this species that you're seeing here,
blue pine or Pinus wallichiana, that is highly fire-prone.
It's much like Ponderosa pine, a close relative out west.
And because we're at mid elevations, you know,
just up the mountain slopes,
this is where you find a lot of the most important
cultural sites in Butan, you know,
Buddhist temples, monasteries, that sort of thing
that are surrounded by these blue pine forest
that are highly combustible.
Okay, so here's a map of vegetation in Bhutan, and you know,
you're seeing everything from tropical to boreal,
but the purple is this margin or this band
of blue pine forest at mid elevations that surrounds, again,
some of the most important urban areas in the country.
It's an early successional species, it's shade intolerant,
but there's a lot of young blue pine now
that has regenerated on abandoned agricultural lands.
And one of our hypotheses in this project,
the larger project,
was that seems to be particularly susceptible to fire,
more so perhaps than some of the older,
more fire-resistant forest structures.
The other really important thing to know
about this case study is that the climate there
is strongly influenced
by the monsoon precipitation dynamics.
The monsoon season is roughly June to September.
More than 70% of the precipitation falls
during the monsoon season.
And there's some evidence now that with climate change,
the monsoon dynamics are getting all messed up.
Sometimes they fail completely,
sometimes they're dampened,
sometimes they arrive late.
So much of the connection between climate change and fire
is through this alteration of monsoon dynamics
that we're seeing throughout the Himalayas.
Here's an example of these younger forests
regenerated on abandoned agricultural lands that I mentioned
that seemed to be burning with ever greater frequency.
And again, right down into these suburban and urban areas,
this is the Royal Palace complex in Thimphu.
And, you know, the fires coming right down
to the outskirts of that.
So that's just a little bit of a setup for our study.
And we wanted to know whether climate change
is likely to alter fire regimes.
Does it pose particular threats
to the wildland-urban-interface?
And could we use models to predict and map
where those threats would be greatest?
So this is the workflow or a summary of the methodology.
It began with a very intensive data collection in Bhutan
over two field seasons.
It was a lot of fun to be there and doing that,
working with a couple of different crews.
We collected data from something like,
102 randomly distributed inventory plots
in two different research areas
that I'll mention in a minute.
The data were fed into, well actually,
there was a lot of processing of the data
that had to be done first to parameterize and calibrate
the fire behavior algorithms
that we needed for this study.
That all went to a wildfire behavior simulation model
called FlamMap.
And then finally, we calculated a fire hazard index
based on the output of FlamMap.
So I don't have a lot of time today,
but I'll just walk you through this quickly.
We used two major valley systems in Bhutan.
The roads and infrastructure there to create
what we considered to be the wildland-urban-interface,
and then randomly distributed our inventory plots with that.
And that's what you're seeing here
in those pictures on the right.
A huge part of this work,
and here's where I will try to make a connection
to what we might do in Vermont.
You know, if we were to use a model like FlamMap,
or any models,
a huge part of the work is just parameterizing
all the equations and algorithms
that have to go into a model like this.
For a million different things,
particularly fuel characteristic, you know,
algorithms like you're seeing here,
and this was a huge part of the work.
And we were fortunate that we had
very detailed inventory data that we could use
for a lot of this,
but in some cases we had to borrow coefficients
from surrogate species and other things,
but we felt like we ended up
with a very robust set of equations.
So from all of that,
there are a number of kind of key parameters
that go into the modeling work that you're seeing here.
These fuel structure characteristics
like stand height, canopy, bulk density,
defined fuel, biomass,
and other characteristics of the fuel,
like foliar moisture content.
And since we just had these inventory plots
distributed across the valleys,
like you've seen down here,
we needed to interpolate a continuous coverage or layer
for those characteristics.
So we did that through kriging across the landscape,
basically kind of interpolating
a continuous spread of of data between our sample points.
And there's a fairly robust cross validation routine
that we needed to go through
to substantiate that that kriging was accurate.
And we felt like in the end,
we had a very accurate layer
representing fuel characteristics across those two valleys.
Okay, so then we're ready for the FlamMap simulations,
and we're using FlamMap
to predict a number of key indicators of fire behavior
that are associated with risk.
So everything from flame length vertically,
the rate of fire spread, the amount of crown firing,
burn probability on an individual pixel basis,
this is all based on a raster digital elevation model
in FlamMap,
and many other assumptions
that have to go into the modeling.
I'm trying to make this quick in the interest of time.
We ran those simulations
under four different climate scenarios,
beginning with a baseline scenario, that's A,
and then using a factorial design
to trade off predicted changes
in temperature and relative humidity,
two of the climate variabilities
that most strongly influence fire behavior.
And this was based on extreme values
that we extracted from weather station data.
We were fortunate to have that in these two valleys
from 1996 to 2017.
We used the 90th percentile of climate
from the month of February,
which is the peak fire season in Bhutan.
And in the end, we ended up
with temperature and relative humidity values
that are very consistent with the IPCC scenario,
the most likely IPCC scenario for climate change
in the Himalayas.
So that's what these four climate change scenarios are.
Okay, so now we're ready to,
I guess, run the model as you're seeing.
FlamMap is designed based on the sort of basic idea
of a fire triangle
that you see in so many fire behavior models.
So the end result of this research,
where these layers that you're seeing here,
maps representing fire hazard
across these two study areas in Bhutan,
and you're seeing this portrayed
for those four different climate scenarios.
And basically what we found is that with climate change,
with changes in temperature and relative humidity,
we're likely to see a doubling of forest fire hazards
in blue pine forests in Bhutan.
So a doubling of fire hazards.
And that was particularly the case for elevated temperature.
I'm sorry, elevated relative humidity,
and the combination of elevated-
I'm sorry, just got a little jumbled there when I lost you.
It was particularly the case
for a decrease in relative humidity
or the combination of a reduction in relative humidity
and an increase in temperature.
So that's where we're likely to see
the greatest effects on fire risks,
again, through less moisture,
particularly in fuels and elevated temperature.
However, those effects of climate change
are likely to be highly variable.
What you're seeing here
are the median and inner quartile ranges
for the four different climate scenarios
for these two different study areas.
And what you're seeing is that there's a wide spread
in these predicted values for fire behavior
under these different climate scenarios.
So there's tremendous spatial variability
in terms of how climate change is gonna affect fire hazards.
And that's really important
if we start thinking about adaptation,
because it allows us to zero in on the specific places
on the landscape that are likely to have
the greatest fire risks with climate change.
Whereas other places, you know,
where fuel profile is more adaptive,
it's more fire resistant already,
would be lower profile for things like fuels treatment
and prescribed burning and other adaptive approaches.
So the paper has a whole variety
of adaptation recommendations
that we presented to the ministries in Bhutan.
And again, I think that there's a high degree of relevance
in this general methodological approach
to things that we might do here in New England.
All right, thanks for your time.
- The first question from Jenny Lauer.
When you refer to middle range forested area,
what elevations are you referring to?
- Yeah, so this is about 1,000 to 3,000 meters.
So that's, you know,
3,500 feet to 9,000 feet, something like that.
So I mean high elevation by our standards,
but that's mid elevation for the Himalayas.
The peaks are 25, 26,000 feet.
- Jay Shaffer asks,
what's your favorite food to eat in Bhutan?
- Well, I tell you, I have a somewhat mild palette.
And so the really spicy chili peppers,
they're green and red, which are in everything,
were a little challenging for me at first,
but I grew to like them a lot.
And one of the fun things about doing field work there
is that the field crews insist on having a hot meal
every day at lunch,
and they'll bring a hot meal in special containers
that they'll share around.
So that was a lot of fun.
- Okay, Ellie Shaper, has there been any studies done
or attempts to study the changes
in cultural or human interactions
due to the increase in wildfires or climate change effects?
- Yeah, that's a great question.
I really appreciate it.
I meant to mention
that like 99.9% of these fires are human caused.
So they're mostly escaped agricultural fires.
We think there might've been natural ignitions
hundreds of years ago, but we have no evidence to go on.
There are some fire scarred, you know, data sets
that suggest that might be the case
in some of the older blue pine forests.
But in these younger forests,
the vast majority of the fire is human caused.
And so there's this really strong interaction
between settlements pushing into this vegetation
and increased frequency of escaped fires,
particularly from orchards that are burned seasonally,
and there's a lot of grazing in these forests,
and they often will burn to produce forage for livestock
and those fires will escape.
So there's that side of the equation.
And then in terms of cultural significance,
this species, blue pine,
is used for a million things over there.
Everything from prayer flagpoles,
to housing construction, and all sorts of things.
So there's really an economic and a cultural impact
of these fires.