- Our speaker today is Jim Duncan,
who is the Director
of the Forest Ecosystems Monitoring Cooperative.
And today he's talking about monitoring trends
in the severity, extent and frequency
of key disturbance regimes in Northeastern forests.
And I just wanna add that there'll be 15 minutes of talk
and five minutes of questions following.
You can either put those in the chat
or at the end of the talk, unmute yourself
and ask your question of Jim directly.
Go ahead, Jim.
- Yeah, thank you, Nancy.
Thank you all for being here.
I am excited to present this work,
but I am really presenting this on behalf
of Emma Tate, and Pia, and others in our team,
and also the larger group that really worked a lot on this.
So while it's exciting to talk about the results,
I'm definitely one of the many people who've worked on this.
So it's a really exciting project to share with you.
And I look forward to hearing your thoughts.
So this effort was really looking
at shifts in disturbance regimes.
As you know, these might be responding to climate change,
they might be responding to other stressors
and kind of compounding factors.
There's a whole bunch of reasons
why disturbance patterns might be shifting
across the region.
This was developed by FDMC to respond to interest
in knowing what our existing data streams tell us
about disturbance regimes in the region
and whether they are shifting.
It's a lofty goal, and there are many smart people
who are doing great work on this question.
And our goal was not to do new research,
not to reinvent the wheel, but really trying
to provide a more digestible starting point
for exploring the question of how disturbances
might be changing over time,
and to do that in a fairly straightforward framework
when possible, so that you can look
at multiple disturbances side by side
and see how they compare.
So the first thing we wanna talk about
is what do we mean by disturbance, of course.
Here disturbance is an event that causes change to
or disrupts the function and services
of forest ecosystems,
and disturbance regimes are the patterns
of a given disturbance event and its impacts.
And so, looking at this project, as we developed it,
we were working with partners to figure out what
are the key drivers and responses to disturbance
that we care about
and that we wanna look at trends over time in,
what are the historical and anticipated shifts in extent,
severity and frequency in those regimes,
and what sources are available for baseline
and monitoring information about these regimes,
like what's already being collected
so we can build on what we have.
There are many potential disturbances to consider.
We, in this analysis that I'm gonna talk about today,
are focused specifically on drivers,
and those include flooding, high winds, fire, and drought,
and then pests and diseases,
which we classified into native pests,
established invasive pests and advancing invasives.
So kind of three different cuts of that.
And as part of the project, we generated two major outputs.
The first is a resource finder.
We want people to be able
to identify where monitoring of forest disturbance
is occurring and quickly find that data
and be able to access it, bring it into their own work,
or potentially replicate it.
The other piece that we wanted to provide
is a trend analysis, so what's the overview of the patterns
in each disturbance driver and analysis of change over time,
and this is the second topic
that I'm gonna spend most of our time on here today.
So the ways that you can get into this information
are primarily two, there's a technical report
that has a detailed analysis and methodology
for each disturbance driver that we looked at,
and we put together a website that allows you
to explore the available resources by disturbance type,
and then also browse the results of the analysis.
You can look at the region wide analysis
or state level analysis for each of the disturbance drivers,
overlay trends, and dig into those,
as well as see highlights
or summaries of those trends on those pages.
Highly encourage you to check out that site
if you wanna explore more on your own.
So I wanted to start with really getting into the drivers
with significant trends over time.
So I think we might spend a little bit more time
on these 'cause this
is where we found something interesting, potentially.
The first we're gonna talk about as high wind.
As you can imagine, high winds
can be a forest disturbance event when it causes wind throw,
uprooting or tree breakage.
We used Global Daily Summaries data set
to be able to pick out five-second wind speed maxes.
So we looked at any wind greater than 55 miles an hour
because of its connection to various scales
that caused tree breakage.
That allows us to have data from 2001 to 2020,
1,800 events across 73 stations shown on the map there.
So what did we find?
Are high winds becoming more frequent?
No, we're not seeing that.
There's a small decrease in Vermont,
but though it's significant, it's not very large.
Is this high wind happening
in more places across the region?
Yes, we are seeing it statistically both in Massachusetts
and at the regional scale.
And are they getting more severe?
And interestingly, they are getting less severe,
and that's happening visually
and in four of the states themselves.
So diving into this a little bit more,
what does that look like?
When we were talking about high winds happening
in more places, is it increasing in extent?
You can see the number
of stations reporting high wind events
that could cause tree breakage is going up over time
by about a number of 20, and that pattern is holding,
though for a first smaller scale, in Massachusetts.
And we're seeing some pretty steep drops in severity.
So if we look both at the average maximum wind speed
and the number of events in the 95th percentile,
both are declining.
The 95th percentile, as you can see,
is really highly driven by hurricane Katrina,
where we had some particularly high winds spread out
across the region.
So that might be more explaining that pattern there.
The drop though in average maximum wind speed over time
is a more clear decline.
And as I've mentioned,
that holds both in Maine and in the region,
as well as the four states shown,
Maine, New Hampshire, New York and Vermont.
Next up, we looked at fire.
This is not something that we talk about as often,
especially in kind of the wild lands,
but it is becoming more of an issue as this,
as the photo in the White Mountains shows.
It was just something that when it does happen,
is very visible and very noticeable,
and it's also a management tool,
especially in Southern New England.
So fire as a disturbance regime is something
that we wanna think about.
We used the Fire Program analysis, FOD,
the fire-occurrence database.
Any fire with acreage reported
was considered a quote unquote fire,
meaning we had 125,000 events
over the period of 1992 to 2018.
Note that you can see the darker colors on that map
are the density or the number of fires reported.
There's a significant reporting to New York.
So many of these fires are occurring in New York.
So just keep that in mind
as we look at some of the patterns.
So we can go back to those same questions,
are extent, severity and frequency changing?
Is fire becoming more frequent?
Yes, regionally and in Connecticut,
Mass, New York and Vermont,
we're seeing more fires happening in a given year.
Are they burning more overall area?
No, but we
are seeing the average area getting smaller regionally,
which is kind of interesting.
And are they burning more area at once?
So is the total extent of a single event getting bigger?
No, we're not seeing any evidence of that.
We do see some statistically significant decreases
in Maine and Rhode Island and some small,
but slight increases in Massachusetts and Vermont.
So there's not a clear picture on whether we're burning,
we're seeing fires getting larger overall.
Looking into some of the data that underlies this,
looking at the number of fires reported per year,
we do have this increase that could be in part
because more people are reporting prescribed burns
through the system, but there's in general,
we would say yes, there is an increase of fire occurring
on the landscape regionally and in Connecticut, Mass,
New York and Vermont.
So those are the statistically significant findings.
There are some other really specific ones within those.
We looked at three other categories, as I mentioned.
And there, in most cases, wasn't a significant
or a really stark trend.
In drought, there are some slight increases
in the occurrence of abnormally dry conditions
in Vermont, Connecticut, and Massachusetts.
So we used U.S. drought monitor data
to look at the presence of any portion of the state
in any level of drought status from D0 to D4.
And it's only a 20-year record for that.
But we do see that there's this kind of increase
in number of weeks spent
in that lowest category across those four states.
But at the regional scale,
there's no clear trends in that right now
using this type of analysis.
And the lack of any trend is very clear in the flood data.
We looked at flooding as any gauges
that report levels above flood stage.
And so, we used this a network of 179 stations
across the region for this 12-year period,
and don't see any trend in either direction
at the regional scale or even at the state scale.
So it's really all over the place.
And there are some trends in the data sources
for native and long-present invasives in the region.
We looked specifically at spruce budworm
and forest tent caterpillar as endemic native pests
that have cyclical outbreaks.
We looked at hemlock woolly adelgid and browntail moth,
which have an elementary disbar,
which have been established in the region for some time,
and newer arrivals, like Emerald Ash Borer.
And there's just either not enough data
or the trends are not clear
because of the different data sources
that were put together.
So there are some trends,
but the interpretation is not straightforward,
so it's complicated,
but it's an area that we'll keep looking into.
And so those are the kind of results
of the statistical analysis.
When we look at what we might do with this tool,
we've kind of wrapped up this project work,
we've done the initial steps that we had planned to do.
What we want to look at next
is what's gonna be valuable for the cooperative.
And so we have a couple of potential next steps
that we could do.
Technically we could customizable charting.
The one thing you can't do to the site right now
is look at, say, drought and fire next to each other.
But we do have that ability with the way
that we structured everything.
So is that something that we wanna add on?
We could do more work on the responses side of the work.
We looked at available resources for say,
stream macroinvertebrates or invasive plants,
which can be a indicator of response to disturbance
when it happens in forests.
But the link between those
that we could provide some sort of trend analysis
and monitoring framework for was a little bit harder.
So those connections are really there,
but is there some way to drive research
to kind of look at trend analysis
and make that connection between drivers and responses?
And at its most basic level,
we can continue to add resources
to increase the breadth of the tools
so that we are further documenting
and sharing where people are monitoring these types
of disturbance regimes
so we have a better regional base to work from.
So I think this does provide a framework
for doing a very simple but initial look
and context setting for what disturbance regime change
might look like in the region.
There's certainly more work we could do
to extend the record backward in time
and do more sophisticated analysis.
But this initial tool and product allows us
to communicate at very basic level,
what's the extent, what's the severity,
what's the frequency, and are those changing.
So with that, I'll give a big thank you
to our advisory committee shown here,
both in name and organization.
We had several meetings with these folks
and really benefited from their insight,
and guidance and help with interpretation.
And as always appreciative of the funding
that we receive to make this work possible.
So with that, I will end
and see if there are any questions you all
might wanna have me address.
- [Nancy] There is a question.
People can put the questions in the chat box
or unmute themselves and ask Jim directly.
Jim, there is a question in the chat box.
Do you want me to read that to you?
- I can read it. - [Nancy] Yeah.
- Let me just pull up the chat.
All right, "In young forest habitat management,
"at disturbance dependent habitat,
"we often say that natural disturbance is insufficient
"to create enough new young forest for wildlife.
"Therefore, we need active habitat management
"to mimic disturbance on the landscape."
So this analysis did not attempt
to address how much should be happening, right?
That's a paleo ecological kind
of historical reconstruction, right?
What were these systems adapted to pre-colonial times
for thousands of years and what was the landscape mix?
And we know that it was different than it is now.
It was much more of a mosaic.
We've swung back towards afforestation,
while also having urbanization.
So there's kind of a hollowing out of that middle
of non-urbanized young forest.
So I think that there
is a lot of attention being paid to that.
Actually, I'm excited to hear Juliet Barton's talk tomorrow,
which will really go into that a lot more.
I don't know that I could say these findings tell you
whether there's enough natural disturbance happening.
When you look at something like fire though,
and we see this increasing number of fires
and a lot more smaller fires happening,
I think that could also be a indication
that you're getting some more
of that gap creation through fire.
It might be a way that management and disturbance
are coming together to create those openings.
All right, well, thank you for attending and your time.
As I showed on the final slide,
you can reach out to me or Pia with questions.
The website is femc/disturbance.
And please let me know if there's any other kind
of directions that you think this product could go.
'Cause as I mentioned, one of the things we're looking to do
is see, we've done this analysis, we built this tool,
is there a need to take it further?
Is there a need to do any more
on one of these disturbance drivers?
That's certainly an option we have, finished the project,
but it doesn't mean we finished the work.
So do reach out to your state partnership committees
or to me, if you're interested
in seeing this project go further.
- [Nancy] Thanks, Jim, and thanks, everyone.
- Thanks, all.