- [Savannah] Hello, I'm Savannah Ferreira,
Forest Health Specialist
with Vermont Department of Forest, Parks and Recreation.
Today, I'm gonna be talking about red pine decline
and how our forest health team has established
and sampled monitoring plots this summer.
Before continuing,
I just wanted to acknowledge Emily Meacham.
She's a protection forester with our department.
And although she won't be presenting today,
she also spent a lot of time and energy on this project.
So red pine, pinus resinosa,
has been in a state of decline
across Vermont over the last decade.
Although established plantations
were showing symptoms of dieback and mortality,
these observations were only ever casually observed
and inadequately assessed.
Early hypothesis alluded to a combination of climate change
and the invasive red pine scale
being possible causal agents.
Red pine scale had been detected
in low populations in both Rutland
and Orange County in 2015.
However, they have never been again observed in the state.
To get an early snapshot of this decline,
a single monitoring site was established and sampled
in 2019 on a 100-year old red pine plantation.
in Groton state forest.
If you're familiar with the Vermont,
this is in the Town of Peacham.
Preliminary sampling showed
that there shoot blight pathogens,
insect stressors, which were identified
by Isabel Munck and Kevin Dodds
from the USDA Forest Service.
This included the pathogens Diplodia pinea,
sirococcus conigenus and pestalotiopsis,
as well as insects,
such as the pine weevil gall and spider mites.
To try to determine if this declining pattern
and fungal and insect complex is homogeneous
across the state,
12 red pine monitoring sites have been established
during the summer of 2020.
Including the initial Groton site established in 2019,
12 monitoring sites were selected across the state.
Sites were divided among four geographic regions,
which included the northeast,
the northwest, Central and southern regions.
We chose to set these sites up by regions,
because it was a way for us to delegate future monitoring
with our protection staff.
It is worth noting,
that as red pine started to decline,
red pine salvage cuttings
were implemented throughout the state
on both private and public lands.
Because of this,
we chose to establish our plots on state land,
so we had control over future management,
and could essentially protect our plots from harvest.
If you look over this map,
you'll see the distribution of state owned lands in Vermont,
and that's shown with the green shapefile.
Now, unfortunately we don't have a shapefile
that shows red pine distribution across the state,
but it's obviously not evenly distributed
in our four regions,
nor is it gonna make up the majority
of our state-owned lands.
So based on ownership and red pine presence,
the following sites were selected for monitoring.
Due to time, I'm not gonna be listing them all out,
but they're shown here on the map in these red circles,
and they're also listed on the slide.
At each of the 12 monitoring sites
four permanent plots were established.
The plot design is a fixed radius 35-feet
with approximately 120-feet between plot centers.
Initially, in Groton in 2019,
protocol stated that these plots should be linear,
but due to varying site conditions and red pine presence,
sometimes the plots were set up in a T formation,
like shown in the bottom picture here,
or separated completely.
The top picture here is of CC Putnam State Forest.
And we actually had to set our plots up
very sporadically at this location,
because red pine mortality was so widespread
that it was difficult to find living trees.
But when we could,
we did try to stick to a linear pattern
with 120-feet between plot centers.
All red pine within the plot where it tagged, measured,
with a minimum of 20 trees being observed per site.
During and only in plot establishment,
we observed and recorded the plot azimuth,
the distance from each red pine to plot center,
the DBH of all red pine,
and their respective crown position.
We ignored anything that was not a red pine.
In addition, we observed red pine
uncompacted live crown ratio,
crown density using the scale
on the top right-hand side of your screen,
the dead shoots and their respective location in the tree,
the crowd transparency using the scale
on the bottom right-hand side of your screen,
and the needle discoloration.
These observations are what we're gonna continue
to observe annually.
Plot establishment was done by two people,
Emily and myself, with COVID-19 compliance.
But now that the plots are established,
observations can be made independently moving forward.
For our experience,
setting up these plots this summer,
it'd be very helpful to complete these observations
in leaf off conditions,
probably in the late fall, early winter.
Some of our plots do have difficult winter access,
so completing observations before deep snow
is what's gonna work well for our team.
Plots are gonna be remeasured annually for five years,
and sampling, which I'm gonna talk about next,
is only gonna be repeated
as drastic changes occur.
This year 10 out of 12 sites were destructively sampled.
We only excluded two
because they were both high use areas,
and it just wasn't safe to fell a tree there.
Felled red Pines were micro sampled
on the main bowl at DBH,
and within symptomatic branches
in the canopy using a sterile bone marrow biopsy tool.
For those of you unfamiliar,
this is a small 0.5 to one millimeter diameter tool
that penetrates the tree, approximately one,
maybe two millimeters,
to excise outer bark tissues
and capture the vascular cambium.
In addition, symptomatic needles were also harvested
from the canopy,
and all plant tissues were brought back
to the forest biology lab,
surface disinfested,
and plated on potato dextrose agar with antibiotics.
Fungal isolates were identified by morphology
and subculture as they appeared.
This past month, our representative subset
were sent to UMass Amherst to be PCR sequenced
to confirm morphology identification.
In addition, to determine how these insect stressors
and pathogens have impacted growth over the last few years,
cross sections were taken at the base of live crown,
BLC and at diameter at breast height, DBH,
from the 10 sampled trees.
This winter FPR staff will be conducting tree ring analysis
to quantify any growth reductions
that these complexes may have caused.
So now that you have some background on our methods,
we can start talking about some of our preliminary results.
So first let's review our crown metrics.
Here's our average crown metrics per region
compared to a standard, asymptomatic, open grown red pine.
If we average all our regions together,
average crowd density
for our observed trees was 46%,
4% less than our standard.
Average dead shoots were 21%,
11% higher than our standard.
Average crown transparency was 37%,
7% higher than our standard.
And average discoloration was 15%,
which is 5% higher than our standard.
The first and most common fungal pathogen
that we observed was Diplodia tip blight.
And this was observed at all 10 of our sampled sites.
This is an opportunistic pathogen that's native to Vermont,
and can often be found across the state in low levels.
Because of its opportunistic nature,
populations can dramatically increase when conditions
favor fungal growth,
and also when conditions favor tree stress.
This pathogen causes browning and dieback
of needle and shoots,
and contrary to what the common name implies,
this pathogen is not exclusive to the shoots or foliage,
and can actually cause cankers,
which can lead to girdling and dieback.
If you look at this cookie here,
there's a Diplodia light canker
that infected the tree in 2018.
Now, although that canker is pretty small,
all of the resins surrounding it and below it
is actually resin soap,
nonfunctional sapwood from compartmentalization.
So although the canker is quite small,
all of the damage that it caused
is actually quite substantial.
If you wanted to look for this pathogen
on the land that you're managing,
it can be present year round in leaf litter.
It can be found on cones.
It can be found on infected needles,
and in the branches.
If you look at this pine cone
on the top right of your screen,
all of those black dots are actually pycnidia,
or the asexual fruiting bodies of this fungi.
Red band needle blight is another pathogen
that was observed at all of our sites,
but symptoms were typically less severe
than Diplodia tip blight,
except for in two locations.
In red pine,
this pathogen causes brown spots on living needles,
which is gonna progress into these red bands over time.
In heavy infections, like shown in these pictures,
needles can be observed as having brown tips,
which is similar to Diplodia,
and they will eventually all die.
In addition to fungal pathogens,
we also observed several insects stressors this year,
which included pine needle scale.
That was at eight of our sites.
As you can see in these top right two pictures,
feeding can be quite noticeable,
and it looks like those whitish yellow spots on the needle.
Luckily for us, red pine scale was not observed
at any of our sites.
Although other new England States
have been reporting red pine scale
as a causal agent of their decline.
Pine weevil gall was again observed at all
but one of our sites,
and are quite noticeable because they leave these galls,
and these really small exit holes,
if you can see my mouse on your screen.
In high populations,
these galls can lead to flagging
and shoot dieback of their infested hosts.
Sawflies were another insect
that we got reports of consistently
throughout the summer outside of this project.
And as you can see, we have sawfly feeding,
which was at all but one of our sites.
This was possibly done by the European pine sawfly,
but because feeding happened so early in the growing season,
we didn't get to see any insects
by the time that we sampled.
Now, although insect damages
did not seem to be the causal agent of our red pine decline,
their presence, big or small,
is gonna influence overall tree health and vigor.
And it's gonna help predispose trees to fungal pathogens.
In addition, it's possible
that any of these insects could vector fungal pathogens
within or between trees.
As I previously mentioned,
sampling also included collecting DBH
and base of live crown cookies.
We've only just started
to sand and date these cross sections,
so I don't have solid results
to share with you at this time.
However, here's just one example of one of our sites.
As you can see, almost up until 2000,
this tree was growing pretty steadily,
but it starts to dramatically drop off starting in 2001
and continuing until 2020, when it was harvested.
I know this ruler isn't straight,
but there is less than a centimeter of growth
over the last 20 years.
Now, there are many abiotic factors
that can contribute to this decline,
and I listed a few that were notable here
in Vermont on the slide,
with the most notable being our severe recent drought,
as well as tropical storm, Irene.
So in summary,
red pine is continuing to decline across the state.
This decline pattern seems to be a combination
of abiotic and biotic factors,
which include severe recent droughts,
as well as insect stressors and fungal pathogens.
In setting up these monitoring sites,
we hope to observe and document this decline
in our state to better understand red pine health
and future management.
With that, I'll take any questions that you may have.
- A question from Jenny Lauer.
"Many western states are losing pine trees to pine beetles.
Is Vermont seeing any of that?"
- Currently we have not been seeing that,
which is really great.
There are Western pine beetles
that we just don't have documented in the state right now,
but we did not see any native beetles
infesting any of the sample trees that we took this summer.
- Kate Miller, more of a comment.
"Great talk.
The progression you found of stressors and RPS
matches what they found in Acadia National Park."
- [Savannah] Great.
- Judy Resowski says,
"Hi, Savannah. Nice talk.
Did you see any sign of wood wasps,
sirex noctilio,
on your plots?"
- No, we definitely did not.
I've had some other sirex species
submitted as lab requests in some of our hardwood stands,
but nothing to do with our red pine stands.
- Okay, and then Kate Miller,
"Did you have a sense of what tree species
are regenerating under the dead red pine?"
- So a lot of the places
where we set up these plots were actually plantations,
so there's almost little to no regeneration.
- Aaron Marcus,
"Thanks so much for this research.
Are you noticing differences
in how natural versus planted stands are responding?"
- So had two,
I believe, two naturalized or non-plantation plots,
and they both seem to be pretty bad.
Our more southern,
we had three plots in the southern region,
and those all seem to have higher crown metrics,
so they were not asymptomatic,
but definitely healthier
than what we were seeing in our central and northern sites.
But between planted and natural,
there wasn't much of a difference.
Even our plantations are still being managed.
We had some releases about 25 years ago,
but we weren't seeing anything significant.
- Ethan Cromley,
"What were the safety issues at Aitken State Forest?"
- So we couldn't,
yeah, Aitken.
We actually had to put the red pine plots
all the way at the top of the forest.
And it's a really big mountain,
if you're not familiar with Aiken State Forest,
and there's about three or four trail heads
that all can join right into our plot.
So in order to fell a tree there,
we'd have to shut down many of the trails,
and we just didn't have the staff
to make sure nobody wandered into our plot
when we were dropping a tree.
- Eric Sorenson,
"Are all of the monitored sites
natural red pine forest or are some plantations?
Is there any evidence of different responses
in plantations and natural forests?"
- So, like I said before,
I think only two were not plantations.
So we're not really seeing enough different responses
because our sample size is pretty small.
- Maddie Brawley,
"I didn't have a camera microphone,
but I'm wondering what forest management approaches
are being taken in response to these stresses."
- Yeah, so right now we are not doing any management
in response to these stressors.
A lot of people have been doing red pine salvage cuttings
in areas where there's widespread mortality.
These are native pathogens that we're seeing.
Other native pine pathogens
like Caliciopsis pinea and white pine,
just managing your stand,
opening it up and thinning it,
decreases the fungal pathogens in the stand
because it dries it out.
And it also increases individual tree health and vigor.
So that's probably what we're gonna see moving forward.
- Charles Cogbill,
"Did you sample
any native red pine stands,
such as Warren Mountain, Bolton Cliffs or Patel Preserve?
- No, we did not.
- And then Eric Sorensen,
"Did history of fire in these stands
affect disease, presence or severity?"
- So in the stands that we sampled,
we don't have a very long history of fire.
So that's not really something that we're looking at."
- Norman Junior.
Sorry.
"What tree species would you recommend using
for under planting of red pine plantations?"
- Yeah, so that's a tricky question.
I guess it depends on where you are.
If you wanted to keep a softwoods understory,
doing other pines are gonna share pathogens with red pine.
So even planting white pine,
that's susceptible to Diplodia pinea as well.
Caliciopsis pioneer can actually affect red pine.
So maybe doing a hemlock,
or if you wanted to take out your red pine plantation,
and just let it come back naturally, regeneration,
with a mixed hardwood forest.
It depends on what your management goals were longterm.
- And then last question,
by Rick Dyre,
"Were the average basal areas for,
what were the average basal areas for your study sites?"
- So we actually have not looked at basal area.