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In this Episode meet

A Window of Resurgence for Red Spruce

Produced and hosted by Jonathan Yales - 37 min.

Research Soil Scientist Mary Beth AdamsResearch Plant Physiologist Paul Schaberg.

In the 1970s, red spruce was the forest equivalent of a canary in the coal mine, signaling that acid rain was damaging forests and that some species – especially red spruce – were particularly sensitive to this human induced damage. In the course of studying the lingering effects of acid rain, scientists came up with a surprising result – decades later, the canary is feeling much better.

Jonathan Yales

Hey. it’s Jon. I’m back with a special episode of Forestcast while we finish up season two for you.

First though, you probably listened to season one during the COVID-19 pandemic. We recorded that season months before the pandemic, and that’s why I never mentioned it in any of the previous episodes. But, I found myself thinking a lot about that season one while COVID-19 spread across the country.

Because of COVID-19, we all now share an intimate understanding of what it’s like to be caught up in an invasion. To put myself in the shoes — or, I guess, the roots — of a tree we talked about in season one, it’s honestly a lot easier now. We’re getting our own taste of what it’s like to be a host species, like an ash tree, when the emerald ash borer invasion is on the horizon.

And all that helped me to see, that the scientists we talked to last season are less scientists just geeking out and freaking out about some tree somewhere, and are more a crucial component to our forests’ health. The Sandy’s, Leah’s, Talbot’s of the world, they’re really the epidemiologists of the trees — they’re our tree health professionals.

And, their science hasn’t stopped either. To mitigate the risk of virus transmission, all of us are working remotely as well as balancing our core values of safety and service. It’ll be more phone calls, but I’m going to keep bringing you their stories — whether we’re in the field, the lab, or we’re all at our homes.

But, today’s episode has nothing to do with COVID-19, viruses, insects, invasions, or anything like that. It’s a special one-off episode celebrating what can happen when citizens, scientists, and government actually come together and coordinate action, and how that can make the world a healthier place — for us, and for a tree. Enjoy.

Archived Recording 1
There is a new environmental fear alive in the land, the fear of something called ‘acid rain.’ Reports of its presence and its danger come from everywhere. Environmentalists, joined by the federal government and some state governments, pushed the button of alarm, and now seldom a day goes by without a news story from somewhere about it. Stories of lakes turning up dead. Fish populations decreasing. Of conflicts between northeastern states and Midwestern states. Between government and industry. Between the United States and Canada. Between and among all kinds of people, with all kinds of interests.
Jonathan Yales
That, was 1980. Back then, acid rain was an issue, and a debate, happening all over the country.
Archived Recording 2
New England receives more of the acid rain than any other part of the nation … The center of the acid rain storm is right here in Pennsylvania ... Acid rain has been discovered near the Continental Divide ... We have it here in Maine, probably worse … Prevailing winds carry acid particles into the higher altitudes of the northeast.
Jonathan Yales
Our scientists remember it, too.
Mary Beth Adams
Really, it was one of the major issues, kind of right up there with segregation and civil rights, those kinds of things. It really was one of the major issues of the time.
Jonathan Yales
That’s Mary Beth, a research soil scientist.
Paul Schaberg
It was in the news at night, especially, the shocking fish kills in the Adirondacks. There were pictures of ponds with dead fish all along the shore.
Jonathan Yales
And that’s Paul, a research plant physiologist.

Both Paul and Mary Beth started their careers in this era of acid rain, but they started their careers nearly a thousand miles apart. And yet, they both saw the same thing: acid rain killing a specific tree. A tree called red spruce.
Mary Beth Adams
I remember a professor – I was at North Carolina State [University], working on my PhD at this point – you know going and looking at the spruce-fir forest on the top of Mount Mitchell in North Carolina and telling the press, ‘These trees are dying and acid rain is causing it.’
Paul Schaberg
I just happened to be in the right place at the right time for this to become a focus of mine. So, the first time folks started piecing together the possible connection of acid rain and red spruce decline was from studies here in Vermont, on Camel’s Hump Mountain.
Jonathan Yales
Red spruce is an iconic North American mountain tree, and one of the most important forest trees in the Northeast. And for some unknown reason, it was especially susceptible to the acid rain.
Mary Beth Adams
Red spruce is kind of one of those iconic New England species, but it actually grows very widely at high latitudes. You find it lots of places in Canada, from the Canadian Maritimes down through Maine, New England, New York, and then kind of down along the Appalachian ranges down to the southern Appalachians – where it grows on the top of the mountains – all the way down to Tennessee and North Carolina. It's a tall tree. It can get to be up to a couple feet in diameter – the tree trunks. It's a conifer with kind of a yellowish-green, but shiny leaves all around the twigs in the branches. And, in fact, that was one of the first signs that we had a problem is when the needles started turning red, I mean, like bright red or orange.
Jonathan Yales
But, this story of red spruce decline doesn’t start here with this acid rain mystery. The 80s were actually the tail end of a nearly hundred year history of us humans whittling away our country’s red spruce.
Mary Beth Adams
The central Appalachians were massively logged, they were kind of the last big logging boom in the eastern United States – between 1880 and 1920. And, much of the red spruce at the time was logged, because red spruce is good for piano sounding boards and violins and paper, it makes really fine high quality paper. So, once they got past the technical difficulties of logging in these narrow mountains, they came in and clearcut it, I mean, skyline to skyline, you know, ridge top to ridge top and beyond. And there were fires because they used railroads to log. We went from half a million acres of spruce-fir forests in West Virginia to probably about 50,000 acres today.
Jonathan Yales
And, where did the fires came from? So, you have railroads? How did they cause fires?
Mary Beth Adams
They were all coal-fired or wood-fired trains and they would dump their coal box out, or there were stray sparks. So, one of the things that I didn't talk about, was that spruce forests generally have nice deep forest floors – these organic layers – and in the old growth spruce in West Virginia it was feet thick, I mean, up to like six feet thick. So, when they logged, after you cut the trees down and of course you take the trees away, it dried out, and it was highly flammable. There was lots of logging slash laying around and this deep dried out organic layer, a spark hits it, and it takes off. And there were just lots and lots of massive fires. There are places on top of Cranberry Ridge where it burned down to bedrock, down basically 3-5 feet down to just bare rock.
Jonathan Yales
This timeline is not adding up for, you know, our own species. It's like we decide to cut them all down, then run railroad tracks through, and then we burned every square inch of it left, and then, you know, a couple decades later we pour some acid rain on it, and it's like, yep, our species is not looking too good here.
Mary Beth Adams
No. And, in all honesty, West Virginia is, in many parts, worse than some of the other areas because West Virginia has this incredibly extractive history. It started with salt, in the salt mines or the salt mix, you know, where you didn't necessarily destroy things by taking the salt out, but then they found oil near those, and then trees, and then coal.
Jonathan Yales
And it’s that coal that would become a major cause of the acid rain problem decades later.
Archived Recording 3
Trucks and cars are big contributors to the stuff that acid rain is made of, but most of the pollution comes from smokestacks of industrial coal-fired boilers. To keep from dumping pollution on the ground where air quality is monitored, the stacks are built taller and taller. The pollutants are carried by wind far from their source.
Jonathan Yales
Now, what actually is acid rain?

It’s not pure acid falling from the sky, but rather it’s rainfall – or snow, or fog, or hail, or even dust – any deposition that has been mixed with elements and gases that have caused the moisture to become more acidic than normal. And it’s that acidity that was doing something to the lakes, the fish, and our red spruce, but we didn’t exactly know what.

And, it wasn’t just affecting nature. The more we looked, the more we saw.

Paul Schaberg
For many folks, it was just shocking that we were having such an impact we were even altering the pH of rain. And, folks started trying to look at, well what does that mean, and finding things like, the rain is so acidic it is helping corrode our bridges, and it's damaging marble facades on grand buildings and in cemeteries, it's making aluminum and other metals more available, it's killing fish in the lakes of the Adirondacks. The more folks were looking, the more they realized that this was a broad, and kind of shocking, phenomenon, and it was having real impacts.
Jonathan Yales
Because it impacted so many parts of our environment – natural and man-made – people were understandably concerned. And, this being the 80s – and not being far removed from the environmental movement of the 70s – people rose up and demanded action.
Mary Beth Adams
This is one of those things, it's just a fascinating story because people brought this concern, this fear about dying trees, to Congress and Congress passed an Act and funded the Act, which set up a 10-year research program to look at the effects of acid rain on everything. But, much of the concern came from fears about the effects on natural systems, and particularly forests that included red spruce.
Jonathan Yales
And that act was the U.S. National Acid Precipitation Act of 1980. And to get to the bottom of the acid rain concerns, and to uncover what exactly was happening between the acid rain and the red spruce, the Act launched a unique research program.
Mary Beth Adams
They passed the National Acid Precipitation Assessment Program – NAPAP – and it was a huge program designed to look at the effects of acid rain on human health, on water quality, on materials – things like concrete, and tires, and marble statues – and on agriculture, on natural systems. It was a very comprehensive program.
Jonathan Yales
And within this program, the Forest Service had its own little corner.
Mary Beth Adams
Part of this NAPAP program was the Forest Response Program, which the Forest Service ran. And, one of the programs within that was the Spruce-Fir Research Program. Which was designed to look at the decline that had been noticed and documented in spruce-fir forests in the eastern United States and evaluate the relationship with acidic deposition and come up with some solid explanations for what's happening, why, and potentially what could be done.
Jonathan Yales
As Mary Beth became involved with the Spruce-Fir Research Program, she was able to get a big picture view of the acid rain issue because of the extent of the Program’s research.
Mary Beth Adams
We learned so much through the Spruce-Fir Research Program. For example, we did not know how much acid rain was falling. I mean, many places we couldn't even tell you how much precipitation was falling. And so, one of the things that came out of NAPAP was what's called the Mountain Cloud Chemistry Program, which actually measured the chemistry of the clouds, which at the highest elevations, these forests are bathed in clouds much of the year. So, it's not just rain, or rain and snow, it's also cloud chemistry. And so, we learned an incredible amount about where the elevational cutoffs are, we learned that clouds are more generally more acidic than precipitation other than snow or rain events.
Jonathan Yales
Mary Beth’s main responsibility was to help synthesize all that new knowledge, all that new data, all that research, in order to answer very specific questions about acid rain. But also, to come up with broad general conclusions about acid rain and the red spruce decline.
Mary Beth Adams
We took all of that research, you know, millions of dollars of research and synthesized it to say what we know. And one of the things that's unique about the Spruce-Fir Research Co-op is we had answers.
Jonathan Yales
And having those answers, and conclusive research, puts facts in the decision makers hands, which allows them to enact change.
Mary Beth Adams
We as Forest Service [and] public scientists don't make policy recommendations, but because we had such sound conclusions, other people were able to make policy recommendations from our research. And what came out of NAPAP was that we needed to reduce acid deposition – or the emissions – from coal power plants, and specifically, sulfur dioxides, and then also the nitrogen. Well, you know, 30, almost 40 years later, sulfur deposition has declined by 75% in most places in the eastern United States as a result of the Clean Air Act Amendments of 1990, which were based on the research from NAPAP.
Jonathan Yales
The Clean Air Act Amendments of 1990 were where things really started to turn around for our red spruce.

Building on congressional proposals during the 80s, and the research of Mary Beth and NAPAP, President Bush – the first one – proposed amendments to the Clean Air Act of 1970.

While the 80s were a so-called era of acid rain, the 90s became the so-called era of clean air.
Archived Recording 4
This legislation will be comprehensive, it’ll be cost-effective, but above all, it will work. We will make the 1990s the era for clean air. And, we have three clear goals, and three clear deadlines. First, we will cut the sulfur dioxide emissions that cause acid rain by almost half – by 10 million tons, and we will cut nitrogen oxide emissions by 2 million tons. Both by the year 2000. We have set absolute goals for reduction, and have emphasized early gains, and that means 5 million tons will be cut by 1995, and the degradation caused by acid rain will stop by the end of this century.
Jonathan Yales
And on November 15th, he signed it into law.
Archived Recording 5
You know, Thanksgiving is still a week away, but I believe this really is a true red-letter day for all Americans. Today we add a long awaited – and long needed – chapter in our environmental history, and we begin a new era for clean air. This legislation isn’t just the centerpiece of our environmental agenda, it is simply the most significant air pollution legislation in our nation’s history, and it restores America's place as the global leader in environmental protection. 1990 is now a milestone year for the environment, and I also hope that it will be remembered as an important year for environmental cooperation.
Jonathan Yales
But, the 90s weren’t only the era of clean air. They were also the beginning of the Forest Service and their partners finally solving the mystery of what was happening between the red spruce and the acid rain.

Everyone knew and could see that red spruce seemed to be dying because of acid rain, but we didn’t know why. We didn’t know what was actually happening to the tree, inside the tree.
Paul Schaberg
That early research saying, ‘yeah, there's a temporal and spatial relationship here with acid deposition and red spruce decline, but we have no idea why that is.’ And so, people started creating hypotheses. So, might it be that the acid is literally eroding the waxes off of needles and so it's physically hurting that foliage and causing it, for example, to lose too much water and the trees are actually, you know, dying of drought? Or maybe it’s that acid deposition mobilizing a lead that's in the soils and the trees are actually dying because their roots are being damaged because of lead exposure? There was a whole series of these hypotheses and different research groups wrote proposals, got funded, and studied those different hypotheses. And as you can imagine, most of those hypotheses turned out to be – not supported by the data.
Jonathan Yales
That’s when Paul stepped in and took the baton from Mary Beth and built off all the red spruce research that came before.

Then, he and his team began to put all the pieces together to try and solve the mystery.
Paul Schaberg
It wasn't acid eroding the foliage. It wasn't lead hurting roots. But, some of that research showed that, oh, calcium is definitely connected with this, that we know that this acid coming in is depleting the calcium in the trees. And during that time period, they also figured out that there are years when the foliage of the red spruce all dies in the winter – you know, it seems like that could be significant? So, one study here, another study there, put together data and evidence indicating a series of important connections. And my group, we put those connections together into a hypothesis, then we did simulated acid rain studies, and then were able to mechanistically tie all those steps together to provide the first kind of mechanistic understanding of how acid deposition depletes calcium from trees, that reduction in calcium makes the trees more vulnerable to stress, and stresses include things like low temperatures that cause the foliage to freeze to death and die.
Jonathan Yales
So, calcium seemed to be the key. And just like if you or I stopped getting calcium in our diets, we’d see some major affects to our body, a tree is the same way.
Paul Schaberg
I think humans, when they think of, what do you need calcium for, you think of your mother saying drink milk because you need strong bones and strong teeth. So in trees, it's not teeth and bones, but it's wood, and cell walls. One thing that calcium does is it helps build and fortify structures, and one of those structures is actually membranes – the little skin on the outside of cells. That membrane is the thing that gets damage when a foliage freezes to death, that membrane actually gets weakened and ruptures. So, that structural component is really important for calcium.
Jonathan Yales
But, that’s not the only thing calcium does.
Paul Schaberg
But even more important is that calcium is also what they call a regulator. Its movement around from the outside of the cell into the cell actually helps the inside of the cell know when there's a stress outside, and change its physiology. And we think it's that second term – that regulatory function – that is really important, for weakening the trees kind of a stress response systems, and makes trees, therefore, have less of a stress response, and therefore, more vulnerable to damage from abiotic factors like low temperatures.
Jonathan Yales
Think of yourself in winter. What do we do when we go outside? We bundle up. We wear coats and gloves and hats, and for the most part, we stay inside – inside our homes – our shelters, so we don’t die from frostbite. To the trees, the acid deposition, via calcium depletion, was basically taking away the trees coats, gloves and hats, and taking away their nice cozy warm home and kicking them out into the winter.
Paul Schaberg
So, ironically, red spruce is barely cold tolerant enough to survive in these cold forests, but then if you have acid deposition on top of that, it just can't tolerate anymore and it gets a freezing injury so foliage freezes to death in the wintertime.
Jonathan Yales
And with so much acid rain, and so much spruce, cold snaps blow through the Northeast and can take down huge swathes of spruce.
Paul Schaberg
And in the winter of 2003, we noticed a huge winter injury event. I was actually on a ski lift in Vermont when I looked over at the trees, and I'm like, ‘Oh my god, those trees are totally red from winter injury.’
Jonathan Yales
So, at this point, Paul and his team had an understanding of what was happening in these winter injury events and how calcium probably played a role. But, they hadn’t proven it yet on a forest-wide scale. Their research before was complicated and replicable, but was with planted saplings, not an entire spruce forest.
Paul Schaberg
We grew red spruce saplings – like small trees – we grew them in very calcium depleted soils, then we pumped back into the trees different levels of calcium so we were controlling the calcium nutrition of the trees, and then we also created two types of simulated acid rain: one that actually was acidic, and one that was close to the regular acidity of rain.
Jonathan Yales
Good thing for him the Forest Service has these things that are perfect for forest-sized research. We call them Experimental Forests, and one nearby, in New Hampshire, had just launched a remarkable study. one that would become very useful to Paul’s research.
Paul Schaberg
So [the] Hubbard Brook [Experimental Forest] was a place where they first discovered acid rain in the U. S. Well, it's also where they found that this acid rain had depleted a lot of calcium from the soils there, and they got money to do a rather remarkable thing. They calculate[d] how much calcium acid rain had depleted from a whole watershed there, and then they put that calcium back in. So they used ground up calcium mineral, and they dropped it over the whole watershed by helicopter. And their hypothesis was that calcium addition was going to help the growth and the health of those trees, but they also thought it was going to take a while before anything showed up.
Jonathan Yales
After seeing what he saw on his ski lift, and knowing what the Hubbard Brook Experimental Forest was up to, Paul had a masters student who needed a project, and she had an idea.
Paul Schaberg
So, she did a project where she went to many, many sites all through New York, Vermont, New Hampshire, and Massachusetts, and looked at how much winter injury there was. And it was massive, and broad scale. We decided then, we should go look at how much winter injury there is on this watershed at Hubbard Brook where they added all the calcium back. And indeed, when we did that and compared it to the adjacent watershed – where it had found that all this acid rain had removed the calcium – we saw that in the watershed where they added the calcium back, they had only about one third of the amount of winter injury in those trees that they had in the adjacent watershed that had all the calcium depletion. So, this was like out in a large forest, and in real woods terms, showing this connection between calcium nutrition and how much injury actually happened out in the woods.
Jonathan Yales
So, they had definitively made the connection between calcium and winter injury. What was next?

Well, they kept researching. They wanted to see how much impact those winter injury events were having on the growth of those trees years later.
Paul Schaberg
Let’s go out to this whole range of winter injury sites, increment core the trees – so, put in a big corkscrew kind of increment core – take out a little sliver of wood, measure those growth rings, and then, try to relate how much injury relates to how much of a reduction in growth, but also do this assessment, five or more years out from when that winter injury event [occurred] so we can maybe see how long that impact in reduced growth lasts over time.
Jonathan Yales
But, while doing that, they came across another mystery.
 
Paul Schaberg
In quantifying that reduction and growth, we were shocked to find something very different, and that was a really significant increase in growth after that winter injury. So, that winter injury event reduced growth in those stands for three, four, sometimes more years. But then after that, growth was really good, in fact, it was, far higher than any time in that tree ring record, including before acid deposition was really a factor in those forests. And that was the start of the, intense joy, but also further questions: if they're doing so well, but why?
Jonathan Yales
So, after a century of bad news for red spruce, something good finally seemed to be happening. But, once again, we weren't sure why.
Paul Schaberg
We've been going out for 10 years now, and it really is shocking, these trees look great. And, it's not just the trees that we're measuring growth on. We've been seeing it in New York and New England, research groups doing tree increment cores in the central Appalachians, and even the Smokies, are seeing significant increases in growth. But, it's not just the mature trees that are growing better. Through surveys on the ground they're finding that there's regeneration coming in. Red spruce seedlings and saplings are very prominent, and they're prominent in areas that they weren't so prominent in before. Even through remote sensing, they can see that the spruce are moving around on the landscape – they're spreading. So, whether you're looking at the wood of trees, you're looking at seedlings and saplings, or you're looking at broad, you know, landscape scale assessments. These forests are doing way better.
Jonathan Yales
A full-blown resurgence was underway, and Paul and his team had another guess as to why.
Paul Schaberg
So, knowing the kind of the history and the physiology of red spruce, there were certain changes in the world, in the environment, that had been happening that we realized could be contributing to red spruce improved growth. One was the 1990 Amendments to the Clean Air Act that mandated a reduction in sulfur and nitrogen pollution – the pollution that causes acid deposition. You know, we all thought that, we knew, from data monitoring air and particulate matter that that pollution was way down. If that pollution was part of the problem, a reduction in that pollution could well lead to this improvement in growth, that was one big factor. Another thing though, is that red spruce, it wasn't just like the acid deposition in the calcium depletion, it was the low temperatures mixed with it. So, another hypothesis was, as we all know, winters are a bit warmer than they used to be. It could be that warmer winters means less winter injury, and therefore foliage staying on the trees, and that's another reason why they're growing better?
Jonathan Yales
And as usual, Paul and his team set back out to answer the mystery once and for all.
Paul Schaberg
Those kinds of hypotheses all seemed reasonable. And that's what led to that 2018 study where we went back and we collected even more tree increment cores over even a bigger area, and then we looked at the relationships of these increases and decreases in growth and how they were statistically related to patterns of temperature, of precipitation, and pollution. And that work basically found that some of the factors that we thought would be important are showing up as being statistically associated with greater growth: higher temperatures during the fall, winter, and spring, definitely a contributor to this phenomenon. But also, reductions in pollution also related to greater growth. And what was interesting was that pollution connection. Our correlations showed that years ago when there was a lot of pollution coming in, there was a very negative relationship between the pollution coming in and red spruce growth. But, as the pollution has lessened over time, that negative impact has diminished. So much so that, right now, we don't see any negative mathematical relationship between pollution inputs and growth.
Jonathan Yales
So, Paul was starting to see, and to prove, that those 1990 Amendments that President Bush signed into law 30 years ago were starting to actually show up in the branches and crowns of red spruce across the country.

And that after a hundred years of human action negatively affecting the red spruce, our latest actions – our research and legislation – were starting to positively affect the red spruce.
Paul Schaberg
Looking backwards, it's a great story showing how science can inform policy, and then science can show the impacts of that policy. So, all of this science on acid deposition and the initial understanding of the mechanisms of how red spruce was impacted, that science helped lead to the 1990 Amendments to Clean Air Act, which really did mandate big reductions in sulfur and less reductions in nitrogen. So, this is an example of how science and policy can inform one another to benefit ecosystems on the ground.
Jonathan Yales
But, as with any science, there is still uncertainty on the horizon.

Yes, this is a positive story – one of America’s greatest environmental rebounds. And the Clean Air Act still stands as one of the most consequential laws in modern American history. But, in today’s changing climate, this red spruce resurgence could possibly just be a window of resurgence, as human activity – again – takes a toll on red spruce, this time in the form of changing environmental conditions.
Paul Schaberg
Moving forward, there's uncertainty, because although reductions in pollution that was very good for the species, the changes in temperature haven't ended yet, and the temperatures are projected to get warmer and warmer, and we really don't know what that trajectory will look like – how warm we'll get, and when will that warmth be most evident? In the winter? In the fall and spring? Will summers become so hot and dry that that'd be very bad for spruce? So, based on modeling that the Forest Service has done, you'll see that those projections are that red spruce will do very badly as the climate changes further, because we'll just get too warm for it.
Jonathan Yales
But, that doesn’t mean we should disregard how well the red spruce are doing right this second on mountain tops across the country. It’s an incredible comeback story.
Paul Schaberg
Now, kind of contrary to that projection. We're finding, at least so far, that red spruce is doing better than it ever has in its growth. And, it's not just in the cool Northeast, that's in the central Appalachians, and even the southern Appalachians.
Jonathan Yales
But, like all stories, we don’t know how this one will end just yet. And, to be honest – with science – there never actually is an end to the story.
Paul Schaberg
Looks good so far, but that is by no means any guarantee it's going to continue to go that way. So, the new science for red spruce is monitoring how these continued changes in the red spruce habitat and environment may cause changes in these populations that we would not predict just yet based on what we've seen.
Jonathan Yales
So, due to the changing climate, we might only be in a window of resurgence.

But, Mary Beth believes that even with all this uncertainty, and the massively complex changes that are happening to our climate, the Forest Service is the best in the world at studying forest problems at this scale, and is prepared to be able to see what’s coming.
Mary Beth Adams
I've said this so many times, the Forest Service does long-term research better than anybody else in the world. Nobody has the network of experimental forest and ranges that we have in the Forest Service and the long-term data. We have a hundred plus years of data on so many sites. And, it is – I think – one of those inherently governmental functions. Because we have these experimental forest and ranges and these really long-term datasets, we have a tremendous responsibility to maintain them because that's what we're going to need as we move ahead in a changing climate and as the world keeps changing.
Jonathan Yales
Thanks for listening, and see you in a few months for season two of Forestcast. And, stay safe.

________________________________________

This special episode was produced and edited by me, Jon Yales. My editors at the Northern Research Station were Jane Hodgins, Sharon Hobrla, and Jim Lootens-White. We had production assistance from Andrea Brandon.

Special thanks to Mary Beth Adams and Paul Schaberg of the Northern Research Station. And thanks to the Department of Entomology at Michigan State University.

If you have any questions or have topics that you want us to cover, reach out to us on Twitter at @USFS_NRS.

And please, take time to review this show wherever you get your podcasts. It helps people find the show.

This podcast is produced by the USDA Forest Service. The Forest Service is an agency of the U.S. Department of Agriculture, which is an equal opportunity provider, employer, and lender.

Thanks, for listening. And, see you soon.

Winter Injury on red spruce. Photo by Gary Hawley. A view from Thunderstruck Rock, Mount Porte Crayon Preserve, West Virginia with red spruce in the foreground.

Featured Science Resources

Environmental Education Resources

  • Help students in grades 7-12 understand the history of acid rain and ecosystem recovery using Hubbard Brook’s Exploring Acid Rain curriculum.

Archival Recordings