Science Friday - Coal Ash, Soil Loss, Sap, Bristlecone Pines. April 5, 2019, Part 1

Episode Date: April 5, 2019

Maple tapping season is underway in the sugar maple stands of the United States. Warm days and below-freezing nights kick off a cycle of sap flow crucial for maple syrup production. But why is the flow of sap so temperature dependent in sugar maples? University of Vermont maple researcher Abby van den Berg explains how ice crystals in the trees’ cells power sap flow, while Yale University’s Craig Brodersen tackles how other trees and plants move gallons of fluid per day from roots to leaves—all without using any energy at all. In mid-March, a late winter storm dumped inches of rain on frozen soil in the Midwest, flooding the Missouri River and tributaries—particularly in agriculture-intensive Iowa, eastern Nebraska, and western Illinois. The storm has submerged farm fields under water, washed-out roads and bridges, caused grain silos to burst from flood damage, and drowned livestock. Many farmers may be unable to plant their fields in time this year, or even at all. But soil experts looking at that same damage will notice another thing: erosion of precious topsoil. This first layer of soil is the key to the Midwest’s immense fertility and agricultural strength, but a resource that is slow to rebuild after major losses like farms are currently experiencing. Mahdi Al-Kaisi, a soil scientist at Iowa State University, explains why erosion is bad news for farmers, and how the damage from this flood event could ripple for years to come. Bristlecone pine trees grow in harsh, dry mountain climates and can live up to 5,000 years old. The trees have adapted to these rough habitats by building up dense woody trunks that can hold up against insects, and rely on the wind to disperse their hard seeds. Ecologist Brian Smithers became interested in these species because “they epitomized growing and living on the edge of what is possible.” Smithers talks about the adaptations and competition the species will face as rising temperatures from climate change force the trees to move up in elevation. Washington University’s analysis of data from Missouri utility companies shows high levels of toxic coal ash contamination near ponds power plants use to dump waste from coal combustion. Will proposed new regulations be enough?   Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

This is Science Friday. I'm Ira Flato. Later in the hour, what the devastating floods in Iowa and Nebraska have done to the top soil. But first, this week, thousands of chemistry professionals met in Orlando, not expressly for a trip to Disney World, but to discuss their research. Sci-fi director Charles Berkwist attended the meeting of the American Chemical Society, and he is back to share some highlights. Welcome. Hi. Before we get to the meeting, there is some news out this week about chemistry elsewhere. in our solar system on Mars.

That's right, Ira. So this week in the journal Nature Geoscience was some findings published about methane. You might remember back in 2013, the Mars rover Curiosity reported seeing increased levels of methane in the air around Gale Crater. The news this week is that the European Space Agency's Mars Express Orbiter

apparently spotted methane in the same area at the same time. Oh. Yeah, so it's an interesting. independent confirmation of that original methane sighting. But we don't know where the methane originated. That's a big issue, isn't it? Yes and no. So they have an idea now of the geographic feature that they think it might have come from near the crater,

but they don't know what caused it. And, of course, there are both biological sources of methane and geologic sources. So it's still up in the air. You'd like to think it was life, wouldn't you? But is there any way to narrow this down? So there's another European spacecraft called the Exomars, trace gas orbiter that arrived at Mars in 2017, it hasn't put out any data yet. So planetary scientists are really going to be keeping an eye on that one. All right, let's get to the Chemical Society

meeting this weekend. There was something about transparent wood. Yeah, so this is a little involved, but if you imagine taking your regular, ordinary piece of wood, it turns out that there's two main components in the wood. There's lignin and there's cellulose. And lignin is the stuff that gives it most of its color and why you can't see through it. So if you manage to wash away the lignin, you're left with just the cellulose. It's like these whitish fibers in a network. And if you fill the space in between the fibers with a material that has the right optical properties, the fibers essentially disappear and you can see through the wood. You've made a composite material that still has a lot of the wood-like properties, but you can see through it. That's not the news here. That was

done a couple years ago, you can actually find demos of how to do it yourself on YouTube if you don't mind messing with a few chemicals. But what these researchers have done now from the Royal Institute of Technology in Stockholm is they've found that if you take a material called a phase change material, which is something that soaks up or releases a lot of heat when it melts or freezes, you stuff that into the pores. You now have a transparent piece of wood that, But imagine if you made a roof panel out of it. During the day, it would soak up some of the excess heat, reduce the temperature a couple degrees,

and at night when it cooled, it would release that energy back out and give you a little bit of extra warmth. Hey, so do we know if anybody's building anything? You know, they're playing with it. I think it's probably not going to be in your roof panels anytime soon. Yeah, it's interesting. I want some of that stuff. Yeah, totally.

And I remember reading years ago about another woody type project like that where the wood actually soaked up the heat during the day and let it go at night. Yeah, it's interesting. It's a great concept because it's passive heating, right? Right. You saw a VR chem there also, Chem Lab. A Chem Lab. So this is a teaching lab for students learning organic chemistry,

and this is a group at North Carolina State University. And they emphasize that they don't want to do away with chem labs. They're not looking to do that. but this is intended for people who may be say they get pregnant and they can't go into the chem lab, right? You can't, for safety reasons, or they're in the military and they get deployed. They need some other way of finishing out the required lab. So in this, you put on the goggles and you see your hands walking around the lab and they've filmed, you know, imagine having the best TA in the entire university talking just to you to explain to you how to do you.

that thing. And what's cool is that they broke up a class into two sections. Some people used the VR demo. Some used the actual physical, regular lab. And at the end, they graded the lab reports blindly, and they did the same on the lab reports. You weren't able to try this one out, did? You did? You put it on? I put it on. So what did you see? What kind of lab? I mean, it's, it's, they actually film, you know, it's not, this isn't a cartoon. This is filmed in a real lab.

So it looks like a, well, they did clean it up. So it's the cleanest lab you've ever been in, right? But, yeah, there's a lab and a TA and you can open the drawers. And you can pull things and touch things and pick things out? Right. Virtually. Yeah. You don't do it with, you're not wearing gloves or anything.

It's not done with your hands, but it's you can like look at something intently, and that tells you, you know, to activate that function on the instrument or whatever. I want one of those. And there's some look-ahead news for next week. This could be pretty exciting, right? It could be. So what's cool is the astronomers involved in a project called the Event Horizon Telescope have announced that they're making an announcement.

They've announced an announcement for next Wednesday. And we don't know what it is. But the entire purpose of that project was to try to take a picture of a black hole. So either maybe they're going to show us a picture of a black hole or they're going to tell us that black holes don't actually exist and something like that. So if you want more information about this, we can prep you on it. There's an interview that we recorded a couple years ago with one of the lead researchers, and it'll be in our podcast feed, so you can check that out. Of course, since a black hole is black, we won't see the hole.

We'll see the event horizon. That's why it's called the Event Horizon Telescope. They are so clever. So are you with Charles. Thank you for taking time to be with us today. Thanks, Ira. Science Friday's director and contributing producer. And now it's time to check in on the State of Science.

This is KERNO. St. Louis Public Radio News. Iowa Public Radio News. Local science stories of national significance because we know big science stories happen everywhere in cities and towns all over the country and we know these local stories can have a big impact on all of our Science Friday listeners.

So our State of Science series is our chance to highlight these science stories and the station reporters who cover them and we will be doing these regularly so you can look forward to them. And this week we turn to Missouri, where the state may soon regulate how utility store toxic waste from coal power plants. This comes after dozens of sites around the state were linked to nearby groundwater contamination. Here with more is our own sci-fi alumna, alumni is Eli Chen Science and Environment Reporter at St. Louis Public Radio. Sorry, Eli, I couldn't give me you a better introduction.

Oh, it's okay, Ira. How's it going? Welcome back to Science Friday. So let's talk about this. Set the scene. What are these coal ash ponds? Why do the utilities have them? So for a long time, many power plants have used water to process coal. So when it comes time to dispose the wet waste that's left over after coal's been burned, it's dumped into pits in the ground, and those pits are coal ash ponds.

And the ponds vary greatly in size and appearance. They've seen one that looks like a lake, another that was capsule, just looks like a large area of dry dirt, but nearly all of them in Missouri and across the nation don't have liners to separate them in the rest of the environment. And a lot of them are near major rivers or bodies of water that people depend on. And some of them have existed for 40, 50 years, but they've been largely unregulated. So if you don't have liners, right? I know in pools, you have liners. These pits don't have liners. These ponds could be contaminating the groundwater? Yeah, yeah. So there's been some new day.

to suggest that these ponds are contaminating groundwater. And under the Environmental Protection Agency's 2015 coal ash rule, utility companies are required to monitor groundwater near these ponds and file an annual report about the levels of chemicals that coal ash contains, like arsenic, lead, mercury, and environmental lawyers at Washington University here in St. Louis have been analyzing data for active ponds in Missouri. And they found levels of chemicals like arsenic that have exceeded federal drinking water standards. And on a national level, there have been environmental groups like Earth Justice that have found

excedences and toxic chemicals for ponds for, I believe, more than 60 power plants across the country. Now, there have been a lot of people living near these ponds for decades. How do they feel about this news? So, unfortunately, a lot of residents near these ponds aren't aware they exist, but there are a few very engaged communities, like the residents who live near Amaran Missouri's power plant, a Labby, Missouri. That's a rural town about 40 miles outside of St. Louis. And they absolutely want the waste excavated and taken somewhere else, but Amaran has decided to cap the ponds without removing the waste. And so some of the residents came to a recent public hearing that the state regulators held a couple weeks ago about its developing rule for coal ash, including 12-year-old Ella Alatu came with her mother.

Everyone we know says that the ash ponds should be dug up and put in the landfill fill and the water cleaned up. We all drink well water, and many of us are scared that the pollution they have found will end up hurting us and our neighbors. These teenagers are going to save all of us. Right. You mentioned that the state wants to regulate these ponds. How strong could that regulation be? Yeah, so I want to back for a second because there's an interesting thing about the federal rule. rule. So the coal ash waste is not classified as hazardous waste because the coal industry

lobbied pretty hard for it not to be. And because it's not considered hazardous waste, the EPA is leaving it to states to regulate coal ash ponds and landfills. So Missouri's been developing its plan and it's planning to send it to the EPA to get approved this year. But there's been a lot of unhappiness from environmentalists and residents who point out provisions that allow utility companies to not have to clean up contamination of their excessive levels or not even to have to do groundwater monitoring. And earlier this month, or last month, rather, the EPA had sent a letter to the Missouri Department announced of resources saying that the state's plan is weaker than the federal rule.

Is that right? Yeah. So that means they would have to beef it up? It sounds like it, but it's hard to say what the state department, rather, is doing right now. because the public comments have the public comment period recently closed, so they're trying to review that data right now. I'm sure there are other places around the country with the similar problem. How does this compare to other parts of the country where they're grappling with coal ash waste?

Yeah, so coal ash ponds are all around the country where there are coal-fired power plants. In Illinois, I've heard a lot of reporting about coal ash contamination, contaminating some really key waterways. and I was contacted actually just a few days ago by a law office in Kentucky that wanted to get some more information about some of the stuff I've reported on. And I believe I heard this week that Duke Energy in North Carolina was ordered to excavate waste from all of its ponds. And that's a pretty big deal. They're a big company. We're out of time.

I want to tell our listeners that you can read more about this story on an entire state of science series at Science Friday. com slash sOS. Eli Chen Science and Environmental Reporter at St. Louis Public Radio. Thank you for taking to happen to be with us today, Eli. Thank you. After the break of flooded Midwestern farms, drowned livestock, damaged infrastructures, but what happens when the soil, the top soil, is washed away? We'll dish the dirt after this break. This is Science Friday. I'm Ira Flato. You have probably seen the photos from the recent historic floods in the Midwest. farms under feet of water, broken grain silos spilling out of last year's harvest, drowned pigs,

roads washed out, lives ruined. As farmers in Nebraska, Iowa, Illinois, and other states start to dry out and assess the damage, one big factor will be the dirt left behind, the soil that was washed away by the water. I'm talking about the topsoil, rich in organic matter, and the key to the incredible fertility of Midwestern fields. Marty Al-Kesi is Professor of Soil Management and Environment at Iowa State University in Ames. He's here to discuss it with me. Welcome to Science Friday. Thanks for having me, Ira.

You've been in Iowa, one of the states hit hardest by the floods last month. What does it look like out there now? There is significant damage to agriculture and commercial properties and infrastructure. on the east side of the state by the Mississippi River, also on the western side by the Missouri River. There is approximately 145,000 acres covered with water flooded compared to 2011, about 127,000. So there is significant damage to agriculture business and farmland. Well, let's talk about the farmland.

Let's talk about a flooded farm. What happens to the top soil there? How do you assess whether the top soil has been eroded or lost? Generally, when you have significant amount of water running off from rivers and streams,

it's going to carry a significant amount of the top soil. And as you mentioned earlier, top soil is the most a productive part of the soil system to support crop production, growth, and animal production, and so on. So these sediments and these soils, rich with organic matter and nutrient will be carried to

lakes and rivers and basically is going to create a lot of environmental problems, cleanup, and loss of productivity in the short term and the long term. Is there any way to measure how much loss of the top soil there was? Generally, you know, in the research, what we do, that basically there is a setting, you set a rain simulator on the field

and flumes to collect the amount of sediments that run off with the different rain intensity and basically you could extrapolate from that measurement into the watershed or on the field. as you have a large scale and big landscape, it's going to be very difficult to assess how much soil was lost. But it's going to be a significant amount of losses, given the amount of volume of water flooded by the Missouri,

or approximately 11 million acre foot of water runoff and cover these areas, comparing to historically, about 7.4. million acre feet in 1952. So that gives you a perspective. Yeah. Is there anything farmers can do to make up for the loss? Can they add the organic matter back? Can they put the microbiome back?

Definitely, it's going to be a lot of work. It's going to be physical, biological and chemical damage to the flooded soil. And what the farmers could do actually after the flooding proceed, and the ground is workable. There are several issues they can work on, and basically they have to have some plant growing on these flooded soils, especially now we are doing the growing season and a planning season, and some of the fields maybe they cannot get to it.

But leaving the soil bear is going to basically compromise the microbial community in the soil system. So what we are recommending to the farmers, even if they couldn't plant the whole season, they need to put some crops, whether cover crop or any crop to grow, because some of these fungi basically live on the system and recycling nutrients to become available to the plants for production. So you're saying a cover crop will actually get the microbiome that was lost or drowned in the soil to regrow?

Exactly, because they need a medium to live on, and especially the mycorrhizzo fungi, it's critical to live under colonize the root system, and they have a symbiotic relationship between the root system, living the carbohydrates at the same time, recycling nutrients, especially phosphorus, from the organic form into mineral form to become available to their plants.

So having living plants on the soil system is going to be very healthy to rejuvenate and compensate or mitigate the losses of these microbial communities due to the flooding condition. There's also an opposite kind of problem, I understand. That is soil deposited on the fields, right? It's been moved and gone someplace else and deposited. Right. And especially when you look at the eastern part of Nebraska. For example, there is a lot sandy soils that's deposited on the areas. And there is a different degree of deposit.

If you have a small amount, the farmers could work it out in the soil system when the soil condition dry. But if you have a huge amount accumulated on the surface, it's going to require some structural changes and some sand removal to bring the soil back to its original condition. So it'll be farmable. plant the crops on these soils. So it's going to be a lot of fork, a lot of expense associated with managing these soils physically and chemically as well. And are we then talking about a lost year in productivity for some of these farmers as

they work to get the soil back? They're not going to be planting their crop and maybe too late. The soil may be too watery. Exactly. You know, when you're, we are doing the growing season now. especially the planning season and the critical time is going to start mid-April and if

you get close to May 20, May 15th every time there is a delay is going to be decline in the productivity so some of the areas may be not recovered until late May or June so that will be a lost season to the

farmers so basically what they're going to do just manage the field and work on it and prepare for the next season, putting a cover crop, and trying to do soil testing in the upcoming season to make sure that there's enough nutrient they need to add to the soil system and so on. Given that, you know, we may be seeing more and more of these floods due to climate change. Can farmers do anything to prepare for the next big flood? There is a lot of management issue that's associated with this unimproductive events due to climate change

and a good indicator of what we have, these extremes with the rain events and amount of snow we got, for example, here in Iowa. From January to March, we got almost 54 inches of snow accumulated. That's equivalent to over four inches of water. and the soil could have processed approximately 1 to 2 inches, so the excess water is going to run off. So if you have a system, for example, use conservation practices, using no-till or using cover crop, that's going to build the soil system,

build soil health, increase the soil storage capacity, increase the soil permeability. So when you have extreme events, the excess water could be processed and move into the soil system, reducing the surface runoff and prevent any potential erosion and sediment loss or tapsoil losses to the streams and rivers. So there is a lot of practices that need to be implemented.

It could mitigate some of these extreme events. Well, that's some terrific information, Dr. El-Kasey. Thank you for taking time to be with us today. Thank you, I appreciate it. Madiel Casey is Professor of Soil Management and Environment at Iowa State University in Ames. If talking about soil, how's you thinking spring? What about sap? That's right.

It's that precious time of the year when the sap is flowing in the sugar maples. And maple syrup producers are hurrying to harvest before the very important cycle of freezing nights and warm days come to an end. Why does sugar maples need that kind of weather, that particular weather, to produce? produce the sap we love. And what about other trees which move many gallons of water from their root systems to their leaves every single day? All without spending any energy at all. When you think about it, it's kind of an engineering marvel, isn't it? Well, here to geek out with us about the hydraulics of a tree trunk from sugar maple to redwood, Dr. Abbey Vandenberg, a research associate professor at the University of Vermont's Proctor Maple Research Center in Underhill, Vermont.

Welcome to Science Friday. Thank you. Thank you for having me. And Craig Borenberg. Broderson is an assistant professor of plant physiology, physiological ecology at Yale University's School of Forestry and Environmental Studies in New Haven. Welcome to Science Friday. Thanks for having me. Abby, I know it's a busy time of the year for you, researching maple sap production, right? Absolutely. I mean, it's just a short period that you have. It is very, very short.

Six weeks, sometimes longer, sometimes shorter. We never know. And what are the ideal conditions for getting maple sap for syrup? As you described earlier, really the ideal and the required conditions are nights where the temperatures are below freezing, followed by days or multiple days where the temperature is above freezing. Well, okay, take us inside the tree and tell us why that condition is so important. It's important for a couple of reasons. The first is there needs to be sap there in the first place. So the below freezing temperatures are what actually enables the process of the water to be drawn up from the soil through the roots and up into the higher parts of the tree.

So that's what gives us water, the sap, in order to collect in the first place. But also there's a little bit of magic of the freezing and thawing, causing the enzymes to get active to load sugar from the cells where it's still. stored in the wood into that sap that's been drawn up into the tree. So there's that sort of dual process going on. Dr. Bratterson, just to be clear, Abby's talking about what sugar maple trees are doing when there are no leaves. What's going on the rest of the year? The rest of the year is a little bit different in that the movement of water up to the top

of the canopy of a big tree, whether it's a redwood or whether it's a sugar maple once it's grown, is water coming out of the leaves. and establishing a pressure gradient that is basically pulling the water out of the soil up through the roots and through the trunk, out the branches, and then ultimately out the little teeny tiny pores in the underside of the leaf that are the stomata that it can open and close. Now, I know that, you know, if you try to use a straw and suck up water, it's only going to go a certain height, right? You can't get it any higher due to atmospheric pressure. So what trick does a tree know to get it all the way to the top? Yeah, so plants have figured out are really remarkable.

way of making this work and in really tall trees in particular. And so to get it up there, what's going on is the, as the xylem, the cells that make up the woods, so the pipes, the plumbing of the plant, during the development of those cells, they start out filled with water, and then we'll eventually start out as a living cell, and then the cells that are conducting the water will go through it's sort of a program cell death, and so they've got water in them to start with, and then they eventually die, and then will start to transport water to the top of the canopy once the leaves start to photosynthesize. And this is all contingent on this sort of continuous column of water that goes all the way from the roots to the, all the way up to the leaves.

This is Science Friday from WNIC Studios. Abby, what's going on? How does a maple, sugar maple tree deal with this? You said that the freezing is important. Does ice in the sugar maple contribute to sucking up this sap? Yes, so the process that Dr. Broterson was talking about is basically the movement of water up from the soil through the roots and out through the leaves is driven by the evaporation of water. But in sugar maples, during the leafless period, this movement of water is driven by the freezing of water instead. So we have those vessels where the sap actually, you know, the sort of the pipes that sap and water move through in the plant.

in sugar maple, those vessels are surrounded by these fiber cells that are actually hollow. And when the water, the liquid water, the sap, and the vessels begin to freeze, ice crystals begin to form on the outside of those neighboring fiber cells, and the growth of those ice crystals is actually what creates the negative pressure, the tension that provides that driving force for water uptake. So freezing of water instead of evaporation of water. Our number 844-8255, if you'd like to talk about tree sap. We love talking about stuff like this.

And we'll be taking a break in a couple of minutes. We'll only get a couple of more questions. And, Craig, this is a whole lot different than how animals move water around, right? Yeah, it's a fundamentally different way of moving large volumes of liquid around an organism. So in human systems, human vascular, we're talking about positive pressure with a heart that is, using a lot of energy to do all those contractions to move the blood throughout our circular system. And the conduits, the veins and the arteries in our body, they're somewhat elastic and so they

can accommodate those differences in pressure that arise. And so in plants, at least in the part that's transporting the water, it's, again, very, it's under, as Dr. Randenberg mentioned, it's under negative pressure, tension that arises as a consequence of the evaporation of the water out of the leaves. And so the pressures that we're talking about are the negative pressures, the tension that we're talking about in the xylem, turn out to be pretty large. And so instead of needing to be able to expand outward like our vascular system does, they need to be really structurally sound so that they don't buckle, they don't collapse

or implode because of the really significant negative pressures that arise in xylem. When we were all in grade school, we did an experiment in science class. We took a stalk of celery and put it in colored water, and we watched the coloring move up the stock of celery. And people talked about capillary action. I didn't hear you or Dr. Vandenberg say a word about capillary action. Is it not useful in a tree? We think that capillary action and in particular the properties, the surface tension properties of water are actually really important for maintaining this continuous column of water. And so what the plant is sort of fighting against is the weight of all the, and gravity that's acting on the water column.

And it's supported by the essentially a wet surface film on the inside of the leaves. And this is where a lot of that tension is supported from the little tiny little meniscus. So if you do these measurements in high school where you're looking at a graduated cylinder and you're always measuring from that meniscus, the smaller the diameter of that pipe, the higher the water can rise. We'll be talking more with Dr. Abby Vandenberg and Craig Brodernson. After the break, our number, 844, 724, 8255. You can also tweet us at SciFRI. If sap is your subject, stay with us. This is Science Friday.

I'm Ira Plato. We're talking sap science, hydraulics, the mysteries of how trees move all the hundreds of gallons of water they use each day. With Dr. Abby Vandenberg from the University of Vermont and Dr. Craig Broderson, from Yale. Our number 844-724-8255. You can also tweet us at SciFry. Let's go to the phones. Let's go to Cincinnati. Hi, Carrie. Hi. Hi there. Go ahead. Yeah, I have a question. We have my family, well, my son and I have been tapping maple trees the past couple of years. And we also tap black walnut trees and have made black walnut syrup, which is very tasty. But we heard. heard a rumor that you could tap sycamore trees and that you could make syrup from that and that it tasted kind of like butterscotch. And I was wondering if they knew anything about that. And if so, if you have to tap them at a different depth, then you would tap a maple or a black walnut tree.

Well, that's a really interesting question. And the fact that you tap walnut trees is also super interesting because they happen to be one of the few closely related tree species to sugar maple that have that very unique anatomy me with the hollow fiber cells that allow this positive pressure to happen and allow us to tap them and collect sap. Sycamore trees are, yes, it appears that they may be able to be tapped, but we really don't have a lot of good data on when they should be tapped and how they should be tapped. I know there are a few people experimenting with that in West Virginia and some of my colleagues

in New Hampshire as well. so I guess the real answer is stay tuned. Craig, you have anything you can add to that? Sure, yeah. There are, as Abby mentioned, there are a few other species that people are starting to play around with. It's sort of a niche market at the moment, but it's certainly expanding as people are getting more interested in doing this on their own

and sort of exploring other options for different species. Abby, is this so easy to do that you can try, you can try this at home? tapping maple trees to collect it? Absolutely. If you live in a place where you have a maple tree, be it sugar maple or red maple or even something crazy like Box Elder, as long as you have those freezing nights followed by warm days, there is no reason why you shouldn't try this at home. You can make very, very tiny quantities of syrup on your kitchen stove, as long as you aren't afraid about removing wallpaper or making a giant mess.

It's something that everyone should try at least once. Can the maples, the sugar maple tree survive if they don't freeze, if you're not in the freezing temperatures in the winter? That is a very good question. I think if there is no freezing, if there's no dormancy, I think the tree would probably have bigger problems than it's freeze thaw, the lack of freeze thaw in the spring, for example. not having winter dormancy creates a whole host of other issues for trees that are adapted to that kind of climate and environment. Because I keep hearing, I live in New England, and I keep hearing about in Vermont the climate change has changed the microsystems, the weather systems, and the maple trees are heading to Canada because it's not cold enough in the winter. Well, the maple trees are definitely already in Canada. We know about it. We know about all the papal syrup up there.

I think it will be quite a long time before species migration goes to that length that we don't have any maple trees here or any freeze saw conditions. I think a long time before that happens, we might have one long season or two very short seasons in the fall in the spring. and there are also, you can do this type of sap collection and maple syrup production really with any species of maple. Sugar maple has always been favored for that because its sugar content in its sap is relatively high, relative to other species, but you can tap a red maple and make maple syrup, for example, and red maples are adapted to a far wider range of climate conditions and growing conditions than sugar maple are. So it will be a while before we will. see this disastrous consequence of climate change. We do see this season changing and have to

adapt our practices right now as an impact of climate change. But technology and practices have allowed maple producers to really adapt to what's already happening. Craig, what effect does drought have on trees? Drought ends up being a big issue. And so what trees generally, the way we kind of talk about it is that trees sort of have to pick during drought. They can either die of starvation or die of thirst. And so the starvation part is that when plants sense that the atmosphere is dry or whether the soil starts to dry out, the little pores on the underside of the leaf will close. And so those are opening and closing primarily to let CO2 in so that the plants can do photosynthesis. And if the plant is sensing that it's dry, it's going to close down the stomata

in order to minimize water loss. And so when they do that, they're no longer able to eat. They're not only able to do photosynthesis. And so as a consequence, they start burning through all the stored carbon that's on the inside of the plant. And there's a finite amount of those resources that the plant has to draw from. And in particular, the thing that we're seeing now is that sort of season after season, year after year of drought, sort of minimizes and draws down a lot of those stored carbohydrates. and if the plant isn't bringing in more carbon than it's spending, then that ends up being a pretty big problem.

And so the plants will shut their stomata and they kind of have to wait it out until it rains again. Let's go to Paul and Durham, North Carolina. Hi, Paul. Hi, very good. Thank you. I appreciate your show so much. No time is short. We're in a very wet period.

I'm just curious, given the hundreds and hundreds of gallons that trees can use with that negative pressure and maintaining it, during normal times. In what way do they adjust their liquid appetite or metabolism in periods of drought? During the drought, so there are a number of different strategies that plants have come up with. There's a huge range. There's tons and tons of different types of species, and so some of them will adjust the ratio of the roots to the amount of foliage that's on the top of the canopy.

So in severe droughts, one of the symptoms that happens after this stomatol closure takes place is they'll actually start shedding their leaves to prevent additional water from evaporating out of the plant. And then once the water comes back into the soil, one of the first things that they'll do is starting to start to grow new roots to access all that water. So considering that stream of water that runs all the way up from the top to the bottom of a plant, the worst thing that could happen could be an air bubble in that stream. That's right. So the water that's in the xylem sap is under tension. And so as a consequence, it's a negative pressure in the liquid. And as a consequence, it's called what we, called being metastable, and that it sort of wants to become a change from the liquid phase to the gas phase because it's below the vapor pressure for water. And so these bubbles can arise from basically the separation of the water molecules, these cavitation events that lead to a bubble. And then those bubbles have a tendency to propagate through the vascular system of the plant. that's when the plant really gets into trouble. So if we, as engineers, knew how the plant did it, we could make our own devices. Well, it depends on how quickly we want to transport water. So the actual rates of water transport up the tree can be high in some species,

but it's probably not at the rate that we would need it to move for running our faucets. Thank you very much. Very interesting conversation. Craig Broderson is an assistant professor of plant physiological ecology. That's a long term at Yale University School of Forestry and Environmental Studies in New Haven. Dr. Abbey Vandenberg is a research associate professor, University of Vermont's Proctor Maple Research Center in Underhill, Vermont. Thank you both for taking time to be with us today. Thank you.

Staying with our tree theme, if you had to take a guess of what type of tree lives the longest, what would you say? I'd guess the redwood. Well, I'd be wrong. But the most ancient trees actually live on mountaintops in harsh dry climates, and they are called bristlecone pines. These trees have evolved lots of adaptations to live in rough terrains. But it's going to get even tougher. Climate change is raising temperatures and pushing the trees to adapt once again. So how will these trees survive in a warmer future?

That's a topic of our latest macroscope video, which features my next guest. Brian Smithers, Assistant DeCology Research Professor at Montana State University in Bozeman, and you can watch the video up on our website at ScienceFriday.com slash pine. Welcome to Science Friday. Thanks for having me. It's really a pleasure. You're welcome. When you say pine trains, a pointy Christmas tree comes to mind, but these bristled, they're not really like a Christmas tree, are they? Interestingly, where they grow protected with plenty of water, they do.

They grow nice and straight and look lovely. The problem is that happens pretty rarely where these grow. These are found throughout the Great Basin, which is a dry area, mostly kind of centered around Nevada at the tops of mountains, and they get just beaten down by the conditions, by wind, by snow, by drought, by heat. They get them all. And so they really get gnarled and twisted and deformed by the physical conditions. which they live. So they've had to adapt over the years to be some of the longest living trees?

It's part of living in that kind of a climate is you can't grow quick and fast, like you mentioned a redwood or a sequoia where they get plenty of water. Their adaptation is to grow slowly, and a byproduct of that slow growth means they have incredibly dense wood, and that dense wood allows them to just keep on growing. They don't get knocked over by wind. They can't get invaded by parasites or pests. And so they just keep on trucking along. So how old do they get?

We don't really know the answer to that. There are a couple of specimens that we have aged to over 5,000 years, which you said they were the oldest tree. They're actually the oldest organisms on Earth that aren't clonal in some way. I'm just, I'm silent because I'm in all, a 5,000-year-old tree. Wow. And these trees are going to need to find, I mean, you say how tough they are, but they're facing another challenge, which is climate change with warming temperatures.

They're going to have to move up the mountain to cooler climbs? They will. You can imagine a 5,000-year-old tree has seen quite a bit of climate change in its life. Adults are probably fine, for the near term anyway. It's really about how will the young trees establish, how will they establish in response to climate change? Can they establish in places where the adults are found now, or is it now too warm and hence too dry to establish there? Or do they need to move up slope in order for the species to keep up with climate change? So when we say that they have to move up the mountain, it will be the young trees, the new trees,

falling, you know, trying to take a root in a different place and surviving better than their parents down the mountain. Correct. And that's how it actually moves. Adult trees are really bad at moving. It's really about the seeds and the young that need to make that move. That's all plants, of course. Of course.

I'm Ira Flato. This is Science Friday from WNYC Studios. talking with Brian Smithers of Montana State University in Bozeman. Why do the trees need these cooler temperatures? We were just talking about these other maple trees. What about these trees? Are they the same story? That's funny.

I really enjoyed the conversation you were having with the prior guests. There's a brisiccone pine growing in front of the California State Capitol in Sacramento, California. It is not known for being cool in Sacramento, California. and temperatures up to 120 degrees in the summer, that tree is doing just fine because it's getting watered. Brissacone pine isn't relegated to these rough, dry, windy spots because it enjoys it. It's there because there's not a whole lot of competition.

What it does well is grow slowly and persistently, but it doesn't compete well with faster growing, trees that are typically found further down slope. And it's interesting that you say that because isn't there another species, a limber pine that is competing for the same real estate? Yeah, that's right. So there is a species that they sort of coexist, although limber pine is typically found a little further down slope, can handle hotter and drier temperatures.

And they have what we called leapfrogged right over bristlecone pine and are charging up slope in the last, say, 50 years we've seen this trend, where limber pine is establishing in far higher numbers than bristlecone pine is above what is usually all adult bristlecone pines. And so the concern is, are they taking all of the good spots? Are they taking all of the available real estate up slope of where you do find these bristlecone pine trees? We don't know the answer to that. Sorry.

Go ahead. No, you almost answered my question. I was going to ask, is there going to be a definite winner in this race? There's certain. I don't know the answer to that question. There certainly looks like there is a short-term winner, and that's limber pine. The problem with saying something like short-term is that we probably think of that as decades or something. But when we talk about trees that live for thousands of years, short-term can be 5,000, 10,000 years, multiple generations.

of these trees where we will probably see a far higher abundance of limber pine in these historically or prehistorically bristlecone pine forests. I think we won't know the answer to your question for 10,000 years, 20,000 years. We'll meet back here and talk about it. Yeah, we'll talk. That's great. Yeah. But this is one case of changes that happen due to climate change, right?

It's absolutely a climate change issue. but these, and a recent climate change issue. Interestingly, there are, of course, natural climate changes, which have also happened. Because these trees grow so slowly and respond to climate so slowly, they're still actually responding to coming out of what we call the Little Ice Age, which started getting warmer around 1850. They're still actually responding to that climate change, much less the more recent anthropogenic climate change.

so it's kind of a convoluted mess out there. Well, that's a great way to end this conversation, thinking about it, still adjusting 1850. Brian Smithers, assistant ecology research professor at Montana State University in Bozeman. Thank you for joining us today. Thanks so much. It was my pleasure. And you can watch our latest macroscope video featuring Brian

and these bristlecone pines at our website at science friday.com slash pine. One last thing before we go, we're headed to Boulder, Colorado. Maybe we'll see some bristle cones out there. and we'll be putting on an evening of science conversation, live music demos, and more at the Chautauqua Auditorium right up there at the foot of the flat irons. Here's the date. Circle it, Friday.

It's not Friday. It's Saturday night, June 15th. Saturday night, June 15th. You're not going to want to miss this. We have a lot of great stuff that we're going to be doing. More info and tickets at ScienceFriety.com slash Boulder. Not a Friday afternoon. It's going to be Saturday night, June.

June 15th. We hope to see you there. Charles Berkwest is our director, our senior producer, Christopher and Taliatta. Our producers are Alexa Lim, Christy Taylor, Katie Feather, technical and engineering help today from Rich Kim, Sarah Fishman, and Kevin Wolfe. And of course, we're active on social media all week, Facebook, Twitter, Instagram, and you can have your smart speaker ask it to play Science Friday. You'll get the latest edition of that. I'm Ira Flato in New York.