Joshua Ginsberg 0:00
I don't really need to introduce this speaker, because this is the trifecta of the hat trick. Doug is a recidivist. This is his third lecture at Cary. Why do we have him keep coming back? Well, first of all, he's an engaging speaker who's talking about important issues in ecology and conservation and things that are important for making this world a better place, but most importantly, things that you can do to make this world a better place, and that is rare. Secondly, I mentioned that we had 1,700 people sign up. Doug's last talk had about 1,000 people virtual and a full house. And since he has given that talk, 30,000 people have streamed the talk. So from a Cary Institute, you know, marketing perspective, I have no better partner. Thank you. Thank you, Doug. But you know, Doug is a PhD scientist, you know, taught at University of Delaware for many years, a PhD out of Maryland. You know, all the right credentials, but what he is also is an amazing communicator. His books are not just eloquent and important, they're fun to read. He is giving a key message on the importance of native plants. So after hearing Bringing Nature Home: How You Can Sustain Wildlife with Native Plants, and in 2000 that was 2010, 2023, Nature's Best Hope: A New Approach to Conservation that Starts in Your Yard. It's really a great pleasure to introduce Doug Tallamy and have him talk tonight to us about some of my favorite trees, The Nature of Oaks: The Rich Ecology of Our Most Essential Native Trees. Thank you very much.
Doug Tallamy 1:58
Thank you, Josh, any questions? I think we're gonna, we're gonna lower the lights here a little bit. Recidivist.
Doug Tallamy 2:08
I'm gonna have to look that up. I've been called a lot of things, but not that before. Okay, is that where the lights are gonna, gonna be? Good.
Speaker 1 2:17
Yes, there we go. All right, let's talk about about oaks.
Doug Tallamy 2:22
Before we talk about that, let's talk about how important insects are. They're actually related to oaks. You probably have heard that insects are the little things that run the world. E.O. Wilson told us that way back in 1987. Life as we know it depends on insects, and if we lose them, we lose 90% of our flowering plants, we lose terrestrial food webs, we lose most of our important decomposers. We also lose humans. So they're very important. But we do have a problem, and that is the planet has already lost 45% of our insects, and that's a 2014 statistic, so it's worse than that. Why? Well, lights kill insects. Neonicotinoids kill insects. Deforestation kills insects. Cars kill insects. Climate change kills insects. When you take that and you turn it into that, it kills insects.
What does that have to do with oaks? Well, there is no better way to share our spaces with insects than to plant an oak. So that's what we're going to talk about tonight. We're going to, we're going to use the oaks that I have planted on our property, starting in the year 2000; I might have planted the first one the year 2001 but that's what it looked like when we moved in in the year 2000. So what we did was, was buy a 10-acre lot of a farm that was broken up into 10-acre lots. It was an old farm; been farmed almost 300 years. And the last thing they did before they sold it was mow it for hay. And this is Oxford, Pennsylvania. And when you mow for hay in Southeast Pennsylvania, you're really mowing the rootstocks of all the invasive plants from Asia. So when you stop mowing, that is what comes back. So when we actually moved in, that's what the 10 acres looked like. Now you don't plant your oaks until you get rid of that, and I don't want to minimize the amount of work it is, but it's not that hard when you get your spouse to do it, and when she's done, you can start planting your oaks. There's an oak about a mile and a half down the street, a white oak dropped a lot of acorns that year. Now, white oaks germinate in the fall, so you have to plant them right away. And they stick out their little root, their radical, put it down, and that's all they do in the fall. In the spring, they will put up their first pair of leaves, and that's all they do in the spring. And they kind of sit there. It may, it gives oaks the impression, it gives you the impression that oaks grow very slowly. They're not growing that slowly. It's just that in the beginning, most of their growth is below ground. Oaks are putting on 10 times more root biomass than above ground biomass in that first year.
That is the oak we're going to follow. There it is. It's got a little cage around it. We do have a deer issue, and if you don't cage your oaks, you don't have your oaks. But that's what it looked like that first year. This is what it looked like 18 years later, 45 feet tall, 47-inch circumference, canopy spread of about 30 feet, still a baby, but that's, it's only 18 years old, so you get a real landscape tree much faster than people think. Now, one of the things we're going to stress; now, I want you to plant oaks, but I want you to understand why you need to plant oaks, and one of the reasons is they are a lifeline to an awful lot of creatures. There are dozens of species of birds that depend on oaks. There are mammals, rodents, many rodents. These are things that are eating the acorns: bears, raccoons, possums. A big oak has a lot of hollow spaces in it, so that's where rats and snakes spend the winter, and fence lizards. There's several species of butterflies that are specialists on oaks. Hundreds of species of moths depend on them, as well as their predators and their parasitoids. We'll talk about cynipid gall wasps that are specialists on oaks. A lot of beetles: June beetles, longhorn beetles, metallic wood-boring beetles. If you drop below, weevils, too, don't forget the weevils. When you drop below the oak into the leaf litter underneath it, then you've got another whole community of organisms: a lot of spiders, dozens of arthropods and mollusks and annelids that depend on the leaf litter. So it is a really diverse, complex web of life that's associated with oaks.
The problem is it typically goes unnoticed. Most people don't know what's happening on their oak. And if it's unnoticed, it is unappreciated, and that is why I wrote the book The Nature of Oaks. It is a month-by-month guide to the life that's associated with oaks. And the idea is to provide the knowledge that would then hopefully generate interest in your oak. And then interest generates compassion. And compassion often generates action, and we need a lot of action in the field of conservation.
So first, a few facts. Oaks are in the genus Quercus. There's 91 species in North America, about 435 species globally. That's determined mostly by DNA, because they hybridize a lot. The word Quercus comes from the Celtic quer, meaning "fine," and cuez meaning "tree," and they are indeed fine trees. We're not going to talk a lot about taxonomy, but there are four major sections that are part of North American oak flora. There's the Quercus group, the white oak group; Lobatae, the red oak group. And you hear these terms, Virentes is the live oak group, if you move down south, and a much smaller Protobalanus group, canyon oak group, in the West. This is the distribution of oaks nationwide. There is at least one species of oak in every area except the brown area. So in the Northern Rockies and the drier part of the plains, there are no oaks. But every other place we've got one or more species; there are 16 species of oaks that you can find in New York State.
Oaks live a lot longer than we typically think, or they can if we treat them well. Now these data come from Europe, but 300 years of growth, 300 years of stasis and 300 years of decline. So 900-year oak is not that uncommon, or at least it didn't used to be. This is the Bedford oak, by the way. It's an old one lives right around here. Each one of those periods there's distinct ecological associations during that period of growth. So we want, we want our old oaks around, because a lot of things depend on them. What's the oldest oak in the country? Some people say it's the Pechanga oak. It's a coastal live oak in California, estimated to be 2,000 years old. But the real winners don't look like oaks at all. They're little shrubby things, the Palmer oaks that root in one place, and then they slowly crawl along the ground, and they die over here, and they're living over here. This individual has been been, they say it's 13,000 years old, so not sure how they figured that out. But so there's actually some of the oldest living things on the planet. Now, oaks get big, not all of them, not all of them. We have some small ones that you can put in your yards, but the oaks can be enormous, and they have superior ecological function. We'll talk a lot about that. I say that because they have the highest biodiversity value, meaning they are supporting more species than other trees. They're sick because of that huge size, they're sequestering more carbon. They're very dense, so they can hold that carbon, and then they hold it a long time when they live a long time. They have large root systems, so they're very good soil stabilizers. They make the best leaf litter in that it lasts the longest, and all of that promotes healthier watersheds. Uh, so we're going to start this talk. And I started the book in October. People say, "Why did you start in October?" Well, October is when my wife said, "You should write a book about oaks."
Doug Tallamy 10:11
So I looked out the window. There's our oak. We're going to follow it. Of course, what's happening in October? You know, it starts in September, but in October, that's really the month that you see the acorns out there. And oaks make a lot of acorns. A single oak can produce up to 3 million acorns in its lifetime. And an acorn is, it's a little packet of very valuable food. It's full of fat, full of protein. 180 species of birds and mammals eat acorns, and many of them depend heavily on those acorns. And we're talking about rodents; we're talking about, I guess the squirrels are rodents. Yeah, teeth. But things you don't think about is eating acorns do, like raccoons, certainly our cute little deer eat them. The big guys do as well. Bears are spending most of the fall scouring the forest floor looking for acorns to put on the fat to help them get through the winter. Same thing with turkeys. They're doing exactly the same thing for the same reason. As a matter of fact, a number of birds depend on acorns, things like red belly woodpecker, this red headed woodpecker, titmice, towhees believe it or not, flickers, ducks, particularly the wood duck. They love acorns. A viable acorn hits the water and sinks. If it floats, that's not good. So the ducks dive down and they pull it off the bottom, but they come up on the shore and eat them on the ground as well. Sandhill cranes eat a lot of acorns. Acorns are supporting an awful lot of creatures, even small creatures like the acorn weevil. That is an acorn weevil larva tunneling out of an acorn, and that's what the adult looks like. There's a complex of moths called acorn moths. They all look just like that. You need DNA to separate the species, but as a caterpillar, they live in the acorn, then they come out as an adult. So you have all these things eating acorns. And if you look under an oak tree, maybe a week and a half, two weeks after the acorns fall, it's utter destruction. I dare you to find a viable acorn. They've all been been taken. And you might wonder how oaks ever successfully reproduce.
And this is where a mutualism between jays and oaks comes to the rescue. It's a very old association. Both jays and oaks evolved together. Their lineages evolved together about 56 million years ago in what is now the Arctic, and right away they got to know each other and they liked each other. They liked each other because jays get food from oak trees in the form of those acorns. What do jays do for oaks? They give them mobility, and this is how that works. Jays, of course, store the acorns for winter food. They don't cache them. So they're not putting a big pile in one place the way many squirrels do. They bury the acorns singly. They can carry more than one at a time in their crop, but they will bury them singly. So they'll pick one up, then they'll fly up to a mile, sometimes a mile and a half, from the parent tree, and then they tap it below the surface of the soil, usually in a disturbed place, bury that acorn. Now if they think--the object is going to have something to eat in the wintertime--if they think another jay has watched them bury that acorn, they'll wait around for a few minutes, then they'll dig it up and move it because jays know that jays steal acorns. So there, yeah, the wintertime, they're going to go back and get their acorns. Here's the key. A single jay will bury 4,500 acorns each fall, but they only remember where one out of every four is, which means a single jay has planted 3,360 oak trees each year. And if they do that a mile from the parent tree, that's farther than other animals are moving these acorns around. So that's why they're giving oaks mobility. They also know how to plant them. So an acorn that is planted by a jay has a much higher germination rate than one planted by us. So that's pretty interesting.
And it's not just blue jays that are doing this. All the species of jays are doing it. We've got a number of species of scrub jays, the California scrub jay, the Woodhouse's scrub jay, the Florida scrub jay, island scrub jay, Steller's jays. We have grandkids in Portland, Oregon, and I wanted to get a picture of a Steller's jay with an acorn. And these birder guys out there say, "They don't eat acorns." I said, "They don't?" One guy called me and he said, "They're eating acorns at my house." So I went over to his house. Mexican jays, pinyon jays, green jays..they're all eating and spreading acorns around, and they do it in Europe as well.
Okay, another bird that has a close association with with acorns is the acorn woodpecker. It's a bird of the Southwest, actually goes up the coast of California into Oregon. Now, they don't bury their acorns, but they do store them for the winter in little holes that they drill into trees. They call these trees acorn trees. It's usually a dead tree that's a snag, and they're very stable out there, so they stick the acorn in there, and then when they get hungry, they go get it. Now an acorn tree is a very valuable resource. It can have 50,000 holes in a single tree, and they'll use it year after year. So families of acorn woodpeckers guard their trees. They don't share them with any other family. It's a social, social thing. So if you have an acorn tree in your yard, it's very entertaining.
Okay, we're on. We're done with October and into November. And this is when you you might notice another interesting thing about oaks, and that is that they make acorns, but some years they make very few, and some years they make a whole bunch. It's not a steady production of fruit the way chestnuts were. Chestnuts used to have a big mast every single year. When they make a lot of acorns, it is called a mast year; when they don't make a lot of acorns, it's not called anything. But it's asynchronous reproduction, and people want to know why. Ecologists always want to know why. These are four major hypotheses; not the only hypotheses, and we'll talk about each one. They are not mutually exclusive, so they all could be operating at the same time: predator reduction, predator satiation, improved pollination, and energy partitioning.
Predator reduction. So if you have a lot of acorns in one year--and I think this was a mast year in a lot of places--the squirrel populations, the deer, everybody who eats them does really well. They have lots of babies, and their populations grow. Then the next year, you often have very few acorns, and there's actually starvation. It causes the predator population to crash. Usually go two or three years before there's another mast year. So when there's a mast year, there's not that many acorn predators around. So you've reduced the predator reduction by the asynchronous fruiting.
Predator satiation. Then of course, when you do make another mast of acorns, there aren't enough things like the acorn weevil to eat all the acorns. If the acorns were produced the same number every single year, the weevil population would stabilize around and they'd eat almost every single one. So that asynchrony helps keep that from happening.
Improve pollination. These are the male catkins that drop pollen. Oaks are wind pollinated. The female flowers are little teeny things up here; you don't even see them. A single oak cannot pollinate itself. So what they do is they drop the pollen and it floats in the air and that's because the female flower on an individual doesn't mature at the same time that the pollen drops. So when you have a mast year, what you're having is lots of oaks in an area dropping pollen at the same time, and that improves the chances that pollen will hit the female flowers. And that doesn't happen every single year.
Energy allocation. By the way, if you're wondering if oaks can have good fall color, they can. This is the scarlet oak in my yard. Very beautiful. There's never enough energy to go around. You ever feel that way? I do right now. So they allocate it, they put a lot of energy towards reproduction one year, or they put a lot of energy towards growth. But rarely do they do both at the same time. So remember, these four hypotheses are not mutually exclusive. They all could be explaining the asynchronous reproduction in oaks.
December. This is when you might notice another unusual trait with oaks, and that is that, particularly in the white oak group, they do not drop their leaves. It's a condition called marcescence. Now this is a deciduous tree that doesn't drop its leaves. Very unusual. So again, why? Well, the leading hypothesis is that not long ago, eight, 9,000 years ago, before humans wiped them out, really, there were a lot of big Pleistocene mammals, particularly in the temperate zones. This is the group of large mammals that were in Mexico alone, three species of mammoths, the giant sloth could reach up 18 feet, camels, horses, rhinoceros. There were like 44 species of rhinoceros in the world, and many of these were browsers. A browser is not out there eating grass. It's eating woody material, typically the buds on trees and shrubs that will produce growth the next spring. So if you surround your buds for the following year with dead, old leaves from the past year, a browser cannot get that without getting a mouthful of very untasty leaves. And the distribution of marcescent leaves suggests that that could be true, because they go up about 18 feet, which is as far as that giant sloth could reach, and then they stop. It's not marcescent at the top. So, you know, impossible to test that hypothesis today, but it makes a nice story. It also makes marcescence gives you a landscape opportunity here. If you don't like your neighbor, you can actually screen them out in the summer and the winter by planting a member of the white oak tree.
January, it's cold in January. It is cold. We don't spend a lot of time outside looking up in our oaks, but if you do, you often see little birds flitting around in the trees. Now they're not playing, they're looking for food, and by little birds, I'm talking about chickadees and titmice and golden crowned kinglets. Kinglets are particularly interesting because you presume they're looking for insects in the trees in the middle of January, but we all know there's no insects in the trees in January, and kinglets--now, the titmice and the chickadees, about 50% of their diet is seeds so they can go find food someplace else--but 100% of the kinglet's diet is insects. It should have migrated, but they don't. They migrate a little bit, but they stay up in the cold areas. I took this picture in my yard in January, and that is a kinglet looking for insects. Well, that's called the kinglet paradox. It's a bird that should have migrated to where the insects really are. Bernd Heinrich, a retired entomologist, does not like paradoxes, so he looked in the crop of golden crowned kinglets in Maine in January, and he found they were full of caterpillars. There's a caterpillar right there. So it turns out there actually are a lot of caterpillars, particularly in the oaks. We didn't know they were there because they look just like sticks, but the kinglets know that they're there. When it gets cold--there's a caterpillar right there--they have proteins in their cells that keep them, it's antifreeze. It keeps the cells from bursting. So they shrink a little bit when it gets real cold, and when it's warmer, they swell a little bit, but they just sit there all winter long. So there really is no kinglet paradox. The kinglets are sticking around because there's a lot of caterpillars in those trees. The real question is, why are there a lot of caterpillars in the trees? Why are they spending the whole winter just sitting there? There's nothing to eat, and again, we don't know, but this is one possible explanation. Those are almost fully grown caterpillars, fourth or even fifth instar caterpillars. And in the spring, of course, you have bud break and young leaves come out. If you overwinter as an egg, you're really tiny. And if you overwinter as an adult, you've got to emerge, find a mate, then lay an egg and then hatch. If you overwinter as a cocoon or a chrysalis, you've got to emerge as an adult and find a mate and lay an egg. So the caterpillar that's spending the winter up there is ready to go. He can beat everybody to this unlimited food supply. And who knows if that's true either, but that's my story.
All right. February, this is the quietest time of year for oaks, so it's the time I'm going to talk about what I call landscaping myths, oak landscaping myths. People, there's all kinds of excuses why they don't want to use oaks. They're too expensive; they grow too slowly to use as landscape trees; they get too big for a small lot; if you do plant them, they're going to fall over and crush your house; or they'll lift up your hardscape--your driveway or your sidewalk. Now, of course, myths are usually based on a little bit of fact in there, so let's talk about each one of these.
Are oaks too expensive? You know they can be if you insist on buying a large oak; the bigger it is, the more the nursery is going to charge you. This is a risk of doing that. It depends on who's growing the oaks. But when you grow a tree in a pot, the roots have nowhere to go, so they go round and round. It's called being root bound. And you can plant it. It will live for a while, but the roots continue to go round and round, and eventually will choke itself off and have a very short life. This is at least 10 large oaks that were planted in a park in Newark, Delaware. I don't know how much money they spent on each one, but every single one died the same season that they planted. So planting a large tree can be risky. It's because we want instant gratification. Well, nursery men have actually gotten a lot better at growing trees in pots. They call them air pots, and the tree somehow, the way the pot is constructed and air gets into and prevents the roots from becoming root bound. But it's still a very small amount of root area for the size of the tree that it has to support. So when you plant it, the first thing it does is try to build a root mass. And it will spend 10 years trying to build that root mass so you'll have your tree, but it's not going to grow a lot in the beginning. The other option, of course, is balled and burlap, where you actually chop off all the roots, wrap it in burlap, so it looks nice, and then you you plant it. But you know, it is hard on the trees. If I plant an acorn the same day I plant one of these things, in 10 years, my acorn will be bigger and much healthier than a root bound or balled and burlap tree. And I actually did that. I didn't know I was was doing an experiment, but my brother-in-law actually has a nursery, and he had dug like a 15-foot red oak. The sale fell through. The guy never came and picked it up or anything. So he said, "Do you want it?" I said, "Sure." So dug a giant hole. He gets the tractor and puts it in. That's that tree right there. The same day, I planted an acorn of a willow oak, only about 20 feet away. He said, "Why are you doing that?" I thought I had the acorn put in the ground, but look, there it is. Took these pictures on the same day. The one I planted from an acorn is much bigger, much healthier. This guy has never, never looked good. It's probably going to die in the end.
So if you wait a little bit, they grow slowly in beginning, but then they really do take off. And speaking of that, how slowly do oaks grow? Let's have a race between my little friend Bella and the oak that we're following. Here the oak is six years old. Now everybody says this is my daughter. It's not. It was my surrogate granddaughter. And when we got real ones, we got rid of her. Here she is two years old. We're gonna have a race between the white oak and Bella. And we all know that white oaks grow really slowly, so maybe Bella can catch up. So there's Bella is two. Here she is at three, four, five...she's losing...six, seven, eight, nine, 10, 11, 12, 13, 14, 15, 16.
Doug Tallamy 27:08
Bella's got her mask on so you know it's COVID year, and she actually stopped growing so she has lost, but she did pretty well. But Bella is 5' 11", she's better than me, so. But you know this, that's the oak we're following, and it is, they do grow, they do grow quickly when you treat them well. The point is, they don't have to be big and mature to contribute to your landscape. This is a pin oak that has just popped its head above the leaves there, and there's a caterpillar standing on the ground eating the leaves of that tree. And people say, "Oh, it's going to kill the tree." No, an ovenbird is going to come eat that in the next 20 minutes. So it's contributing to the food web, even as a first-year seedling. And that's the importance of oaks. They're contributing a lot ecologically.
Are oaks too large to put in small yards? Well, you're not going to get anybody to suggest you put an oak in a yard that big, but they used to, and you can still find it in a number of places. This is a street as I drive into the University of Delaware. It's lined with big red oaks like this that were probably planted when the houses were built, which is probably more than 100 years ago. Remember, 100 years ago, there was no air conditioning. A shaded house is 10 degrees cooler than one that's not shaded. They haven't dug up or lifted up the hardscape. They haven't fallen over and crushed the houses. But again, nobody's going to recommend that today. This is a large oak in front of a large church. And I'm glad they didn't take the oak down, because it's a wonderful specimen. This is a Quercus garryana, the Oregon white oak, in a very tiny yard in Portland, Oregon. So you can find big trees in small yards, but if you have a small yard, we do have dwarf or very small oak options. In the East, those are all the options that you have. Dwarf chestnut oak is the one I would recommend, Quercus prinoides. It does very well around here. You can find it in the nursery trade. If you live out West, you've got a lot more options. Dwarf chestnut oak. Here it is. Look at it: knee high, and it's making acorns already. This one was in my yard. It still is, but it's bigger now, but it was about five feet tall when it started to make, excuse me, acorns. So you can have a productive oak in your yard and get it to acorn size very quickly.
But if you plant an oak, is it going to fall over and crush your house? Now this is not just a feature of oaks. Large trees are falling over and crushing houses. And of course, we know about every one because the news media will cover it. They do never, do not cover that oaks that do not fall on your house, that's not news. But there's no doubt trees fall over. Why? Because we plant every single one as a specimen tree, we isolate it. So when you get a lot of rain, a lot of wind, over it goes. This is the way trees grow in the forest. They grow close together. The roots are intertwined. They form a very stable matrix. They lock themselves together. This is a stream cut near my house that shows how that happens. There's one, two, three, four trees here, and believe me, it takes a big wind to blow over all four of those at the same time. So instead of this, let's consider this, those are actually the oak trees I got my original acorns from. That's three feet apart. They were there before they put the road in. I doubt if anybody planted them. Now, when you put trees close together, they're not going to be as magnificent and splendid as they would if they were isolated. So you view them as a group. Michelle actually gave me this picture. This is the three sisters in Northwest Connecticut, red oaks growing together. You can find situations like this in parks all the time. Big trees can grow close together, and they form a little grove that locks their roots together. This is a planned planting. This is at Mt. Cuba Center in Hockessin, Delaware. It's a DuPont estate. Very big red oak back here. These are hemlocks. These are big roadies here. There's a little hardscape up here. It used to be a cornfield, so people planted that. If you have three or four acres of lawn and you're wondering what to do, you can put in a planting like that. It's beautiful. It forms habitat, and it's very stable. It's not going to blow over.
Is your oak gonna lift up hardscape? Well, it depends on what you plant it over. So this is a pin oak right next to this road. Hasn't lifted it up at all. These are some big oaks that I've run into not lifting up the hardscape. There's a big red oak at the University of Delaware right next to the curb. If you plant your oak on bedrock, the roots go laterally. It will lift up whatever is next to it. If you plant it over agricultural Pan. Pan occurs when the plow went down about 18 inches for 100 years in a row, and it really compacted the soil underneath it. The roots will go down and hit that pan, and then they'll go laterally. So if you know you're over an old ag field, break up the pan first, and then your roots will go deep enough.
Okay, March, that's when those leaves are finally dropping. So let's talk about oak leaves a little bit. A lot of people think all oaks have lobed leaves. Several of the species do, but not all of them. This is a shingle oak, that's a water oak, that's an emery oak in the West. Willow oak, that's a live oak, so doesn't have to have lobes to be an oak. Some of the lobes are pointy. Some of them are rounded. Those are all taxonomic traits. But oaks, you know, trees in general, make a lot of leaves. A single large oak will make 700,000 leaves. And if you line them all up together next to each other on tennis courts, it would cover four tennis courts. And that really is one of the major reasons why we want to leave the leaves, because they form a blanket on the ground that protects the soil community. Everything that lives in the soil depends on high humidity, and if you let it dry out, which happens when you have bare soil, that community either goes really deep or it dies altogether, and that includes the mycorrhizal fungi that are transferring nutrients from the soil to your plant roots. So that's one of the important things that leaves do. The reason I said oak leaves are the best is because a single oak leaf can take up to three years to break down, so it's providing this benefit a long time, particularly through a single season. Tulip tree leaves, birch leaves, maple leaves; they don't make it through a single season. They're gone, and then you've got bare soil. Lot of things live in the soil. There are more species that live underground than above the ground. Many of them are tiny. But if you have a single square meter of oak leaf litter, 250,000 mites, 100,000 springtails--that's a little Sminthurides springtail--90,000 proturans, which are primitive insect-like creatures. You need a microscope to see them. A million nematodes. Lot of life there. Most of these guys are detritivores. They're breaking down the leaves, returning the nutrients that your tree used that year to the soil so that it can use it again. When you rake your leaves away, you're starving your tree. There are pretty things like the red-banded hairstreak that actually eat dead oak leaf litter. That's what the caterpillar eats. So not all caterpillars eat living leaves. As a matter of fact, there's 70 species of moths that we call litter moths, that develop on dead leaves, things like the ambiguous litter moth, the American idia, the dark-spotted palthis, and 67 other species. So again, when you rake up your leaves, you're throwing all that away. Then you have the predators that are after all of those insects, lots of species of carabids and many other predators, including fireflies, lightning bugs, whatever you want to call them. They're not flies and they're not bugs; they're beetles. That, of course, is what the adult looks like. There's the lantern, but that's what the larva looks like. It is a predator in leaf litter. So when you throw away your leaf litter, you're throwing away the habitat that our fireflies require.
The reason we throw away our leaves is because we got this idea that if you leave them in our beds, it's going beds, it's gonna kill all your flowers. Is that true? Well, if it's five feet thick, yes, that is true. But a normal layer of leaf litter, the plants are very good at getting through those leaves. I mean, think about it. Who was raking the leaves before we got here? And there were plants in North America, I read about it. This is violets in my yard coming through a shingle oak bit of leaf litter. I don't rake my leaves for a couple reasons. I shouldn't, and I'm here, I'm not raking the leaves. So here it is a week or two later, a week or two after that, and then finally, get full bloom. Never touch those leaves. They come right through and do just fine. And you can find that's true with an awful lot of the plants.
Okay, April, this is when you start to get bud break. It's when you can see one of the most ephemeral biological interactions in all of nature. That lasts about five minutes a year, but it's common, so if you're there in the right five minutes, you can actually observe it. And I'm talking about when cynipid gall wasps create their galls, when the female gall wasps lay their eggs in the buds of oaks. And that's exactly what's happening here with this particular species. There's the female, there's her little ovipositor. She's injecting an egg into this bud. This is a male who is, we call it, riding her, or mate guarding. He's already mated with her, but he wants to make sure that she uses his sperm to fertilize that egg. This male wishes he was that male.
Doug Tallamy 36:53
So here's a female. She's injecting an egg into this bud, but she's also injecting plant hormones that will control the growth of the cells in this bud. They're essentially stem cells. They can go in all different directions, depending on the hormones that the cynipid is injecting. But the oak itself has hormones too. So the gall that results is a compromise between the cynipid and the tree. And there are a lot of species of cynipid gallers. More than 1,000 species are associated with oaks. A single oak tree can have 70 different species of gallers on it. As a matter of fact, if you have an oak that has no galls, there's a problem. There should be galls on your oaks.
Many of these galls are hollow. What's that all about? This is the apple oak gall, or the oak apple gall. I've seen it written both ways. If you cut it open, the galler itself, the cynipid larva is in that hard center there, but you've got a bunch of air here. Why is that? Well, turns out that that cynipid gallers have more natural enemies, more parasitoids, than any other insects, and we're talking about other wasps. This is a pteryman wasp. They have very long ovipositors, and what they do is they lay their egg in the cynipid gall so it develops, and then the galler doesn't, but they have to be able to reach the galler. So this the gall. That space between where the gallar is and the outside of the gall has to be longer than this ovipositor. Otherwise, the wasp can reach it.
Now, in the beginning, the gall is small, and that is when the wasp has an opportunity to reach the gallar. But they grow very quickly and outpace the length of the ovipositor. This is a Torymus wasp on the West Coast, has the longest ovipositor of anything, and it has created the largest gall, because the gall has to keep getting bigger and bigger so that ovipositor cannot reach the center of the gall. There's a lot of diversity in gall size and shape. Many of them are just round blobs on leaves or round blobs on sticks. Some of them look like that. Many of them look like plant diseases. That's actually, each one of these is a gall. Some of them look like pottery. Some of them look like brains. Some of them look like a buttocks. Some of them look like spindle. This is called the spindle gall, and I've made up these names. This is the cotton candy gall. This is the bowling pin gall. Out in California they've got really pretty ones. They all look like candy. Another candy gall out there. This is the cutest one. I call it the gnome house gall. That's where the galler emerged. So it's not really a door, but there's also very interesting association with galls and our recorded history. It turns out, if you grind up a gall like this and add particular chemicals, it makes an indelible black ink, and that is the ink that our recorded history was recorded with for thousands of years. The Bible was written with gall ink. The Magna Carta is written with gall link. The Declaration of Independence was written with gall ink, so you can share that little fact at your next cocktail party.
Okay, April is also the month that you get the catkins, the male catkins, coming out. And there's a very interesting relationship with this moth. The Nemoria arizonaria, and it occurs in Arizona, believe it or not, but it has two forms of crypsis depending on the two generations; i has two generations a year. In the first generation--there's the caterpillar right there--it mimics the catkins really well. So when it sits on these catkins, you do not see that caterpillar. Well, the catkins is only around for a week or so, and the second generation of this moth mimics the stems, the sticks itself of the new growth, and doesn't look at all like that first generation. It's the same species, but very interesting crypsis.
Okay, May. This is when the new biological year really takes off, when those leaves expand. And close on the heels of those expanding leaves are the caterpillars that eat those expanding leaves. And close on the heels of those caterpillars are the birds that eat the caterpillars. It's no coincidence that spring migration is coordinated very closely with the emergence of the caterpillars that are eating our young leaves. And if you're a birder, you know that if you want to see warblers, you go to oak trees, because that's where they go. And we know that for sure. One of my students a long time ago looked at the amount of time warblers spent foraging in different plant families. This is the fagaceae here; that's the oaks, the chestnuts, and the beeches. But there were no chestnuts and beeches in her study site. This was done in cemeteries. They were all oaks. And look, that's where the warblers spend their time. And they spend their time there because that's where the caterpillars are. You know, these birds are coming north in the spring. There are no berries or seeds; at that point, the plants haven't made them yet. So what fuels the migration is caterpillars, things like the purple-crested slug, the buck moth, the white-marked tussock moth, the saddle prominent, double-lined prominent, white-dotted prominent, the checkered-fringe prominent, the Laffer, the lace-capped caterpillar, the two-spotted oak punky, the skiff moth, the white-blotch heterocampa, the oblique heterocampa, the variable oak leaf caterpillar, the hickory tussock moth, the red-lined panopoda, the yellow-necked caterpillar, the smaller parasa, the unicorn caterpillar, the crown slug. These guys are called slug caterpillars because the head is tucked up underneath. They're not really slugs. They're really caterpillars. This is the streaked dagger moth, the epilated dagger moth, the hesitant dagger moth, the lesser-oak dagger moth, the medium dagger moth, the greater-oak dagger moth, the afflicted dagger moth, the red-humped oak worm, the pink-striped oak worm, the confused wood grain, the spiny oak caterpillar. This is my favorite, the spun glass caterpillar. And hundreds more species are associated with oaks, so that's why the birds go there.
Now, this is what our property looks like in the summertime today, taken from pretty much the same place we took that first picture, and we put some of the plants back, not all the plants. We're still working on it, but I have been counting the number of species of caterpillars that now make a living at our house. I am still at it, but I'm up to 1,366 species that are there because we put what they need back. We put the plants back. Twenty-eight percent of those species use oaks. Almost a third of that huge number depends on oaks. Which is why oaks are such important plants. And because so many of those caterpillars are types of bird food, we have recorded 62 species of birds that have bred on our our property--not flew by, but bred. Oaks are really important, and that is why I call them keystone species. Remember what a keystone is: it's a stone in the middle of the Roman arch, and if you take it out, the arch falls down. Well, if you take oaks or these keystone plants out of your food web, the food web collapses because they are making most of the food. Just 14% of our native plants, of the keystone plants, are supporting 90% of the caterpillar food that drives the food webs that are out there. And oaks are the number one keystone plant in this country for that reason. They're supporting over 1,000 species of caterpillars nationwide.
Who cares about caterpillars? Why do we need them? Well, they are transferring more energy from plants to other animals than any other type of plant eater. So if we have landscapes that don't have a lot of caterpillars in them, we eventually have failed food webs, and then eventually failed ecosystems. That's why Dan Janzen, famous ecologist, calls them the bread and butter or the meat and potatoes of terrestrial food webs. And it's not just the migrants that need those caterpillars, the resident birds do as well. You've all heard the chickadee statistic: 6,000 to 9,000 caterpillars to get one nest of chickadees to the point where they leave the nest, and after they leave the nest, the parents continue to feed them caterpillars another 21 days. So it's tens of thousands of caterpillars required to make a bird that's a third of an ounce. One nest! We want a whole community of birds. Takes millions of caterpillars, and that's why oaks are so important.
Okay, June, cicada month. You guys have cicadas up here? Was it this year? All right, you already know about cicada, so we won't talk a lot about them, but we're talking about the periodical cicada, of course, 17-year brood, 13-year brood; in a few places they actually overlap, then you get a lot of cicadas. What was interesting to me, we had the cicadas maybe four years ago, listening to the media talk about this. Of course, it's predictable. We know exactly when they're going to come out, so the media gets a hold of it and it was amazing what they said. You should consider moving before it happens, it's going to be a terrible invasion, they're going to sing so loud you would go crazy and kill your babies. I heard this on the radio, believe me. It's none of those things. One of the most fantastic biological events you'll ever be privileged to witness. Now it was big in Newark, Delaware a couple years ago; those are the shed skins of the nimsa that they come out of the ground. But look what they're doing. They leave the, they're aerating the soil so that your oaks and everything else are much happier. The water and the oxygen gets down there. You don't have to pay anybody to do it. But there were a lot of them, so many that 11 Mississippi kites flew up to Newark, Delaware, and stayed for two weeks, eating the cicadas.
Doug Tallamy 46:47
This is what happens. They come out at night. They hang upside down, they split their exube, and they hang, then they get a swing up, and then what they're doing is hanging there while they tan their exoskeleton. They're like a soft-shelled crab now, so they're very vulnerable, which is why they do it at night. But they hang there till their exoskeleton is completely hard, and then their muscles can attach and they can do what they need to do.
Now, if you're a male cicada, what you need to do is attract a female, and you do that by singing. There are two membranes in the back of the thorax there. And what they do is they vibrate them, but it's more like a clicking Coke can, but they do it something like 400 times a second, and it creates a buzz, and the buzz can be loud, and the louder he buzzes, the greater the chances that he will attract a female. And he did. He attracted a female. So they're doing what they need to do. Then it's the female's turn. This is her ovipositor, and what she's going to do is lay eggs in the sticks of trees. And they really like oak trees. This is the pin oak in the front of my house, and there she is. She's got it buried in there. You should try it, get a pin someday and try to stick it into the branch of an oak tree. You're going to bend the pin. I don't know how they do it, but they get it in there, and they lay an egg, and they lay one egg, two eggs, three eggs, four or five or six in a row, and then they go to another branch and they do it again. And from that point out, often, not always, but often, it kills the branch. It's called flagging, and people get upset. "It's going to kill my tree." It's not going to kill your tree. It's going to prune your tree once every 17 years. And that's okay. I had a student look at where the most flagging was, which species of trees in Newark, Delaware. The green bars are species of oaks, so they had the most flag. And they do hit other trees, but they do like oaks. And then they die. That's it. Two or three weeks. That's the end of your cicadas. The real question is, why are they spending 17 years underground? And again, the leading hypothesis is predator satiation. They come out by the millions, and there are not enough, there's no specialized predator that can wait 17 years before it eats. So when they come out, the squirrels and everybody's eating, but it's not, they're not enough predators around, and many of them survive.
Okay, July, this is the when the night chorus begins. By the night chorus, I mean when the katydids start to sing. If you're wondering why Katy did sing, this is why. Once upon a time, there was a young woman named Katy who fell in love with a handsome young man. Alas, he did not share her feelings, and he married another. Soon thereafter, he and his young bride were found poisoned in their bed. Who perpetrated the crime was never determined, but some say the insects in the trees were watching that night, and each summer, they solved the mystery by singing, "Katy-did, Katy-did." Oh, there it is. You hear it? You've all heard it. We've got a lot of katydids in the summertime here. I did a lot of camping in my youth in northern New Jersey, and the katydid sang me to sleep many times. So there's four species of katydids out here. The males, of course, are singing to attract a female, same as the cicadas. The loudest male attracts the most females. This is what a female looks like before she's in her fourth instar here. She hasn't expanded her wings yet, but that's the ovipositor. It's a big, flat structure, and that's what the eggs look like. They glue them to sticks, usually up in the canopy, but occasionally it's low enough that you see them. And people always wonder, what are these things? These guys have already hatched, but those are katydid eggs. Again, why so loud? Because the loudest male attracts the most females.
All right, August, this is when it's the toughest time to be an herbivore of oaks, because oak leaves get really, really tough. Now, in the spring, they're nice and tender. That's that's a great time to eat oak leaves, but in by August, they're filled with tannins. They're filled with lignins. They're kind of like boards. So the way that insects get around that is, there's two ways. One is to feed gregariously. Everybody eats it at the same time. Somehow that makes it easier. This is the yellow neck Caterpillar when they're young. That's the yellow neck Caterpillar when they're older. But they're always cooperating when they're when they're eating. So all the big caterpillars in August are gregarious. This is the orange humped oak worm, the pink striped oak worm. It's a strategy to get around those very tough, tough leaves, and of course, people worry that they're going to defoliate the oak. But I counted 410 caterpillars on the lower branches of our oak there in the end of July, I think way back in 2014 just walking around the tree, no ladders or anything. And 115 of them were yellow net caterpillars. Then I stood back and took that picture so I could ask you, do you see any of that damage? No, do you see any caterpillars? No, they're there. But if you're you know, if you view the tree from the distance we typically view our trees, you don't even notice it. There's a woman in New Orleans, Tammany Baumgarten, that says we should all practice the 10 step program. Take 10 steps back from your oak and you won't see any damage at all. Your insect problems disappear. The other way that insects take advantage of August oak leaves is to become very specialized leaf miners. They become so small that they can eat the soft material in between, the very tough cuticle, epidermis on the outside. So it's really mining, just like you're mining a seam of coal. These are caterpillars. The egg was laid here. This is called the serpentine leaf mine, and the caterpillar eats along here, the little dark spot is that's grass. That's Caterpillar poops. He pushes it all to the center there. This is where they finished eating and pupated and has already already left. This is called the blotch mine. There's the caterpillar right there. He just goes in a circle. There it is backlit. That's a very nice picture by Salvador vitenza. Now, it doesn't look like a caterpillar because it's very specialized to be really small inside of a leaf, but when they come out as an adult, they do look like moths. This is one of the kamaraia species, solitary oak leaf miner, the gregarious oak leaf miner. Number of species are leaf miners to get around that tough oak leaf situation in August, okay, September. This is our last month. This is when cricket populations peak. By the way, most of the crickets are black. They're on the ground gorillas, pennsylvanica and other species. If they come in your house and sing, it's good luck. So don't kill them. But not all of them are black. Some of them are up in the trees. They're called bush or tree crickets. That's what they look like. And what are they doing? Well, the males are doing the same thing that the cicadas and the katydids are doing. They're trying to attract a female, and they know they've got to be allowed to do it. But these guys are smart. They find a hole in a leaf, and they stick their head through there, raise their wings, move them back and forth. Most leaves have a slight parabolic shape to them, and it projects the sound louder and farther than if he sang on a flat surface. So he's actually sending the female a false message, saying, I'm the biggest male. If you believe a male would send a female a false message. But it might not be that false, because the female does go and mate with him. He may not be the largest male, but it could be the smartest man that could be, that could be good enough. It's also the month that you might find walking sticks. These guys are typically up in the canopy all all summer long, but they start to come down a little bit in the fall. This is the only species we have up here in New York, diaper, Amara fumarata. But as you go further south, particularly into the tropics, there are a lot of species. Interesting relationship between walking sticks and spring ephemerals like blood root. They of course, make make pods, and inside those pods are beautiful seeds that for. About when the pod de hisses, and they've got these little white structures on them called eliasomes. And those structures are there to attract ants. Ants love to eat Elias some. So they come. They pick up the seed, they take it back to the nest. Everybody eats the Elias some. The see'ly hard. They can't eat that, so they throw it in the garbage dump of the ant nest, which is about an inch below the surface of the soil Well, walking stick eggs, the female just walks along the canopy and drops the eggs to the forest floor. They have a white stripe on them, just like an eliasum. And I'll bet there is chemical mimicry here, when I bet they smell like Eliasson, because the ants come pick them up. There's actually nothing for them to eat there. They take them to the nest. They say, oh, there's no real life some here. So they throw them in the garbage dump, and it's a perfect place for the ants, for the walking stick eggs to spend the summer, safe underground until they hatch. All right, we've talked about just a few of the things that are happening on the oaks, in in your yard each each month of the year. So let's talk about some serious things right now. We do have a biodiversity crisis, and we have a biodiversity crisis because we humans are not sharing the Earth. We talk about things disappearing. They're not disappearing. We're killing them. We're killing our birds. We're killing our insects. We're killing the nature that supports us, which means the earth is now heading towards the sixth great extinction event that has ever occurred here. So it's a crisis. It's a crisis because we humans do depend on nature, but it has a grassroots solution, and that's where the home grown National Park we'll talk about in a few minutes, comes in. But there's very easy ways that each one of us can fight this, this biodiversity loss, using oaks, there are four things that every landscape needs to do if we're going to reach a sustainable relationship with with Mother Nature. Every landscape, wherever you are, it has to be happening on your your landscape. Every landscape has to capture carbon to support or to to fight climate change. You know, a third of the climate, of the carbon that's up in the atmosphere right now has come from us chopping down the mostly the trees on this planet. If we put them all back, we'd pull a third at and we'd be in much better shape. So we're not going to put them all back, but we can plant a lot more trees than than we are doing. Every landscape has to manage the watershed within where it lies. Every landscape has to support a diverse community of pollinators, and every landscape has to support a complex food web. If you don't do these things, you don't have a functioning ecosystem. When you plant an oak, you're addressing all four of those, those landscape requirements. You're putting a tree in that, over its lifetime, is going to sequester. Going to sequester more carbon than other trees. It's going to manage the watershed better because it has a bigger root system. It's going to support the most complex food web of any tree that is out there. It even is going to help pollinators, even though oaks are wind pollinated, because the spring bees do go to Oak catkins and they gather up the pollen. Now, they're not pollinating, they're not taking it to the female oak flower, but they're still that's a resource for our spring bees. Despite all those wonderful landscape attributes, our oaks are in trouble for a number of reasons. You know, we used to have the forest were loaded with with giant oaks that supplied lots of ecosystem services, they're mostly gone at this point. When you hear about a big one, it's a special event, because they were in the way of farming, and we use them for lumber. The percentage of oaks in our eastern forest has been cut in half. Over the last century and a half, we've introduced a lot of serious oak pests, like the spongy muff, like oak wilt, like
Doug Tallamy 58:42
bacterial leaf scorch, sudden oak death syndrome. These are all hitting oaks very hard. Deer overabundance is a very serious problem. We'll talk about that in a second. They're preventing oak regeneration, habitat fragmentation. We're separating our oaks so much that the pollen that they need to go from one oak to another to get good pollination isn't reaching other oaks anymore. So they're there. They're living, but they're not making those acorns. And because of all those reasons, 28 over 91 North American oak species are now threatened. 1/3 of global oaks are actually endangered. The Oregon White Oak has lost. Been lost from 97% of its range up and down California and Oregon into Washington, 2300 species that rely on oaks in Great Britain are threatened because of the loss and of oaks in Great Britain. Now we humans live our lives out in just an instant of ecological time, and we can't return those giant oaks to the forest in that time period, but we can start the process, and it won't take that long if we plant oaks, I would say, normally today, but today is not a good day to plant them. But if you plant an oak this year, in just a few years, it will assume just about all the Keystone roles in your yard that. It would eventually play much after faster than you might think. We are all responsible for good Earth stewardship, because we all absolutely depend on it, and the best way to exercise that responsibility, I think, is to embrace the power of oaks. So for the sake of our turkeys, our chickadees, our woodpeckers, our warblers, our jays, our thrushes, our lightning bugs, our fireflies, our galls, our weevils, our arthropterans, our moths, for our own sake, plant an oak. Plant a living community. Plant the future. Thank you very much. But before don't go we have to talk about home grown National Park. If you plant that oak, it is your perfect segue into being a member of home grown National Park, joining the movement of protecting the biodiversity on our own properties. We're real. It's a small nonprofit at this point, but you join for free simply by registering your property on the biodiversity map and recording the amount of area that you're pledging to be a good steward of. Maybe you're going to reduce the area of lawn. Maybe you're going to plant an oak. Whatever you do goes into the database, and then your little piece of your county is going to light up with a firefly. And our goal is to our ultimate goal is to light up the world with fireflies, but we'll start with the US and Canada, and we're off to a good start. But this is, this is a movement you can be in the cutting edge if you go to our website and register today. So I'm going to move into into questions. But a number of questions were submitted to me before I even got here. So I'm going to, without asking you, I'm going to do the first two questions, and then we can open it up for questions. And a lot of them have to do. All right, go ahead.
Doug Tallamy 1:02:06
All right. Thanks. That's enough. Thanks. That's because we have so much to talk about tonight. We have a lot of problems with oak regeneration. They're not doing as well in our forests as they used to do. Why is that? Well, there's a couple of reasons oak seedlings don't do well in very deep shade. They'll germinate and they'll sit there for several years, but if it doesn't open up at some point, they're going to eventually die, and then we've got too many deer eating eating those seedlings as soon as they come up. Pre settlement, oak populations were much larger, primarily because Native Americans, indigenous tribes all over all over the country, were farming oaks for acorns. Acorns were a major food source, and they did it by using fire oaks like more open forests and fire controls the black cherries and the birches and many, many other things. So of course, we don't use fire anymore, and the the forests have have closed in. You've heard that, that when the settlers got here, you could ride through a forest full speed on horseback, no problem at all, because the trees were giant, but they were separated, and that was all really the the Native Americans get, get, get credit for that. They were farming oak trees and chestnuts, and they then largely lived off of those trees. So the chestnuts, of course, were killed by the chestnut blight. And they did open things up for oaks for a while, but now it's, it's it's closed up. When you hear about efforts to to open up our forest level, let a more little bit more light in that is going to favor oak trees. And if you have the chance to do controlled burns, that will favor them as well. But we are going to have to control our deer, because even if you do those other things every and we've got deer populations about 14 times over the carrying capacity of of you know what the environment carrying passing means you can live there without destroying everything else. And that's what the deer are doing. They're eating all the natives that come up. Our invasive species problem is really serious, because the deer don't eat those plants, and they do eat the natives. So our it's it tips the competitive balance against our natives, so part of returning oaks to dominance in our first has got to include deer management. What do you do in the meantime? And this is what I do, got to put a cage around if you don't have a cage, you don't have an oak. I like cages like this more than tree tubes, because it gives the oak it can spread out a little bit. I'm not a fan of tree tubes for a couple of reasons. Okay, another question that I often get is, what about climate change? The climate is warming. Should we be planting plants, in this case, oaks that are adapted to warmer climates up north because. In a few years, it's going to be warm up there too. That's called assisted migration, and it's controversial. I'm not a fan for a couple of reasons. This is one of them. Climate change is not a gradual warming of the planet. It is on average,
Unknown Speaker 1:05:17
but Excuse me,
Doug Tallamy 1:05:21
what really is happening is increased climate variability. So this is the jet stream, and particularly in the wintertime. In the old days, it was pretty well behaved. Above the jet stream, it was pretty cold. Below it, it was more mild. You had wobbles, but they weren't serious wobbles. This is what's happening today. You get these giant wobbles, and when it goes way up here, then it's much warmer up here than it should be. But when it goes down here, it's much colder than it used to be. Last year in Baton Rouge, Louisiana, they got nine inches of snow, and it got down to nine degrees. It killed lots of plants, including natives that have been there for a long time. So if we start moving plants up from the south, this is called a polar vortex, we're getting them more and more more seriously. So that's not going to be good for those plants. You move up. The other reason I don't like it is when you move plants away from the community they co evolve with there, they've lost their the interactions that make a healthy ecosystem. You will be moving them away from the insects that then feed those birds. We did a little little study comparing what was using red oaks in Pennsylvania, where they they belong. Lots of things use them in Pennsylvania, and compared them to red oaks that are planted ornamentally in in Oregon, it's an important yellow ornamental plant out there. Nothing uses them in Oregon. Lots of things use them in Pennsylvania. So it's, it's that's not a north, south movement, but it's a movement away from the community they call evolve with. So that's another reason I don't, I don't support assisted migration. We just have to hope that our, our plant populations have the genetic variability required to adapt to the crazy weather cycles that we're throwing at them. Chris, it would be great to to get climate change under control as well. All right, now I'll really open it up to questions,
Unknown Speaker 1:07:11
because that's all I have. Yes. Thank
Speaker 2 1:07:13
you so much for your talk. So awesome. You're welcome some research on red oak, Pennsylvania, actually, and then you have two tornadoes eastern Pennsylvania, about five zero, and it killed 84% of our roads. Wow. And what was really interesting about this was that each of the Oaks were actually uprooted. So a lot of the other trees, they like the some of the more dominant trees, they snapped, but most of these oaks were just completely uprooted. So I guess my question is, so I looked at like the mortality of the oaks, and that was my project. But do you think that these oaks will still be supporting the same invertebrates tall standing, like a lot
Doug Tallamy 1:07:50
of trees? Yes. So when an oak falls over, when it gets blown over, is it going to support the same invertebrate community on the ground that it did when it was standing? No, but it's going to support an invertebrate community. There are lots of things that depend on rotting logs, and a lot of things that really like oaks, the salad best beetles, for one, Sarah bissed Beetles, Longhorn beetles, the metallic wood boring beetles, carpenter ants. There's a whole giant fauna associated with what we call coarse woody debris. And, of course, oaks break down more slowly than than many other trees. So they do perform lots of services once they're they're on the ground. Was this a wet area? No, not, particularly not, yeah. Well, you know, there's, there's, we're talking about blow downs. You know, plant your oaks densely. Nothing's going to protect it from a real tornado. That's just a tough weather situation. They all went together. Great. I just forget what I said, Yes, in this area, our Ash has been devastated by emerald ash borer. Is there anything like that on the horizon threatening oak? Well, we do have, we do have several oak diseases. Oh yes, the emerald ash borer has really threatened our ashes. And by the way, that story is happier than you might think at this point. But is there anything as devastating threatening oaks? No, not to my knowledge. Now, there are several threats to oaks, those diseases I mentioned, the Gypsy Moth, there's now the spongy moth has been here for over 100 years. Really hitting oak forests hard, hard, but those forests, yes, it kills some, but they spring back. It's not devastating the way the chestnut blight was that essentially took them all out. Every one of those oak diseases that has been studied, and I think they've all been studied, what is showing up is there's resistance in every single oak population. There are susceptible trees and they die. You can put a lot of money into it and get paid the arborist, but it. Going to it's going to die. But there are resistant trees as well. So I got bacterial leaf scorch on my property, and they hit the black oak or the red oak grew pretty hard, and I've lost two black oaks and a red oak, but there's a whole bunch that are just fine. So they were really susceptible. The others are, yeah, they were susceptible. The others are showing some resistance. That's true even with sudden oak death syndrome in the West. So what we have to do is weed out the susceptible genotypes and and the resistant ones are the ones that are going to take over the forest in the future. And the Jays help with that because they weigh the acorns when they pick them up, they only want to take the good ones. So they take the biggest, heaviest acorns and the ones that come from a sick, declining tree. They just shot them aside. So the ones that are being dispersed, they're selecting for the healthiest, resistant trees. So we have to be patient. We're stressing all of our trees with different ways, but we want that resistance to spread, and those will be our future forest. Two more questions. Yes, that's oak wilt. That's that sudden oak disc syndrome. That's bacterial leaf scorch. They all have resistance in the populations.
Speaker 1 1:11:20
Yes, what do you think about shredding leaves into wands instead of leaving them?
Doug Tallamy 1:11:25
There was an interesting I was in, what about shredding leaves? What does that do?
Doug Tallamy 1:11:30
Well, I gave a seminar in Buffalo this fall, and a woman whose name I forget, but who was publishing this spring, had an interesting project with her class. She collected the bags of leaves that people put out to the curb to take away, and they went through the leaves to see what was actually still in those bags. And she's got this big chart of, like, you know, 26 different kinds of insects in the bags. And that was, actually, I just learned today, that was after she had stored them in her garage all winter long. So really, they're probably a lot more than that, if she had looked at it right away. There are lots of things associated with those, those leaves. I walked out my front door about two months ago and I looked up and my my shingle oak branch. Here's a nice Polyphemus moth cocoon hanging there. And I watched it every day. It was great. And then we had a big wind storm, and it looked it was gone. Well, it's down in the leaf litter. If I, if I run the lawnmower over the leaf litter, I'm going to chop that up. I'm going to chop up the Luna moth. I'm going to chop up all the lightning bugs, all the things that are in that leaf litter so and it also doesn't last as long then. So you want your oak leaf litter to last as long as you can. When you chop it up, it shortens its life period a lot. Yes, it looks a little neater, I guess, but it's you've lost ecological function. Okay, that's it. Thank you.
Joshua Ginsberg 1:13:15
So I apologize for the 372 questions that Doug didn't get time to answer. I'd like to thank you all for coming. If you see those little names on the back of the seats, those are all Aldo Leopold members. It is a privilege that you get as a seat reservation. If you want to know more about that corral me or anybody with a label. I also want to just do a pitch for our next talk, which is February 12, on Thursday, February 12, and it's by a local speaker, Laura heedy, who works for the New York State Department of Environmental conservation's Hudson River Estuary Program. But in her spare time, Laura is amphibian nut, and she's going to talk about the remarkable work she does on amphibians in the region, and the title is, I love a rainy night the rhythm of forest amphibians. So please come back, and then we'll have another special event in March, and we'll tell you about that in February, so you'll learn about that first if you're here. Thanks very much. You.
