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Brian Lehrer: Brian Lehrer on WNYC. Now for our August check-in with BLTrees, our year-long project to follow the life of a tree, maybe your tree, through the four seasons, the 12 months, really looking at and learning about the trees around us, what they do for and to us and what we do for and to them. New York City and the surrounding area have millions of trees. We hope you picked yours to follow this year and have been tweeting us a photo each month using the #BLTrees as we've invited you to do. We started this journey with our trees last November, so we're in the homestretch now. We've been talking about how trees fit into the larger ecosystem of the cities and towns in the area.

Today, we're going to look at the ecosystem that is a tree, the tiny living organisms that rely on that tree to sustain them. Get out your magnifying glasses folks and prepare to hear about the connections between the US Constitution, what, and the sexologist Alfred Kinsey of Kinsey Report [unintelligible 00:01:12] what, Darwin too and the movie Alien, what, and the party going on right now on your local tree. Quite a story about to come your way. Back with us is our guide for this adventure, urban ecologist Marielle Anzelone, founder of New York City Wildflower Week who proposed this project and has offered her expertise in putting it together. Hi again, Marielle. Happy August.

Marielle Anzelone: Hi, Brian. Happy August to you.

Brian Lehrer: She's joined by two other guests this month, James Lendemer, a lichenologist at CUNY and the New York Botanical Garden and the co-author with Jessica Allen of Urban Lichens: A Field Guide for Northeastern North America and Miles Zhang, an evolutionary biologist specializing in the study of parasitic wasps with the United States Department of Agriculture. Miles and James, welcome to WNYC.

James Lendemer: Great.

Miles Zhang: Thanks, Brian, for having us.

Brian Lehrer: Listeners, we may have time for a few phone calls for our guests, so if you have a question about lichens or gall wasps or other creatures living in your chosen tree that we have definitely never talked about on this show, call us at 212-433-WNYC, 212-433-9692 or tweet @BrianLehrer. James and Miles, you each study different, I'll say, living things that make their homes on trees. Lichen for James and parasitic wasps, and specifically gall wasps, for Miles. Let's hear more about them. Miles, where would we find gall wasps in New York City, for example, and how would we know one if we saw one?

Miles Zhang: They're mostly found on oaks. I think in New York, you guys have a lot of pin oaks. Try looking on the leaves, the stems. If you find some sort of growth on there like a little ball shape or some kind of almost like a tumor, that's a gall that's made by a gall wasp. They lay their eggs in there and the larva will eat and develop inside the gall and then start emerging and then they will repeat the cycle all over again. They do this twice a year. Just go out there, look for oaks, and you should be able to find them.

Brian Lehrer: If someone has picked an oak tree as the tree they're following around, it sounds like-- following through the year, seems like they're likely to see these wasps flying around. Do they sting?

Miles Zhang: No, no. They're really small, generally about less than 5 millimeters, so they only lay eggs into trees, so they cannot sting you at all, which is why I like studying them, harmless.

Brian Lehrer: Now you have a connection between gall wasps and the United States Constitution. Do I have that right?

Miles Zhang: Yes. I'm actually at the American Museum of Natural History visiting right now. I'm looking at some of the collections here. Gall wasps are probably most well known because back in the days we used to make ink out of them, because there's a lot of tannin in these oak galls. They're concentrated of plant chemicals and we actually used that to distill it into iron gall ink. It was popular. It's actually used to sign the constitution and a lot of the paintings back then were also done partly using this ink.

Brian Lehrer: How about the connection to Alfred Kinsey, best known for studying human sexuality?

Miles Zhang: Before he became a sexologist, he actually was a gall wasp taxonomist. He actually collected around Mexico and across the US. The American Museum actually has the world's largest collections and mostly are his specimens. I think they estimate we have seven million specimens here stored and I'm just trying to go through as many as I can during my visit here. It's a phenomenal collection.

Brian Lehrer: You'll write about it with the ink from gall wasps perhaps. James Lendemer, let me turn to you. I know that lichens are now found on almost all trees in the area and that's considered a good thing, but what are lichens exactly? A lot of listeners, some listeners, might not even recognize the word when I'm saying it, L-I-C-H-E-N, lichen.

James Lendemer: There are these really amazing symbiosis that are formed between fungi and algae. The fungus provides a home for the algae and the algae provide food for the fungus. These two things get together and they don't look like much if they were able to grow on their own. They are not able to grow on their own. They grow together and they form these really beautiful, fabulous structures that are just absolutely beautiful. They're the colorful things that you see all over your trees.

Brian Lehrer: Why are they a good thing?

James Lendemer: For all the reasons. They're the party of the forest. I think one of the folks on your show described them as the influencers, which maybe is a better word, but they're like hubs of the ecosystem. All sorts of plants and animals rely on them. There's little tiny insects and snails that eat them, large animals like reindeer rely on them for some of the diet for the year, just all sorts of things use them. They also provide all sorts of essential services in terms of nutrient cycling, you've probably heard of the nitrogen cycle. They're really involved in that. They act like sponges. They have this really remarkable ability to soak up water really quickly and then release it slowly back into the environment.

They have this way of when they're present in large numbers, really regulating the temperature and the humidity of the forest and just the general area they're in, which makes it much more hospitable for a whole host of plants and animals to survive.

Brian Lehrer: From what I read preparing for this segment, there was a time not that long ago when New York City trees had no lichen. We only have to go as far back as the 1960s for that. Is that accurate?

James Lendemer: Absolutely. Within the lifetimes of many listeners, potentially. It's a relatively recent phenomenon that the lichens have begun to return to New York City and that's because they're really remarkable bioindicators, which means they're really sensitive to pollution and to disturbance, especially the kinds that humans tend to generate. The air pollution that coincided with the 1960s ultimately and led to the creation of the Clean Air Act, that really did a number on the lichens. We know there used to be hundreds of species here growing in the city several hundred years ago, but by the 1960s, there were almost none present anywhere in New York City.

Brian Lehrer: Listeners, we can take a few phone calls if you want to ask a question about the ecosystem within a tree, other living things that coexist with or feed off a tree, the ecosystem of a tree, meaning not just the tree itself, 212-433-WNYC, 212-433-9692 on this August edition of our year-long BLTree series. Marielle Anzelone, let me ask you to take a step back and just put these two examples that we've been talking about, gall wasps and lichen, in even a larger perspective of maybe the number of things or the variety of things that live on or within a tree.

Marielle Anzelone: Well, I think it's so important to think about trees. Trees are not alone. They're not living by themselves. In nature, trees are never alone. Trees always grow in a forest or some kind of other plant community. We often will look at trees and think of them as individuals, but in fact, you can also think about them as a place where lots of other plants and animals live. Smaller plants live on trees and those kinds of things are called epiphytes. The lichens would be a kind of epiphyte and then you also have things like liverworts and mosses, which are both plants. They grow on trees as well.

You can get really small insects that live on trees. Springtails is one kind of insect, lace bugs is another kind. You can see insect activity on trees, so little burrowing tunnels from wood borer beetles. There's a lot to look at on the tree. It's a really fun thing to just take a magnifying glass like you mentioned and take a look. It's important to say that the [inaudible 00:09:57] things, especially the lichen and the wasps are not hurting the tree at all.

No one should be trying to take lichen off the bark of the tree or moss off a tree. The galls are typically not hurting trees, but these are things that they've evolved with over time and the epiphytes growing on the bark are just hanging out there. They're not hurting the trees at all.

Brian Lehrer: Don't bring your power washer out to your tree, get all the lichen off and think you're doing it a favor. Miles, we made the connections between the gall wasps and the United States constitution and Alfred Kinsey. There are two more crazy sounding ones at first blush to get to. One is Charles Darwin and the other is the Alien movies. You want to do Alien first?

Miles Zhang: Sure. When I tell people I study parasitic moss and that's commonly what I talk about, that the movie Aliens, the Xenomorphs where they lay eggs into other creatures, humans in this case, and then they burst out of their chest, that's basically what parasitoid wasps are doing. In fact, they actually took the inspiration from the parasitic wasps and made that for humans and it's terrifying to us, but it's actually happening to insects on a daily basis.

Brian Lehrer: When they aren't preying on cute caterpillars, they are playing a key role in keeping things in balance, it sounds like.

Miles Zhang: Yes, we actually use them a lot for bio control as well, instead of spraying pesticides.

Brian Lehrer: That's great. That's good to know. Parasitic wasps had something to do with Charles Darwin being a heretic?

Miles Zhang: Yes, he had a famous [unintelligible 00:11:46] where he basically saw how the the wasps take over the caterpillar and then eat them alive from the inside and he said because of this, he has trouble believing in God because no benevolent God will create a creature like this.

Brian Lehrer: There you go. Therefore evolution was not from God, but that's probably another show. Barbara in the Hudson Valley, you're on WNYC. Hi, Barbara.

Barbara: Hi, we have white oaks in our yard and at the base of one of the trees, maybe a few weeks ago, we noticed there's this little-- it looks like white goo, white spit and all the little bees and ants come and are eating it or something. We were trying to figure out if it's something that's wrong with the tree or if it's something to do with an insect.

Brian Lehrer: Marielle, you want to take this or who's best for this?

James Lendemer: I could do that.

Marielle Anzelone: Go ahead.

James Lendemer: I would suspect that that's probably a slime mold or some other fungus and it may not be hurting the tree, especially if it arose quite so quickly and it's obviously providing an important food source for the things there in your yard. More generally speaking, a lot of people ask whether the things that they see on their trees are hurting the trees if they're lichens because they see fungi that are normally things that would decompose wood or infect unhealthy tree. Generally, these things that grow really quickly over a period of a few days or a few weeks would be wood rotting fungi or slime molds or something. They may or may not be hurting your treat, but they are not lichens.

Brian Lehrer: Thanks, Barbara. Lindy in Suffolk County, you're on WNYC. Hi, Lindy.

Lindy: Hi. I just wondered first of all, how is it going to impact the tree population of the spotted lanternfly and also just a quick second one, will we ever see the American chestnut come back and be prolific as it once was?

Brian Lehrer: Thank you. Miles, is that for you because she's asking about an insect?

Miles Zhang: The spotted Lanternflies, unfortunately, it's an invasive species from Asia for those of you that don't know and it's been spotted across the East Coast from New York all the way even down to where I live in D.C. now. Unfortunately, not much is what we can do about it at the moment. There are research going on about trying to find its natural enemy back in Asia and then bring them to North America. We can release them and then hopefully reduce their population. It's probably impossible to wipe them out at this level because they're already established here.

Brian Lehrer: Now, James, I'm intrigued that you and your co-author wrote a field guide to urban lichens just for this area. There are enough different urban lichens just in the New York Metro area to fill a book?

James Lendemer: Easily, yes, more than that. We had to be selective. [laughs]

Brian Lehrer: Amazing. Let me ask you this. No, I will take this call. Peter in Bayonne has another spotted Lanternfly question. Peter, we have 20 seconds for you. No, Peter hung up, so we won't take that one. I think we're going to talk more about spotted Lanternflies in their own segment on the show tomorrow. Marielle, let me wrap it up by asking, how is your tree doing this month? Listeners if you don't know this BLTree series, we've invited you each to pick out a tree and follow it for a year. How is your tree doing this month? It's been pretty brutal for humans lately.

Marielle Anzelone: It has. It's been so hot as you know and so we are currently in your listening area, Brian, we're in a drought. My tree is doing pretty well. It's weathering the drought because it's an old mature tree. It's well established, but I'm noting that the leaves on it are flagging which means they're droopy. Also, some of the tips of the leaves are browning and I did see some brown leaves on the ground, which means it's drought stressed and probably every tree in the listening area is drought stressed.

I would encourage your listeners to please water the trees you love. If you're able to, you can get a bucket or get a hose and have the water levels be slow and low so you're not scouring the soil, but you're going to take a bucket and slowly water the tree or let it run on low at the foot of the tree for 15 minutes maybe, at least once a week. It'll keep the tree healthy and help get them through the hot summer temperatures.

Brian Lehrer: That is such good advice that a lot of people probably never thought about, to water your tree. Marielle Anzelone, urban botanist and ecologist, founder of New York City Wildflower Week. James Lendemer, lichenologist at CUNY and the New York Botanical Garden and co-author of Urban Lichens: A Field Guide for Northeastern North America, and Miles Zhang, evolutionary biologist specializing in the study of parasitic wasps with the USDA. Miles, we'll let you get back to Kinsey's collection now and thank you all for a wonderful segment.

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