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Brian Lehrer: Brian Lehrer on WNYC now for our February check-in with our chosen trees. It's month four in our year-long month-to-month project to follow the life of a tree. Any tree you have chosen or can still choose through the four seasons 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 alone has at least a million trees.

Did you hear the news from yesterday the five Borough presidents are asking Mayor Adams to commit to planting another million during his administration? Here's Manhattan Borough President, Mark Levine.

Mark Levine: Your Borough presidents are bringing you a giant bouquet of trees.

Brian Lehrer: A giant bouquet of trees if it comes to pass. Now for your individual tree, we hope you've picked the one that you want to follow and maybe even tweeted us a photo using the hashtag BL trees. I tweeted out my February photo this morning of a tree in my neighborhood that looks so glorious in the snow on Sunday morning. Today we're going to talk about groups of trees and whether every wooded area constitutes a forest. Back with us is our guide for this adventure in urban ecology. It's Marielle Anzelone founder of New York City Wildflower Week, who proposed this project and has offered her expertise in putting it together and coming on once a month for a year. Hi again, Marielle.

Marielle Anzelone: Hi, Brian. Good morning.

Brian Lehrer: Today she's joined by Myla Aronson, a professor in the ecology of illusion and Natural Resources Department at Rutgers, director of the Hutchison Memorial Forest, which is one of the last remaining old-growth forests in New Jersey, and co-director of the Urban Biodiversity Research Coordination Network, or UrBioNet. Welcome to you, Myla. Thanks so much for coming on.

Myla Aronson: Thank you, Brian. Thanks for having me.

Brian Lehrer: Marielle, to reset for people who are new to this, we've invited folks to pick a tree one outside your window in your backyard, elsewhere in your neighborhood, just a tree that catches your attention as you make your way through the park, or the neighborhood and get to know it, and remind us what then.

Marielle Anzelone: Then we want you to share it with us on Twitter using the #BLTrees. We have a really wonderful robust community of tree lovers who're talking about their trees, and when something unusual happens, they'll share it. We're getting a lot of reports that are more than once a month, which is really fun.

Brian Lehrer: I've just asked you real quick about the tree that I posted a photo of this morning with like so many trees in our area, had a layer of snow on the tops of the branches on Sunday morning. Then by later in the day, it was gone. It was absolutely gorgeous. The whole little scene outside my window, even here in Manhattan was gorgeous with the snow on branches. What does snow do to trees anything?

Marielle Anzelone: Yes. Well, the snow was so beautiful and I feel like that's one of the fun things in winter with a deciduous tree, which I know you have your calorie pair that it really highlights the architecture of the tree. You can see so clearly what it looks like with new leaves. The snow overall, in winter, the trees are hardened off so they're like really prepared for the cold and snow on the tree itself I know in the ground underneath trees, it provides a warm layer.

It can be a layer of insulation on the forest floor and [unintelligible 00:03:56] wildlife that's active in winter to be warm underneath that layer of snow. We do the same thing for plants and tree roots. On the tree, I think ice and cold and snow are things that our winter deciduous trees are used to.

Brian Lehrer: Myla, let me bring you into the conversation, and just for people who don't know this part of New Jersey since you're director of the Hutchison Memorial Forest one of the last remaining old-growth forest in New Jersey, where is it and if I were to go there right now, what would I see?

Myla Aronson: The Hutchison Memorial Forest as you said, is an old-growth forest in Somerset County, New Jersey. It's in Franklin Township so it's right in the middle of Central New Jersey. It's never been cut. It was owned by the same Dutch family that settled the land in the early 1700s until it was transferred over to Rutgers where Rutgers has been doing so studies on forest ecology and succession or how forests change over time, since the 1940s.

If you were to go there now we'd see a lot of snow on the ground. We have oaks and hickories, and maples, so deciduous trees, and we might see tracks of coyotes and foxes and turkeys. We have a large wild turkey population, very large trees and it's a beautiful place to go any time of the year.

Brian Lehrer: We know the old saying you can't see the forest for the trees. Well, from what I understand there's an important distinction between a bunch of trees in one place and a forest. What is it?

Myla Aronson: A forest is really an interacting patch of habitat. It's including lots of different tree species or other plant species, shrubs, vines, wildflowers. The forest trees interact with each other as well as with the insects, such as caterpillars that eat our leaves. They particularly love our oak trees, which then of course they become important future pollinators, and their food for supporting incredible diversity of birds especially New York City supports incredible diversity birds. Below ground and forest, we have full critters and fungal networks and that's incredibly important for the benefits the trees, as well as those interactions, are important for driving the benefits of soil provides like water retention, which reduces flooding in our cities and storing carbon.

Brian Lehrer: Listeners tweet your tree pictures now or anytime as this project goes on through next fall, tweeted with the hashtag BLTrees BL for Brian Lehrer BL trees, tweet your tree photos, and we can take some phone calls for our guests. Do you have a question about the urban forests or about your chosen tree? Call us at 212-433-WNYC 212-433-9692. We'll go to some calls in just a minute. Marielle I mentioned the snow but also this week, we're seeing temperatures cycle from 20 degrees to 60 degrees and back again. How to trees handle the swings in a month like February?

Marielle Anzelone: That's a great question. Well, the trees don't like it. Trees that live especially wild trees, over the time, but they have adapted to living in the mid-Atlantic states, you know where we are they are used to cold in winter and they know what to expect. These wild fluctuations in temperature are throwing them off. Trees and plants are able to assess seasonality through what's called a photoperiod. It's a measure of darkness, the amount of darkness.

That's the main marker for how they know spring is approaching. Temperature is another cue, it's a secondary cue but it can be a very strong cue for some plants. With these warmer temperatures, plants are being tricked into thinking that it's warmer out. In some cases might be breaking buds thinking that it's safe to open up and release the flowers, the little baby flowers, and little baby leaves that'll be coming out from the buds. If that happens, and then there's a freeze again, then that kills off the leaf and the flower. That'll prevent both of those from being around this growing season.

Brian Lehrer: Is it unusual to have these swings in the winter or do we get this usually at some point as winter is going on, and most of the trees can power through and the bugs in the leaves and the flowers grow as usual in this way?

Marielle Anzelone: Yes, that's right. We do have and have had in the past. I think this past winter has made me pretty sad. It's not been we haven't had like long, sustained periods of cold and the plants that live in our region really need that for lots of things to break open the seeds if they have six seed coats, in order to be ready to germinate in the spring and trees have a different some of the tree's seeds might have to go through that as well.

The cold is just something that they're used to and having it be especially warm, it might reduce the number of flowers. Maybe you know 15% You and I would not see that. Just looking at it with our eyeballs. If someone were to measure, I'm sure that there could be measures that would show that there's a decrease in productivity of tree biomass via flowers and leaves.

Brian Lehrer: That's really interesting.

Myla Aronson: It definitely-

Brian Lehrer: Go ahead. Myla.

Myla Aronson: Definitely stresses the trees out to start to flower and then freeze again and start to flower and freeze again. Sometimes they may flower completely, but before the insects come out to pollinate them, so you would see reduced seeds set or less seeds being produced by the trees because the insects aren't ready the same time that the flowers are. That's a real concern with climate change is that we will start to see these shifts in, or these mismatches in the timing of the flowering or the leaves coming out and the insects coming out, or the birds even migrating up here.

Brian Lehrer: As we continue with Marielle Anzelone founder of New York city wildflower week, who proposed this month-to-month tree observation project that we're doing on the show, and Myla Aronson professor in the Ecology Evolution and Natural Resources department at Rutgers and director of the Hutcheson Memorial Forest. We're getting a couple of good Hutcheson Memorial Forest questions coming in. So let's take one of those. Nat, in Central Jersey you're on WNYC. Hi, Nat.

Nat: Hi Brian. Thank you so much for taking my call. I had a question specifically for Myla.

Myla Aronson: Hi.

Nat: The Hutcheson Forest was my backyard for about 35 years and I lived on [unintelligible 00:11:21] Road. When people would ask me about the forest, which I believe is a total of 185 acres, I would tell them that the oldest part of the forest, which was about 55 acres was the only Virgin hardwood forest on the east coast. I was never sure that I was speaking the truth when I was saying that. Is it the oldest hardwood forest on the east coast?

Myla Aronson: No, it's one of them, there are a few others. There's a few in New York City as well as there're scattered. They're very small, as you said it's about 65 acres of the old-growth in the Hutcheson Memorial Forest or otherwise known as Mettler's Woods, which is named after the original family, but there are pieces of old-growth forest. The definition of old-growth changes too. It's based on how old it is, but the important part of old-growth forests, in particular, is that they haven't been under agriculture or developed.

They have old trees as well as all of these interactions that are occurring above ground and below ground and the soil's never been disturbed. They're really valuable in terms of supporting biodiversity in both above-ground and below ground in the soil.

Brian Lehrer: Nat, thank you for your call. I think you might have just answered Elmo and Bergen county's question, but let's see Elmo, hi you're on WNYC.

Elmo: I'm so excited to talk to you. I listen to you every day. I have a question. We live on the retreat route from Alpine to Hackensack New Jersey. On our particular property, we have a lot of Oak trees and actually Chestnut trees and Walnut trees that have been there for a long time. I go down the street, how old is old growth in Bergen County or in Northern New Jersey? Would it be 200 years old and what is the caliber of the tree that would consider making it an old-growth tree?

Brian Lehrer: Myla, you want to take that?

Myla Aronson: Yes, that's a great question. Many people describe old-growth as maybe over 200 years old and there's different definitions. In some cases, if you're really strict about it you would say, well, an old-growth has to never have been cut before, but honestly, most of our forests across the Eastern United States have been cut over several times. I would say a forest that is maybe over 200-years-old, but we also have to remember that there was a lot of management before European colonization. In particular, the [unintelligible 00:14:09] used to use fire as a management tool to enhance the Oak growing and other species.

Brian Lehrer: Elmo, the thank you. We're going to move on and get some other questions in. We really appreciate it and thanks for listening. We coincidentally got a press release from the natural resources defense council and 70 other organizations today calling on President Biden to let older trees grow that that's more effective against climate change than new plantings they say. Is this a distinction you're familiar with Myla?

Myla Aronson: I say a little bit, but I would argue that we need both. We need to let older trees grow, but we also need to plant new trees. In particular in our region, in New Jersey in New York, we have a really big problem with trees regenerating or the baby trees so the seedlings and the saplings, the baby and the teenage trees coming up because we have heavy deer pressure, as well as other invasive plant species that are out competing. We do need to plant, we need to do both within our existing forest.

We need to let them grow, but we also need to plant new trees so that we can ensure the future of our forest. We also need to understand that small forests are very important, so we don't want to cut those down and replace them. We want to enhance them by conserving and restoring our forest.

Brian Lehrer: Yes. Marielle, I even heard a commercial for a credit card the other day that was like, you can have a carbon-neutral life through this credit card because every time you make a purchase with this credit card, we're going to plant a tree. I thought, well, but what if you're buying SUVs and stuff like that? I don't know if you've heard about that one, but the connection to the last question is that it appears to rely on new trees, but I thought the whole concept was weird.

Marielle Anzelone: Yes. I'd say they did a good job greenwash a little bit there. Also just thinking about planting trees and the even the million trees that the borough presidents are talking about, all of that trees. At the same time just like Myla said it's so critical to keep the trees that we have and the forest that we and maintain them and manage them well. We need funding to do that and even the idea of planting a million trees, let's also take care of the trees that are existing.

In the time of the first million trees there were forests in New York City that were cut down and developed that were on parcels that were owned by the city, but they were planting a million trees and people thought that was exciting, but then other trees were being cut down. It's important to value both.

Brian Lehrer: Kevin in Flushing you're on WNYC. Hi, Kevin.

Kevin: Good morning and I have a question about vines on trees because every time I see a vine climbing up a tree, I think is going to kill the tree. The question I have is if you cut the vine off at the base will that eliminate the vine or does it live off the tree?

Brian Lehrer: Do you know Marielle?

Marielle Anzelone: Yes. Well, it depends on the vine, which is probably what no one wants to hear. Like Myla's really familiar with all the lovely native grapevines that grow in our forested areas in New York and New Jersey. You don't ever want to cut them down. They're awesome and they're part of the forest. They're part of the forest, they're part of the forest ecology and the trees know that they're there and are used to them, but there are other invasive vines like Oriental bittersweet that grow in such a way that they wrap around and almost strangle the trees that they're on.

English Ivy grows on a lot of trees [inaudible 00:18:17] that we see more commonly in like long and English Ivy is not my favorite plant, but if it's growing on a street tree or a long tree that's not the worst thing either. I don't think it's necessary. I think there's a problem with too much management of trees and people thinking of them as needing to be tidy and have no fines and things growing on them. To me messy is more of a forest and that's a good thing.

Brian Lehrer: Oh, that's really interesting. In our last minute or so Myla, I mentioned at the beginning, New York city's five borough presidents all got together, including the sole Republican, among them from State Island [unintelligible 00:18:56] to urge mayor Adams to launch a million more trees project to place new and replace some of the trees that have been lost since mayor Bloomberg's million trees initiative and to pay particular attention to equity and to neighborhoods lacking trees, which of course tend to be low income and those housing more New Yorkers of color.

I'm sure you think it's a good idea. I'm curious what advice you would give them as they work toward replanting trees. What kinds of trees make the most sense as street trees? If you want to start tomorrow's old-growth trees stand in our last 30 seconds or so, where would start?

Myla Aronson: I think it's a great initiative. I think that we know there's lots of benefits that trees provide, but I think what's more important for human health and biodiversity in the city are natural areas. I would recommend and New York City has an incredible parks department and they do a very good job on restoration of trees and planting trees, but we really need to think about more parks and more natural areas in our parks. Because that's the nature just as professor Cal discuss in January, that's the nature that mental and physiological health. We'll see our mental and physiological health.

Brian Lehrer: [unintelligible 00:20:16] We thank Marielle Anzelone an urban botanist and ecologist and founder of New York city wildflower week and Rutgers University, urban ecologist, Myla Aronson. Folks pick out a tree in your neighborhood if you haven't done it yet and tweet the photo with the #BAtrees. Thanks both of you very much.

Myla Aronson: Thank you.

Marielle Anzelone: Thank you, Brian.

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