MR. KOJO NNAMDIFrom WAMU 88.5 at American University in Washington, welcome to "The Kojo Nnamdi Show," connecting your neighborhood with the world. Later in the broadcast, we'll talk with one of the archeologists excavating slave quarters on a plantation near eastern Maryland, a plantation on which Frederick Douglass was once a slave. But first, it's been a long, cold winter. Now, at last, we're seeing hints of spring. The cherry blossoms are blooming, and a few hardy daffodils are up. And most of us are itching to put away our heavy coats and get outside.

MR. KOJO NNAMDISpring is the season in Washington for living life outdoors. There are endless possibilities in our area. Head to one of the many public parks and plazas where the outdoor fountains are soon going to flow, and the farmers markets will be setting up shop. You might have a coffee at one of the many sidewalk cafes that are now staples of both the city and the suburbs, or you just might be motivated to clean off your patio furniture and park a chair right on your own front porch. The options are many, and joining us to discuss them is Roger Lewis. He's an architect, professor emeritus at the University of Maryland's School of Architecture and author of the "Shaping the City" column in The Washington Post. Roger, good to see you again.

PROF. ROGER K. LEWISNice to see you, despite today's wintry weather.

NNAMDIYes. It's hard to figure out that spring is here, but we're hoping for better. April is National Landscape Architecture Month. That's appropriate, especially in an area as full of greenery as ours. We're all busy rushing to and from jobs, doctors' appointments, picking up the kids, but there are benefits, psychological stress reducing benefits, to enjoy how beautiful spring is in our area, aren't there?

LEWISAbsolutely. The wonderful thing about Washington, and it's quite unique in many respects, but we can easily forget over the course of winter months when the trees are leafless, that, in fact, it's one of the most intensely vegetated cities in the United States.

NNAMDIYes.

LEWISAnd that vegetation does all kinds of things for us, I mean -- especially when it foliates in the spring. Giving us shade, it cools the environment in the summer. The vegetation absorbs carbon dioxide and emits oxygen. Not many downsides other than pollen and hay fever.

NNAMDIYou make an interesting statement that I heard -- overheard earlier. This is a four-season town, unlike a lot of other towns.

LEWISYes. The -- one of the things that brought me and my wife to Washington was -- from Boston, where it's either very cold for six months, or it gets pretty steamy, or my hometown of Houston, where it's -- there's two seasons, hot and hotter, high humidity and all. What -- I love Washington's four seasons. They're about the same length. They're each about three months, as they, well, should be. And whereas -- a lot of cities actually, there are long winters and long summers bracketed by relatively short springs and falls. And Washington, on the other hand, I think, has a wonderful balance between each of these four seasons, and they're each very distinct from a vegetation point of view.

NNAMDIAnd that's because we have so much of it. For a lot of people, this is the best season for getting outside. If you'd like to call us, where do you like to spend time outdoors in the spring, 800-433-8850, or go to our website, kojoshow.org. Send us a tweet, @kojoshow, or e-mail to kojo@wamu.org. It's not hot or humid yet. Of course, we're in the midst of the cherry blossom festival right now, although some of the trees, Roger, seem to think that it's still winter, and I can't say that I blame them, because they haven't bloomed completely yet.

LEWISWell, one of the things that, again, is wonderful about Washington is the variety of ornamental vegetation, shrubs and trees. So what -- if you really pay attention -- if one pays attention, one sees some early bloomers, like Forsythia, the yellow -- the intensely yellow shrubs that pop out pretty early, a whole variety of cherries. I mean, I'm not a horticulturist. I'm not an expert on this, but I have paid attention, in part thanks to my wife who's really into this.

LEWISI think the wonderful thing about spring is you do get various colors and blossoms throughout the -- particularly the months of April and May, and even into June. And, of course, later on, the annuals start coming up. The bulbs are popping. It's really a delight, and the Park Service helps. They go and plant all the flowers that we see also in -- on the federal land around the...

NNAMDIAnd it seems as though outdoor spaces for sitting and strolling are really in vogue right now. Most restaurants now have sidewalk tables. I used to joke a few years ago, but now it's real, that if I ever went broke in Washington, I was going to put a few tables on the sidewalk in front of my home, and I could guarantee that within minutes, people would be sitting at those tables, not even knowing what I was serving from inside.

LEWISWell, I remember when I came here in '67-'68, you hardly could find a sidewalk cafe.

NNAMDIThat's correct.

LEWISFirst of all, there weren't that many great eateries, but it was a rare occurrence. I believe there were even some regulatory constraints that prohibited restaurants and cafes and bistros from occupying and using the sidewalk. Fortunately, that has changed, and I would say now we're not quite rivaling Paris or Prague. On the other hand, we're moving in that direction because today in Washington D.C. and also in many of the suburban -- urbanized or suburbanized areas of this metropolitan area, you will see in the next few weeks, a tremendous amount of outdoor eating and drinking and having a good time. I think that's a really wonderful thing because not all of us have patios or terraces or backyards in which to dwell during the months when you could do that. And fortunately, the public realm is now accommodating it.

NNAMDIHave you been noticing a new trend for restaurants having large garage doors that open in the spring, summer, fall and that makes the space indoor-outdoor at the same time? There have been a few places we've been noticing that.

LEWISYes. And that -- you know, the building industry has actually, in addition to the garage doors, the rollup kind or the tilt up kind there. You can also get all kinds of accordion or sliding doors. I'm sounding like an architect now, aren't I?

NNAMDIMm-hmm.

LEWISYou can -- the whole notion is to sort of make the wall disappear, to bring the street and the sidewalk into the interior space and conversely to take the interior space out and seize the sidewalk. Yes, that -- I think that's a very, very popular, and I don't want to say trendy, but it is a trend.

NNAMDISpeaking of trendy, but before I get there, do you have outdoor spaces, home -- Roger mentioned our porches and our patios or maybe you have a balcony, do you use it in good weather, or do you forget about it until it gets too hot and buggy? Call us, 800-433-8850. Roger, places like Silver Spring, Columbia Heights have created plazas and pedestrian areas that make it really pleasant to walk around.

LEWISThat's right. I mean, that's -- the other thing that I always like to remind people, to walk -- I mean, this is the season to walk. I actually think what's happening because of these changes to our city over the last several decades, that once the weather is good and pleasant, people will actually walk a quarter of a mile, a half mile or a mile. It takes 20 minutes to walk a mile. People will do that now, and I think people are probably going to get out their bicycles, dust off their tennis rackets and golf clubs and go outdoors, and I think that's all to the better. We certainly need the exercise.

NNAMDIA lot of farmers markets are going to be opening up around town pretty soon. We got an e-mail from Richard in D.C. "A favorite place to head for a walk during each of the seasons is Roosevelt Island across from the Kennedy Center. I get a sandwich at the Tivoli deli and then head over for lunch and a walk around the island." We've talked about Roosevelt Island before.

LEWISWell, it points out something -- again, Washington has this incredible inventory of place -- parks, open space, plazas. I mean , you can find, without having to go too far, I would venture to say, a place to be outside that is really what you're looking for. It can -- it might be a playground if you've got kids where there's stuff to -- for the kids to play on. School sites, public parks, squares. I mean, it's a -- we could spend an hour just listing all the destinations for outdoor living, other than your own backyard or your balcony or terrace, it's -- no, this is -- there's a wealth of opportunity here.

NNAMDIWe won't necessarily list them, but let's talk about a few of them. There are a lot of beautiful parks, gardens in D.C., including some hidden gems. What are some of your favorite spots? I think I can guess one of them that I've heard about, Dumbarton Oaks.

LEWISWell, that's, of course -- that's in Georgetown, for those of you who haven't been there, you should put it on your list right away. The gardens at Dumbarton Oaks are really extraordinary. They are -- it's a hillside. There's a series of different landscaped rooms. We architects and landscape architects talk about outdoor spaces just like we talk about indoor spaces and buildings, and one of the things about Dumbarton Oaks Park is that it's a fabulous hillside with these various -- let's call them spaces or rooms of different styles, different vegetation. It's really one of the most beautiful such parks in Washington and one of the best in the United States.

NNAMDIIt includes the Pre-Columbian Pavilion designed by Philip Johnson. Can you describe that pavilion and how it fits into the gardens around it?

LEWISWell, the pavilion is actually is sitting up near the streets that abut it, which are -- the street running parallel to Wisconsin. I can't remember which one that is, but it's right off of our street, Reservoir.

NNAMDII know exactly what you're talking about.

LEWISAnd there's also a cemetery nearby. There's -- and there's -- I should mention that this landscape of Dumbarton Oaks anchored at the west end by the Philip Johnson Pavilion then cascades down to Rock Creek Parkway so the -- on the east side, let's say you have Rock Creek and the parkway. And the Philip Johnson building is a series of cylindrical volumes which are enveloped by glass, little domes over each of these cylinders, one of his better works. Of course, his better works, in my opinion, were the earlier works, and this is one of his earlier works. It's certainly worth seeing. I think Dumbarton Oaks, I believe, is own by Harvard University, the last time I looked, and it's open to the public, and it's well worth a visit.

NNAMDIGot an open-air fountain area at the center, right?

LEWISIt's been a long time since I've been in there, but, yes, there's -- basically, the cylinders, I think, encompass a courtyard, but it's at the edge of the garden. It's really at the top, very top of the garden. There's also a vintage house there. There's a historic house, the original Dumbarton Oaks house, which is separate from the Philip Johnson Pavilion. It's worth a visit as well.

NNAMDIHere is Mark in Washington, D.C. Mark, you're on the air. Go ahead, please.

MARKHi. How are you?

NNAMDIWell.

MARKThanks for taking my call. You know, I was listening to the initial comments, Kojo, when your show came on. I'm with Casey Trees, and I just wanted to pull a little bit of statistics in. The District has 35 percent tree canopy, and the District Department of the Environment, Mayor Fenty, and the current administration has a goal to increase that to 40 percent by the year 2025. And so that necessitates planting about 8,600 trees per year and Casey Trees has been working real hard, along with many of our partners, public and private, to try to attain that goal.

MARKAnd, you know, it's interesting we talk about how green the District is. It's not something that we need to -- we should take for granted because that green canopy can go away pretty quickly. About 200 and some odd special trees, or trees over 18 inches in diameter or 55 inches in circumference have been removed this past year alone, and we’re concerned about the replacements of those trees. So I just wanted to put some statistics to the beauty talk that we are all speaking about there on the show.

NNAMDIYeah, and it's my understanding that with the rise in the number of deer in the Washington areas like Rock Creek Park and others are, to some extent, threatened, aren't they?

MARKWell, yeah. I mean, if you look at a forested area like Rock Creek Park or other forested areas throughout the District, what you'll find is basically a one-tier forest, which means you've got an overstory with very little understory. And the reason for that is that the deer is such a voracious herbivore, that they will each pretty much anything. They're very opportunistic. They prefer certain vegetation, but when they're hungry, they'll pretty much eat anything.

MARKAnd that includes, of course, as you probably know, your gardens and everything else. So what happens is, when you have that type of herbivory, you have forests that are -- you know, they look pretty from the outside, but as you really start to delve into them, what you find is that the understory of the trees, the small trees that will take their place when they fall down, are absent or very few.

NNAMDIRoger.

MR. ROGER LEWISLet me talk about deer and wildlife in general. Thanks for the call because Casey Trees is doing the Lord's work, in my opinion. I think -- I know this deer -- we have deer who live -- who own our property.

NNAMDII know.

LEWISI -- and I can't tell you how many times a month we find them spending the night just behind our house because there happens to be a little stand of woods. It's not very big. They walk around like they own the property. I'm mentioning in a column I'm writing that when I grew up in Texas, you were lucky to get within two or 300 yards of a deer. I could go out and pet them in my house. I think the deer population are just one small part of the ecosystem.

LEWISOne of the things about Washington that, again, again, it makes it unique in addition to all the vegetation is it's a metropolitan area laced by this network of stream valley parks and river -- stream valley -- excuse me, stream valleys and rivers that create pathways for migration and movement of animals. So -- in fact, there's a whole ecosystem in this metropolitan area that, again, you're not gonna find in New York City. I'm -- I've often wondered, you know, you never see a dead squirrel or a dead mole except in the street.

NNAMDIThat's right.

LEWISYou don't find them in the woods because there are all these predators and scavengers. You know, you -- where are all the squirrels, right?

NNAMDIThat's true.

LEWISSo what you discover when you think it through is that there really is an entire wildlife ecosystem mapped into our human system, if you will. And it's unique to Washington, and it's enabled by this network of valleys -- stream valleys and rivers.

NNAMDIMark, thank you very much for your call. We've got to take a short break. If you have called, stay on the line. The number is 800-433-8850. Do you have outdoor space at home, porch, patio, balcony? Do you use it in good weather? Or do you forget until it gets too hot and buggy? We got an email from Jennifer who says, "I started a progressive balcony party with a different icy cold beverage and appetizer every spring on the balconies of Tiber Island in Southwest. Good times, great views."

NNAMDITiber Island, in case you didn't know, it is a housing complex near the Waterfront in Southwest Washington. As I said, we're gonna take a short break, but you can still call us. I'm Kojo Nnamdi.

NNAMDIWelcome back. We're talking with Roger Lewis, architect, professor emeritus at the University of Maryland's School of Architecture and author of the "Shaping the City" column of The Washington Post, about spring, outdoors and how its look changes during the course of the spring, either because we haven't been noticing it that much during the winter, or because changes are actually occurring. Roger, what about at home? A lot of people do have some outdoor space at home, whether it's a backyard patio or front porch, balcony in their apartment, and this is the time to make use of it. But in many cases, we don't use these as much as we should. What would you recommend people do to make their outdoor space more inviting?

LEWISWell, of course, some people have invested a great deal in improving or enriching their outdoor space. And there are two kinds of outdoor space. You can have space that's on the ground, or you can have space that's on the structure, that's on a deck or a rooftop or balcony. I will say right from the get-go that one of the problems that a lot of balconies projecting from apartments is they're too small to do much of anything. That's a problem and I -- unfortunately, an awful lot of balconies that you see in Washington or around the country are just not used or they're -- you know, they store -- you'll see people storing their snow tires or putting things there.

NNAMDIThat's true.

LEWISAnd I -- in fact, once I -- years ago, I designed a project in Florida, and one of my -- it's a pet peeve of mine, undersizing balconies. So we built some very large balconies, terraces. I mean, they're really rooms that you can inhabit. I mean, I think that part of it has to do with a number of factors, whether you can use and enjoy outdoor space. Begin with orientation. I mean, if you're -- if you have an outdoor space on the north side of a building, it's gonna have very different microclimate than a space that's facing the south, against the sun.

LEWISThe vegetation would be different. My -- generally, what I've always advised my clients is that the ideal space, if you're living in a city, is one where there's a combination of hardscape, where you can put table and chairs and a cooker, and then some soft space, where you have trees and flowers and vegetation. And if it's well-composed, it's going to be used. It's also important to be able to get there easily. One of the problems with some outdoor space is particularly, again, in urban settings, is that the accessibility, getting there may require going down a full story of stairs or some awkward relationship. That can be a problem.

NNAMDIAnd this is the best season, isn't it, before the mosquitoes and the heat make it uncomfortable to be outside?

LEWISYes, although I think fall is, in many ways, just as nice as spring. And I think one of the things about Washington's summer, while there's some nasty humid, hot days, there's still a number of days in the summer, particularly if you've got shade trees -- I'm gonna talk about that in a second...

NNAMDIRight.

LEWIS...when it can be very pleasant to be outside. Our strategy, where my wife and I live, is we actually feed a lot of birds. We have a -- we're not too far from the Potomac River. There's a lot of birds that come by there. They get rid of the insects. We have very -- we can sit outside on our deck in the summer and actually have very few insects because of the feeding of the birds. The other thing that -- I wanna talk about trees. We didn't mention this before. Trees have a tremendous environmental benefit that we've, I think, implied, which is that they cool the environment. And you can save money on your energy bills.

LEWISIf you've got large deciduous trees shading your house, shading your deck, shading your backyard, you're going to be much more comfortable in the summer and in the -- when the sun is out than if you don't have those trees.

NNAMDIHere is David in Dunkirk, Md. David, you're on the air. Go ahead, please.

DAVIDOh, thank you so much, Kojo. And I appreciate the time. I'm with a company, Victor Stanley. We do outdoor site furnishing. And we've seen the evolution -- you know, this idea of public space. We've been in business for 50 years, and we've seen this evolution go from our type of items, you know, benches and trash receptacles, planters, things like that, go from utilitarian items into actual architectural amenities to -- for the betterment of these public spaces that you've been talking about.

NNAMDICould you explain in more detail what you mean?

DAVIDWell, you know, a -- it's wonderful to hear, you know, that you're getting contributions from landscape architects because we work with them on a regular basis, and it's a wonderful profession. They're the original, you know, green people. (laugh) But they -- you know, we went from very simple, you know, simple wood park bench to ornamental and architecturally designed site furnishings like you might have seen on the city streets in Washington, the metal trash receptacles.

DAVIDYou know, there's an element there that coordinates with the other elements that are in a public space, the use of different materials, steel, recycled plastic, wood, you know, all bringing about a feel, you know -- it's a very subtle thing sometimes. You walk into -- you come into a place and it's there are these, you know, benches, trash receptacles and various amenities, you actually get, like, a feeling that you are in a place, you know, as opposed to, kind of, going into a more deserted area.

NNAMDICare to comment on that, Roger Lewis?

LEWISSure, because I think it's a good point. If you look around at a lot of public spaces that have been redone in recent decades, what he's talking about is absolutely correct. They -- there are a whole lot of elements, which we generally referred to as street furniture, coupled with the vegetation, with landscaping. He mentioned trash receptacles, bus shelters, signage, wayfinding signage, identification signs, kiosk for displaying information, there's a whole range of stuff that is part of the furnishing of a streetscape, that's part of a landscape -- lighting, various kinds of lighting, light fixers, light standards.

LEWISAnd what I think you're getting at, and I certainly support this -- in fact, I'm working on a project where we're going to be dealing with this stuff in the next few months. It can be designed. It can be done thematically. It can start to unify or pull together the space of a plaza or of the street in addition to the vegetation. So I think that -- although we're focusing on vegetation to some extent because that's what changes with the seasons. These other elements don't change with the season. And by the way, some of these elements have been increasingly designed for security purposes, not that that's an element or subtopic of this discussion.

LEWISBut I think your point is well taken, that many years ago, I think, as an afterthought, someone went into a catalog, they said, oh, well, you have six of those benches and three of those trash receptacles and they scattered them around, they get moved and stolen or what have you. Those -- yes, we're beyond that. We are now designing much more comprehensively these occupied urban spaces.

NNAMDIThank you very much for your call, David. Here's Maria in Northwest Washington. Maria, your turn.

MARIAYes. Good afternoon, Kojo. Great show. My question is twofold. I'll make it quick. I lived in the Petworth area, and I have relatives there growing up, so I moved to the area in our lot. And I remember as a child, the city would come through and spray the trees. Never was there a problem with mosquitoes. In the Petworth area, the mosquitoes are so bad, you can't sit out back. You can't sit out front. You can light the candle, all of that, nothing seems to work. The other question is...

NNAMDIAre you talking about in the Petworth area?

MARIAYeah.

NNAMDIOkay.

MARIAAnd I don't know if it's exclusive to Petworth, but all the neighbors would seem to have the same problem. You can't sit out front or back. The mosquitoes are horrible. I'm calling them mosquitoes, it's some type of biting fly. The other problem that the trees in Petworth seem to be dying in abundance. I don't care -- you can go on a one block, two block radius, and they have what we call the mark of death, that orange paint on them where the trees are going to be cut down because the trees are dying.

MARIAAnd I talked to a couple of the removal people, and they said the trees are dying internally out because they are diseased. What can the city do to combat this throughout the city, because I know our council person Muriel Bowser is working on it, but what can we do, as a community, to save the trees and get rid of those biting whatever they are?

NNAMDIMaria, here's Roger Lewis. (laugh)

LEWISWell, you identified something that, again, is the reality of living in a city or, for that matter, suburb, which is that there is some amount of stewardship necessary. I think the case in trees, people, again, have been very good about making efforts to help the city achieve this, which -- I mean, you do have to care of these things. It is natural -- trees are going to die. They are living things. They're organisms that do have -- that do get infected. They get diseases. And they have to be tended to, either cured or removed. And the same thing is true, I think, of insects.

LEWISI know that every -- once the weather gets warm, we, in our house, are contending with ants. They show up. We get wasps. We get deer ticks. We get tent caterpillars. We get wood boring carpenter bees that will drill a perfect hole in anything that's made of wood, mosquitoes, I mean, these things are everywhere. I mentioned that having -- one of the things about having the kind of ecosystem we've got threaded through our built system is a lot of birds are around, and birds get rid of a lot of these insects.

LEWISThe spraying -- I don't know enough about the strategy of spraying tress. I suspect there are some perhaps adverse effects of that, side effects, depending on what the chemicals are. But presumably, the city is worrying about this. I mean, ideally, that's what should be happening. The city should be worrying about these public trees.

NNAMDIMaria, thank you for your call. We got this email from Sally in Chevy Chase, Md. "I would like to sing the praise of screened porches. Washington is a city of porches and balconies, decks and patios, which are all wonderful, but limited in use because of bugs and rain. Our screened porch is a three-season room that is comfortable even on the hottest days. I highly recommend one."

LEWISNo argument there. Yeah, screened porches are fabulous. And the only reason our deck is not screened is because of the birds.

NNAMDIThere you go. Here is Daniel in Arlington, Va. Daniel, you're on the air. Go ahead, please.

DANIELHi, Professor Lewis.

LEWISHi.

DANIELReally, I thought it was very interesting thing you're talking about Arlington and Washington as, kind of, an ecological zone for more than just people. I've been living in Beijing for the last year and a half, and I just recently returned. And one problem right now confronting Asia is the, you know, the monoculture of humans, and there's really no wildlife anywhere in the cities. What is the feasibility of converting existing cities or ecological zones, like putting, you know, rooftop gardens and even trees growing off the sides of buildings?

NNAMDIGreen roofs and Roger can talk about green walls also.

LEWISWell, there's no question that, again, once you expand the biospheres, as the caller just called, of a city, you -- it won't take long for wildlife to begin showing up and having those habitats. I -- this is not something I'm an expert in or have studied, but I do know that even a very small amount of vegetated space, it's not long before the flora and fauna show up, particularly the fauna. I mean, you get everything from tiny insects to small mammals. And the more you have, the more diversified the wildlife will be. I suspect, I mean -- I've been in some cities, you know, where you see very little wildlife. I would think that to significantly change that, you have to start making major structural changes.

LEWISYou'd have to introduce substantial amounts of greenery and earth, exposed earth. I mean, you know, we -- which is another one of the things we have here in Washington, not only are there are a lot of trees growing out of grates on sidewalks, I mean, there's a lot of the earth exposed here, grass or groundcover. And what -- and that does some other good for us. It catches rainwater. It holds it in the ground. It keeps erosion from occurring. I mean, it's -- I think to go retrofit a city where there is no wildlife or no system of living things other than humans to suddenly introduce all these others -- that would be a big intervention. That would a major problem.

NNAMDIAnd I'm afraid that's all the time we have. Roger Lewis is an architect. He's the author of the "Shaping the City" column for The Washington Post and professor emeritus at the University of Maryland School of Architecture. Roger, always a pleasure.

LEWISLikewise. Thank you.

NNAMDIWe're gonna take a short break. When we come back, this is the second in our series of looking at local archeology projects. This one on the family plantation at which Frederick Douglass once served as a slave. I am Kojo Nnamdi.