Humans’ growth spurts stop by late adolescence, but trees accelerate their growth and get bigger as they age. According to a global study by 38 international researchers published in Nature, these findings could have implications for how the world’s forests are managed to contain the ill-effects of climate change.
Nate Stephenson, the study’s lead author and a forest ecologist with the U.S. Geological Survey (USGS), said: “This finding contradicts the usual assumption that tree growth eventually declines as trees get older and bigger. It also means that big, old trees are better at absorbing carbon from the atmosphere than has been commonly assumed.”
Stephenson added, “in human terms, it is as if our growth just keeps accelerating after adolescence, instead of slowing down. By that measure, humans could weigh half a ton by middle age, and well over a ton at retirement.”
According to the USGS, a global team of researchers took measurements of more than 670,000 trees from more than 400 species across tropical, subtropical, and temperate regions in six continents. They used the same methods to calculate “the mass growth rates for each species” and then analyzed trends across all species. The study found that nearly 99 percent of trees accelerate growth rates as they age. “For most tree species, mass growth rate increases continuously with tree size — in some cases, large trees appear to be adding the carbon mass equivalent of an entire smaller tree each year.”
With their miraculous, ever-increasing growth rate, older trees are then better at adding weight faster than younger ones. The Guardian writes that an older trees can add up to 600 kilograms of weight each year. These older, faster-growing trees, account for a “disproportionately important role in forest growth.” For example, “trees of 100 centimeters in diameter in old-growth western U.S. forests comprised just 6 percent of trees, yet contributed 33 percent of the annual forest mass growth.” This is because older trees continue to add girth as well as branches and leaves. More leaves mean more carbon absorption.
However, as USGS noted, it’s important to not lose sight of the forest for the aged trees. The accelerated rate of carbon absorption by some older, larger trees doesn’t mean “a net increase in carbon storage for an entire forest.” As living systems, forests are constantly in a state of flux — and that’s a good thing. A mix of older and younger trees in a forest may help limit the amount of carbon returning the atmosphere at any given time from the death of older trees.
Adrian Das, a USGS coauthor, said: “old trees, after all, can die and lose carbon back into the atmosphere as they decompose. But our findings do suggest that while they are alive, large old trees play a disproportionately important role within a forest’s carbon dynamics. It is as if the star players on your favorite sports team were a bunch of 90-year-olds.”
Stephenson told The Christian Science Monitor that these findings would ideally lead to more effort put into saving old growth forests. “Maybe if environmental changes are hitting your biggest trees the hardest, this is sort of an added impetus to go: ‘Oh my gosh, we need to mitigate that.'” Doug Boucher, director of tropical forest and climate initiative at the Union of Concerned Scientists, added that “it reinforces the value of old-growth forests for the storage of carbon in the biosphere.”
One key take-away for local officials, planners, and design professionals: Do as much as you can to keep those old trees in place. It will be much harder to accomplish the same positive climate impact with younger trees.
John Bela, ASLA, is a founding principal at Rebar. He is an urban designer and landscape architect focused on public space design. As Rebar, Bela created Park(ing) Day, The Panhandle Bandshell, The Civic Center Victory Garden, Parkcycle Swarm, and other projects. Bela teaches at the California College of Arts in San Francisco and University of California, Berkeley. This interview was conducted at the 2013 ASLA Annual Meeting in Boston.
What is the adaptive metropolis, the title of a conference you recently co-curated at UC Berkeley? Does this already exist, or is this an ideal to aspire to?
It’s an ideal to aspire to. The conference, which is organized by UC Berkeley and Rebar, looked at emerging practices in built environment disciplines, such as open source design and public participation, new tools and instruments, new design approaches for flexible urbanism, and then some new ways of funding urban change such as crowdsourcing and crowd equity. We explored these emerging phenomena and then evaluated them according to a set of values we share with a lot of people in the built environment professions, such as livability, resilience, and social justice, social equity.
We ended up creating more questions than answers, but it’s the beginning of a dialogue. We’re carrying that dialogue forward with a new adaptive metropolis alliance, basically an association of practitioners who are doing this kind of work. We will continue the conversation in a more focused way with a series of salons and other events.
What is user-generated urbanism? How is this different from tactical urbanism and other buzzwords that have been floating out there? Can you provide some examples?
Tactical urbanism, DIY urbanism. There are a lot of buzzwords floating around out there. We came up with the term user-generated urbanism to capture the change happening in the built environment professions. In the same way that media and communication technologies have radically altered many industries, we feel like that same kind of change is occurring in planning and design, where the role of a designer is shifting from one who delivers the design products or services to one who’s more creating a platform, in some cases, for participation. The traditional authority of the designer has been deposed. Basically, the designer’s role is shifting to be one of a teacher, or cultivating platforms for participation. User-generated urbanism describes the synthesis of top-down and bottom-up practices engaged synergistically to cultivate greater participation. This synthesis help us achieve the goals we outline with the adaptive metropolis of resilience and social justice.
In 2005, you and your design partners designed to turn a parking space into a park for the day, launching Park(ing) Day, which nearly 10 years later is now a global movement. Amazingly, more than 1,000 parking spaces were transformed for Park(ing) Day just this year. Why do you think this idea spread? Has it translated into real changes in how cities address streets and public spaces?
The idea spread through the anachronism of the how-to manual we created for parking, which was a guerrilla art installation which enabled a one-off two hour design intervention. This one-off urban intervention became a global public participatory art and design project. This how-to manual, which is an example of open-source design, enabled the transformation from one-off thing into a meme. We intentionally created the code so anybody on the planet who has metered parking spaces can create one. Anyone can take the seed of the idea we created in San Francisco and recreate it in their own environment for their own purposes, their own values, their own kind of social and political agendas. It’s an interesting example of open source design.
We have attempted to guide or control the growth of the movement to avoid its over-commercialization. We have attempted to make it free, make it an act of generosity, as much as it has been about design firms or other businesses promoting their own business. There’s a fundamental value about making Park(ing) Day an act of human generosity. You’re setting up something for others to enjoy for free. That’s the ethos of the piece.
Has it translated into real changes in how cities address streets in public space? I think so. Park(ing) Day and other projects like that are examples of participatory design, what we call user-generated urbanism or tactual urbanism. Over the past decade, it has been fascinating to witness these projects being created and produced by not only artists and design activists, but now major city governments and planning entities in both the public and private sector around the world under the rubric of pilots and trials. The idea of a temporary urban intervention as a way to catalyze change and demonstrate new possibilities has really matured. It’s now being used again across many sectors, translating into real changes. In San Francisco, Park(ing) Day have now been absorbed into public policy framework, what’s called the Pavement to Parks program, run by the San Francisco Planning Department, and the creation of the Parklet Program.
You were involved in some of the first parklets in San Francisco with your modular Walket system. You’ve said these are a cost-effective way of creating public space for cash-strapped cities. However, I’ve talked with some people who are concerned that the temporary nature of these parklets could undermine investment in long-term parks and plazas. Do you think there’s a real trade-off?
Yes, that’s a problem. If you look at a traditional sidewalk widening project in many cities, that’s a multimillion dollar, multi-year project. It results in a well-built, generous investment. It represents a generous investment in the civic realm, and investment in infrastructure of the U.S. We don’t have the same set of values around creating public and civic spaces as other kind of industrialized nations do. We’ve fallen behind in terms of investing in our public realm.
Tactical urbanism projects in the U.S. are an effort to improve the public realm through public participation. I agree that temporary is not always a great replacement for greater investment in public space, in the civic resources of cities. However, the parklet program is different from a more traditional sidewalk widening program. Parklets can created highly-nuanced city-scapes. They really do an interesting job of representing the values, interests, and aesthetic sensibilities of the project sponsors. They lend this kind of richness, an informality to places, in a way that top-down city-led projects don’t.
You’re mobile parklet concept, Parkcycle, fascinated me. I love the idea of swarms of parks forming and reforming where needed. Was this just an idea, a concept to illustrate some sort of future? Or could you see Parkcycle actually being used? What was your motivation?
We actually created them. I collaborated with a group in Copenhagen called N55 and we actually built Parkcycle Swarm. We shipped it to Baku, Azerbaijan, in the context of a public art installation. We literally pedaled around these four mobile public parks and created a pedal-powered open source distribution system. The idea is you can deliver open space anywhere, when and where it’s needed. Multiple users could could come together to create their own mini parks working together, aggregating together to form a larger open space. It’s conceptual, but it’s actually taken form with this Parkcycle Swarm.
It’s fun, playful idea. It’s also about demonstrating new possibilities for landscape in terms of mobility, flexibility, and adaptation. I don’t know exactly where it’s going to lead. It’s certainly not a replacement for other investments in public space, but it adds a new dimension which is flexible, playful, and fun.
You’re are doing some interesting work on the East Coast with streetscape and public realm design guidelines for a 20 year revitalization effort in D.C.’s capitol riverfront area. How does this project reflect your ideas on the adaptive metropolis and user-generated urbanism?
We were brought onto a team led by AECOM to do the streetscape and public realm guidelines. Our role was to develop an early activation plan. In the case of many larger-scale developments, there’s a 10, 20, or 30 year time frame. There’s an increasing desire to take advantage of temporarily vacant spaces to insert new programs, to test spatial ideas, and to fulfill some unmet needs in the community prior to the full build-out of the project.
The old approach was a project is complete when the last brick of the final streetscape or building is complete. The new approach is more iterative, where you test ideas and use temporary programs to inform your longer term strategic thinking. Increasingly, this is an approach that’s being used in both the public and private sector under the rubric of early activation, or phase-zero projects, or what we sometimes call interim use and cultural activation. It’s a way of changing the way that people perceive a place prior to brick and mortar construction.
Lastly, please tell me about some other projects you aren’t working on but think are intriguing or inspiring. What projects excite you these days?
At the ASLA Annual Meeting, I went to a talk by Kate Orff, ASLA, at SCAPE Studio. I was surprised to hear how she is adopting some of the approaches we have at Rebar in terms of creating open source platforms for participation. Where our work diverted — and what I found extraordinarily interesting — was with her approach to the idea of distributed infrastructure and ecological infrastructure. She is exploring how we are going to solve the pressing environmental crises facing the globe today. Is it going to be through government-led top-down initiatives, or is there a role for user-generated or community-generated projects? Kate Orff’s work represented soft infrastructure versus hard infrastructure. She’s exploring how smaller groups and community members in partnership with government can solve really pressing problems, which is a different way of thinking in comparison with 20 or 30 years ago.
I’m really interested in work I’ve seen in Europe recently, especially the Urban Play Project in Koge, which is southeast of Copenhagen. There, a real estate developer has formed partnership with the small town of Koge. They’re testing the idea of culture as a driver of development.
Some of the most radical work in urban planning today is where people are literally abandoning the idea of a master plan and looking at other approaches that are more participatory, inclusive, and iterative. These experiments acknowledge that circumstances change over time. You can’t always predict what a site, or a community, or an environment is going to look and feel like, what its needs will be 20 years from now. There’s this urge to build in adaptive capacity. That’s what we mean by the adaptive metropolis.
Image credits: (1) John Bela / Rebar, (2) Park(ing) Day / Rebar, (3-4) Walket system in San Francisco / Rebar, (5) Parkcycle Swarm in Baku / Rebar, (6) Parkcycle swarm in San Francisco / Rebar, (7) Parkcycle Swarm meets Parklet / Rebar
According to new research out of the UK, moving into a home near green spaces, particularly in urban areas, provides people with long-term mental health gains up to three years after the move. Scientists at the University of Essex, who tracked 1,000 people over five years, found that moving next to a green space had a “sustained positive effect, unlike pay rises or promotions, which only provided a short-term boost,” writes BBC News. In the journal Environmental Science and Technology, the researchers argue that the research shows “access to good quality urban parks is beneficial to public health.”
Co-author Mathew White, from the European Centre for Environment and Human Health at the University of Exeter, UK, said his study built on an earlier one that showed people living in “greener urban areas displayed fewer signs of depression or anxiety.” His team tried to find out whether nature really was having an impact, or there was some other unknown variable at work.
As White explained to BBC News, “there could have been a number of reasons, for example, people do all sorts of things to make them happier: they strive for promotion at work, pay rises, they even get married. But the trouble with all those things is that within six months to a year, they are back to their original baseline levels of well-being. So these things are not sustainable; they do not make us happy in the long-term. We found that within a group of lottery winners who had won more than £500,000 that the positive effect was definitely there but after six months to a year, they were back to the baseline.”
Using data from the British Household Panel Survey, which has collected information about 40,000 households each year since the early 90s, the team found that “even after three years, mental health is still better, which is unlike many of the other things that we think will make us happy.” He added that “there is evidence that people within an area with green spaces are less stressed and when you are less stressed you make more sensible decisions and you communicate better.”
In The Mail, another co-author, Dr. Ian Alcock, also at the University of Exeter, said: “these findings are important for urban planners thinking about introducing new green spaces to our towns and cities, suggesting they could provide long term and sustained benefits for local communities.”
While the health benefits of adding more green spaces are now apparent, there would also be economic benefits. In 2012, the World Health Organization (WHO) said depression was the leading cause of disability worldwide. Disabled workers are expensive for both governments and employers. Imagine if disability due to depression could be reduced simply through the addition of parks.
White said more policymakers, at least in the UK, are taking this type of research seriously, but these studies may raise sticky financing questions. “For example, environmental officials will say that if it is good for people’s health then surely shouldn’t the health service be putting some money in. …What we really need at a policy level is to decide where the money is going to come from to help support good quality local green spaces.”
Marion Pressley, FASLA, is principal at Pressley Associates. In addition to her practice, Pressley has taught for the past 40 years landscape history at the Landscape Institute of the Arnold Arboretum at Harvard University, and now at the Landscape Institute at Boston Architectural College. Marion received the 2004 BSA Women in Design Award of Excellence and the 2002 Massachusetts Horticultural Society Gold Medal Award.
For almost 30 years, you have restored and updated Frederick Law Olmsted’s Emerald Necklace, his famed system of parks. What has this project taught you about Olmsted? What do you think he did best? What do you think he should’ve done differently?
We started on it in 1984, and, actually, I worked on some parts of the system back in the mid-seventies. It has been a long time. It was part of an important statewide-Olmsted initiative that included 12 park sites.
What it really taught me is the man had the ability to not worry about politics. This system is owned by two municipalities and the parkway is under state jurisdiction. You have Brookline, with a small amount of the Emerald Necklace, and Boston, with the majority of the Necklace. When he designed it, he really didn’t care who owned it. In Olmsted Park along Riverdale Parkway, the system for pedestrians was sometimes on the Boston side and sometimes on the Brookline side. For him, this was one landscape. He reset the boundaries between the municipalities. That’s really one the most important things I learned about what he was doing.
I haven’t really looked to see if there’s other park systems he worked on that have been owned by different entities. I don’t know of one. Buffalo, the first system of parks he designed, was owned by Buffalo.
What he did best is bring all the parties together as he did the design. So that’s the attitude we took with the rehabilitation: This was one park and all groups met together. It didn’t matter whether you were municipal or state; everything was done that way. That’s possibly the best thing he accomplished when he created this system of parks and parkways.
What would he have done differently? One thing he never really thought about is the maintenance of these parks. The maintenance could be uneven because one town could have more money than the other. One might have a different aesthetic than the other, even though Olmsted designed it as one place. He also didn’t foresee as much active recreation coming into any flat space it possibly could, although I think it was late enough for him to recognize it would happen. He didn’t really provide a lot of space for active recreation. His Emerald Necklace was really a passive, linear system. You would pass through it in a linear way. That’s one of the things he might have done differently.
In his writings, there was one thing about Central Park that struck me: if his landscape was still intact 50 years or 100 years from now, he would know he’s been successful. The best thing he’s achieved is that this system has held itself together. The individual parks have had some changes. Some of the changes came with the dam going in, and changing saltwater to fresh at the Fens, but he created a system that was able to sustain itself.
With your deep understanding of Frederick Law Olmsted’s designs, what do you think he would make of Boston today? What would he approve of? What developments would dismay him?
He would very much approve of the Emerald Necklace Conservancy and Brookline, Boston, and the state, getting together and recognizing it as one park. He would be amazed that it happened, in some ways. He would be really pleased with the fact that the park system has maintained itself. Different ownerships really could have allowed it to split. He would be most pleased that his vision continues today.
One of the things that would dismay him is the fact that most of the understory areas in critical places, like the Riverway and Olmsted Park, were wiped out over time. But this happened in all parks. It happened in universities. It happened everywhere where people all of a sudden felt unsafe, so the shrub and herbaceous layer had to be wiped out. That’s something that he wouldn’t have foreseen.
All of his plantings were very dense — if you look at photos in 1906, a few years after it was finished in 1895, and then, the 1920s, you see it as he envisioned. He was trying to use the density of the planting to achieve the picturesque. To see these plants totally wiped out would have upset him, because he was trying to create and control views with the plants. He was creating this vegetation with openings in it, so you could see the water. There was a very definite sequence of open and closed and open and closed, as you went down through. The fact now that some areas that are just totally open or totally closed off would really disturb him.
Beyond Olmsted, you’ve worked on other important historic landscapes, too. The Museum of Fine Arts, Boston recently got a Norman Foster design addition. His new building sits right on top of a courtyard created by landscape architect Arthur Shurtleff, a site you had updated in the 1990s. I understand you were brought back in after the Foster additions. How did you reconcile the remnants of the old Shurtleff design with the new Foster one?
We were frustrated when it happened because there’s not a lot of Arthur Shurtleff’s work in existence that you can go and see. The 1928 courtyard had been closed and went into benign neglect. They literally just closed the door and left it like that for many, many years. The trees were still extant. All four were growing beautifully. The Shurtleff landscape was extant. So the reopening and rehabilitation was a fairly easy thing. It was frustrating, given it was such a perfect example of his work, to see them take it out. But the new building is beautiful.
We were brought in by one of the major donors from the museum, who was very concerned the landscape hadn’t achieved what they had hoped it was going to achieve. So we were called in to look at it. It was mostly vegetation that they were concerned about; they wanted a native woodland theme. Interestingly, Foster kept a part of the Shurtleff design, because the building was placed within a sunken area in the middle of the courtyard.
In the Shurtleff design there was a pool with a fountain, four major deciduous trees, and plantings. There were these outer areas that were lower in elevation that were like long slots containing garden quality sculpture, paving, and plantings. Those edges are what remained as four small courtyards, when Foster’s building addition was constructed within the courtyard.
What Foster did was a very unique thing. If you haven’t had a chance to see it, you should go into the museum. As you’re walking through the new building you see into the four courtyards or what are now called slot gardens. It’s quite beautiful, actually. As you’re walking through the museum, and everything’s always so enclosed, all of a sudden, you get this little vignette of woodland planting and sculpture. This just happens all the way around, and it’s a very nice thing.
You also have worked on the landscape surrounding Philip Johnson’s Glass House and the other buildings in that compound so they are more accessible. What was it like to work with Johnson’s vision of this place and update this historic landscape?
We were asked by the National Trust to make it possible for people to get into the Glass House, and the brick house, its counterpoint, and other structures: the sculpture studio, the painting studio, the Monster, etc. What were most concerned about was the main core area. We were asked to do this to meet current codes without destroying it.
Putting ramps all over the place would’ve been a disaster, so we looked very closely at the grading and met the 5-percent rule. We just regraded paths slightly in order to achieve the right pitch. We had an idea, which we’ve used at one of our Harvard projects many years ago: a temporary ramp that is brought out, put down, and allows you to not have these ramps all over the place. The temporary ramp allows you to provide access for a person in the wheelchair or with a cane and then take it away.
This is all possible because every visitor has to check in at the historical society before they are taken to the site. They society knows before anybody comes if there’s a need for universal access so when they put them on the bus and bring them there, they’re all set for it. It has been working beautifully because we didn’t have to totally change the landscape. We were able to regrade pathways, including his little eyebrow bridge. We were able to work with the local municipality so we did not have to put handrails.
In short, we were able to make it like when you go in for a haircut and you come out and don’t want anybody to know you had your haircut.
Among your contemporary projects, you have done some wonderful work in Boston. You have transformed some brownfields into real community assets. In East Boston, you turned an old pier that was a brownfield into a park. A 600-foot long promenade takes visitors out into the water, where they get some of the best views of Boston. What was the experience of that project working with the community? And what do you think the legacy of that project is in East Boston?
A park was a very important thing for the community of East Boston. I don’t know how much you know about this Boston community, but these were the same women who had been out at the Boston airport runways with their baby carriages, telling Massport that they couldn’t put in more runways. You had a group of people who absolutely wanted a park. They had also lost an Olmsted park, which now sits under an airport runway. This was absolutely the most important thing to this community. They wanted it to be a community park for everyone. They wanted it to be the best park it could possibly be. They worked very, very hard to get it. They were absolutely great fun to work with, actually.
The site was a brownfield. It has three foot of cover. There’s the layer so you know when you hit it. The whole park had to be raised because of flooding. If we knew what we know today, we probably would’ve raised it higher. But at that time, three feet was enough.
The pier was the only solid piece. It was an area where grain and other goods were delivered. There were larger wooden boardwalks on either side. But there was this core of soil and, basically, riprap on the sides. We were able to save that as this 600-foot linear pier.
It’s a very popular place for wedding pictures. The park is heavily used. It has playgrounds, spray pools, an amphitheater, an exercise area. It has everything these people wanted.
Plus the pier promenade, which gives them the view of the city. They have one of the absolutely best views of Boston.
You also transformed a landfill into a park. With the Pope John Paul II Park, your firm built natural land forms, brought back native plants, created meadows set within wetlands. What were the challenges in making all that a reality?
Another very important brownfield, but, of course, brownfields always so much depend on the engineers, as it did with the East Boston piers. The engineers made it possible to have these things happen. In this particular case, we were able to do more with the site.
We had a garbage dump and we had a drive-in theater. The dump was used for trash for years. That’s why there’s this rolling landscape, which we kept and accentuated.
All of the area had completely become overgrown with invasive plants. The landscape was a complete urban wild. But it was still an important park to these people, even in that condition because everybody walked their dog there. There were paths people had cut through themselves. Nobody had made it into a park. It was a community asset, as far as they were concerned, for certain things.
Again, we had a very active community. We worked with a state agency. At that time, it was the Metropolitan District Commission.
We were able to create wetland areas. Because this area is tidal, just like Piers Park, there’s a nine-foot tidal change of water here.
We were able to what they wanted: A place where they could walk or wander through. There were plantings and an area of community gardens. There were shade structures that looked out over the water.
We took the brownfields area that was the drive-in theater, which was really one of the more contaminated areas, and turned into a series of fields now mostly used for soccer. That was very popular. A playground with a shelter structure was also added. This became a totally new park with both active and passive uses. The community invested in its design.
Lastly, looking over your multi-decade career, what advice do you have for young people who want to get into landscape architecture today? What special advice do you have to those who want to focus on historic preservation and design?
One of the hard parts about going into preservation is that most of our academic institutions don’t really teach you enough landscape architectural history to make you an authority on even American landscapes. Forget about European or Asian or any place else. Most of us who are in this field at my age, and who started in the early seventies, are self-taught in many ways. What it really means is you need to build up a base of understanding of history. If you’re going to do preservation, you need to understand the theories and how things were done at particular times. You need to obtain this knowledge by either supplementing it with additional courses or you need to teach yourself.
There are some programs who are trying very much to add to this. There are four or five programs now doing this. Georgia is definitely one. I know ESF has a program. Education is an important piece and hopefully they will expand it, but no matter how much they expand it, you really have to know your history to know when you walk into a design what you’re looking at. You have to know what its context is. There’s so much you have to know to do these cultural landscape reports. It’s a process of self-education.
For example, with Steepletop, which was Edna St. Vincent Millay’s house, you have to look at other writers and artists who had similar landscapes during the period of significance. The homes of Edith Wharton, Robert Frost, or Theodore Dreiser are examples. There’s a whole series of these people, who were writers who created their own landscapes. You have to have that context in order to know what you’re preserving or bringing back. You have to know what’s important and what has integrity.
I would advise young landscape architects entering this field that they have to realize there’s going to be a lot of work they have to do before they get to this point. They should join a firm that’s doing that kind of work because that’s how they’ll learn to do it.
Most people who go into landscape architecture and stay with landscape architecture absolutely love their jobs. There’s a great deal of love in the profession. That’s one of the reason landscape architects keep working to such an old age. They just can’t give it up.
Image credits: (1) Marion Pressley / Pressley Associates, (2) Olmsted Park restoration by Pressley Associates / Marion Pressley, (3) Olmsted Park pathways by Pressley Associates / Marion Pressley, (4) Museum of Fine Arts Boston / Nigel Young, (5-6) East Boston Piers Park / Kaki Martin, (7-8) Pope John Paul Park II / Kathry O’Kane