A biologist believes that trees speak a language we can learn

Photo by Jeffrey L. Bruce

Written by
Ephrat Livni

 I’m in a redwood forest in Santa Cruz, California, taking dictation for the trees outside my cabin. They speak constantly, even if quietly, communicating above- and underground using sound, scents, signals, and vibes. They’re naturally networking, connected with everything that exists, including you.

Biologists, ecologists, foresters, and naturalists increasingly argue that trees speak, and that humans can learn to hear this language.

Many people struggle with this concept because they can’t perceive that trees are interconnected, argues biologist George David Haskell in his 2017 book The Songs of Trees. Connection in a network, Haskell says, necessitates communication and breeds languages; understanding that nature is a network is the first step in hearing trees talk.

For the average global citizen, living far from the forest, that probably seems abstract to the point of absurdity. Haskell points readers to the Amazon rainforest in Ecuador for practical guidance. To the Waorani people living there, nature’s networked character and the idea of communication among all living things seems obvious. In fact, the relationships between trees and other lifeforms are reflected in Waorani language.

In Waorani, things are described not only by their general type, but also by the other beings surrounding them. So, for example, any one ceibo tree isn’t a “ceibo tree” but is “the ivy-wrapped ceibo,” and another is “the mossy ceibo with black mushrooms.” In fact, anthropologists trying to classify and translate Waorani words into English struggle because, Haskell writes, “when pressed by interviewers, Waorani ‘could not bring themselves’ to give individual names for what Westerners call ‘tree species’ without describing ecological context such as the composition of the surrounding vegetation.”

Because they relate to the trees as live beings with intimate ties to surrounding people and other creatures, the Waorani aren’t alarmed by the notion that a tree might scream when cut, or surprised that harming a tree should cause trouble for humans. The lesson city-dwellers should take from the Waorani, Haskell says, is that “dogmas of separation fragment the community of life; they wall humans in a lonely room. We must ask the question: ‘can we find an ethic of full earthly belonging?’”

Haskell points out that throughout literary and musical history there are references to the songs of trees, and the way they speak: whispering pines, falling branches, crackling leaves, the steady hum buzzing through the forest. Human artists have always known on a fundamental level that trees talk, even if they don’t quite say they have a “language.”

Photo by Jeffrey L. Bruce

Redefining communication

Tree language is a totally obvious concept to ecologist Suzanne Simard, who has spent 30 years studying forests. In June 2016, she gave a Ted Talk (which now has nearly 2.5 million views), called “How Trees Talk to Each Other.”

Simard grew up in the forests of British Columbia in Canada, studied forestry, and worked in the logging industry. She felt conflicted about cutting down trees, and decided to return to school to study the science of tree communication. Now, Simard teaches ecology at the University of British Columbia-Vancouver and researches “below-ground fungal networks that connect trees and facilitate underground inter-tree communication and interaction,” she says. As she explained to her Ted Talk audience:

I want to change the way you think about forests. You see, underground there is this other world, a world of infinite biological pathways that connect trees and allow them to communicate and allow the forest to behave as though it’s a single organism. It might remind you of a sort of intelligence.

Trees exchange chemicals with fungus, and send seeds—essentially information packets—with wind, birds, bats, and other visitors for delivery around the world. Simard specializes in the underground relationships of trees. Her research shows that below the earth are vast networks of roots working with fungi to move water, carbon, and nutrients among trees of all species. These complex, symbiotic networks mimic human neural and social networks. They even have mother trees at various centers, managing information flow, and the interconnectedness helps a slew of live things fight disease and survive together.

Simard argues that this exchange is communication, albeit in a language alien to us. And there’s a lesson to be learned from how forests relate, she says. There’s a lot of cooperation, rather than just competition among and between species as was previously believed.

Peter Wohlleben came to a similar realization while working his job managing an ancient birch forest in Germany. He told the Guardian he started noticing trees had complex social lives after stumbling upon an old stump still living after about 500 years, with no leaves. “Every living being needs nutrition,” Wohlleben said. “The only explanation was that it was supported by the neighbor trees via the roots with a sugar solution. As a forester, I learned that trees are competitors that struggle against each other, for light, for space, and there I saw that it’s just [the opposite]. Trees are very interested in keeping every member of this community alive.” He believes that they, like humans, have family lives in addition to relationships with other species. The discovery led him to write a book, The Hidden Life of Trees.

By being aware of all living things’ inter-reliance, Simard argues, humans can be wiser about maintaining mother trees who pass on wisdom from one tree generation to the next. She believes it could lead to a more sustainable commercial-wood industry: in a forest, a mother tree is connected to hundreds of other trees, sending excess carbon through delicate networks to seeds below ground, ensuring much greater seedling survival rates.

Foreign language studies

Seedling survival is important to human beings because we need trees. “The contributions of forests to the well-being of humankind are extraordinarily vast and far-reaching,” according to the United Nations Food and Agriculture Organization 2016 report on world forests (pdf).

Forests are key to combating rural poverty, ensuring food security, providing livelihoods, supplying clean air and water, maintaining biodiversity, and mitigating climate change, the FAO says. The agency reports that progress is being made toward better worldwide forest conservation but more must be done, given the importance of forests to human survival.

Most scientists—and trees—would no doubt agree that conservation is key. Haskell believes that ecologically friendly policies would naturally become a priority for people if we’d recognize that trees are masters of connection and communication, managing complex networks that include us. He calls trees “biology’s philosophers,” dialoguing over the ages, and offering up a quiet wisdom. We should listen, the biologist says, because they know what they’re talking about. Haskell writes, “Because they are not mobile, to thrive they must know their particular locus on the Earth far better than any wandering animal.”

https://qz.com/1116991/a-biologist-believes-that-trees-speak-a-language-we-can-learn/

Street Trees Really Do Make People Healthier

Jason G. Goldman

It’s easy enough to claim that being in nature makes people feel better. It certainly feels like it’s true. A weekend in the mountains, or even a few hours in a park after a long day at work, truly feels like it is somehow restorative.

There are some good reasons to believe that green space could have a causal relationship with health and happiness. For one thing, trees scrub pollution from the skies, allowing those nearby to breathe cleaner air. Exposure to nature has also been linked with reduced blood pressure and stress, and it seems to motivate folks to become more active and less sedentary. Then there’s the Japanese practice of shinrinyoku, or “forest bathing.” The Japanese believe that what essentially amounts to a nature walk promotes human health and wellbeing. Plants are also part of a complex food web that, together, provides things critical to our survival like oxygen to breathe, fresh water to drink, and food to eat. Even if all these things are true – and they probably are – that still doesn’t mean that it’s nature, per se, that’s having the apparent health benefit.

To make that claim we need real, quantifiable data. That’s where University of Chicago psychology graduate student Omid Kardan and University of Chicago professor Marc G. Berman come in. They and their colleagues looked to Toronto, Canada, a city for which there is plenty of satellite imagery (which allows them to measure green spaces) and self-reported health information through the Ontario Health Study. By using a set of common statistical techniques, the researchers were able to really see whether there’s anything to the idea that greenery makes people healthier.

But it wasn’t green spaces in general they were interested in; it was trees in particular. By leaving lawns and bushes out, the researchers hoped to zero in on what they thought was “potentially the most important component for having beneficial effects.” First, they took data on trees from two databases maintained by the city of Toronto: “Street Tree General Data” and “Forest and Land Cover.” Together, those databases provided information on street trees as well as those in parks and backyards. They chose Toronto in part to rule out the effects of health insurance; unlike in the US, Canadians are guaranteed universal publically funded healthcare, regardless of employment status or income level. Still, despite equal access, not all Canadians choose to avail themselves of healthcare in equal ways. Indeed, those with lower incomes and fewer years of schooling tend to see doctors less often, which is why the researchers made note of that sort of demographic data.

They found that those who live in areas with more street trees reported better health perception than those in neighborhoods with fewer trees. Regardless of their actual health, they felt they were healthier. But it turns out they were actually healthier too: they suffered from fewer cardio-metabolic conditions.

But that’s not all. To really drive the point home, Kardan reduced the findings to cold, hard cash.

His team found that by planting 10 more trees per city block, Toronto could improve health perception as much as if every household on that same block earned $10,000 more every year, or magically became seven years younger.

The results were even more striking for actual health. Planting just 11 more trees per city block would reduce cardio-metabolic conditions the same extent as if everybody living on that block earned $20,000 more each year or somehow became 1.4 years younger.

So what’s the secret? Kardan doesn’t know, and his study isn’t explicitly designed to get at the underlying mechanism. But a close look at the data offers up a suggestion. It wasn’t proximity to trees in a neighborhood that was the most important variable, but the number of trees on the streets. That suggests that it’s not necessarily that the trees are themselves providing important services (they do that, though that might not be what accounts for these health effects). Instead, it could be something as simple as peoples’ ability to literally see trees, and the most common place for most people to see trees is on the street. It’s also possible that street trees are disproportionately responsible for capturing street pollution, and that could be driving the team’s findings.

Maintaining a street tree for a year costs between $30 and $500, depending on where it is. In other words, planting ten or eleven trees per city block would be far cheaper than paying everyone $10,000-20,000 more each year. That should be good news for city planners.

http://conservationmagazine.org/2015/07/street-trees-really-do-make-people-healthier/

Stormwater Master Class Series at Forester University Expands

Jeffrey L. Bruce FASLA is now teaching Fundamentals of Green Infrastructure for the Post-Construction Stormwater BMPs Master Class Series at Forester University.

http://www.foresteruniversity.net/masterseries-postconstruction-Stormwater-BMPs.html

Rate of Tree Carbon Accumulation Increases Continuously with Tree Size

Forests are major components of the global carbon cycle, providing substantial feedback to atmospheric greenhouse gas concentrations1. Our ability to understand and predict changes in the forest carbon cycle—particularly net primary productivity and carbon storage—increasingly relies on models that represent biological processes across several scales of biological organization, from tree leaves to forest stands. Yet, despite advances in our understanding of productivity at the scales of leaves and stands, no consensus exists about the nature of productivity at the scale of the individual tree, in part because we lack a broad empirical assessment of whether rates of absolute tree mass growth (and thus carbon accumulation) decrease, remain constant, or increase as trees increase in size and age.

A global analysis of 403 tropical and temperate tree species, shows that for most species mass growth rate increases continuously with tree size. Thus, large, old trees do not act simply as senescent carbon reservoirs but actively fix large amounts of carbon compared to smaller trees; at the extreme, a single big tree can add the same amount of carbon to the forest within a year as is contained in an entire mid-sized tree. The apparent paradoxes of individual tree growth increasing with tree size despite declining leaf-level and stand-leve productivity can be explained, respectively, by increases in a tree’s total leaf area that outpace declines in productivity per unit of leaf area and, among other factors, age-related reductions in population density.

Results resolve conflicting assumptions about the nature of tree growth, inform efforts to undertand and model forest carbon dynamics, and have additional implications for theories of resource allocation and plant senescence.

http://www.nature.com/nature/journal/vaop/ncurrent/full/nature12914.html

Condition of Vegetative Roofs Years After They're Exposed to the Real World.

In KieranTimberlake's extensive survey of roof gardens, it identified species that were planned, had thrived, or were rogue (l to r, respectively): prairie dropseed (Sporobulis heterolepsis); two-row stonecrop (Sedum spurium fuldaglut); moss pink, pink phlox (Phlox subulata) Credit: Bruce Peterson

It’s one thing to Photoshop a green roof into a rendering; it’s another thing to plant and sustain one. And it’s all but unheard of to go back and analyze the state of these living roofs years after their completion, as Philadelphia-based Kieran Timberlake did for its groundbreaking Green Roof Vegetation Study. The study responds to “a lack of long-term data on real buildings with diverse and dynamic plant communities,” according to the firm. Instead of concentrating on one engineering or horticultural aspect of green roofs, the firm looked at “how green roofs function as ecosystems and how they change over time.”

The jury highlighted two innovative aspects of the study: its comparative method and its ecological thesis. In 2011 and 2012, Kieran Timberlake surveyed six of its completed green roofs, ranging in area from 1,744 to 10,000 square feet, and designed between 2003 and 2011. Using the Relevé vegetation survey method and the Braun-Blanquet abundance scale to quantify its findings, Kieran Timberlake assessed the roofs’ vegetative cover, species richness, and species diversity in 2-meter-square sections. The researchers also interviewed facilities and grounds maintenance personnel at each site. Juror Bill Zahner praised the study’s “way of collecting the data needed rather than saying, ‘Well, let’s just put seeds down and keep our fingers crossed.’ ” Juror Jing Liu agreed: “What they’re doing is different. The research is to study the long-term dynamics of green roofs.”

The resulting report confirms that roof ecologies are indeed dynamic and that changes will occur spatially and over time from the original planting design. More importantly, it details the nature of those changes, and raises questions about what the changes might indicate for long-term resiliency. In many of the case studies, the prevalent species observed on the roofs in 2012 that were part of the initial planting design were accompanied by dozens of new or “emergent” species. Artemisia (commonly known as mugwort) at the Yale Sculpture Building and Melilotus (or sweet clover) at Cornell University’s Alice H. Cook House independently found their way to roof tops, took root, and eventually made themselves at home in the roofscape design. Roof biodiversity often increased, although the report cautions that the results of any single survey could be deceptive: “What appears to be major shifts in species composition may in fact be short-term fluctuations or cycles caused by unpredictable changes in experienced climate and environmental conditions.”

While the report rigorously maps the distance between design intent and material outcomes, it also sets the stage for even more radical research to be conducted on the interplay between landscape and architecture. Kieran Timberlake envisions deploying sensors on the roof to measure thermal and moisture conditions in relation to the building’s internal climate and energy consumption. The report also suggests that architecture “is responsible for the … vegetative dynamics and ultimate performance of the roof.” On the roof of a dining hall at Middlebury College, for example, the otherwise feeble grasses and forbs become lush and verdant around the skylight cones, whose shade presumably helps the soil retain moisture. “Architectural design creates microclimates across a roof, determining availability of sunlight, water, and nutrients,” the report states.

Kieran Timberlake is already putting its newfound knowledge to use on the forthcoming Penn State Center for Building Energy Education and Innovation at the Philadelphia Navy Yard, which itself will serve as an ongoing laboratory and teaching center for scientists, students, and professionals interested in eco-effective architecture. The firm has developed a proposal to create a green roof test bed on this building; currently, it is in the process of raising funds.

But documenting the consequences of a designed green roof subjected to unforeseeable or uncontrollable environmental forces has wider implications for architecture in general, juror Jing Liu said. “If you think of the green roof as an ecological system, you can have architecture as an ecological system,” she said.

In the messiness of the real world, architecture depends on dynamic variables. Buildings are never really complete. Rather, they are subject to the vicissitudes of client maintenance regimes, the inconsistencies of occupant behavior, and the unpredictability of weather. That is why post-occupancy studies—of both indoor and outdoor environments—must be as meticulous as they are fearless.

Project Credits 
Project Green Roof Vegetation Study 
Design Firm KieranTimberlake, Philadelphia 
Project Team Roderick Bates, Stephanie Carlisle, Billie Faircloth, AIA, Stephen Kieran, FAIA, Taylor Medlin, Assoc. AIA, Max Piana, James Timberlake, FAIA, Ryan Welch

 

 In 2005, when Kieran Timberlake planned the green roof of Cornell University’s Carl L. Becker House, in Ithaca, N.Y., the rigorous planting plan comprised three types of succulents (two-row stonecrop, tasteless stonecrop, and houseleeks), combined with strips of prairie dropseed. When Kieran Timberlake surveyed the roof in 2012, the vegetation was healthy and full, but there were a few surprises—54 of them, in fact. That is the number of new plant species that had taken root over the years.

An aerial view of Cornell campus dormitories shows Kieran Timberlake's green roofs outlined in white; the Carl L. Becker House is at the right side of this image. Credit: Kieran Timberlake

According to KieranTimberlake's study, the most biodiversity was found in the Becker House's southernmost bay, where shading along the adjacent building edge minimized the effects of record droughts.

 

Various poplar species were found on the Becker House roof, despite not appearing in the original roof planting plan.

Credit: Kieran Timberlake

http://www.architectmagazine.com/green-building/green-roof-vegetation-study.aspx



Natural Swimming Ponds Ditch the Chemicals

This gorgeous swimming pool isn’t a typical chlorine-filled watering hole–it’s actually a natural swimming pond that relies on plants to filter the water. (Don’t worry, you’re not swimming among the plants and stepping in squishy mud; the plant regeneration area is kept separate from the swimming area.) Even if you already have a swimming pool, you can enjoy the benefits of a chemical-free pond and relaxing natural environment using the structure you already have with a few design changes

Natural swimming ponds are already quite popular in Europe and are gaining interest in the US. Companies like Clear Water Revival (UK) and Total Habitat (US) can help you design your perfect dream pond, or revamp the pool you already have. The cost of new natural ponds versus conventional swimming pools is said to be comparable, but maintenance costs for a chemical-free pool will be much lower. (Just think of the increased health benefits as an added bonus.)

A natural pond is usually larger than a normal pool to accommodate the plants, rocks, and natural vegetation that comprise the filter zone (separate from the designated swimming area). Once water filters through the plant zone, it is then pumped through a UV filter to ensure maximum cleanliness and aeration. Typically, natural ponds have a waterfall to pump water back into the swimming area. Design and shape options are endless.

Whereas a conventional pool is little more than a concrete tub, a natural pond is a landscape centerpiece that will enhance the value of your home and quality of your life. What could be more beautiful than that?

http://inhabitat.com/?p=24114

Reconsidering the Underworld of Urban Soils

by Laura Solano

Look down. If you are in a city or large town, below you is a vast network of hidden systems that support your life: pipes that carry natural gas, potable water, stormwater, sewage, and communications wires. These pipes rarely come to mind, but we agree that their operation is for the common good, that survival is not possible without them, and that armies of workers should keep them running. Surrounding those pipes are soils that are equally critical to our existence but to which we give much less attention. If we truly understood the delicacy of soil as a dynamic living system integral to the health of our towns and cities, our neighborhoods and families, we would be more cautious about how it is perceived, treated, and protected. Healthy soil performs important functions such as sequestering CO₂, mitigating stormwater runoff, supporting plant life, and sustaining the microbial populations that form the basis for all living things. So essential and complex are the conditions for soils in more developed areas that a new branch of science has arisen and is now being intensively pursued: the science of urban soils.

The Challenges of Urban Soils

Urban soils are are naturally-occurring soils that have been disturbed by development in a way that affects their functioning and properties. Urban soils are distinguished by a number of similar features: Their horizons (the natural vertical order of soils) have become jumbled by excavation. This makes urban soil horizons confoundingly diverse; one layer may be hospitable, but adjacent layers may not be, creating abrupt changes that can cause impermeable interfaces. Soil structure (the balance of solids and pores) has been crushed out of existence by mechanical compaction that chokes off water and air exchange. Organic matter (the source of plant nutrients) is low or missing from lack of replenishment, and this imbalances the soil biological community (bacteria, fungi, nematodes, arthropods, earthworms, insects, and more). Soil volumes that are important for plant health decrease because of interruptions from urban debris such as construction waste and rocks. Finally, the predominance of pavement separates soils from natural inputs such as nutrient-rich leaf litter, and this separation causes the nutrient cycling system to slow or shut down.

In the urban environment, soils are likely to be sealed off from the agents that build healthy soil—including wind, precipitation, ice, temperature, gravity, and mineralization—which frequently have been replaced by anthropogenic processes detrimental to soil functioning. Urban soils often become defined by human activities and land use histories at a particular location rather than by the continuum of geologic processes. This disrupted order makes urban soils particularly challenging to analyze, manage, and construct.

Urban Soils in the Service of Stormwater Management

Urban soils have the potential to be an important partner in stormwater management, use, and protection. The Natural Resources Conservation Service has recognized that soils with good infiltration and permeability can significantly reduce stormwater runoff rates and volumes that might otherwise overwhelm and impair the performance of the chain of water bodies that sustain our water supplies and the ecosystems that are necessary for healthy living [1]. Good infiltration reduces runoff by letting water soak into soils before it builds up to damaging volumes and velocities that would erode topsoil and carry both silts and pollutants to waterways. Permeability influences how quickly absorbed water drains through soil to useful depths for plants and recharge. Water that reaches root zones reduces irrigation needs. Some soil can filter toxic compounds or excess nutrients by holding them, degrading them, or otherwise making them unavailable. All of these benefits are feasible when soil has adequate pore space, which is only possible when soil’s natural physical texture and structure have been preserved or created.

Over-compaction of soils is one of the greatest deterrents to implementing best practices for stormwater management, because crushed particles minimize pore space and prevent water and air from moving through. In a study by the University of Florida, soil compaction from construction vehicles reduced infiltration by 70 to 90% [2].  This is perilously close to impermeable pavement.While people recognize that reducing pavement is the primary way to improve stormwater management, few see the same connection with soil. It is not enough to substitute pavement with plant beds if nothing has been done to prevent construction compaction. Without a soil management plan that includes practices for dealing with compaction before, during, and after development, urban soils will continue to become, plot by plot, a decommissioned resource in stormwater management.

 A Partnership between Urban Soils and Vegetation

The greatest positive effect of healthy urban soil is most evident in plants, the workhorses of the environment that clean the air, absorb CO₂, abate high temperatures, support wildlife, slow stormwater runoff, and keep erosion in check. In recent years, there has been resurgence in support for increasing the vegetation and tree cover in American cities. We are well aware of the positive ecological, social,[3]  and economic value of plants for individual properties, community open space, and urban regions [4]. Ecologically, a single large tree in the city is said to be ten to twenty times more beneficial to the environment than a single tree in the forest [5]. Yet the health of urban trees is declining at a rapid rate. A recent study by the U.S. Forest Service looked at twenty cities and found that they are losing tree canopy cover on average by 3% per year [6]. While this loss may seem small, over time the cumulative effects are severe. For example, Washington, D.C. lost 64% of its acreage-coverage from 1973 to 1999 at an average annual rate of 2.5% [7]. Still we continue to ignore the most basic need of trees: healthy soils. On most urban sites, fertile topsoil is absent, plant roots are restricted, air and water movement is suppressed, and nutrients cannot be exchanged. All this puts plants at an extreme disadvantage. The evidence of poor soil is all around, telegraphed by unhealthy plants. So if trees are to become “beautiful utilities” as urban tree expert Henry Arnold [8] suggests, then soil must also be treated in projects as an essential utility: analyzed, engineered, budgeted, scrutinized, and maintained.

Advocating for Soil

There are sound economic reasons to invest in good soil. As one of the core infrastructural materials in every urban landscape project, soil needs only to be tended more carefully to make it a viable component of stormwater management. Using soils to store and retain water as part of the stormwater management system can reduce costs for piping, drainage structures, runoff storage tanks, irrigation systems, and infrastructure maintenance and can provide more flexibility in design, since hard systems can add horizontal and vertical complexity that limits design options. Plants (especially street trees) with well-functioning soil are more able to start and sustain the nutrient cycling system without big infusions of maintenance after establishment and in maturity. When they do get maintenance, they are more likely to respond. Healthy soils beget trees that live longer and grow bigger, enabling them to cast more shade, and absorb more CO₂, and runoff. Even asphalt benefits from healthy trees, since shade improves its performance and durability [8]. Last, trees in good quality soil are far less prone to infection and pests, virtually eliminating the need for chemical treatments [9]. Investing in soil is critical for the long-term health of urban trees and by extension for the success of sustainable landscape projects and green infrastructure programs.

Why then do urban soils get so little attention when they are such a critical part of our environmental infrastructure and, ultimately, of human well-being? Some of the unawareness stems from societal and governmental ignorance. While keeping water and air usable is an unquestioned necessity, few people have the same association with city soils. For the most part, urban soil is considered mysterious, complex, and costly. Design professionals have an important role to play in dispelling unwarranted concerns and helping solve tangible problems: They should lead the way, project by project, educating their clients, agencies, and others about the need for healthy soil. Before that happens, designers must step up their own soil education. My interactions with colleagues suggest a dearth of understanding of basic soil science and the need for soil management in landscape projects. Often other landscape architects reach out for soil advice only when something has gone wrong. Designers do however have a thirst for this information as is shown by the increasing number of packed sessions in soil education at the annual meeting of the American Society of Landscape Architects (ASLA), the professions’ largest organization. Perhaps the neglect is also due to the fact that soil is not yet a hip topic; it has no visual presence. For many, design attention is reserved for visual effects; the hidden, infrastructural elements of landscape have long been considered the domain of engineers and scientists.

In my work as a landscape architect at Michael Van Valkenburgh Associates, soil discussions begin early, sometimes in the concept phase and always by schematic design. Soil is always an item on the design checklist. Just as all practitioners request surveys to locate utility lines, we request USDA soil tests to understand what we have to work with. Partnering with soil scientists, we have learned to interpret laboratory tests so we can ask the right questions and frame discussions. We keep up with developments in soil science (biology is the big topic now), often consult allied professionals, incorporate quality control practices into our specifications, and closely monitor sourcing, blending, and installing of soils during construction. We consider soil rigorously, as we do any other product or system in our projects.
I don’t mean to imply that assuring good soil is obvious or easy; it is neither, even for a firm that has been attempting it for twenty years. Every project brings unique soil challenges and clients with different agendas. The client may be unfamiliar with non-traditional stormwater approaches and therefore reluctant to consider soil-dependent systems. Brownfield properties often have contaminated soil or no useful soil at all. In other kinds of properties, existing soils could be reused if amended, but space may be too limited to manage soil-blending operations. Sometimes soil chemistry is limiting. For example: elevated pH from concrete or limestone rubble can interrupt nutrient exchange and narrow plant selection; high salinity in soil near tidal waters wreaks havoc on water uptake and cellular structure in plants. Local contractors often have no experience with installing designed soils. In my experience, construction managers show little tolerance for any aspect of landscape construction that is dynamic, an inherent characteristic of soil in particular and landscapes in general. Unless we have a repeat client, the process of educating, convincing, and making monetary tradeoffs to get good soil starts anew on every project. Sometimes we battle the sins of others’ projects in which someone tried but failed to improve soils. Projects with unsuccessful or difficult soil processes often produce rumors that the landscape architect specified unrealistic soils that cost too much and slowed the schedule, even if the problem was caused by the laxity of a member outside the design team.

Repositioning Soil as Infrastructure

How can we begin a campaign for good urban soil? We can start by talking with city hall, one of the biggest makers of landscapes and planters of trees, about the importance of soil. How many of the thousands of landscapes planted every year include soil improvement? Atlanta, Detroit, Denver, Los Angeles, and many other cities have tree-planting programs. Ambitious past and current mayors like Richard Daley and Michael Bloomberg launched campaigns to plant a million trees. Despite current commitments to increasing urban vegetation through tree planting, under current practices the mortality rate for young street trees is shockingly high: Some studies have found that over twenty-five percent of newly planted trees die within two years of installation [10,11], wasting already strained public funds and leaving behind a depressing reminder of failed nature. Wouldn’t it be more strategic to forgo planning one million trees in poor soil and instead plant 500,000 trees in good soil? [12]

To be stewards of urban soils, we need to ask pointed questions early in and throughout projects and insist on satisfactory answers that ensure positive long-term results for stormwater and planting. When zoning requires developers to add or replace trees, we need to ask for more than in-kind caliper inches and to require a soil management plan. When contractors install soil, they need to treat it like the valuable commodity it is or bear the cost of remediation. State and municipal specifications (which are used by contractors defensively instead of proactively) already define which dirt is suitable for backfill—why not extend this thinking to include requirements for the type, procurement, handling, and installation of planting soil? Landscape architects and anyone else who works with the landscape need to heed these too. Such guidelines should not be overly technical or onerous. Plant species should be matched to soil conditions, especially its pH and water supply. Trees should be planted at the right elevation to expose the root flare so soil doesn’t suffocate the tree. Adequate soil volume (800 to 1400 cubic feet per tree) and shared root space to encourage root spread should be provided [13]. Soils should be arranged to mimic the horizons in nature in which the top is rich in nutrients, the middle has the correct structure to encourage root growth, and the bottom is drainable. To resist compaction and maintain water and air exchange, soils higher in medium-to-coarse sands (rather than easily compactable fine sands and loam) should be used, and limits on density should then be set. Wet or frozen soils should not be moved or installed. To promote water and air exchange, rootball zones in tree pits should be exposed and at least half of the surface area of a plant bed should be left open, or a simple aeration system should be installed. Well-aged compost should be used to to provide 5% to 10% organics to the top layer of soils. And last, utilities should be placed at least three feet from trees.

There are more technical elements and specifications to consider, especially for sites with no soils, but as Stuart Shillaber the superintendent of horticulture at Boston’s Rose Fitzgerald Kennedy Greenway Conservancy advised me recently about introducing organic maintenance, “be happy when someone can implement 60% of the program. The rest will come when clients see results.”

The installation and upkeep of our existing “hard” utility systems requires substantial public and private investment. Creating well-functioning soils would not require large funds from the public since this work can be achieved project by project.  Upkeep of hard utilities is costly and disruptive; not so for soils that can be tended several times a year with substantially less trouble. The ASLA estimates that every year nearly 4.6 million acres are affected by public and private landscape projects [14]. Making headway on a quarter to third of that amount would start a revolution.

The Future of Urban Soils

From my vantage point, prospects for improving urban soils are good. In my thirty-year career as a landscape architect, there has never been a time of greater interest, research, and resources for managing urban soils and as many successfully constructed projects using urban soils. Advocacy for higher quality soil is rising nearly forty years after Dr. Phil Craul (professor emeritus at SUNY) and his colleagues started the field studies on urban soils that led to his 1992 publishing of the seminal Urban Soil in Landscape Design. Today, the USDA’s National Resources Conservation Service has substantial mapping, literature, and research on urban soils [15]. Ted Hartsig, a division chair of the Soil Science Society of America, tells me that the organization recently formed an urban soils division and committee whose focus is issues of urban soils including morphology and classification, the relationship of chemicals and nutrient quality, physics, biology, and structure, as well as the restoration and management of these soils. Urban soils studies are proliferating at public and private universities like Johns Hopkins and Kansas State.

Most critically, the public is starting to understand at the personal level of their gardens that the old adage “better to put a $5 tree in a $50 hole than to put a $50 tree in a $5 hole” is correct. Remember that until professionals and individuals teamed together to demand action, climate change was downplayed. Landscape architects and other professionals must play a part, whether through projects, lobbying our government, writing articles, lecturing, self-education, or speaking up in any propitious situation. We can be plausible leaders in the discussion to invest in another underworld utility, the first that is purely for the public good.

References

[1]  Soil Quality Information Sheet. Soil Quality Indicators: Infiltration”, Natural Resources Conservation Service, USDA, January 1998 http://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs143_019144.pdf

[2]  J.H. Gregory, M.D. Dukes, P.H. Jones, and G.L. Miller, “Effects of urban soil compaction on infiltration rate,” Journal of Soil and Water Conservation, Volume 61, Number 3. http://abe.ufl.edu/mdukes/pdf/stormwater/Gregor-et-%20al-JSWC-compaction-article.pdf

[3]  Geoffrey H. Donovan, David T. Butry, Yvonne L. Michael, ScD, Jeffrey P. Prestemon, Andrew M. Liebhold, Demetrios Gatziolis, Megan Y. Mao, American Journal of Preventive Medicine, “The Relationship Between Trees and Human Health: Evidence from the Spread of the Emerald Ash Borer,” Volume 44, Issue 2, pp. 139–45, http://www.ajpmonline.org/webfiles/images/journals/amepre/AMEPRE_3662-stamped_Jan_8.pdf

[4]  “Statistics on the Economic Value of Trees,” Conservation Montgomery, http://conservationmontgomery.org/resources2.html

[5]  “Study: Nations urban forests losing ground; New Orleans, Albuquerque, Houston losing Trees.” News Release, USDA Forest Service, February 23, 2012, http://www.fs.fed.us/news/2012/releases/02/urban-forests.shtml

[6]  Stephen C. Fehr, “Mayor Working To Keep It Green; Williams Pleads For More Trees,” Washington Post, November 17, 1999, http://caseytrees.org/wp-content/uploads/2012/02/02.01.1999-original-article-washingtonpost.pdf

[7]  Henry Arnold, “Sustainable Trees for Sustainable Cities,” Arnoldia, Volume 53, Number 3, 1993, http://arnoldia.arboretum.harvard.edu/pdf/articles/1993-53-3-sustainable-trees-for-sustainable-cities.pdf

[8]  E. Gregory McPherson and Jules Muchnick, “Effects of Street Tree Shade on Asphalt Concrete Pavement Performance,” Journal of Arboriculture, Volume 31, Number 6, November 2005, 303, http://www.fs.fed.us/psw/publications/mcpherson/psw_2005_mcpherson001_joa_1105.pdf

[9]  “Basics of Organic Maintenance”, UMass Extension, Center for Agriculture, http://www.extension.org/pages/62978/basics-of-organic-landscape-maintenance

[10]  “New Research Survey Suggests Urban Trees are On the Decline,” Public Radio International, March 16, 2012, http://www.pri.org/stories/science/environment/new-research-survey-suggests-urban-trees-are-on-the-decline-8967.html

[11]  Jacqueline W.T. Lu, Erika S. Svendsen,
Lindsay K. Campbell, Jennifer Greenfeld, Jessie Braden, Kristen L. King, and Nancy Falxa-Raymond, “Biological, Social, and Urban Design Factors Affecting Young Street Tree Mortality in New York City,” City and the Environment, Volume 3, Issue 1, 2010, http://digitalcommons.lmu.edu/cgi/viewcontent.cgi?article=1069&context=cate

[12]  “As City Plants Trees, Some Say a Million Are Too Many,” The New York Times, October 18, 2011, http://www.nytimes.com/2011/10/19/nyregion/new-york-planting-a-million-treestoo-many-some-say.html?pagewanted=all

[13]  James Urban, Up by Roots: Healthy Soils and Trees in the Built Environment, International Society of Arboriculture, 2008

[14]  “What is Landscape Architecture?” American Society for Landscape Architects, http://www.asla.org/nonmembers/LicPac99.htm

[15]  Soil Quality Information Sheets, Soil Quality Institute in cooperation with the National Soil Survey Center, NRCS, USDA; and the National Soil Tilth Laboratory, Agricultural Research Service, USDA, http://soils.usda.gov/sqi/publications/publications.html#utn

Suggested Reading

Timothy A. and Philip J. Craul, Soil Design Protocols for Landscape Architects and Contractors, Jon Wiley & Sons, 2006.

James Urban, Up by Roots: Healthy Soils and Trees in the Built Environment, International Society of Arboriculture, 2008

“Standards for Organic Land Care, Practices for the Design and Maintenance of Ecological Landscapes”, NOFA Organic Land Care Program publication, Northeast Organic Farmer’s Association, 2011. http://www.organiclandcare.net/sites/default/files/upload/standards2011.pdf

“Landscape Performance Series: Benefits Toolkit, Fast Facts Library, Scholarly Works”, Landscape Architecture Foundation, http://lafoundation.org/research/landscape-performance-series

http://landscapeurbanism.com/article/reconsidering-the-underworld-of-urban-soils/

Increased Carbon Dioxide May Lead to Greener Deserts

But researchers warn that CO2 fertilization could also result in other environmental shifts.

Increased levels of atmospheric carbon dioxide may have contributed to a gradual greening of some desert regions over the past 30 years, a process that will continue, according to a new study. But the authors warn that this "CO2 fertilization effect" could also have consequences for native plants and the wildlife that depends on them.

The study, published May 15 in the journal Geophysical Research Letters, was conducted by researchers from the Commonwealth Scientific and Industrial Research Organization (CSIRO), Australian National University and the Australian Research Council Centre of Excellence for Climate System Science.

The researchers went into this project knowing that satellite data collected since the 1980s has shown a worldwide increase in green foliage. Scientists around the world have theorized that this may have been a result of increased levels of CO2, a theory this new study supports. The authors of this new study looked at desert areas on four continents — where increases in vegetation would be easier to see and quantify — and created a mathematical model to calculate how they might have been affected by CO2 fertilization.

With those calculations in hand, they then compared their predications to satellite imagery data from 1982 to 2010. Knowing that CO2 levels have increased 14% during that period, the researchers calculated that desert foliage would have increased from 5-10% during that 28-year period. The satellite data revealed that they average increase in foliage during that time was 11% (a number that was adjusted for short-term precipitation changes). The researchers call this correlation "strong support for our hypothesis," although it is not conclusive proof.

"Lots of papers have shown an average increase in vegetation across the globe, and there is a lot of speculation about what's causing that," lead author Randall Donohue of CSIRO said in a news release about the study. "Up until this point, they've linked the greening to fairly obvious climatic variables, such as a rise in temperature where it is normally cold or a rise in rainfall where it is normally dry. Lots of those papers speculated about the CO2 effect, but it has been very difficult to prove."

The direct link of this greening to CO2 has remained a theory for because, as Donohue explained to NBC News, "There are so many processes occurring simultaneously that affect plant behavior, it is very difficult to determine which process is responsible for any given change."

 The researchers warn that CO2 fertilization could have negative effects for native plants in these desert regions. "Trees are re-invading grass lands, and this could quite possibly be related to the CO2 effect," Donohue said. "Long-lived woody plants are deep rooted and are likely to benefit more than grasses from an increase in CO2." Increased tree levels in arid regions could, meanwhile, increase the threat of forest fires.

Donohue said the effect of increased carbon dioxide levels on plants should be a greater focus of global study. "It needs to be considered as an important piece of the overall global-change puzzle that we are still trying to figure out," he told NBC.

http://www.mnn.com/earth-matters/climate-weather/stories/study-increased-carbon-dioxide-may-lead-to-greener-deserts

U.S. Urban Trees Store Carbon, Provide Billions in Economic Value

From New York City's Central Park to Golden Gate Park in San Francisco, America's urban forests store an estimated 708 million tons of carbon, an environmental service with an estimated value of $50 billion, according to a recent U.S. Forest Service study.

 

Annual net carbon uptake by these trees is estimated at 21 million tons and $1.5 billion in economic benefit.
In the study published recently in the journal Environmental Pollution, Dave Nowak, a research forester with the U.S. Forest Service's Northern Research Station, and his colleagues used urban tree field data from 28 cities and six states and national tree cover data to estimate total carbon storage in the nation's urban areas.
"With expanding urbanization, city trees and forests are becoming increasingly important to sustain the health and well-being of our environment and our communities," said U.S. Forest Service Chief Tom Tidwell.

"Carbon storage is just one of the many benefits provided by the hardest working trees in America. I hope this study will encourage people to look at their neighborhood trees a little differently, and start thinking about ways they can help care for their own urban forests."

Tens of thousands of people volunteered to plant and care for trees for Earth Day and Arbor Day this year, but there are opportunities all year long. To learn about volunteer opportunities near your home, visit the Arbor Day Foundation. The Forest Service partners with organizations like the Arbor Day Foundation and participates in programs like Tree City USA to recognize and inspire cities in their efforts to improve their urban forests. Additionally the Forest Service is active in more than 7,000 communities across the U.S., helping them to better plan and manage their urban forests.

Nationally, carbon storage by trees in forestlands was estimated at 22.3 billion tons in a 2008 Forest Service study; additional carbon storage by urban trees bumps that to an estimated 22.7 billion tons. Carbon storage and sequestration rates vary among states based on the amount of urban tree cover and growing conditions. States in forested regions typically have the highest percentage of urban tree cover. States with the greatest amount of carbon stored by trees in urban areas are Texas (49.8 million tons), Florida (47.3 million tons), Georgia (42.4 million tons), Massachusetts (39.6 million tons) and North Carolina (37.5 million tons).

The total amount of carbon stored and sequestered in urban areas could increase in the future as urban land expands. Urban areas in the continental U.S. increased from 2.5 percent of land area in 1990 to 3.1 percent in 2000, an increase equivalent to the area of Vermont and New Hampshire combined. If that growth pattern continues, U.S. urban land could expand by an area greater than the state of Montana by 2050.
The study is not the first to estimate carbon storage and sequestration by U.S. urban forests, however it provides more refined statistical analyses for national carbon estimates that can be used to assess the actual and potential role of urban forests in reducing atmospheric carbon dioxide.

More urbanization does not necessarily translate to more urban trees. Last year, Nowak and Eric Greenfield, a forester with the Northern Research Station and another study co-author, found that urban tree cover is declining nationwide at a rate of about 20,000 acres per year, or 4 million trees per year.

http://www.sciencedaily.com/releases/2013/05/130507195815.htm

Phyto-remediation: Healing Urban Landscapes

Aspects of Phytoremediation

by Marti Gil 

There is no doubt that we, as humans, contaminate our environment by activities related to our lifestyle. For instance, the production of energy, food, clothes, infrastructure, and industries produce a concentration of substances that enter the Earth, affecting the conditions of the air, water, and soil ecosystems.

There are many procedures to eliminate these contaminants from the environment. One especially interesting method is the use of living organisms or bioremediation such as bacteria, mushrooms, algae, protozoa, and plants. Through this procedure the concentrations of the pollutants are decreased, taking advantage of their capacity to degrade these elements.

In a Landscape Architects Network article titled “Phytoremediation: Healing Urban Landscapes”  Yuliya approached the subject by using a great theoretical example from the Netherlands and this article begins by explaining how the healing of an environment with plants functions and the types of plants that we should use in order to eliminate specific contaminants.

Active Modular Phytoremediation Wall System, CASE

Phytoremediation is a set of methods, performed by plants that degrade, detoxify, assimilate, or metabolize contaminants deposited in the soil, water, or in the atmosphere. These contaminants are: pesticides, metals, organic compounds, herbicides, explosives, and other compounds that in many cases, cannot be degraded, but can be assimilated by the harvestable part of a plant.

The advantages are that this process is cost-effective because it is a natural process that uses solar energy and it is in situ. Furthermore, it can be an excellent method to implement in large areas, and it has been widely accepted by society and can be performed in an aesthetic manner. Some of the limitations are that it requires lengthy periods of time. Additionally, the contaminants cannot exceed the maximum level that the plants can assimilate. Phytoremediation does not work on profound soils or water due to the size of the plant’s roots and lack of research on a particular topic.

Living Machine

In order to select plants we need to investigate the concentration of the pollutants, the cost of the irrigation, the related maintenance, the length of time, the risk of pests, and the planting scheme. Plants that can be used to heal an ecosystem may vary depending on the characteristics of the environment, but we can generally expect healing from plants with deep roots (due to their scope), pastures (due to soil retention), legumes (due to the fixation of Nitrogen), and aquatic plants, which can be found worldwide.

According to Alejandro Mentaberry, Ph.D. from the Universidad de Buenos Aires in Argentina, there are six basic mechanisms in which plants do their work with the help of chemical and physical processes:

• Phyto-extraction: Mainly for the concentration of metals and other inorganic toxic compounds in the harvestable parts. It is important to consider plants with an important biomass, principally on the aerial part such as sunflowers, dandelions, and mustard.
• Rhizo-filtration: The roots are used to absorb, precipitate and concentrate heavy metals and organic compounds in liquid effluents. The plants should have roots that grow fast and abundant ramification like different algae and Thypha latifolia.
• Phyto-stimulation: Uses the roots exudates to promote the growth of degradation organisms like mushrooms and bacteria, efficient with organic hydrophobic compounds like oil sub products. Phreatophyte plants (with the roots in the water), trees from the genus Populus, pastures like Rye, phenol compounds producers like apple, and aquatic plants are great performers.
• Phyto-stabilization: Plants resistant to metals are used to avoid and reduce the movement both in air and to underground layers. The use of phreatophyte trees and pastures are recommended.
• In both Phyto-degradation and phyto-volatilization a transformation of the contaminants are present so the use of phreatophyte trees (Populous sp.), pastures and legumes are recommended. The plants are used to capture and metabolize organic compounds to produce less or non-toxic sub products in the degradations, and to collect heavy metals and organic compounds releasing them into the atmosphere through transpiration on the volatilization.

All these techniques and technologies are improving daily and becoming more efficient.  It is important to consider that collectively they can be part of a system that combines different kinds of mechanisms to heal our ecosystems improving the results.

Shanghai Houtan Park, Turenscape

Of course, it does not mean that we can continue polluting without remorse just because we have found a way to clean the world naturally. It means that we can change what we, as humans, have done and begin to produce more environmentally friendly methods of eliminating contaminants not only in big, gray facilities, but in projects such as the Shanghai Houtan Park, which maintains a beautiful landscape with a practical use.

http://landarchs.com/aspects-phytoremediation/

Streams Stressed by Pharmaceutical Pollution

Antihistamines Alter Sensitive and Essential Habitat

 

Pharmaceuticals commonly found in the environment are disrupting streams, with unknown impacts on aquatic life and water quality, according to a new ecological applications paper released by the Cary Institute of Ecosystem Studies in Millbrook, N.Y.

The paper, written with input from researchers at Indiana University and Loyola University Chicago, highlights the ecological cost of pharmaceutical waste and the need for more research into environmental impacts. Globally, lakes and rivers are polluted by an array of pharmaceutical and personal care products. Freshwater fish and the invertebrates they eat are increasingly bathed in a weak solution of caffeine, estrogen, antibiotics, and antihistamine drugs – but little is known about the levels at which these compounds become toxic or lethal, or what the effect on our drinking water may be.
 “Pharmaceutical pollution is now detected in waters throughout the world,” said lead author Dr. Emma Rosi-Marshall, a scientist at the institute. “Causes include aging infrastructure, sewage overflows, and agricultural runoff. Even when wastewater makes it to sewage treatment facilities, they aren’t equipped to remove pharmaceuticals. As a result, our streams and rivers are exposed to a cocktail of synthetic compounds, from stimulants and antibiotics to analgesics and antihistamines.”

With colleagues from IU and Loyola, Rosi-Marshall looked at how six common pharmaceuticals influenced similar-sized streams in New York, Maryland, and Indiana. Caffeine, the antibiotic ciprofloxacin, the antidiabetic metformin, two antihistamines used to treat heartburn (cimetidine and ranitidine), and one antihistamine used to treat allergies (diphenhydramine) were investigated, both alone and in combinations, using pharmaceutical-diffusing substrates.

“We focused on the response of biofilms – which most people know as the slippery coating on stream rocks – because they’re vital to stream health,” Rosi-Marshall said. “They might not look like much to the naked eye, but biofilms are complex communities composed of algae, fungi, and bacteria all living and working together. In streams, biofilms contribute to water quality by recycling nutrients and organic matter. They’re also a major food source for invertebrates that, in turn, feed larger animals like fish.”

Healthy streams are slippery streams, Rosi-Marshall said. And it turns out that antihistamines dry more than our noses. The most striking result of the study was diphenhydramine’s effects on algal production and microbial respiration. Exposure caused biofilms to experience up to a 99 percent decrease in photosynthesis, as well as significant drops in respiration. Diphenhydramine also caused a change in the bacterial species present in the biofilms, including an increase in a bacterial group known to degrade toxic compounds and a reduction in a group that digests compounds produced by plants and algae.

Results suggest that this antihistamine is disrupting the ecology of these sensitive biofilm communities. “We know that diphenhydramine is commonly found in the environment,” Rosi-Marshall said. “And its effect on biofilms could have repercussions for animals in stream food webs, like insects and fish. We need additional studies looking at the concentrations that cause ecosystem disruption, and how they react with other stressors, such as excess nutrients.”

The other pharmaceuticals investigated also had a measurable effect on biofilm respiration, both alone and in combinations. More work is needed to understand how drug mixtures, which most natural streams experience, impact freshwater systems, the report noted.

Society’s dependence on pharmaceuticals is not likely to wane. Nor is its need for clean, fresh water. This study adds another piece of evidence to the case calling for innovations in the way we manage wastewater, Rosi-Marshall said. Currently, only a fraction of the world’s wastewater is treated, and the infrastructure in many developed nations is aging, she said.

Rosi-Marshall received funding from the Wallace Genetic Foundation, Inc. and the Cornell-Douglas Foundation to help build an artificial stream facility on the Cary Institute's campus, to facilitate the research. She said few places exist without some level of these contaminants, so scientists need artificial streams to serve as control waters for research.

Contributors to the project included Dustin Kincaid and Heather Bechtold of the Cary Institute of Ecosystem Studies, Todd V. Royer from the School of Public and Environmental Affairs, Indiana University, and Miguel Rojas and John J. Kelly from the Department of Biology, Loyola University Chicago.

http://www.sustainablecitynetwork.com/topic_channels/environmental/article_17d05fd2-a232-11e2-9f07-0019bb30f31a.html?mode=story


Herzog-de Meuron Breaks Ground on Public Bathing Lake in Riehen

In 1979, just a year after founding their practice, Herzog-de Meuron won a competition to design a public swimming pool for the Swiss municipality of Riehen. After developing several unrealized iterations over the following years, the project was put on hold indefinitely in 1982. Twenty-five years later, in 2007, Herzog- de Meuron were commissioned to rethink the project and proposed to abandon the conventional pool concept with its mechanical and chemical water treatment systems in favor of a pool closer to natural condition with biological filtration.

Understood as a bathing lake, Naturbad Riehen was modeled after the natural pool on the local “Badi”, Basel’s traditional wooden Rhine-side baths, which combine a lively atmosphere with a timeless appearance. Planted filtering cascades purify the water and define the soft edge of the lake, as the site’s southern perimeter opens up to the river, bounded only by a green hedge.

A multi-functional timber wall, that offers a 200-meter long sheltered solarium with recliners, shields the site on the north and west from the adjacent roadway as it connects to an entrance on the east that provides support amenities.

The biological water treatment basins – the non-mechanical “heart” of the baths – are embedded in the sloping landscape on the opposite side of the road. Together with various leisure facilities provided here, they form a recreational area open the whole year round to the municipal population. In terms of ecological cleaning capacity, the baths are designed to accommodate 2 000 bathers per day.

Rosenfield , Karissa. "Herzog & de Meuron Breaks Ground on Public “Bathing Lake” in Riehen" 09 Apr 2013. ArchDaily. Accessed 10 Apr 2013.

New York's Green Roofs Are Crawling With Fungi

Demand for green roofs might plummet if they became known as "fungal roofs." But that is what they are, at least in New York – and contrary to what it may sound like, it's not a bad thing.

The world just became a little more aware of the hidden-but-teeming biomass of green roofs thanks to the intrepid work of researchers from Barnard College, Columbia University, Fordham and the University of Colorado. Recently, these guys found themselves wondering if the gardens in the sky might support different kinds of life than the stuff at dog-pee level. It's a realm into which few scientific minds have tread. While green roofs as heat-island dampeners and rainwater-runoff plugs have been widely discussed, the extent to which they serve as urban "biodiversity reservoirs" (in the researchers' words) is something of a mystery.

So in the summer of 2011, the team set out to test the soil composition of 10 green roofs stationed at recreation centers throughout the five boroughs: Using soil corers, they hunted for fungi, because fungal communities play a key role in a roof garden's health and longevity. For comparison's sake, they also took samples from five city parks near some of the roofs, including Central Park and the High Line. A little magic from "inductively coupled plasma atomic emission spectroscopy" at Alabama's Auburn University Soil Testing Laboratory, as well as a dollop of phospholipid fatty-acid extraction and Illumina-dye sequencing, and they had their results, which were published this month in the journal PLOS ONE.

So what were the conclusions? For one, these sun-kissed carpets of gray goldenrod and smooth blue aster are absolutely crawling with fungi. The researchers logged an average of 109 types of fungi per roof, such as Glomus, Acaulospora, Rhizophagus and Funneliformis, suggesting that green roofs can indeed contribute to urban biodiversity. As they explained:

"We found that green roofs supported a diverse fungal community, with numerous taxa belonging to fungal groups capable of surviving in disturbed and polluted habitats. Across roofs, there was significant biogeographical clustering of fungal communities, indicating that community assembly of roof microbes across the greater New York City area is locally variable. Green roof fungal communities were compositionally distinct from city parks and only 54% of the green roof taxa were also found in the park soils."

In other words, the roofs are home to fungi not typically given to squelching around in normal parkland. They also seem to be better for growing stuff you might, you know, put in your mouth: While the soil in New York's parks showed a greater biomass of microbes, it also tested higher for heavy metals, a scourge of urban gardens that can be unhealthy if consumed in larger quantities.

Here's a comparison the researchers put together illustrating how the roofs stacked up against the parks, in terms of the abundance of fungal phyla:

Needless to say, this is hardly the first news of green roofs supporting life. The elevated gardens are routinely patrolled by insects and in some cases much larger fauna. In Australia, for instance, the Adelaide Zoo maintains several grassy roofs that are designed as homes for urban plants and wildlife, like reptiles, insects and bats.

And an immense green roof in the U.K., mounted on a wastewater treatment facility near Brighton, attracts seagulls and crows that pluck at its quaking grass in search of food. To fight those hungry birds, the roof's overseers have released even more animals over the roof – ferocious goshawks, a golden eagle and even a great horned owl.

http://www.theatlanticcities.com/neighborhoods/2013/03/new-yorks-green-roofs-are-crawling-fungus/4960/

Coding Urban Metabolism

Urban Reef. Kyle Belcher, Dylan Barlow and Geoffrey Gregory, 2009.

As we struggle to bring population density and energy consumption back into alignment, a new ecological code and framework is needed to drive design decisions and to strengthen the connection between energy consumption and renewable energy production. Yesterday’s models of zoning and planning are outmoded. Perhaps it’s time for a new ecological urban framework.

Rethinking Zoning as an Urban Ecology

A response to the conditions of contemporary urbanism must be prepared to address present cultural, economic and environmental challenges with solutions that combine tectonic and performative aspects of design. As we struggle to bring population density and energy consumption back into alignment, a new ecological code and framework may be needed to drive design decisions and to strengthen the connection between energy consumption and renewable energy production. In the fields of urban planning and design, traditional zoning restrictions and ordinances have remained rooted in limitations and regulations rather than guidelines for enhanced performance.

Traditional zoning emphasizes public rights to resources (light, air, or services and infrastructure, for example), rather than productive initiatives or other transformative strategies. Current initiatives, such as the Solar America Communities Program initiated by the U.S. Department of Energy have begun establishing foundations to build sustainable solar markets, and increase the demand for renewable energy through policies and incentives. However, these strategies are currently not linked to citywide ecological frameworks and codes that can support design strategies.

Read more:
http://landscapeurbanism.com/article/coding-urban-metabolism/