Tag Archives: green infrastructure

urban bee habitat

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The BBC has an article on urban habitat for bees:

There is widespread concern that wild bee populations in rural areas are being adversely affected by a number of factors, including pesticides.

“For a bee species to be present in [an urban] habitat, it must be able to find food and nesting substrate,” said co-author Laura Fortel, a researcher from the French National Institute for Agricultural Research (INRA).

“Urban and periurban (the transition between rural and urban) sites can provide high quantities of flowers all year long; they show a high diversity of land cover types and are often warmer than surrounding landscapes.”

She added: “Also, such habitats are seldom treated with pesticides, which are involved in the decline of bees elsewhere.”

It seems like a reversal of conventional wisdom that cities could be important reservoirs of biodiversity when rural agricultural areas have become degraded. In a way it is a negative story, but in another way it is reminder that we should not cynically assume that urban landscapes are always biological dead zones. There is a lot we can do to make them much more ecologically functional for important species of pollinators and birds. If it is happening to some extent by accident, then it could work even better if we did it by design. We can think about how the individual small patches are designed, then think about how they can connect better to each other, to larger urban parks, and to the rural landscape.

July 2014 in Review

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I’m going to do a “month in review” post where I sort selected posts that talk about positive trends and ideas vs. negative trends, predictions, and risks. Just for fun, I’ll keep a score card and pretend my posts are some kind of indicator of whether things are getting better or worse. I’ll give posts a score from -3 to +3 based on how negative or positive they are.

Negative trends and predictions (-6):

  • The “trophic theory of money”, which to oversimplify just says that economic growth will always add to humanity’s ecological footprint. I don’t buy this 100% but our footprint is certainly continuing to grow with no obvious signs that we are about to turn the corner. (-1)
  • New dams on the Mekong, a hotspot of aquatic biodiversity, may block fish passage although some mitigation measures are being tried. (-1)
  • A new book by Edan Lepucki describes a future where people “traverse a cross-section of mid-collapse landscape, framed by the gradual decline of civilization”. (-1)
  • 100 years ago, exactly now, Europe was dissolving into the mostly unexpected chaos of World War I. Which led later to the extraordinary pain of the Great Depression. (-3)
  • Artificial intelligence and robots are finally turning into a commercial reality, with positive and negative implications like crushing labor unrest. Also, they can identify dog breeds with some accuracy. (-0)

Positive trends and predictions (+4):

  • Urban trees can mitigate a small, but not insignificant (around 2%), amount of a city’s carbon emissions. And that’s with business-as-usual practices – I speculate that this could be boosted to 5-10% with a concerted effort, which combined with emissions reductions could make an actual difference. (+1)
  • “Blue Urbanism” gives some examples of how cities could be more aware of their impacts on the oceans (but clearly, those impacts are still huge so I’m not giving this any points). (+0)
  • On the green infrastructure front, Biophilic Cities lays out a hopeful vision of how urban areas can be more integrated into the natural world. A new website, Falling Fruit, is trying to combine information on worldwide urban green infrastructure with a focus on edibles. (+2)
  • Some EU cities are considering a complete ban on the internal combustion engine…by 2050. Stockholm however is envisioning a “single, supple mesh of mobility” by 2025. (+1)
  • Autonomous vehicles are not quite a commercial reality, but they will be and there are both positive and negative implications of that. (+0)
  • Dubai is building a gigantic, climate-controlled city-like mall under a dome. Children who grow up in places like this will be able to adapt readily to gigantic, climate-controlled mall-like cities in outer space. (+0)

So my Hope for the Future Index stands at -2.

Subirdia

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Welcome to Subirdia: Sharing Our Neighborhoods with Wrens, Robins, Woodpeckers, and Other Wildlife

NPR reviews an upcoming book called Subirdia, which says that in temperate areas, there are more bird species in the suburbs than in cities or even forests:

So what have suburbs got that forests don’t? Suburbs, he says, offer a wide range of artificially designed garden habitats, providing a smorgasbord of nuts, fruits, seeds, insects and ponds, in dense concentrations. Because they are rich with different kinds of bird food, suburbs are rich with different kinds of birds…

But let’s not get crazy about this: suburbs are not the birdiest zones on earth. Any patch of tropical forest, with its dazzling populations of plant and animal life, will trump a garden-rich suburb. But if you are comparing suburban bird diversity to temperate wild spaces — say the Cascades, the Smokies or the Adirondacks — the suburbs, shockingly, win.

So maybe our goal in denser cities should be to create a landscape with more of this variety of garden habitats. That is doable, and a much more attainable goal than trying to create forest-like habitat in cities. There are some shy species that won’t come to the city, but the city can be pleasant for a wide variety of species, even humans, if we work at it.

nurse trees

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I find the idea of “nurse trees” interesting. From Wikipedia:

A nurse tree is a larger, faster-growing tree that shelters a smaller, slower-growing tree or plant. The nurse tree can provide shade, shelter from wind, or protection from animals who would feed on the smaller plant.

Eventually the younger plant outcompetes the older one, and the older one dies, or I suppose it can be cut down by humans. I am thinking about how to apply these ecological concepts to give a helping hand in more urban areas. In my professional work on stormwater management, we often dig up urban soils and replace them with a manufactured soil mix that is more permeable to water and better for plant growth. But all that digging and trucking and waste disposal has a cost and an environmental impact, when we are doing all this to try to help downstream water quality. Maybe we can use carefully chosen trees or plants early on to loosen and add organic matter to the urban soils, then come back a year or two later and plant the trees and plants that we want for the long term. Even better if there is some plant mix where the first phase is faster growing, but then gradually gets out-competed by the second phase, just like the nurse tree concept described above.

green roofs

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Green roofs are still pretty expensive and not all that common, at least in North America. But here’s a study in Ecological Engineering where they turned out to work better than people thought in Hong Kong, a humid subtropical area.

Urbanization replaces permeable surfaces with relatively impervious ones to intensify mass and temporal response of stormwater runoff. Under heavy rainfalls, urban runoff could impose tremendous stress on the drainage systems, contributing to combined sewer overflow and flooding. Green roof offers an on-site source-reduction sustainable stormwater management measure that mimics pre-development hydrologic functions. It can retain and detain stormwater as well as delay and suppress peak discharge. However, previous studies were conducted mainly outside the tropics. Since green-roof hydrologic performance can be notably influenced by local meteorological conditions, dedicated investigation in the tropics are necessary. Moreover, substrate depth has long been regarded as an influential factor in green-roof stormwater retention, but recent findings have implicated that such relationship may be more complex. This study (1) evaluates green roof stormwater mitigation performance and potentials in humid-subtropical Hong Kong; and (2) investigates systematically the effect of substrate depth and addition of rockwool, a high water-retention growth medium, on quantitative performance. Using multiple 1.1-m2 raised green-roof platforms placed on an urban rooftop, the effect of four substrate-depth treatments on stormwater mitigation performance was examined over a 10-month study period. The results show that, while the retention under Hong Kong’s frequent and heavy rainfall regime seems to be less effective, remarkable peak reduction and peak delay were evidently expressed even when the green-roof systems have reached full moisture-storage capacity. No statistical significance was found between treatments, despite the slightly higher mean performance of the 80-mm soil substrate. Satisfactory peak performance of the 40-mm soil substrate implies that a thin substrate can provide effective peak mitigation, especially if building loads are of concern. Extensive green roof remains as a promising alternative mitigation strategy to urban stormwater management in Hong Kong with potential application to other tropical areas.

Part of me doesn’t like using an inorganic material like rockwool. But if somebody comes up with a simple, cheap material that we can practically just staple or spray on to roofs in urban areas, it could be a quick way to restore a lot of hydrologic function – retention, evaporation, peak flow reduction, and cooling – in urban areas. It could be a transitional step on our way to restoring both hydrologic and ecological functions together – ideally we would want to capture that water and use it to grow something of use to either people or wildlife or both. But we are far from ideal today, so I’m all for some smaller steps in the right direction.

 

restoring the American Chestnut

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I like this abstract in Restoration Ecology on the most efficient way to reseed the American Chestnut to eastern forests.

Efforts are underway to return the American chestnut (Castanea dentata) to eastern forests of North America following its decline due to the introduction of the chestnut blight (Cryphonectria parasitica). Approaches include developing blight-resistant chestnut lines through breeding programs and via genetic engineering. Reestablishment of resistant chestnut to eastern forests would produce one of the most extensive ecological restoration transformations ever attempted. However, this undertaking is costly and optimization of reintroduction methods is needed. We used the computer program NEWGARDEN to model whether some patterns of founder placement (regular vs. random spacing at differing densities) produce more rapidly expanding populations across a range of gene dispersal distance conditions (via both offspring and pollen). For a simulated introduction project employing 169 founders, placing founders randomly in a square of side 0.85 km produced higher rates of predicted population growth compared with larger or smaller squares under near gene dispersal conditions; this side distance was 1.0 km under far gene dispersal conditions. After 100 population bouts of mating and under near gene dispersal conditions, the trial with founder placement producing the greatest population expansion rate exhibited a 314% increase in census size compared with the founder pattern yielding the slowest expansion. Neither loss of alleles nor inbreeding or subdivision was significantly increased under the founder placement patterns yielding the most descendants. Exploring different numerical and geometrical founding scenarios using NEWGARDEN can provide first estimates of founding patterns or stand manipulations that will return the most descendants produced per founder planted in restoration projects.

So it is possible to give an ecosystem a helping hand. Maybe we can use similar principles not just to restore species and ecosystems that used to exist, but to create truly functional ecosystems in rural, suburban, and urban areas and the transitions between them.

parking design

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ReThinking a Lot: The Design and Culture of Parking

As I mentioned recently, I will return frequently to urban design and urban infrastructure issues because I think these are key to long-term sustainability – and I am talking about sustainability in the dictionary sense of a system (in this case, our human civilization here on Earth) that is built to last. I think of urban sustainability as having two major sides, which are obviously intertwined. The first is green infrastructure, which I am convinced is the answer to managing water and ecosystems. The second is the built environment – buildings and the manmade infrastructure we need to move people and stuff around (roads, rail, pipes, electric lines, and so on).

In the short term, we might think of land use as driving the type of transportation systems we build. But in the longer term, it is really a chicken and egg problem – the way we choose to get around will have a big effect on how urban areas are built. Parking is a big part of this, because currently most cars sit idle most of the time and take up enormous amounts of space that is then taken out of the picture for any other kind of use. Not only that, but car parking takes up so much space that we then need to use cars just to cross the distances taken up by other cars – stuff is just so far apart that walking is not as practical, not to mention hot, dangerous, and deadly boring.

So on that note, here is a new book about parking. Here is the Amazon description:

There are an estimated 600,000,000 passenger cars in the world, and that number is increasing every day. So too is Earth’s supply of parking spaces. In some cities, parking lots cover more than one-third of the metropolitan footprint. It’s official: we have paved paradise and put up a parking lot. In ReThinking a Lot, Eran Ben-Joseph shares a different vision for parking’s future. Parking lots, he writes, are ripe for transformation. After all, as he points out, their design and function has not been rethought since the 1950s. With this book, Ben-Joseph pushes the parking lot into the twenty-first century.

Can’t parking lots be aesthetically pleasing, environmentally and architecturally responsible? Used for something other than car storage? Ben-Joseph shows us that they can. He provides a visual history of this often ignored urban space, introducing us to some of the many alternative and nonparking purposes that parking lots have served–from RV campgrounds to stages for “Shakespeare in the Parking Lot.” He shows us parking lots that are not concrete wastelands but lushly planted with trees and flowers and beautifully integrated with the rest of the built environment. With purposeful design, Ben-Joseph argues, parking lots could be significant public places, contributing as much to their communities as great boulevards, parks, or plazas. For all the acreage they cover, parking lots have received scant attention. It’s time to change that; it’s time to rethink the lot.

 

the future of urban transportation

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I like the vision of future urban transportation laid out in this article from Atlantic CityLab:

My utopian vision of how this could play out is to rededicate a lot of space in cities that was de facto applied to cars in the 1950s, after the death of the streetcars and the explosion of expressways, over to active transportation. Cars entering city limits would have to be autonomous or switched to driverless mode, as these will be deemed safe for all users of the transportation system and will operate in much less road space than drivers need now. (As a reference point, auto accidents are the leading killer of young people worldwide.) Parking needs could decrease dramatically, too, as most autonomous vehicles will be on-demand and active, compared to the 95 percent of time that current cars sit parked. We would have a transit backbone consisting of heavy and light rail/streetcars, and regional/arterial buses. The rest of the network and space would be slanted towards walking, bike-share, and other alternative modes.

I don’t necessarily think this is a “utopian vision”. I think a lot of it is just going to happen and is already happening. Enormous amounts of space that have been devoted to car maneuvering and parking are going to be available for other uses. The question is, are we just going to let all the space sit there or have a good plan for what to do with it? Some of it can be used for housing and economic activity, some for parks, wildlife habitat and movement corridors, and food growing, and some for managing water or harvesting solar energy. And of course, combinations of these are possible. But we do need to have a vision and a plan, which some can call “utopian” if they so choose.

falling fruit

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This website, called Falling Fruit: Mapping the urban harvest, is attempting to be a worldwide map of harvestable food in urban areas. I think this is a great idea both for sustainability and for livability in urban areas. There must be a lot of fruit and nut trees on private land and in forgotten spaces of public land – median strips, the “tree lawn” between street and sidewalk, and so forth. But in many cases the people who own or control this land may not be interested in taking care of these trees. At the same time, I believe there are a lot of frustrated urban armchair gardeners out there who would love to take care of them, but don’t have permission to access the private property, or don’t know about or feel comfortable taking care of the trees on the public property. So a website like this could begin to connect the trees to the people who are willing to take care of the trees.

That’s just the trees we have now. If something like this took off, we could gradually replace more of our ornamental urban landscaping with edible landscaping – fruit hedges, strawberry lawns, and so on.  We could incorporate rain barrels, rain gardens, compost bins, even chickens and rabbits for people who are open to that. We could take wildlife habitat into account to, and start to take a larger view of the landscape – how patches of urban habitat can be connected, and how patches of urban habitat can be connected to larger urban parks and rural reserves.

By the way, I don’t mean for urbanism to be the primary subject of this blog. The subject is how our civilization is connected to, and impacting, and dependent on, the natural world and what that means for the future. But at the risk of stating the obvious, urban areas are where the people are so I will return to urban design and urban hydrology and urban ecology and land use and transportation topics fairly often.

Biophilic Cities

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Biophilic Cities: Integrating Nature into Urban Design and Planning

Yesterday I mentioned Blue Urbanism by Timothy Beatley. An earlier book of his was called Biophilic Cities: Integrating Nature into Urban Design and Planning. This echoes some of my personal ideas about building a civilization that is truly in harmony with nature. Here’s the description on Amazon:

Tim Beatley has long been a leader in advocating for the “greening” of cities. But too often, he notes, urban greening efforts focus on everything except nature, emphasizing such elements as public transit, renewable energy production, and energy efficient building systems. While these are important aspects of reimagining urban living, they are not enough, says Beatley. We must remember that human beings have an innate need to connect with the natural world (the biophilia hypothesis). And any vision of a sustainable urban future must place its focus squarely on nature, on the presence, conservation, and celebration of the actual green features and natural life forms.

A biophilic city is more than simply a biodiverse city, says Beatley. It is a place that learns from nature and emulates natural systems, incorporates natural forms and images into its buildings and cityscapes, and designs and plans in conjunction with nature. A biophilic city cherishes the natural features that already exist but also works to restore and repair what has been lost or degraded.
In Biophilic Cities Beatley not only outlines the essential elements of a biophilic city, but provides examples and stories about cities that have successfully integrated biophilic elements–from the building to the regional level–around the world.
From urban ecological networks and connected systems of urban greenspace, to green rooftops and green walls and sidewalk gardens, Beatley reviews the emerging practice of biophilic urban design and planning, and tells many compelling stories of individuals and groups working hard to transform cities from grey and lifeless to green and biodiverse.