Tag Archives: green infrastructure

November 2017 in Review

Most frightening stories:

  • I thought about war and peace in November. Well, mostly war. War is frightening. The United States of America appears to be flailing about militarily all over the world guided by no foreign policy. Big wars of the past have sometimes been started by overconfident leaders thinking they could get a quick military victory, only to find themselves bogged down in something much larger and more intractable than they imagined. But enemies are good to have – the Nazis understood that a scared population will believe what you tell them.
  • We should probably be sounding the alarm just as urgently, if not more urgently, on biodiversity as we are on global warming. But while the case against global warming is so simple most children can grasp it, the case against biodiversity loss is more difficult to articulate.
  • A theory of mass extinctions of the past is that they have been caused by massive volcanic eruptions burning off underground fossil fuels on a massive scale. Only, not quite at the rate we are doing it now. Rapid collapse of ice cliffs is another thing that might get us.

Most hopeful stories:

Most interesting stories, that were not particularly frightening or hopeful, or perhaps were a mixture of both:

  • You can get an actuarial estimate of your life span online. You can also search your local library catalog automatically whenever you consider buying a book online. Libraries in small, medium, and large towns all over the U.S. appear to be included. Only, not my library. Boo, Philadelphia Free Library.
  • “Transportation as a service” may cause the collapse of the oil industry. Along similar but more mainstream lines, NACTO has released a “Blueprint for Autonomous Urbanism“, which is my most popular post at the moment I am writing this.
  • It’s possible that the kind of ideal planned economy envisioned by early Soviet economists (which never came to pass) could be realized with the computing power and algorithms just beginning to be available now.


disappearing bugs

This surprising study from Germany raises the possibility that a catastrophic loss of insects is occurring and that it could lead to ecological collapse.

More than 75 percent decline over 27 years in total flying insect biomass in protected areas

Global declines in insects have sparked wide interest among scientists, politicians, and the general public. Loss of insect diversity and abundance is expected to provoke cascading effects on food webs and to jeopardize ecosystem services. Our understanding of the extent and underlying causes of this decline is based on the abundance of single species or taxonomic groups only, rather than changes in insect biomass which is more relevant for ecological functioning. Here, we used a standardized protocol to measure total insect biomass using Malaise traps, deployed over 27 years in 63 nature protection areas in Germany (96 unique location-year combinations) to infer on the status and trend of local entomofauna. Our analysis estimates a seasonal decline of 76%, and mid-summer decline of 82% in flying insect biomass over the 27 years of study. We show that this decline is apparent regardless of habitat type, while changes in weather, land use, and habitat characteristics cannot explain this overall decline. This yet unrecognized loss of insect biomass must be taken into account in evaluating declines in abundance of species depending on insects as a food source, and ecosystem functioning in the European landscape.

I knew about the frogs, elephants, tigers, bees, and loss of larger animal species and biomass in general, but I hadn’t really heard this idea that insects are disappearing. I can see a silver lining to this – I can’t really create elephant or tiger habitat around my house, and frog habitat is a little tough, but insects – I can actually help the little guys. On a larger scale, there is the question of green infrastructure – can we deliberately design habitats in cities, larger reserves, and corridors connecting them to support as much ecological function as we can? I think so, but I don’t think our public officials, engineers, urban planners, scientists, and others in a position to do this are tuned into the issue or even very open to hearing about it.

trees and public health

A new report from the Nature Conservancy makes the case for the value of urban trees to human health. They go through a number of economic valuation studies that are out there, and the literature on health benefits: air quality, heat stress, mental and physical health, climate change. Then they make a case that urban tree canopy in the U.S. is actually declining and that it is severely under-funded in most cities.

Also, on the tree front, here is a recent paper on the rate at which wood inside urban trees decays. I think one important concept with urban trees is to think of them as infrastructure that has to be maintained and replaced at some rate. They just don’t live as long as forest trees, because they are in stressful environments, performing functions for us, and getting worn out. And the cost of maintaining and replacing them is actually low, and their benefits high, compared to other types of infrastructure. But even though the engineering, planning and architecture professions have been talking a lot about green infrastructure for at least a decade, most of us still aren’t taking it seriously as infrastructure, and the construction industry, bureaucrats and politicians are not taking it seriously, if they have even absorbed the concepts at all. I think this is a case where wealthy private foundations or individuals could make an enormous difference if they wanted to, because the institutions to plant and maintain trees typically exist, but are just severely underfunded. So all I have to do is become a wealthy private individual and I will take care of this. Okay, a solution exists and I’ll get right on that.

The overlooked carbon loss due to decayed wood in urban trees

Decayed wood is a common issue in urban trees that deteriorates tree vitality over time, yet its effect on biomass yield therefore stored carbon has been overlooked. We mapped the occurrence and calculated the extent of decayed wood in standing Ulmus procera, Platanus × acerifolia and Corymbia maculata trees. The main stem of 43 trees was measured every metre from the ground to the top by two skilled arborists. All trees were micro-drilled in two to four axes at three points along the stem (0.3 m, 1.3 m, 2.3 m), and at the tree’s live crown. A total of 300 drilling profiles were assessed for decay. Simple linear regression analysis tested the correlation of decayed wood (cm2) against a vitality index and stem DBH. Decay was more frequent and extensive in U. procera, than P. acerifolia and least in C. maculata. Decay was found to be distributed in three different ways in the three different genera. For U. procera, decay did appear to be distributed as a column from the base to the live crown; whereas, decay was distributed as a cone-shape in P. acerifolia and was less likely to be located beyond 2.3 m. In C. maculata decay was distributed as pockets of variable shape and size. The vitality index showed a weak but not significant correlation with the proportion of decayed wood for P. acerifolia and C. maculata but not for U. procera. However, in U. procera, a strong and significant relationship was found between DBH and stem volume loss (R2 = 0.8006, P = 0.0046, n = 15). The actual volume loss ranged from 0.17-0.75 m3, equivalent to 5% to 25% of the stem volume. The carbon loss due to decayed wood for all species ranged between 69 to 110 kg per tree. Based on model’s calculation, the stem volume of U. procera trees with DBH ≥ 40 cm needs to be discounted by a factor of 13% due to decayed wood regardless of the vitality index. Decayed wood reduces significantly the tree’s standing volume and needs to be considered to better assess the carbon storage potential of urban forests.

planning and landscape architecture podcast

The American Society of Landscape Architects has a blog post listing a bunch of podcasts about planning and landscape architecture. I have no professional training in either (actually, I have plenty of training and experience in practical water resources planning and green infrastructure, just not urban and regional planning the credentially profession), but these sound pretty broad so I might try a listen in my vast free time. Okay, realistically, if I find myself having a bout of insomnia in the near future.

green roofs

Green roofs continue to catch on very, very slowly in the U.S. They are pretty common in Europe. Toronto has a fairly aggressive ordinance requiring them on most new non-residential buildings. Meanwhile, in the U.S. we have scattered demonstration projects and a few tax incentives. San Francisco has just become the first U.S. city to take steps toward requiring them in private development.

We have a strange relationship with technology in this country. We have embraced information technology, but in more traditional fields like civil engineering, architecture and construction our professionals seem to lack information, imagination, and intellectual curiosity about what is going on elsewhere in the world. The thinking typically goes that a new technology is not cost-effective because it is not common, and it is not common because it is not cost-effective. Short-term market forces don’t drive development of the technology in this situation, especially for long-lived technologies like buildings, highways, or pipes. Government can estimate the potential long-term benefits of adopting new technologies, then fund research, development, and lower barriers to new business creation by, to give just one example, freeing entrepreneurs from the burden of having health care tied to a full time corporate job. But our politicians seem incapable of understanding these slightly complex issues, and our citizenry is not demanding that they do.

Sowing density effects and patterns of colonization

That’s plant colonization, in case you were wondering what kind of colonization I am talking about. This study has a fairly simple premise – that in restoration you can sow the seeds that have the most trouble establishing at the highest densities, and seeds of plants that germinate and spread easily at lower densities, or even not at all.

Sowing density effects and patterns of colonization in a prairie restoration

A cost-effective approach in plant restorations could be to increase sowing density for species known to be challenging to establish, while reducing sowing density for species that easily colonize on their own. Sowing need not occur evenly across the site for rapidly dispersing species. We explored these issues using a prairie restoration experiment on a high-school campus with three treatments: plots sown only to grasses (G plots), to grasses and forbs (GF1), and to grasses and forbs with forbs sown at twice the density (GF2). In year 2, GF1 and GF2 plots had higher diversity than G plots, as expected, but GF2 treatments did not have twice the sown forb cover. However, high forb sowing density increased forb richness, probably by reducing stochastic factors in establishment. Cover of nonsown species was highest in G plots and lowest in GF2 plots, suggesting suppressive effects of native forbs on weedy species. Colonization of G plots by two sown forbs (Coreopsis tinctoria and Rudbeckia hirta) was apparent after 2.5 years, providing evidence that these species are self-sustaining. Colonization was greater in edges than in the central areas of G plots. Through construction of establishment kernels, we infer that the mean establishment distance was shorter for R. hirta (6.7 m) compared to C. tinctoria (21.1 m). Our results lead us to advocate for restoration practices that consider not only seed sowing but also subsequent dispersal of sown species. Furthermore, we conclude that restoration research is particularly amenable for outdoor education and university-high school collaborations.


Swale is a public food forest on a barge in New York City. Here’s what they’re growing:

Swale’s plant community is made up of perennial native fruit trees and shrubs, leafy self-seeding annuals and salt loving grasses. Our model for landscape design is inspired by edible forestry,  permaculture, and salt-tolerant estuary ecosystems. Our plants have come from many generous donations from Greenbelt Native Plant Center, the New York City Parks Department and Visitors onboard! Our plant list is always expanding. Want to bring a plant onboard Swale? Let us know!

Here’s what’s currently onboard:

Beach Plum, Black Chokeberry, Black Tupelo, Black willow, ‘Enterprise’ Apple, ‘Goldrush’ Apple, Fuyu Persimmon, Goji Berry, Hawthorn, Italian Alder, Newtown Pippin Apple (native to Queens NY!), Liberty Apple, ‘Northern Spy’ Apple, Northline Serviceberry, Pitch pine, Red Chokeberry, Sweetbay Magnolia

American Red Raspberry, Arkansas Blackberry, Blue Ridge Blueberry, Dogbane, Eastern Juniper, False Indigo, Flame Willow, Golden Curls Willow, Gooseberry, Missouri River Willow, Northern Highbush Blueberry, Pennsylvania Blackberry, Red Stem Dogwood, Rosemary, Sassafras, Triple Crown Blackberry, Winterberry

Asparagus, American, Blackgrass, Black eyed Susan, Buck’s Horn Plantain, Bugleweed, Anise Hyssop, Aster (New England), Bee Balm, Black Eyed Susan, Borage, Comfrey, Dandelion, Daylily, Echinacea, Evening primrose, French Sorrel, Garlic Chives, Goldenrod, Ground Cherry, Hopi Red Dye Amaranth, Lavender, Lemon Balm, Lettuce, Lovage, Meadowsweet, Milkweed, Miners Lettuce, Oregano, Peppermint, Perpetual Swiss Chard, Red Mustard, Red Russian Kale, Roman Chamomile, Rosemallow, Scallion, Saltgrass, Saltmeadow rush, Sea pea, Shore little bluestem, Spotted Joe Pye Weed, Stinging Nettle, Swamp Goldenrod, Sylvetta Arugula, Tansy, Virginia mountain mint, White Avens, Wild leek, Whorled mountain mint, Yarrow

Ground Cover
Creeping Thyme, Creeping raspberry, Golden oregano, Purslane, Strawberries, White Clover, Wild Low bush blueberry

Adam’s yucca, Groundnut, Jerusalem Artichoke, Walking Onion, Wild Yam

Vertical Layer
Clematis, Grapes, Hardy Kiwi, Hops, Scarlet runner beans

“fleur de lawn”

This “flowering lawn” is a mix of perennial rye, hard fescue, micro clover, yarrow, Achillea millefolium, sweet alyssum, Lobularia maritima, baby blue eyes, Nemophila menziesi, English daisy, Bellis perennis, and O’Connor’s strawberry clover, Trifolium fragiferum. The lawn below is clearly mowed, so I don’t think anyone is claiming this mix is maintenance free, just a bit more drought tolerant, ecologically valuable, and visually interesting mix than a typical lawn, which might have a chance of slipping past your homeowner’s association. From a quick search, the yarrow and baby blue eyes are natives while the others are introduced. Which isn’t a problem for me in and of itself, as I am enjoying watching native bees feast on a mix of clover and yarrow right before my very eyes.


“Fleur de Lawn” – https://www.thespruce.com/flowering-lawn-reduces-mowing-adds-color-2152721

roads and railways as wildlife movement corridors?

At least, I think that is what this paper in Conservation Biology is about. The key conclusion is that biodiversity impacts (of the roads and rails themselves? it’s unclear) can be reduced by up to 75%. I am presuming this is by locating a linear park of sufficient width along the road or railway. Presumably you might need to do something to keep the animals off the road too. Could a few larger reserves located along the corridor reduce the impact to zero? I would find it very encouraging both to know that it is possible and to know that we have the quantitative tools to accurately predict the outcomes of policy and design choices.

Quantifying the conservation gains from shared access to linear infrastructure

The proliferation of linear infrastructure such as roads and rail is a major global driver of cumulative biodiversity loss. Creative interventions to minimise the impacts of this infrastructure whilst still allowing development to meet human population growth and resource consumption demands are urgently required. One strategy for reducing habitat loss associated with development is to encourage linear infrastructure providers and users to share infrastructure networks. Here we quantify the reductions in biodiversity impact and capital cost under linear infrastructure sharing and demonstrate this approach with a case study in South Australia. By evaluating proposed mine-port links we show that shared development of linear infrastructure could reduce overall biodiversity impacts by up to 75%. We found that such reductions are likely to be limited if the dominant mining companies restrict access to infrastructure, a situation likely to occur without policy to promote sharing of infrastructure. Our research helps illuminate the circumstances under which infrastructure sharing can minimise the biodiversity impacts of development.