Tag Archives: green infrastructure

street tree survey using Google Street View

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An automated analysis program can produce street tree data using Google Street View.

Google Street View shows promise for virtual street tree surveys

Geospatial technologies are increasingly relevant to urban forestry, but their use may be limited by cost and technical expertise. Technologies like Google Street View™ are appealing because they are free and easy to use. We used Street View to conduct a virtual survey of street trees in three municipalities, and compared our results to existing field data from the same locations. The virtual survey analyst recorded the locations of street trees, identified trees to the species level, and estimated diameter at breast height. Over 93% of the 597 trees documented in the field survey were also observed in the virtual survey. Tree identification in the virtual survey agreed with the field data for 90% of trees at the genus level and 66% of trees at the species level. Identification was less reliable for small trees, rare taxa, and for trees with multiple species in the same genus. In general, tree diameter was underestimated in the virtual survey, but estimates improved as the analyst became more experienced. This study is the first to report on manual interpretation of street tree characteristics using Street View. Our results suggest that virtual surveys in Street View may be suitable for generating some types of street tree data or updating existing data sets more efficiently than field surveys.

Edward Glaeser on infrastructure

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Edward Glaeser questions the idea of massive federal spending on infrastructure.

While infrastructure investment is often needed when cities or regions are already expanding, too often it goes to declining areas that don’t require it and winds up having little long-term economic benefit. As for fighting recessions, which require rapid response, it’s dauntingly hard in today’s regulatory environment to get infrastructure projects under way quickly and wisely. Centralized federal tax funding of these projects makes inefficiencies and waste even likelier, as Washington, driven by political calculations, gives the green light to bridges to nowhere, ill-considered high-speed rail projects, and other boondoggles. America needs an infrastructure renaissance, but we won’t get it by the federal government simply writing big checks. A far better model would be for infrastructure to be managed by independent but focused local public and private entities and funded primarily by user fees, not federal tax dollars.

I get the argument that investing without a plan leads to waste. We don’t really have any real planning at the federal level. I think it would help for the federal government to set a vision and direction for what the smart infrastructure of the future should look like, and not just transportation (public, private and human muscle-powered) but energy, water, communications, freight, manufacturing, housing and even green infrastructure. One of the problems with local authorities and companies doing the planning is that they focus on only one of these things at a time, so they miss out on potential synergies and opportunities for hybrid infrastructure. An example might be highway corridors that serve as rights of way for high speed rail, high-voltage lines, pipelines and movement corridors for wildlife. Another might be a system of parks that move water resources, improve water and air quality, absorb floodwaters, counteract climate change, provide habitat and improve peoples’ health.

He is right though that a lot of planning needs to be at the metropolitan area scale and incorporate hard-nosed cost-benefit analysis. This is already done to a certain extent by designated “metropolitan planning organizations”, but this only applies to transportation. It could be more comprehensive. I also see a middle ground between pure local funding and pure federal funding. Federal funds can be targeted only to projects that are in line with the national vision and the local comprehensive plan. They could be low- or no-interest loans rather than outright grants. They could be grants but require local matching funds and encourage private investment. They could be loans that are partially forgiven if the projects meet performance and cost-effectiveness criteria.

Having both federal and local plans ready to go, along with a federal infrastructure bank able to issue bonds, would also mean the country could really take advantage of periods of unemployment and low interest rates both to stimulate the economy in the short run and boost productivity and prosperity in the long run.

tree type and heat mitigation

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Here is an article on how the specific type of street tree affects the urban heat island locally, focusing on plant area index.

Microclimate benefits that different street tree species provide to sidewalk pedestrians relate to differences in Plant Area Index

The way a street tree is able to modify the local microclimate on pedestrian walkways may vary according to tree species according to key canopy and leaf characteristics, such as leaf angle, leaf size, canopy architecture or simply canopy density. Three similar north-south orientated streets, with three different tree species possessing different canopy and leaf characteristics were studied in summer 2014. Microclimatic parameters were measured on pedestrian walkways below and away from tree canopies between 06:00 and 20:00 on three cloudless days. Physiological Equivalent Temperature (PET) was estimated to indicate pedestrian thermal comfort. Microclimate conditions were measured below and away from trees at solar noon for a wide range of trees with different Plant Area Index (PAI) as determined using full-frame photography. In streets with Ulmus procera and Platanus x acerifolia trees, the microclimatic benefits were significantly greater than the street with Eucalyptus scoparia trees, however no significant differences in the estimated PET. Microclimate benefit increased with increasing PAI for all three tree species, however no significant difference in under-canopy microclimate amongst tree species when the PAI was similar. It appears that differences in PAI are paramount in determining the microclimatic and PET benefits. Obviously, certain tree species have a limit of the PAI they can achieve, and that should be considered when selecting or comparing tree species for shading and cooling benefits. This study assists urban planners and landscape professionals in selecting street tree species for cooling benefits based on the expected or managed tree canopy area.

I’d heard of Leaf Area Index before I read this abstract, but not Plant Area Index. A search for Plant Area Index on Google brings up a Wikipedia definition of Leaf Area Index as the top hit.

Leaf area index (LAI) is a dimensionless quantity that characterizes plant canopies. It is defined as the one-sided green leaf area per unit ground surface area (LAI = leaf area / ground area, m2 / m2) in broadleaf canopies.

The best explanation of the difference I could find on the internet is here:

Leaf (or needles in the case of conifers) should be seen here as a generic term for designing the above ground aeral extent of vegetation. if no distinction is made between leaves (needles) and the other elements, the proper term to use is PAI: Plant Area Index rather than LAI.

So I guess the plant area index accounts for the trunk, branches, stems, etc.

macroinvertebrates (aka worms and bugs) in rain gardens

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Even though the names imply they are living ecosystems, stormwater management engineers still have a tendency to think of rain gardens and bioretention basins as inert systems. It’s good to see the profession working with other disciplines and taking soil science more seriously these days. And where most are focused on physical, chemical, and plant-based processes, a few are looking more closely at the importance of animal activity.

Soil invertebrates in Australian rain gardens and their potential roles in storage and processing of nitrogen

Research on rain gardens generally focuses on hydrology, geochemistry, and vegetation. The role of soil invertebrates has largely been overlooked, despite their well-known impacts on soil nutrient storage, removal, and processing. Surveys of three rain gardens in Melbourne, Australia, revealed a soil invertebrate community structure that differed significantly among sites but was stable across sampling dates (July 2013 and April 2014). Megadrilacea (earthworms), Enchytraeidae (potworms), and Collembola (springtails) were abundant in all sites, and together accounted for a median of 80% of total soil invertebrate abundance. Earthworms were positively correlated to soil organic matter content, but the abundances of other taxonomic groups were not strongly related to organic matter content, plant cover, or root biomass across sites. While less than 5% of total soil N was estimated to be stored in the body tissues of these three taxa, and estimated N gas emissions from earthworms (N2O and N2) were low, ingestion and processing of soil was high (e.g., up to 417% of the upper 5 cm of soil ingested by earthworms annually in one site), suggesting that the contribution of these organisms to N cycling in rain gardens may be substantial. Thus, invertebrate communities represent an overlooked feature of rain garden design that can play an important role in the structure and function of these systems.

new technology for mapping street trees

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Philadelphia Parks and Rec has used a Google Street View-like technology to map street trees.

CycloMedia’s tool is “like Google Maps on steroids,” said Parks and Rec’s lead GIS Specialist Nora Dougherty, who spearheaded the project. It is a way of capturing all kinds of high-definition imagery that is geolocated, which means it can be used for a variety of projects. The tool is easy enough for non-experts to use, according to Mark Wheeler, Chief Geographic Information Officer for the Office of Innovation and Technology, plus the custom-captured imagery can be fully integrated with the city’s existing GIS software. CycloMedia’s tool captures an unprecedented level of detail in the images it records: You’re able to see features like address numbers and even deterioration of rooflines. Plus, every image is date and time stamped, so the user can verify that the images are consistent. This tool is also highly accurate for measuring distances and heights.

After all the streets in Philadelphia were captured using the technology, GIS technicians Tom McKeon and Stuart Olshevski virtually traveled down every street and dropped pins marking the location of each tree. The result is an inventory of nearly 112,000 street trees with geolocation data, which means street trees are now represented in a new layer of geographic information that can be mapped and analyzed. (Forest trees make up the other thousands of trees in Philadelphia, but it’s nearly impossible to accurately inventory them.) Information about the health and species of street trees is also being recorded…

The street tree inventory will be available on August 5 on Open Data Philly, and in an interactive map will be on the city’s website. Citizens can use that information to create their own maps and take action to monitor the trees in their neighborhood.

July 2016 in Review

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3 most frightening stories

  • The financial crisis triggered by U.S. banks in 2008 may have been a major factor behind a resurgence of right-wing politics in Europe.
  • Household chemicals may have adverse effects on the developing brain, including a contribution to the risk of “neurodevelopmental disorders that affect the brain and nervous system including autism, attention deficit hyperactivity disorder, intellectual disabilities, and other learning and behavioral disabilities”.
  • The CIA is just not that good at spying.

3 most hopeful stories

  • There are new tools for considering ecosystem services and biodiversity in development decisions.
  • Uber Pool could be a game changing technology that ushers in a new kind of flexible transportation system.
  • The problems of a civilization in overshoot can seem overwhelming, but one thing you can do is convert your lawn to a sustainable ecosystem. Moss is an option. Also related to this, some ecologists are paying more attention to soil.

3 most interesting stories

  • I was a little side-tracked by U.S. Presidential politics. Nate Silver launched his general election site, putting the odds about 80-20 in favor of Hillary at the beginning of the month. The odds swung toward Trump over the course of the month as the two major party conventions took place (one in my backyard), but by the end of the month they were back to about 70-30 in favor of Hillary. During the month I mused about NAFTA, the fall of the Republic, the banana republic, The Art of the Deal, how to debate Trump, and Jon Stewart,
  • It’s really okay to cook pork chops medium rare.
  • It’s really hard to predict earthquakes. Many scientists think it is impossible, but once upon a time they thought that about predicting weather.

ecological landscaping

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I recent linked to an article by Odum on ecological landscaping, or sustainable gardening, or whatever you want to call it. Her article linked to a number of other articles in the mainstream press. These are the articles I would share with friends and neighbors if they were to express an interest (or quite possibly, skepticism) about my own gardening methods. I’ll grab an interesting paragraph from each. The articles also have lots of interesting pictures and links to even more articles.
“Outgrowing the Traditional Grass Lawn” from Scientific American

Experimenting with alternatives to grass lawns does not require banishing turfgrass altogether, however. As Smith’s research underscores, turfgrass has a useful property not easily matched by other plants: its impressive material resilience. Grass tolerates a lot of trampling without dying and will spring back when compressed by cleats and lounging people’s backsides. Some scientists are currently focusing on how to make regions of private lawns and public green spaces more attractive to native pollinators, without uprooting a lawn altogether. Emily Dobbs of the University of Kentucky and her colleagues visit golf courses in the state and persuade the managers to transform some out of the way spots into wild habitat by planting a mix of perennial, native, low-maintenance wildflowers that bloom from April to October—coneflowers, columbines, black-eyed susans, clover, hyssop, and goldenrod, for example. The owners of five golf courses, including one belonging to Marriott Hotels and Resorts, have agreed so far—and the results are astounding.

“What is Sustainable Landscaping?” from Daily Kos

A landscape based on a small palette of non-native species supports less than 10% of the insect species needed to sustain native birds (Bringing Nature Home). Replacing these landscapes with a diversity of native trees, shrubs, grasses and wildflowers supports the hundreds of species of native insects needed to sustain birds and other organisms such as frogs, toads, lizards, and bats, which help control annoying or dangerous insects such as flies and mosquitoes.  It also links together an increasingly fragmented landscape that isolates natural areas between areas of biological desert.

“It’s come to this, yards are the next frontier of conservation” from Fusion

Native plants boost insect populations significantly, Louderman said.

“In your backyard, if you have just a lawn and non-native plants, you’d find just about a dozen species of native insects. If you have native plants, you can usually find hundreds of almost all native and beneficial insects,” Louderman said.

These are not bad or dangerous insects, Louderman pointed out. In fact, the honeybee is the only one that might sting a human.

teenagers and green environments

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This article says that teenagers in green environments are less aggressive, even after controlling for socioeconomic factors.

The researchers describe several “possible pathways” that could explain their results. Easy access to the natural world may reduce maternal stress, which can lead to children acting out. It can encourage physical activity, reduce air pollution levels, and “act as a buffer for ambient noise.”

In addition, they write, green space in urban areas has been shown to preserve “the microbial biodiversity needed to drive immunoregulation, and to optimize brain health.”