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robertogreco : vegetation   5

Trees, a new partner in the fight against urban crime | USAPP
"Crime is a persistent problem in many urban areas, both large and small. In new research, Kate Gilstad-Hayden and Spencer R. Meyer examine the effects of tree cover on this crime. They find that for every 10 percent increase in tree canopy cover, there was a 15 percent decrease in the violent crime, and a 14 percent fall in the property crime rate. Trees, they write, can help to increase ‘eyes on the street’ through recreational use, reduce mental the fatigue which can lead to crime, and offer landscaping opportunities which act as a ‘cue to care’.

Crime remains a persistent challenge in many cities in the United States and worldwide. Solutions to this problem require a multi-faceted approach. Recent studies conducted in cities across the United States suggest that urban greening, including planting more trees and other vegetation, could be a relatively low-cost contributor to reducing crime.

Traditionally, law enforcement agencies thought vegetation contributed to crime, by obstructing surveillance and providing cover for criminals. However, recent studies using crime data from police reports and other sources have found the opposite may be true. A 2001 study of a public housing development in Chicago was the first to link vegetation with actual counts of crime from police reports. Greater vegetation surrounding apartment buildings, as measured via aerial and ground-level photographs, was associated with fewer reports of total, property and violent crimes, even after controlling for confounding factors (e.g., number of apartments per building, vacancy rate, building height). Recent studies in Baltimore, Maryland, and Philadelphia, Pennsylvania have replicated the Chicago results using high-resolution aerial imagery to measure vegetation and more sophisticated statistics to account for spatial dependency since crime tends to cluster around nearby neighborhoods.

We set out to see if earlier research is generalizable to medium-sized cities by examining the association between vegetation and crime in New Haven, Connecticut, a city with a population of 130,000 people and a crime rate of 65 crimes per 1,000 people, or 2.7 times the state rate and 2.0 times the national rate. Known as the Elm City, New Haven is home to 32,000 street trees and parks covering 2,200 acres. Approximately 38 percent of all land is covered by tree canopy, slightly higher than the average tree canopy cover for US cities of similar size. Our study draws upon the advanced statistical and spatial methodologies used in Baltimore and Philadelphia and is the first to apply these techniques to crime reporting from the Federal Bureau of Investigation’s Uniform Crime Report (UCR). Our crime outcomes include property crimes (burglary, theft, motor vehicle theft and arson) and violent crimes (murder, rape, robbery and assault) and provide a nationally replicable measure of crime that is consistent with criminology and economic literature on differential incentives and deterrents to property and violent crime.

Results from our analyses showed that for every 10 percent increase in tree canopy cover there was a 15 percent decrease in the violent crime rate and a 14 percent decrease the property crime rate. We controlled for socio-economic factors, including neighborhood-level educational attainment, median household income, racial/ethnic composition, population density, vacancies and renter-occupied housing, suggesting that our results are not confounded by higher socio-economic neighborhoods having more trees. Maps of tree canopy cover and crime (see Figure 1) clearly showed that neighborhoods with more tree canopy cover tended to have less violent, property and total crime. While we did not identify a causal relationship between trees and crime in our study area, prior research suggests that vegetation may offer crime-reducing benefits through three main mechanisms. First, green spaces attract people for recreation and other activities, leading to more “eyes on the street,” which provides actual surveillance. Second, trees offer attractive landscaping that acts as implied surveillance or a “cue to care” by demonstrating to potential criminal threats that residents pay attention to and care about their neighborhood. Third, trees and the presence of nature has been shown to reduce mental fatigue, a precursor to violent behavior.

Figure 1 – Quantile classified choropleth maps of crime outcomes and tree canopy cover by Census block group in New Haven, CT


Notes: Darker shading indicates more crime or more tree canopy cover; Crime rates represent average number of crimes annually from 2008-2012 per 1,000 residents; Tree canopy cover is measured as the percent of ground that is covered by leaves and branches of trees when viewed from above.

Our study expands previous research on trees and crime in major cities to a medium-sized city known for its high crime rate. We found strong evidence that more trees are associated with lower rates of both violent and property crime. We can confidently add crime-fighting to the growing list of benefits associated with urban trees such as air pollution removal, cooler temperatures, and capture of rainfall thereby reducing storm water runoff. City residents often express far more concern about crime and quality of life issues rather than issues of environmental quality, suggesting that our new evidence can play an important role in swaying voters- as well as proponents of urban greening, law enforcement officials and city leaders to plant more trees to benefit both crime prevention and urban ecosystems.

Future studies should examine changes in tree canopy cover and crime over time and test for potential mediators, including social cohesion and park use, to help to clarify the relationship between trees and crime. In addition, looking at the relationship between the quality of trees (e.g. street trees versus park trees or tall trees versus shrubs) and crime could provide insight into the most effective ways to use urban greening to reduce crime. Such studies could bolster support for urban greening as a crime reducing strategy."
trees  crime  foliage  urban  urbanism  2015  kategilstad-hayden  spencermeyer  lawenforcement  surveillance  treecover  vegetation 
november 2015 by robertogreco
Badru’s Story: Early Warnings From Inside an Impenetrable African Forest by : Yale Environment 360
"Each year Badru Mugerwa sets 60 camera traps in Bwindi Impenetrable National Park in Uganda to monitor life in one of Africa’s most diverse forests, home to roughly half the world’s mountain gorillas. As site manager for the TEAM Network, a global web of field stations, Badru collects images and data that serve as an early warning system for the loss of biodiversity and the impact of climate change in tropical forests.

In this six-minute video, winner of the 2014 Yale Environment 360 Video Contest, Benjamin Drummond and Sara Joy Steele document the researchers' work in Bwindi's remote, mountainous landscape. For the filmmakers, just preventing their equipment from snagging on the dense understory while trying to keep up with Badru and his colleagues posed a serious challenge. But their efforts were rewarded with remarkable camera-trap images of the park's primates, elephants, giant anteaters, and leopards – striking evidence of what is at stake in Bwindi and the world's tropical forests.

As a Ugandan wildlife manager tells Drummond and Steele, “This is the only forest on earth where you find gorillas and chimpanzees feeding together. Where shall we get it again?”"

[Video here: ]
cameras  forests  uganda  africa  badrumugerwa  nature  biodiversity  benjamindrummond  sarajoysteele  tropics  climatechange  bwindi2014  animals  wildlife  elephants  gorillas  anteaters  macaques  leopards  primates  cameratraps  science  vegetation  teamnetwork  itfc 
september 2014 by robertogreco
The Flora of the Future: Wild Urban Plants: Celebrating the Botanical Diversity of Cities Places: Design Observer:
"New Infrastructural Taxonomies

The plants that appear spontaneously in urban ecosystems are remarkable for their ability to grow under extremely harsh conditions — most notably in soils that are relatively infertile, dry, unshaded and alkaline. [14] Through a quirk of evolutionary fate, many of these plants have evolved life-history traits in their native habitats that have “preadapted” them to flourish in cities. Stone or brick buildings, for example, are analogous to naturally occurring limestone cliffs. [15] Similarly, the increased use of de-icing salts along walkways and highways has resulted in the development of high pH microhabitats that are often colonized by either grassland species adapted to limestone soils or salt-loving plants from coastal habitats. Preadaptation is a useful idea for understanding the emergent ecology of cities because it helps explain the patterns of distribution of plants growing in a variety of distinctive urban habitats, including the following:

The chain-link fence is one of the more specialized habitats of the urban environment. They provide plants — especially vines — with a convenient trellis to spread out on and a measure of protection from the predation of maintenance crews. Chain-link fences also provide “safe sites” for the germination of seeds, a manifestation of which are the straight lines of spontaneous urban trees that one commonly finds in cities, long after the fence that protected the trees is gone. Root suckering species such as Ailanthus grow particularly well along chain-link fence lines.

Vacant lots that have been cleared of buildings are often mulched with masonry and construction rubble. Their soils typically have high pH levels, and they are usually colonized by a suite of plants that I like to refer to as a “cosmopolitan urban meadow.” Many of these plants, including mugwort (Artemesia vulgaris) and curly dock (Rumex crispus), are common in the dry, alkaline grasslands of Europe.

The highway median strip is typically only a few feet wide, with minimal topsoil above a compacted subsoil layer. Initially these areas may have been planted with lawn grasses, but they usually end up dominated by crabgrass (Digitaria spp.). As most homeowners know, crabgrass comes up in lawns in late spring, when temperatures consistently get above 70 or 80 degrees. It’s a warm-season grass that thrives when it’s hot and dry, and because it is an annual species, the road salt used in winter has no effect on its development. In short, the median strip is perfect for crabgrass.

Stone walls and masonry building façades provide great habitats for plants — especially when their maintenance has been neglected. From the plant’s perspective, these structures are good stand-ins for a limestone cliff, and many cliff species are well adapted to growing on city walls. [16]

Pavement cracks are among the most distinctive niches in the urban environment. Wherever you have two types of paving material coming together, you have a seam, and the different materials expand differentially in response to summer and winter temperature to create a crack. We tend to think of pavement cracks as stressful habitats, but in fact, as the water sheets off the pavement, it flows right into the crack, making it a rich site in terms of its ability to accumulate moisture and nutrients. With oil from cars as a carbohydrate source available for decomposition by fungi and bacteria, cracks can develop significant microbial diversity.

Specialized microclimates are as important in cities as they are in natural environments. As an example, carpetweed (Mollugo verticillata), a summer annual from Central America, subsists only on air-conditioner drip. Its seeds germinate under a window air-conditioning unit when it is turned on in early summer, and it dries up and sets seed when the unit is turned off in September. Many annuals common in cities display similar capacities to exploit ephemeral urban niches.

River corridors, annually disturbed by fluctuating levels of water during the course of the year, are typically dominated by spontaneous vegetation with broad environmental adaptability. They serve as important pathways for the migration of both plants and animals into and out of the city. The same is true for railway corridors. At the Arnold Arboretum in Boston, where I have worked since 1979, coyote, deer, fox and pheasant are commonly sighted, often coming up from the suburban south following the railroad line that borders the eastern edge of the property."
peterdeltredici  2014  nature  plants  flora  interstitial  interstitialspaces  borders  boundaries  urban  urbanism  between  fences  biology  cities  botany  landscape  ecology  vegetation  betweenness 
april 2014 by robertogreco
adventures in the cryptoforest by wilfried hou je bek | THE STATE
[Wayback: ]

"Cryptoforests are feral forests—planted tree zones, for instance along motorways, that have been allowed to become wild to the point that their wildness is outgrowing their manmadeness. They are in limbo forests—tree-covered plots that feel like forests but technically probably aren’t; states of vegetation for which lay-language has no name. They are incognito forests—forests that have gone cryptic and are almost invisible; forests in camouflage, forests with a talent for being ignored. They are precognitive forests—lands that are on the brink of becoming forested, a future forest fata morgana. And they are unappreciated forests—forests regarded as zones of waste and weed, forests shaming planners, developers, and the neighbourhood. NIMBY forestry.

Cryptoforestry is a psychogeographic art; the above is therefore not a definitive list and only serves as a pointer for serendipitous search and identification. Generally speaking, a cryptoforest is either a place that looks like a forest but isn’t, or a forest that nobody knows about. But there is no need for cryptoforest fundamentalism. A cryptoforest is a place where the urban is discontinued; a disturbed place where fast-growing, weedy, plants can thrive. I have found beautiful abandoned car parks where grasses were flowering through the cracks of the pavement and the blackberry, my perennial companion whenever I go cryptoforesting, was only just spreading its first thorny fangs across the paving. I think of such places as cryptoforests even though not a single tree grows there.

All cryptoforests are unique and they all have their own story to tell, but the word I desperately—and mostly unsuccessfully—try to stay away from is ‘nature.’ The easiest way to relate to cryptoforests is by describing them as places where the city has temporarily retreated, and nature has been given the chance to grow undisturbed. It’s a description that goes a long way, but one which suffers from its lack of precision and for the way it implies a rigid distinction between city and nature—and by extension, between people and nature. People are nature; cities are part of nature, though not of a natural origin, and no nature has been left untouched."

"Cryptoforestry argues that you shouldn’t let your image of a city be determined only by what is built, but also by what remains empty. A place may be free of buildings but that does not mean that it is devoid of relevance and adventure. Cryptoforests offer a unique experience. Find them, enter them, take your friends there, be careful, and become a native; you never know what you will find."
landscape  precognitiveforests  forests  feral  plants  vegetation  cryptoforests  cryptoforestry  2012  via:chrisberthelsen  wilfredhoujebek 
may 2012 by robertogreco

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