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Posts Tagged ‘trees’

Economic Value of an Urban Forest: $80 billion

Posted in Models, Research, Tools by Kate Archdeacon on March 22nd, 2012


Photo by Mike_tn via flickr CC

From “Environmental contribution of Tennessee’s urban trees: $80 billion”  by James Holloway:

A study published by the US Forest service values the State of Tennessee’s urban forest at $80 billion thanks to its contributions to the environment. With an urban population of 284 million, that equates to a mean value of $282 per tree.

The total is based on a number of costs that are to some extent offset by the presence of Tennessee’s urban forest (its urban tree population, in other words). These include $350 million-worth of carbon storage based on the current standing stock, over $204 million every year in pollution removal, $18.4 million per year in additional carbon sequestration, and $66 million per year in energy savings-“the most significant contribution” made by the urban forest, according to State Forester Steven G. Scott. But how are the environmental benefits of the trees evaluated?

Data was collected and analyzed using the Forest Service’s own i-Tree Eco software. Using a mobile app providing strict protocols for data collection, researchers took information from 2418 trees and saplings across 255 field plots. Variables noted include species, diameter at breast height (or DBH—taken at 1.4 meters above ground), height, crown dimensions, foliage transparency, damage, and proximity to buildings. The pool of sample data is assumed to be representative of the total population, and from there the software crunches the numbers using “peer-reviewed equations” to paint a macro-scale picture of the urban forest, based on quantifiable characteristics that describe its structure, condition and function.

>>Read the full article by James Holloway on Ars Technica.
>>Read the US Forest Service study.


Extending Value: The Life Box

Posted in Models by Kate Archdeacon on July 19th, 2010

Source: Core 77

From “The Life Box: Packaging That Turns Into Trees“:

Now this is some truly brilliant package design: Mycologist Paul Stamets’ Life Box, a simple cardboard box impregnated with a mixture of Department-of-Agriculture-approved seeds.

The Life Box suite of products builds upon the synergy of fungi and plants by infusing spores and seeds together inside of packaging materials that can be planted.  The Tree Life Box is made of recycled paper fiber. In this fiber, we have inserted a wide variety of tree seeds, up to a hundred, dusted with mycorrhizal fungal spores. The mycorrhizal fungi protect and nurture the young seedlings. For millions of years, plants and beneficial fungi have joined together in a mutually beneficial symbiotic relationship.

You can get started by simply tearing up the box, planting in soil, and watering.

The fungi “sprout” or germinate to form an attachment with root cells and extend into the soil with a network of fine cobweb of cells called mycelium. The mycelium mothers the seed nursery by providing nutrients and water, thus protecting the growing trees from disease, drought, and famine.

Stamets estimates that 1 tree out of 100 will survive to the 30-year mark, at which point it will have sequestered one ton of carbon. And how’s this for an endorsement: Al Gore is shipping his new book, Our Choice: A Plan to Solve the Climate Crisis, in Life Boxes.

Read the full article on Core 77.


Greening the Concrete Jungle: Report

Posted in Research by Kate Archdeacon on July 14th, 2010

Source: The Ecologist

From “Trees a ‘low-cost’ solution to air pollution and biodiversity loss in cities“:

Native woods and trees in urban areas, including gardens, provide haven for wildlife, reduce air pollution, surface run-off and flooding  Reversing the declining numbers of native trees and woods in cities would provide numerous benefits at ‘relatively little cost’, says a report from the Woodland Trust.  As well as access to green space, the report, ‘Greening the Concrete Jungle‘, says trees provide a wide range of free ecosystem services including reducing the risk of surface water flooding and improving air quality that could save millions in flood defence and healthcare costs.

The UK has one of the world’s highest rates of childhood asthma, around 15 per cent, particularly amongst lower socio-economic groups in urban areas. Research shows asthma rates among children aged four to five falls by a quarter for every additional 343 trees per square km, as they help keep the air clean and breathable and reduce ambient temperature.  Trees are also able to reduce the pressure on the drainage system during flooding. The University of Manchester has shown that increasing tree cover in urban areas by 10 per cent reduces surface water run-off by almost 6 per cent.  A major international study published earlier this year, The Economics of Ecosystems and Biodiversity (TEEB), put the global value of services provided by forests and biodiveristy at between £1.2-2.8 trillion a year.

Despite these ‘invisible’ benefits, the report says urban tree cover is actually deteriorating in many areas, with concerns over tree safety and insurance claims as well as development. Many places have seen a decline in older trees with large spreading crowns, replaced with smaller, more manageable alternatives. Smaller crowned trees have less capacity to intercept rain.  Fewer than 10 per cent of city dwellers have access to local woodland within 500m of their homes. Evidence suggests proximity to a wood encourages physical exercise, whilst a woodland walk lowers the heart rate and mental stress.

The Woodland Trust said socially disadvantaged groups were the most likely to lose out with around two-thirds of urban trees in private or less accessible public grounds. It is campaigning to plant 20 million native trees annually accross the UK for the next 50 years.

‘Towns and cities also tend to put into sharp relief some of the key problems we are facing as a society – physical and mental health problems, childhood obesity and asthma, differences between rich and poor, air pollution, soaring summer temperatures, flash flooding, energy conservation, diminishing wildlife – so they are a good place to start when trying to illustrate just where green space can deliver significant improvements for relatively little cost,’ said report author Mike Townsend.

Read the full article on The Ecologist.