apes chapter 28. introduction urban trees provide pollution solution sciencedaily november 25, 2015...
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APES CHAPTER 28
IntroductionUrban Trees Provide Pollution Solution
ScienceDaily
November 25, 2015
Urban environments can cause contaminated runoff, which can cause pollution and algal blooms
Incorporating soils, grasses, and trees can filter the runoff
University of Melbourne conducted an experiment to see how well trees grew with stormwater and how well they filtered extra nutrients
Four different trees in three different soils
Given either stormwater or tap water
Stormwater: high in nitrogen, phosphorus
After 13 months, all four species of trees grew significantly larger when watered with stormwater than with tap water
All trees good at removing extra nutrients as well
Significance: more trees should be planted in an urban environment because it greatly helps with the problem of runoff pollution
28.1 City Life
Cities are considered the worst areas of pollution. Urban environments have also been affected greatly. CIties have caused more pollution in the past but the future populations are spreading out into urban areas at an increased rate. Businesses and people have moved from cities to spread out into urban areas causing issues in those environments.
28.2 The City as a System
Cities must maintain a flow of energy to function.
A city takes in raw materials from surrounding countryside such as, food, energy, water, and minerals. The city then takes these raw materials, processes them and exports them back out to the countryside as material goods.
Cities also export wastes such as polluted air, water, and sewage.
Average citizen annually uses 229 tons of water, .8 ton of food, 3.5 ton of fossil fuels
Average citizen annually produces 1,826 tons of sewage and 440 lb of air pollutants
28.3 Site and Situation: The location of Cities Cities are not located randomly but are built because of local conditions and regional beliefs.
The location of the city depends on:
Site- the summation of all environmental features of that location. A good site includes a geologic substrate suitable for buildings; such as firm rock base and well drained soils above the water table and nearby supplies of drinkable water along with agriculture and forests.
Situation- the placement of the city with respect to other areas
Easier to build a city where climate is benign meaning it doesn't suffer from extreme temperature and rainfall.
Cities are founded close to mineral resource such as salt,( Salazburg, Austria) Metals (Kalgoorlie, Australia), or medicated waters and thermal springs (Belgium, Great Britain, France)
An ideal location for a city has both good site and a good situation like Paris.
Site is provided by the environment, but technology and environmental change can alter a site for the better.
28.4 City Planning and the EnvironmentCity Planning- formal, conscious planning for new cities- can be traced back as far as the fifteenth century.
Two dominant themes in formal city planning are defense and planning for beauty.
The City Park- Parks have become more and more important in cities. A significant advance for U.S. cities was the nineteenth-century planning and construction of Central Park in New York City, the first large public park in the United States.
The park’s designer, Frederick Law Olmsted, was one of the most important modern experts on city planning.
An extension of the park idea was the garden city, a term coined in 1902 by Ebenezer Howard. Howard believed that city and countryside should be planned together. A garden city was one that was surrounded by a greenbelt. The idea was to locate garden cities in a set connected by greenbelts, forming a system of countryside and urban landscapes.
28.5 The City as an Environment
A city changes the relationship between biological and physical aspects of the environment. Ex. Pollution, water management, climate
The Energy Budget of a City
The city and the environment are constantly exchanging energy (Solar energy, evaporation, fossil fuels)
The Urban Atmosphere and Climate
Cities affect the local environment
Cities are less windy than non urban areas
Cities typically receive less sunlight than countryside areas, yet they are warmer
Solar Energy in Cities
Until recently, the use of solar energy to heat up homes was common.
We now use fossil fuels to heat homes but we are starting to turn back to solar energy
28.5 The City as an Environment
Water in the Urban Environment
Cities tend to be hotter than surrounding areas due to water being unable to evaporate from the soil. Without much evaporation, cities have lower humidity levels than surrounding areas.
Cities have 5-10% more precipitation than surrounding areas.
Flooding and over taxation of storm sewage systems are problems in cities.
Soils in the City
Soil is covered by cement, asphalt, or stone. Big reduction in the amount of gases exchanged with air.
The soil that is important to modern cities is the soil that is in made lands.
Pollution in the City
Motor vehicles, stationary power, home heating, industries
Through careful design it is possible to reduce exposure to pollutants. Ex. Placing houses and recreational areas away from roads
28.6 Bringing Nature to the CityChallenge for cities to incorporate nature into the city
landscape
Specific occupations exist (ex. tree wardens, urban foresters, etc)
Factors such as climate, soils, and urban influence must be accounted for
Cities on Rivers
Can connect city to nature, but traditionally used for transportation and waste removal
Kansas City, Missouri: uses Missouri and Kansas rivers as transportation corridor
Portland, Oregon: Riverfront Park, shops, walkways, pocket parks
Vegetation in Cities
Vegetation (trees, shrubs, flowers, etc) provides a variety of benefits
Shade, peace, quiet, solitude, habitats
28.6 Bringing Nature to the CityUse of trees in cities has grown since Renaissance
Europe in 18th century: first to use trees to line streets
Paris and London are some of the cities
Previously used just for gardens, now greatly incorporated into the urban scene
Reduce effects of climate
Shade and wind protection
Habitat
Endangered Plants
City Stresses
Soil: compacted, poorly drained, susceptible to extremes of drought and floods
Must specially prepare streets
Air Pollution
Ex. ozone, dust
Damage: physical (ex. vehicles), fungal disease, insects
Result: generally shorter lifetime
28.6 Bringing Nature to the CityDifferent species of trees are better in cities
Ideal tree: resistant to urban stresses, aesthetically pleasing, require little cleaning up after
Limits amount of species, yet large diversity is necessary
Disturbed areas allow space for early successional plants
Include wild and exotic plants, many weeds
Wildlife in Cities
Most wildlife are considered pests
Types of species can be divided into:
Cannot continue to live and disappear
Can tolerate urban environment, yet do better elsewhere
Adapted, abundant, and neutral/beneficial to humans
Overly successful, become pests
28.6 The City as an Effective Habitat Typically people do not view cities as a habitat for many creatures, but the odd fact is that it
indeed does provide a home for countless animals/insects.
○ EX: Foxes feed on the garbage of the streets and roadkill
● In some cases cities actually provide a more suitable habitat for animals such as chimney swifts, chimney swifts typically live in hollowed out trees in the woods but it is very possible for their to be more chimneys in one city then in a forest.
● Cities also contain parks and reserves where hundreds of species thrive, for example New York city’s national park contains 260 species of birds.
● Urban kitchen gardens are also used to provide flowers for endangered hummingbirds to live off of.
● Urban Drainage structures offer waterways and storage areas that provide fish and other mammals with habitats that don't interfere with the city's process.
28.6 Controlling Pests
Most common pests: cockroaches, fleas, termites, rats, and pigeons.
Pests compete with people for food and spread disease.
Before medicine these pests spread tons of disease and ended up causing the bubonic plague.
Most people believe that the only way to control pests is by poison, but in reality the best way to control them and their population is by eliminating their habitats
EX: Rats- Reduce open garbage and eliminate hiding/nesting spots
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