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