Final Envi Sci (Fall 09)
Global Forest Cover (types and coverage)

  1. Forests= 27% of global land area
  2. Canada, US and Brazil >50% of Earth’s forests
  3. 3 types:
  • Boreal: An extensive biome occuring in environments with cold winters, short but warm growing seasons, and moist soils, and usually dominated by coniferous trees.
  • Tropical: Characterized by moist climates with abundant, year-round precipitation and warm climates. Because wildfire is uncommon, old-growth forest is commonly found here.
  • Temperate: Occurs in relatively moist, temperate climates with short and moderately cold winters and warm summers, and usually composed of a mixture of angiosperm tree species.

;

**Boreal Forests are the Lungs of the world**

Deforestation
A permanent conversion of forest into some other kind of ecosystem, such as agriculture or urbanized land use.
Canadian Forests

  • Boreal forests are the largest biome in Canada
  • Coastal temperate forest produces high timber volume
  • Largely publicly owned… means that polocy can be implemented to protect or conserve

**BC has a wider variety in forest types as it’s watershed and topography is the most varied** 

Deforestation in  Canada

  • Minimal regeneration after cutting before 1990s
  • 1979-1993: Only 36% of harvested area was replanted
  • In Alberta it is now common practice to plant 2 trees for every 1 that is harvested….

… The isssue with replanting is temporal: How long does it take to regenerate a harvested area and how much effort is needed to ensure successful regrowth?

Alberta Forests (3 types)

  1. Boreal: Mostly coniferous trees (fir, larch, pine, or spruce), this biome is characterized by cold winters, shot, warm grwing seasons, and moist soils.
  2. Parkland:
  3. Montane forest: Occurs at sub-alpine altitudes on mountians in temperate latitudes. Similar in structure to high-latitude boreal forest ans is also dominated by conifers.
  • Canada is comprised mainly of Boreal and Parkland forest, however Montane forest is also prominent in mountainous areas.

Whay are Forests Important (4)

  1. Economics: Forests provide many kinds of resources (utilitarian)
  2. Ecology: Forests are important compartments in nutrient cycling (carbon storage and filtration, cycling of nitrogen and sulphur, as well as hydrologic cycle) and in providing habitat for a variety of organisms and preventing erosion. (ecological value)
  3. Recreation and Tourism: This imbues forests with (intrinsic value) as many people expect consistent, healthy condition of forests used for this.
  4. Spiritual and Cultural Values:  self explanatory…

Whay are the Boreal forests important (Canada) (3)

 ** Importance lies in how it affects the carbon system, climate system and hydrologic cycle**

1) Carbon Cycle:

  • Carbon sink: Produces 02 and stores C02… in other words, massive stands of trees and vegetation (or lack thereof) contribute to the cycling of carbon both globally and locally. 
  • Stores Biomass: forests with high productivity do not release C02 until they are burned or they decay

2) Global Climate:

  • Changes Albedo: of Earth’s surfaces by absorbing energy for photosynthesis
  • Transfers C02 and Water Vapour: by cycling these, forests are able to impact the warming;and cooling of the atmosphere.

3) Thrives on Disturbance:

  • Boreal forest thrives in environments characterized by fire, insect infestation and disease

Old Growth Forest

A late-successional forest characterized by the presence of old trees, an uneven aged population structure, and a complex physical structure

;

IN OTHERWORDS… Old growth forest is a climax ecosystem in relative equilibrium, with trees at all stages of development, hence there is a varied and complex web of connections between organisms and the environment!

Old Growth Forest (Climax ecosystem)

Refers to the fact that old growth forests are in a state of relative equilibrium with the presence of trees in all stages of development…

…This is what all ecosystems aspire too

Old Growth Forests (Ecosystem Functions it provides)

  1. Biodiversity: The canopy layers and gaps between them provide a range of habitats for organisms, many of which can only be found in Old Growth forest or who depend on specific layers for stages of development.
  2. Carbon Storage: This is contentious as on the one hand, these forests store immense amounts of carbon over theor lifetime, but, on the other hand, when the decay (remember that there is more decay going on here than in most forests) it releases immense amounts of C02.
  3. Slope Stability and Stream Habitat: these forests mitigate erosion; and subsequent sediment transfer from the environment to river systems.
  4. Cleaning air and water: filtering CO2 and producing O2 and filter water by lessening erosion of sediments.

Old Growth Forests (Carbon Storage?)
This is contentious as on the one hand, these forests store immense amounts of carbon over theor lifetime, but, on the other hand, when the decay (remember that there is more decay going on here than in most forests) it releases immense amounts of C02.
Plantation Forests

Anthropogenic; forest of relatively simple character compared with natural, mature or old-growth, mixed species;forests that originally occupied the site.

;

  • After harvesting it is common to erect new crops of trees (most often conifers) which are then intensely managed to increase productivity.
  • Has potential impacts on biodiversity as many native species of the natural forest are unable to utilize the habitat available in a plantation. On the other hand may actually promote new species or enhance existing populations of some species.
  • Usually monocultured (called cohort)

Harvesting of Forest (4 types)

1) Clearcutting: Removal of all of the economically useful trees from an area at the same time.

  • Considered cost effective, safe,
  • and ecologically appropriate…;depending on the ecosystem: i.e. Boreal Forest: some argue that clear cutting mimics;natural disturbance (fire, insect, etc) however if there is an actual event of disturbance, this may exacerbate the impacts.
  • High grading: cutting the best, easily accessible forest
  • Continuous clearcutting is banned and now replaced with clearcuts…;

2) Selection cutting: Harvesting of only some trees from a stand, leaving others behind and the forest substantially intact.

;

3) Shelterwood cutting: Cutting the taller trees so that the underwood can grow to take its place… this allows better light and nutrients to cyle to the undergrowth.

;

4) Patch cutting: Leaving connections between cut patches in order to preserve biodiversity (birds and mammals especially)

;

Stem Only vs. Whole tree harvest: Leaving root systems mitigates the amount of nutrient loss from the soils in forests (decay replenishes some of the nutrients) and preserves the habitat of some organisms that depend on stem and roots.

Stem Only vs. Whole tree harvest

Leaving root systems mitigates the amount of nutrient loss from the soils in forests (decay replenishes some of the nutrients) and preserves the habitat of some organisms that depend on stem and roots.

Forestry Impacts (4)

1) Nutrients: Removal of biomass (varying in stem only or whole tree harvest) results in removal of nutrients that may result in degraded productivity. If harvesting takes place in short rotations, nutrient capital may not be replenished by natural inputs (precipitation, nitrogen fixation, weathering of minerals) removal of roots may also lead to nutrient leaching as nutrients leach downward without onstuction.

2) Biodiversity: clear cutting and other types of harvesting cause disturbances in the forest that may benefit some organisms while being detrimental to others in terms of habitat and nutrient availability.

  • Vegetation: Ruderal (low stress, high disturbance) plants succeed in immediate post-clearcut, at the expense of other plants which do not thrive in open and disturbed areas. However, with the new abundance of nutrients and light, biodiversity can be increased in subsequent regrowth.
  • Mammals: Deer may increase as more platable plants succeed in disturbed areas and more ecotonal (edge lands) are created, however if there is tooo much disturbance or lack of tree cover entirely this may result in degredation of populations. Moose and Elk can also benefit, while Caribou may not.
  • Birds: Some require mature forest for breeding, migration or wintering, while others thrive in recently succeeded forest.
  • Small mammals: relatively undisturbed in logged areas, however if their habitat is comprised of fallen logs and roots, etc.. could be problematic.
  • Cavities of old trees and deadwood provides homes for some organisms and, if logging removes them, succession does not replace them, thus affecting these organisms.

;

3) Erosion: In most cases this is due to the poor construction of roads, using streams as trails to haul logs, running log trails down slopes instead of across them, or harvesting trees on steep slopes…

  • May lead to exposure of bedrock: inability for subsequent regrowth
  • Erosion of sediment into aquatic systems (siltation)
  • Nutrients are lost with the loss of soil: regrowth becomes more difficult
  • Geomorphic events become more numerous: floods and landslides

Erosion can be prevented by planning logging roads that do not corss streams, installing culverts, avoiding heavy equipment crossing streams, leaving a buffer zone close to watercourse (riparian buffer zone), allowing forests to regenerate quickly, selectively harvetsing or not harvesting trees on slopes or other vulnerable areas.

;

4) Hydrology: When trees are removed from an area, their hydologic inputs (transpiration) are compormised and this water then enters the watertable as ground water.

;

  • Microclimate (related to hydrology):
  • ; EvapoTranpiration
  • ; Precipitation interception
  • ; Snow accumulation and melt
  • ; Wind, temperature

Integrated Forest Management

Forest management plans that accomodate the need to harvest timber from landscapes, while also sustaining other values, such as hunted wildlife, outdoor recreation, and biodiversity.

;

Benefits:

;

; Biodiversity

; Forest ecosystem conditions and productivity

; Soil and water resources

; Contributions to global ecological cycles

; Multiple benefits to society

; Sustainable development

Net Useful Energy

  • Useable amount of energy available from a source;over its lifetime
  • Subtract all losses (waste from discovery, processing and transportation): Second law of thermodynamics… each transfer results in loss of energy.
  • 15 units of coal produces 10 units of electricity… so net loss is 5 units.

Fossil Fuels

Organic rich geological materials, such as coal, petroleum and natural gas… Formed by the lithification of partially decomposed biomass into hydrocarbons and other organic compounds which may include sulphur or nitrogen…

;

Coal: An organic-rich, solid fossil fuel mined from sedimentary geological formations that vary in quality and hardness (harder had higher energy density). Most coal is combusted in large industrial facilities, which accounts fo 50% of global use and 70% in Canada. Also 75% is used for manufacture of steel.

;

Oil and Heavy oil (petroleum): a fluid mixture of hydrocarbons with some impuirities, such as organic compounds containig sulphur and nitrogen. OIL refers to relatively pure hydrocarbons, while HEAVY OIL refers to oil deposited in shale or sand.;Petroleums from different places vary greatly in their physical and chemical qualities, it must be refined to remove the hydrocarbons from other impurities resulting in:

  • gasoline: a light hydrocarbon fraction used in automobiles
  • diesel: slightly heavier fracitions for trucks, trains, and home-heating
  • kerosene: used for heating and cooking and as fuel for aiplanes
  • dense residual oils: used in oil-fired power plants and as ship fuel
  • tarry, semi solid asphalts: used to pave raods and manufacture roofing products

Natural gas: Methane is the dominant hydrocarbon… used to generate electricity, heat buildings, to cook food, to power light vehicles, and to manufacture nitrogen fertilizer.

Energy Reserves and Consumption

Globally there is about 133 years left of reserves in coal; 60 years of natural gas; and 42 years of petroleum…

;

because most of the worlds petroleum resources come from the Middle East, Russia and Venezuela, the most devloped contries depend on interactions with those countries to maintain their consumption levels.

;

Russia has the largest total hysdocarbon capital with stocks of coal, petroleum and natural gas.

Pros and cons of fossil fuels

Pros:

  • High Net Energy

Cons:

  • Aerosols, Greenhouse gases, and SO2
  • Mining Impacts
  • Oil spills

Energy Sources (7)

  1. Nuclear (fission)
  2. Hydroelectric (run-of-the-river/resevoir)
  3. Solar
  4. Geothermal
  5. Wind
  6. Tidal
  7. Biomass

Energy Sources: Nuclear (description and pros/cons)

  • ;~13% of Canadian electricity, 40% of Ontario;s
  • Unstable isotopes of Uranium (235 U) and plutonium;(239 Pu);decay in a process known as fission which produces free neutrons.
  • Releases energy and more neutrons in a controlled chain reaction;

Pros:

  • Fewer emissions: 1/6

    ;

    th CO2 of coal

  • Cheaper, less land disturbance

;

Cons:

  • Waste heat (what to do with heated water)

  • Uranium mining (non renewable)

  • Safety (Chernobyl);

  • Climate change (if it is too hot, the reactor cannot be used)

  • Radioactive waste must be dealt with for 10,000 years

;

;

;

;

;

Hydroelectricity

Energy generated through the conversion of kinetic energy through a turbine

  • ~12% if Canadian power
  • Run of the river vs resevoir dams

Pros:

  • long lifespan
  • few pollutants

Cons:

  • Few development sites left
  • River and landscape changes

Types of energy: Solar Power (pros/cons and description)

Electromagnetic energy converted to electricity and heat

;

Currently 3X greater use than in 1995

;

Active Solar energy relies on the use of machinery to collect and cirulate solar energy whereas Passiv Solar Energy involved the direct absorption without external machinery.

;

Pros:

  • Renewable source of energy

Cons:

  • Cost of materials and maintainance of equipment makes it expensive to operate;
  • Materials for;cells is rare and expensive to mine, also not renewable;

Types of Energy: Geothermal (description and pros/cons)

Tapped in in the few places where magma fromt he Earth’s mantle occurs relatively close to the Earth’s surface and heats ground water. Boiling water is piped to the surface where it can produce electricity or heat buildings.

;

Pros:

  • Renewable if groundwater supply is managed right

Cons:

  • not available in all areas

Energy Sources: Wind Energy (Description and Pros/Cons)

Kinetic enrgy of moving air masses, can be tapped ans used in various ways. Extensive windfarms consisting of highly effecient wind turbines are erected in consitently windy places (eastern Quebec, Northern California, and south eastern Alberta)

;

Pros:

  • Subsidies
  • No emissions

Cons:

  • birds/bats
  • aesthetics
  • Cost is relatively high in some areas when there is not a substantial market.

Tidal Energy

Kinetic energy from tidal flows harnessed to drive turbines and generate electricity. The Bay of Fundy in eastern Canada is an example

;

Pros:

  • Renewable

Cons:

  • Not available everywhere
  • more research needed

Energy sources: Biomass (description ; Pros/cons)

potential chemical energy stored in biomass; (which is actually solar energy fixed through photosynthesis) is combusted to provide thermal energy to heat homes and buildings, or used in industrial-scale generating stations to produce steam that drives a turbine and generates electricity. Can also be used to produce methanol to be used as a liquid fuel in vehicles.

;

*PEat from bogs is a commonly mined source of biomass energy*

;

Pros:

  • Renewable if the harvested ecosystems are allowed to regenerate

Cons:

  • Rarely managed properly as the demand is higher than the supply regenerates

Energy Production and Consumption

Production: Overall about 85% of commercial energy;production in developed countries is from non-renewable sources.

;

In Canada this is about 86% with 31% from natural gas, 35% from petroleum, 12% from coal, and 8% from nuclear… the remaining is moslty;from hydroelectricity (10%), 4% in biomass fules.

;

In terms of consumption:;;in developed countries the levels of consumption are dramatically higher than in developing countries… 150 GJ/person/yr vs 25 GJ repectively.

;

Canada has about 349 GJ/person/yr makingi t one of the;most energy;using nations. due to cold weather, appliances and;affluence and industrialization

;

Rapidly industrializing nations, like China, India and others are starting to consume more and more;energy, which throws into question the sustainability of;non-renewable resource economies.;;

;

;

30% industry,30% transportation

40% agriculture/homes/businesses

6 industries use 81% of industrial energy:

pulp ; paper, smelting/steel making, mining, cement

Energy Efficiency

Transportation

; vehicle efficiency

; shipping goods

;

; Industrial

; co-generation: e.g., landfill

methane

;

; Household

; windows, doors, efficient

–home/water heating

 

 Energy use by Industry, transportation vs agricultural/home/business

 

 

 

 

30% industry,30% transportation

40% agriculture/homes/businesses

 

6 industries use 81% of industrial energy:

pulp & paper, smelting/steel making, mining, cement

Sustainability

Ability of an ecosystem to maintain it’s ecological processes, functions and biodiversity over time.

 

Sustainable Development

Refers to progress toward an economic system that uses natural resources in ways that do not deplete their stocks or compromise theor ability to future generations.

 

The idea is to improve quality of life yet stay within the ecosystem’s carrying capacity…

 

There are three aspects:

1) Ecological

2) Social

3) Economic

Ecological Footprint

The area of an ecoscape (i.e. landscape or seascape) that is required to supply a human population (or individual) with the necessary food, materials, energy, waste disposal, and other crucial goods and services.

 

For Canada it is 8.6 ha (the 2nd largest in the world)

Cities as Ecosystems (3 reasons why it is an ecosystem)

  1. Need for enormous inputs of energy and materials ro sustain its human population and its diverse economic activities, and to maintain its structure and grow.
  2. A complex metabolism including well-developed webs of transfer, prosessin, and storage material, energy, and iformation among interacting organisms and economic sectors.
  3. Immense outputsof heat and other waste materials, which are disposed of in surrounding ecosystems, causing pollution and other environmental problems.

A city comrpises a urban-industrial techno-ecosystem and it affects all of the natural environmental processes we’ve discussed (nutrient/carbon/water cycling, and biological productivity)

Megacities
A large city, sometimes described as having more than 8 million people 
Environmental conditions in the Urban Ecosystem (Atmosphere)

Microclimate: Temperatures are usually warmer by 3-6 C0; have 5-10% more cloud cover; receive about 20% less solar radiation; have 20-30% lower eind speeds; have 5-15% lower relative humidity; receive 5-15% more precipitation.

  • The most dramatic climatic difference is manifest on the “heat-island effect” in which the area of a city is considerably warmer because:

                  -emissions of large amouts of heat from buildings and machines

                  -interference by buildings with the dispersal of warm air by wind

                -the absorption of solar radiation by dark surfaces (roads, parking  lots, etc) anf re-emitting of longwave radiation relative lack of plant foliage (less cooling via transpiration)

 

Air Quality:

  • Suspended particulates from vehicles, furnaces and other combustion sources.
  • oxidants… Ozone smog
  • SO2 and NOx gases: though reduced as a result of legislation still contributes to acid deposition and may affect sensitive plants. 

Environmental conditions in the Urban Ecosystem (Hydrosphere) (5)

  1. Changing supply
  2. Seepage, runoff, pollutants
  3. impermeability of some surfaces
  4. High treatment and high use
  5. Use for recreation

*All of this is uderscored by the fact that there is a high energy input*

Environmental conditions in the Urban Ecosystem (Energy)

  1. Increased consumption of energy
  2. Malls and indoor attractions
  3. Cooling (byproduct fo the urban heat island effect)
  4. Transport (suburbs to work, recreation, etc)

Environmental conditions in the Urban Ecosystem (Solid Waste)

  • Canada is a leader in waste production with 1.7 Kg daily per capita vs 0.8 in Sweden.
  • Some cities ship their waste elsewhere (Vancouver to Cache Creek; Toronto to the US) while others use Landfills or incineration.

Some methods of dealing with waste in urban ecosystems:

 

1) Dumping: long-term disposal of solids to landfill, gases to atmosphere, and liquids to lakes and rivers

 

2) Incineration: combustion of solid watse to reduce amouts of organic material … residual materials (ash, metals, glass) are disposed of in secure landfills. SOme waste to energy  facilities connect to other industry which can use methane or heat from incinerator to function.

 

3) Recycling: reduces waste, produces valuable commodities, and helps to conserve valuable materials by turning waste into resource…

 

4) Composting: disposed organics allowed to decay under warm and aerobic conditions, to become reichly humified soils.

 

5) Waste Reduction and Prevention: choices made by consumers to buy products with less packaging or that are reusable, recyclable or returnable. In essence buying less and promoting the three R’s…

Sanitary Landfills
A facility where municipal solid waste is dumped, compacted by heavy machines, and covered with layers of dirt at the end of the day to prevent infestations. Some have liquid catment systems  called leachate.
Land Contamination (Urban Solid Waste)

  • Old Industrial sites: toxic dumps, spills, leaking hydrocarbons
  • Large Scale Industry: Trail, BC… soils contaminated by Pb (lead) from smelter dust
  • Pesticides/Herbicides: Many municipalities are now banning their use, however much gets into to soils   

 

 

City Greenspaces (Benefits, Potential problems…i.e. examples of introduced species, common sentiment)

Benefits:

  • Moderate microclimate  
  • decrease air pollution
  • reduce storm flows
  • recreational resource

Problems:

  • Not Valued:::: Many people look at them as underdeveloped and underused
  • the ecological benefit is minimal if it is a small area
  • many greenspaces include non-native species Including:
  1. Sticky-touch-me-not: annual wildflower from thr Himilayas that was introduced through horticulture and can be invasive in gardens and wetlands
  2. Dandelion: perennial herbacaous plant originally from alpine habitat in Europe, now occurs in temperate climates throughout the world. Usually on lawns and pastures as a weed. (probably introduced from ship ballasts)
  3. Norway Maple: a native tree from Europe which was intriduced for horticultural use. It now invades hardwood forest.
  4. Oriental Cockroach: an insect from southeast Asia, probably introduced by accident with ship cargo and is now a serious pest in many homes and food storage areas.

Invasive Species Introduced to Cities (know 2, but there is 4 on this slide)

Regarded as “biological pollution” many of these organisms were originally introduced as seeds in ballasts of ships, accidetally/inadvertently introduced, agriculture/horticulture

  1. Sticky-touch-me-not: annual wildflower from thr Himilayas that was introduced through horticulture and can be invasive in gardens and wetlands
  2. Dandelion: perennial herbacaous plant originally from alpine habitat in Europe, now occurs in temperate climates throughout the world. Usually on lawns and pastures as a weed. (probably introduced from ship ballasts)
  3. Norway Maple: a native tree from Europe which was intriduced for horticultural use. It now invades hardwood forest.
  4. Oriental Cockroach: an insect from southeast Asia, probably introduced by accident with ship cargo and is now a serious pest in many homes and food storage areas.

Urban Transportation
Urban Sprawl leads to separations between work, recreation, shopping and home areas, etc.. which makes travelling large distances necessary. Also, because cities are not self-sufficient in providing all the required services/necessities for their inhabitants, there is large amounts of travel between cities and rural areas, etc to provide… 
Urban Pollution (Chemical)

  • Higher concentrations of chemical pollutants in cities compared to rural areas, and sometimes at levels that damage the health of people, plants and animals. 

 

Pollutants include:

  • Hydrocarbons from spills in soils and waterbodies,
  • metals from industrial pollution, Eurtrification from fertilizer,
  • suspended particulates from combustion,
  • oxidants/VOCs from motor vehicles 
  • NOx and SO2 from industry and vehicle exhaust. 

Urban Pollution (Thermal)

when an increase in environmental temperature is sufficient to result in ecological damage, usually to waterbodies from industry.

 

 

Urban Pollution (Noise Pollution)
Urban areas are much noisier than other areas due to running machinery, traffic, airplanes, etc, and causes discomfort and hearing problems as well as places stress on many organisms. 
Urban Pollution (Aesthetic Pollution)
Visually experienced phenomena that some people may find offensive, very subjective and considered less important than other types of pollution.
Urban Biodiversity

Urban environments are usually impovershed of native species and instead characterized by alien species (dandelions, sticky-touch-me-not’s, house mouse, Norway Rat, etc). Sometimes these alien species out-compete native species and may be detrimental to existing populations and ecpological balance.

 

However some greenspaces, like stanely park or fish creek park contain many remnants of native species.

 

It is important to rememebr that many species still exist in urban environments, including birds and mammals (even though many are alien)

 

The key to sustaining biodiversity is preserving large extents of natural habitat that support native species…

Impacts on Agricultural Land

Urban Sprawl encroaches onto agricultural land, infact many cities in Canada are built on otherwise excellent farm land, which can then never be recclaimed as agricultural land.

 

This is especially a problem in specialty crop areas like the Okanagan valley and the Niagra Penninsula where orchards provide fruit (and wine)

 

With grwoing populations, this exacerbates problems of resource availability as potential food providing land is converted.

Soutions and progress

  1. Change urban form: Urban planning that accounts for shorter transportation routes between living and recreation/work/etc areas as well as more greenspace and urban forests.
  2. Conserve: water, energy, materials, ecosystems
  3. Reduce Impacts: on air + water quality as well as improve waste management methods and encourage reducing, reusing and recyclying.

Leave a Reply
Your email address will not be published.
*
*

BACK TO TOP