Environmental Encyclopedia

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Taiga

Taiga is a generic term for a type of conifer-dominated

boreal forest found in northern environments. The word

was first used to describe dense forests of spruce (especially

Picea abies) in northern Russia. It has been extended to refer

to boreal forests of similar structure in North America but

dominated by other conifer

species

(especially Picea mariana

and Picea glauca). Broad-leafed tree species are uncommon

in taiga, although species of poplar (Populus spp.) and birch

(Betula spp.) are present. Taiga environments are character-

ized by cool and short growing seasons. Plant roots can only

exploit a superficial layer of seasonally thawed ground, the

active layer, situated above permanently frozen substrate, or

permafrost

Tailings

Tailings are produced when metallic ores are ground into a

fine powder to free the metal-bearing mineral. Its maximum

particle size of about 0.08 in (2 mm) is small enough to

retain water and support plant growth. Fine dust is one

potential hazard, especially if trapped in the lungs of miners.

The greatest revegetation difficulties come from metals in

lethal concentrations and deficiencies of critical nutrients,

especially

nitrogen

and

phosphorus

. Some old tailings have

remained barren for many years, with consequent high

ero-

sion

rates. However, some metalophytes are able to survive

on these wastes. Curiously, some plants have populations

which can also survive on these tailings.

Tailings pond

Refers to the water stored on-site to wash ore and receive

waste

tailings

as a residue. This provides both a water supply

and a

sediment

trap. Two serious environmental problems

ensue. The water leaches out metals and other dangerous

elements that were formerly trapped underground in a reduc-

1377

ing (non-oxidizing)

environment

; acidic wastes amplify the

leaching

. And though usually stable, some

dams

have burst

during flood stages, unleashing a torrent of toxic materials

and posing a combined hazard of mudflow and

flooding

Takings

The term “takings” refers to the practice of taking, or other-

wise restricting the use of, private property through the

governmental power of eminent domain, environmental reg-

ulation, or other restrictions. The power of eminent do-

main—and the property owner’s right to compensation—is

stated in the Bill of Rights (Fifth Amendment to the U.S.

Constitution): “nor shall private property be taken for public

use, without just compensation.” Likewise, the Fourteenth

Amendment stipulates that no state may “deprive any person

of life, liberty, or property, without due process of law; nor

deny to any person within its jurisdiction the equal protection

of the laws.”

Critics of environmental regulation contend that gov-

ernment cannot constitutionally interfere with a property

owner’s freedom to do as he or she wishes with his or

her own property without compensating the owner. For

example, a farmer who wishes to extend or improve his land

by draining a swamp or other wetland cannot be forbidden

to do so without adequate compensation. A rancher who is

forbidden by law to shoot or trap

wolves

that threaten his

cattle can claim compensation for livestock losses due to

wolf predation. To “take” or otherwise regulate or restrict

the use of their property without full and fair compensation

would constitute a violation of their constitutionally guaran-

teed rights under the Fifth and Fourteenth Amendments.

Many environmentalists maintain that the high cost

of such compensation would mean the effective end of many

environmental regulations regarding

wetlands

, woodlands,

and other habitats on private property. They contend that

the Constitution does not construe the concept of “takings”

as broadly as their critics do. There have long been restric-

Environmental Encyclopedia 3

Tall stacks

White spruce-willow taiga in Alaska. (Photograph by Charlie Ott. Photo Researchers Inc. Reproduced by permission.)

tions on what one may do to or with his or her property.

There are, for example, restrictions on erecting billboards on

private property along public highways.

Automobile

salvage

yards can be required to erect walls to shut out the unsightly

view. In neither case is the owner to be compensated for

loss, cost, or inconvenience. In these instances, the public

interest in avoiding eyesores overrides the private interests

of the property owners. So too, environmentalists contend,

does the public interest in a clean, safe, and sustainable

natural

environment

empower the federal, state, or local

government to enact and enforce laws restricting what prop-

erty owners may do with or to

wildlife

and the

habitat

that sustains them.

The legal and political battles over “takings” continues

to be waged in the courts of law and public opinion. Some

critics of environmental protection (most notably, libertari-

ans associated with the Cato Institute) contend that the

Constitution does not go far enough in guaranteeing the

protection of private property rights and should therefore

be further amended. Some environmentalists claim that the

Constitution should, on the contrary, be amended to extend

protection to animals, ecosystems, and

future generations

1378

It seems plausible to predict that these battles will be waged

well into the twenty-first century.

[Terence Ball]

ESOURCES

OOKS

Epstein, R. A. Takings: Private Property and the Power of Eminent Domain.

Cambridge, MA: Harvard University Press, 1985.

Tall stacks

The waste gases that escape from factories or

power plants

running on

fossil fuels

typically contain a variety of pollut-

ants, including

carbon monoxide

, particulates,

nitrogen

oxides

, and sulfur. The first of these pollutants,

carbon

monoxide, tends to dispense rapidly once it is released to

the

atmosphere

and seldom poses a serious threat to human

health or the

environment

. The same cannot be said of the

last three categories of pollutants, all of which pose a threat

to the well-being of plants, humans, and other animals.

Environmental Encyclopedia 3

Talloires Declaration

During the 1960s, humans became increasingly aware

of the range of hazards, posed by pollutants escaping from

smokestacks. One of the most common events of the time

was for residents in the area immediately adjacent to a factory

or plant to find their homes and cars covered with fine dust

from time to time. They soon learned that the dust was

fly

ash

released from the nearby smokestacks. Particulates (fine

particles of unburned carbon) also tend to settle out fairly

rapidly and cover objects with a fine black powder.

It was clear that visible pollutants, such as fly ash and

particulates, offered a hint that invisible pollutants, such as

oxides of

nitrogen

and sulfur, were also accumulating in

areas close to factories and power plants. As the health

hazards of these pollutants became better-known, efforts to

bring them under control increased.

Certain technical methods of

air pollution

control—

electrostatic precipitation and scrubbing, for example—were

reasonably well-known. However, many industries and utili-

ties preferred not to make the significant financial investment

needed to install these technologies. Instead, they proposed

a simpler and less expensive solution: the construction of

taller smokestacks.

The argument was that, with taller smokestacks, pol-

lutants would be carried higher into the atmosphere. They

would then have more time and space to disperse. Residents

close to the plants and factories would be spared the fallout

from the smokestacks. The “tall stack” solution met the

requirements of the 1970

Clean Air Act

as a “last-ditch

alternative” to gas-cleaning technologies.

As a result, companies began building taller and taller

smokestacks. The average stack height increased from about

200 ft (61 m) in 1956 to over 500 ft (152 m) in 1978. The

tallest stack in the United States in 1956 was under 600 ft

(182 m) tall, but a decade later, some stacks were more than

1,000 ft (305 m) high.

At first, this effort appeared to be a satisfactory way of

dealing with air pollutants. The concentration of particulates

and oxides of nitrogen and sulfur close to plants did indeed,

decrease after the installation of tall stacks.

But new problems soon began to appear, the most

serious of which was

acid deposition

. The longer oxides

of sulfur and nitrogen remain in the air, the more likely they

are to be oxidized to other forms, sulfur trioxide and nitrogen

dioxide. These oxides, in turn, have the tendency to react

with water droplets in the atmosphere forming sulfuric and

nitric acids, respectively. These acids eventually fall back to

earth as rain, snow, or some other form of precipitation.

When they reach the ground, they then have the potential

to damage plants, buildings, bridges, and other objects.

The mechanism by which stack gases are transported in

the atmosphere is still not completely understood. Yet it is

now clear that when they are emitted high enough into the

1379

atmosphere, they can be carried hundreds or thousands of

miles away by prevailing winds. The very method that reduces

the threat of air pollutants for communities near a factory or

power plant, therefore, also increases the risk for communities

farther away. See also Acid rain; Air quality; Criteria pollutant;

Emission; Scrubbers; Smoke; Sulfur dioxide

[David E. Newton]

ESOURCES

ERIODICALS

“The Dirtiest Half-Dozen.” Time 139 (June 8, 1992): 31.

Harris, J. “How to Sell Smoke.” Forbes 145 (June 11, 1990): 204–205.

“New Clues to What An Incinerator Spews.” Science News 140 (September

21, 1991): 189.

Talloires Declaration

The Talloires Declaration was created in October 1990 in

Talloires, France. Jean Mayer, then president of Tufts Uni-

versity in Boston, called together 22 other university presi-

dents and chancellors from universities throughout the world

in order to express their concerns regarding the state of the

world as well as prepare a document that identified key

environmental actions that institutions of higher learning

must take to prepare.

According to their organization, University Leaders

for a Sustainable Future (ULSF), “Recognizing the shortage

of specialists in environmental management and related

fields, as well as the lack of comprehension by professionals

in all fields of their effect on the

environment

and public

health, this gathering defined the role of the university in

the following way: “Universities educate most of the people

who develop and manage society’s institutions. For this rea-

son, universities bear profound responsibilities to increase

the awareness, knowledge, technologies, and tools to create

an environmentally sustainable future.’”

The actions outlined are listed as follows:

increase awareness of environmentally

sustainable devel-

opment

create an institutional culture of sustainability

educate for environmentally responsible citizenship

foster environmental literacy for all

practice institutional ecology

involve all stakeholders

collaborate for interdisciplinary approaches

enhance capacity of primary and secondary schools

broaden service outreach nationally and internationally

maintain the movement

Environmental Encyclopedia 3

Arthur G. Tansley

By May 2002, the declaration had been signed by 288

institutions, including 17 in Africa; 99 in Canada and the

United States; 108 in Latin America and the Caribbean; 33

in Asia, the Middle East, and the South Pacific; and 31 in

Europe and Russia. ULSF has reported that the document

has provided inspiration for other similar official declarations

in locations throughout the world, including Halifax, Nova

Scotia, Canada; and, Kyoto, Japan—home of the monumen-

tal

Kyoto Treaty

Programs have been developed at universities and col-

leges throughout the United States. One exemplary program

was established at Ball State University in Muncie, Indiana.

In an introduction to the Ball State plan, associate professor

James Elfin of the Ball State Department of Natural Re-

sources and Environmental Management, stated that, “If

colleges and universities are leaders in the quest for knowl-

edge, why can’t they be leaders on the path to a sustainable

future?...Academic institutions are regarded—rightly or

wrongly—as vanguards for what is possible and encuring.

They are perceived to be on the forefront of what society

can attain. As an institution, the university endures over a

long span of time—if successful, it can be imagined to last

forever. In an earlier edition of The Declaration...architect

William McDonough was asked how long sustainability will

take. His reply: “It will take forever. That’s the point.’” Ball

State outlined an extensive plan with a list of Action Items,

practical ways in which to implement a “greening” of the

campus.

The list of 10 items are as follows:

audits (three of them: one of campus environment, another

of faculty expertise, and a third of needs of K–12 schools

across the state of Indiana)

campus bikeway system

developing an

environmental education

resource center

(in the meantime, a separate effort on campus has resulted

in the creation of a field station and environmental educa-

tion center, FSEEC)

green issues awareness (or, “green facts” that would be

distributed via various media on and off campus)

retrofit or reconfiguration of the Central (District) Heat-

ing Plant

adopting hybrid electric (or other energy-efficient) vehicles

for the campus motor pool

campus-wide

recycling

program (one has existed, but is

not effectively run nor fully integrated with all campus

operations)

sustainability trunk show (to spread the word to larger

publics outside the university community)

1380

incorporation of sustainability within the university core

curriculum (or, general education program that is required

by all students)

[Jane E. Spear]

ESOURCES

THER

Environmental News Network. The Worldwatch Report: Campus Environ-

mental Programs Spur Action. June 1, 1998 [cited June 2002]. <http://

www.enn.com/features>.

Safe Climate. University of Buffalo: How to Shrink the University’s Carbon

Footprint While Reducing the Cost of Education. 1996 [cited June 2002].

<http://www.safeclimate.net/index>.

RGANIZATIONS

University Leaders for a Sustainable Future, 2100 “L” Street, NW,

Washington, DC USA, 20037, 202-778-6133, Fax: 202-778-6138,

<http://www.ulsf.org>

Arthur G. Tansley (1871 – 1951)

British botanist

Arthur G. Tansley was a highly influential British botanist

and ecologist. He was educated at University College, Lon-

don, and Trinity College of Cambridge University. He

taught at University College until 1906, and then moved to

Cambridge. In 1927, He became a Professor of Botany at

Oxford, and he retired as a Professor Emeritus in 1937.

Much of his retirement was spent working for the

conserva-

tion

nature

in Britain, largely by public advocacy and by

working with the

Nature Conservancy

, of which he was

the first Chairman.

In 1902, Tansley founded the influential botanical

journal, New Phytologist, and was its editor for thirty years.

He was a founder of the British Ecological Society in 1913,

and was the editor of its key periodical, the Journal of Ecology,

for twenty years. Tansley’s classic book, The British Islands

and Their Vegetation, was published in 1939.

Tansley was highly influential in the development of

the field of ecology. He was the first person to use the word

“ecosystem” to describe a basic unit of nature. He coined

the word as a reduction of the phrase “ecological system”

(the word “system” was borrowed from its prevalent use at

the time in the field of physics). The new word was initially

used at a conference at Ithaca, New York, in 1929. It was

first published in 1935 in a highly influential paper in which

Tansley discussed and clarified key terms and concepts in

ecology. His ideas about “systems” were important in helping

ecologists to understand that organisms and their communi-

ties are profoundly influenced by many non-living environ-

mental factors, and vice versa (i.e., organisms and their com-

munities also influence environmental factors). Much of the

Environmental Encyclopedia 3

Tar sands

power of the

ecosystem

concept is inherent in its consider-

ation of the complex, often unpredictable behavior of sys-

tems. The subsequent emergence of the field of systems

ecology drew heavily on physics, mathematics, and computer

science, as well as the more traditional ecological disciplines

of plant and animal ecology. Prior to Tansley’s ideas about

ecosystems, ecologists mostly studied populations of plant

and animal

species

, or their communities, but with relatively

little regard for the influence of and interaction with environ-

mental factors.

Modern ecologists now consider ecosystems as con-

sisting of all of the biotic (plants, animals, and

microorgan-

isms

) and abiotic (

climate

soil

, and other non-living envi-

ronmental factors) elements of a specified area or volume.

As such, an ecosystem can be relatively small (e.g., contained

within a

clod

of earth or an aquarium) or as large as the

entire

biosphere

of the Earth. Moreover, the state of an

ecosystem at any point in time (for example, during

succes-

sion

following disturbance) represents the present balance

between biological and abiotic influences.

Many ecologists also believe that ecosystems do not

just consist of the sum of the qualities of their individual

parts. Rather, there are also “emergent” properties that can-

not be easily predicted, but may nevertheless be extremely

important in the

stability

and

resilience

of the ecosystem.

For example, some particularly important species, known

keystone species

, may have a highly disproportionate

influence on the integrity of their ecosystem, which could

not be predicted based only on their relative contribution of

biomass

or productivity. Some top predators, for instance,

play a key role in setting the structure of their entire food

web, while certain microorganisms (such as

nitrogen

fixers)

have an inordinate influence on overall productivity. Inter-

estingly, in his 1935 paper, Tansley objected to some of the

original, emerging ideas about holism in ecology; neverthe-

less, as evidence of emergent properties has accumulated,

holistic ideas have taken root in the theory and practice of

ecology.

Tansley is also known for his criticisms of the views

of the influential American ecologist,

Frederic Clements

(1874-1945). Clements believed that plant communities

were highly integrated and “organismic” in their qualities,

and not merely a sum of their individual species. He also

suggested that succession, or the process of development of

plant communities after disturbance, should proceed to a

highly predictable and stable

climax

community determined

by regional conditions, particularly climate. This view was

heavily criticized by another American ecologist,

Henry

Gleason

(1882-1975), who argued that plant species re-

spond to succession and environmental gradients in an indi-

vidualistic manner, rather than in a strongly integrated, or

organismic way. Tansley played an important role in this

1381

debate, and favored the individualistic hypothesis as being

most realistic.

Tansley also performed important research that

showed that plant species are capable of growing over a

wider range of environmental conditions than they actually

manage to exploit in nature. His experiments showed that

competition

is the key factor restricting species to a relatively

narrow range of

habitat

conditions. This work influenced

the development of the ecological concept of the

niche

Modern textbooks define the fundamental niche as the in-

herent tolerance of a species to environmental extremes (such

as high and low temperatures), and the realized niche as the

range of environmental conditions that a species actually

exploits in nature, being mediated by competition.

[Bill Freedman Ph.D.]

ESOURCES

OOKS

McIntosh, R. P. The Background of Ecology: Concept and Theory. Cambridge,

UK: Cambridge University Press, 1985.

Sheail, J. Seventy-five Years in Ecology: The British Ecological Society. Oxford,

UK: The British Ecological Society, 1988.

Tansley, Arthur G., ed. The British Islands and Their Vegetation. Cambridge,

UK: Cambridge University Press, 1939.

Tansley, Arthur G. “On Competition Between Galium saxatile and Galium

sylvestre on Different Kinds of Soils.” Journal of Ecology 5 (1917): 173–179.

Tansley, Arthur G. “The Use and Abuse of Vegational Concepts and Terms.”

Ecology 16 (1935): 284–307.

Tar sands

Oil sands, formerly referred to as tar sands, are sandy sub-

strates that contain large deposits of bitumin, a kind of fossil

fuel. Bitumen is a thick, viscous, black, sticky, tar-like form

of liquid

petroleum

, but its physical consistency is compara-

ble to that of cold molasses. Oil sands occurring at or near

the surface can be mined using open-pit techniques. The

bituminous materials are then extracted by heating and the

hydrocarbons

refined and manufactured into a synthetic

petroleum product. Once the readily extractable, surface de-

posits are extracted, deeper bitumen may be mined using

steam assisted, in situ techniques that decrease viscosity and

allow the bitumen to flow so it can be pumped to the surface.

Mined oil sand typically contains 10-12% bitumen, 4-

6% water, and 80-85% mineral sand and clays. About 2.2

tons (2 tonnes) of oil sand must be processed to produce

one barrel (0.16 m

) of liquid petroleum. About 75% of the

bitumen present can typically be recovered from mined oil

sand. After processing, the sand waste and any unextracted

bitumen are eventually used to back-fill and contour mined-

out areas, which are then seeded with vegetation to reclaim

a stable plant cover.

Environmental Encyclopedia 3

Target species

Most economically recoverable oil sand occurs at or

fairly near the ground surface. Initially it is mined in enor-

mous open pits, using extremely large trucks and industrial

shovels, among the biggest of their kind in the world. After

the open-pit mining, remaining deposits deeper than about

250 feet (75 m) and up to 1,300 ft (400 m) or deeper are

recovered using so-called in situ, or in-site practices. Various

techniques are used for in situ extraction of bitumen and

heavy crude oil. They include the injection of steam, solvents,

carbon dioxide

to reduce the viscosity of the heavy fluids

so they can flow and be collected and pumped to the surface.

The largest in situ recovery plant in Alberta is located at

Cold Lake, where steam injection is used to enhance the

ability of the bitumen to flow. This allows it to be pumped

to the surface, where it is treated with liquid natural-gas

hydrocarbon condensate to reduce its viscosity. The treated

bitumen is then shipped by pipeline to a specialized refinery

complex where a relatively light synthetic petroleum is man-

ufactured from the heavy, bituminous, crude fossil fuel.

The world’s largest resources of oil sand occur in north-

ern Alberta, Canada, and in Venezuela, in northern South

America. In Alberta, there are about 54-thousand mi

(141-

thousand km

) of oil-sand deposits. This region contains a

total estimated resource of 1.6 trillion barrels (0.25 trillion

) of bitumen, of which about 311 billion barrels (49 billion

) are thought to be potentially recoverable using known

mining and extraction technologies. Once processed, this

bitumen could yield an estimated 189 billion barrels (30

billion m

) of synthetic petroleum.

The first pilot plant to process oil-sand bitumen was

constructed in Alberta in 1962. The first full-scale facility

was developed between 1964 and 1967, with an initial capac-

ity of 31,000 barrels per day (4.9-thousand m

/day). During

the 1990s, extremely large investments were made to mine

and process the oil-sand deposits of Alberta. Between 1996

and 2000, the total investment in development of this re-

source was $11 billion (Can.), and it was $4.2 billion in

2000 alone. In the year 2000, 66,000 people were directly

employed in the oil-sand industry, and the Government of

Alberta received royalties of $711 billion. In 2001, oil sands

were yielding about one-third of all the petroleum produced

in Canada, and continued investment is expected to raise

this to 50% by 2005. That would be equivalent to about

10% of the total production of petroleum in North America.

Clearly, oil sands are a key component of the resource of

liquid

fossil fuels

in North America, and a critical element

contributing to the domestic energy security on the con-

tinent.

The mining and processing of oil sands results in

important environmental impacts, although the most intense

effects are restricted to the immediate vicinity of the indus-

trial operations. For example, the development of mine sites,

1382

refineries, and pipelines results in severe direct damage to

local natural habitats. In the case of open-pit mine develop-

ment, the

soil

and other

overburden

removed from the

site are generally stockpiled for use as a top-dressing during

the

reclamation

of the pit after it is mined out. The original

surface materials are conserved for this use because they

provide a much more hospitable material for plant establish-

ment and growth than does processed oil-sand waste, which

is a highly mineral and infertile substrate. The reclamation

usually attempts to re-create a facsimile of the original con-

tours of the landscape, and is intended to establish a self-

maintaining vegetation with at least as high a level of produc-

tivity as what occurred prior to the mining. The reclamation

effort is typically designed to develop grassland, forest, or

wetland habitats, or a mixture of these. Often, the intention

is to establish vegetation dominated by native

species

plants. The resulting habitats may then be attractive to indig-

enous species of birds, mammals, and other animals.

The process by which bitumen is extracted from oil

sand and then manufactured into synthetic petroleum results

in some emissions of

sulfur dioxide

, a toxic gas, into the

atmosphere

. The permissible amounts of emissions are

regulated within levels intended to prevent local vegetation

damage. This is achieved by the use of scrubbing technolo-

gies that remove most sulfur dioxide from the flue gases

before they are vented to the ambient

environment

. The

mining and processing processes also require extremely large

inputs of energy to drive their processes. Industrial engineers

have been working to make the processes run more effi-

ciently, and they anticipate achieving a 45% reduction of

carbon

dioxide emissions per barrel by 2010, compared to

1990 levels. This will result in large savings in process costs,

while also reducing the emissions of carbon dioxide, an

important greenhouse gas, to the atmosphere.

[Bill Freedman Ph.D.]

ESOURCES

OOKS

Fitzgerald, J. Gold with Grit: The Alberta Oil Sands. Sidney, BC: Gray’s

Publishing, 1978.

Lyttle, R. B. Shale Oil and Tar Sands: The Promises and Pitfalls. Danbury,

CT: Impact Books, 1982.

Perrini, E. M. Oil from Shale and Tar Sands. Park Ridge, NJ: Noyes Data

Corporation, 1975.

THER

Government of Alberta. Oil Sands. 2002 [cited July 2002]. <http://www.en-

ergy.gov.ab.ca/com/Sands/default.htm>.

Target species

The object of a

hunting

, fishing, or collecting exercise, or

an extermination effort aimed at destroying a particular orga-

Environmental Encyclopedia 3

Tellico Dam

nism. This term is often used to describe the intended victim

of an application of

pesticide

herbicide

. Unfortunately,

many non-target

species

can be affected by so-called tar-

geted activities. For example, Pacific net fishermen target

the yellowfin tuna, but also snare and kill non-target species

such as

dolphins

. Pesticides applied to crops to kill insects

(the target species) can enter the

food chain/web

, become

biologically magnified, and kill non-target species such as

fish-eating birds or birds of prey. See also Biomagnification

Taylor Grazing Act (1934)

This act established federal management policy on public

grazing lands, the last major category of public lands to be

actively managed by the government. The delay in its passage

was due to a lack of interest (the lands were sometimes

referred to as “the lands no one wanted") and due to competi-

tion between the Agriculture Department and the Interior

Department over which department would administer the

new program.

The purpose of the Taylor Grazing Act was to “stop

injury to the public grazing lands...to provide for their orderly

use, improvement and development...[and] to stabilize the

livestock industry dependent on the public range.” To

achieve these purposes, the Secretary of the Interior was

authorized to establish grazing districts on the public domain

lands. The lands within these established districts were to

be classified for their potential use, with agricultural lands to

remain open for homesteading. In 1934 and 1935, President

Franklin D. Roosevelt issued Executive Orders that with-

drew all remaining public lands for such classification, an

action that essentially closed the public domain. The Secre-

tary was authorized to develop any regulations necessary to

administer these grazing districts, including the granting of

leases for up to ten years, the charging of fees, the undertak-

ing of range improvement projects, and the establishing of

cooperative agreements with grazing landholders in the area.

Another important feature of the law called upon the

Secretary of the Interior to cooperate with “local associations

of stockmen” in the administration of the grazing districts,

referred to by supporters of the law as “democracy on the

range” or “home rule on the range.” This was formalized in

the creation of local advisory boards. The law created a

Division of Grazing (renamed the Grazing Service in 1939)

to administer the law, but for a number of reasons, the

agency was ineffective. It became quite dependent on the

local advisory boards and was often cited as an example of

an agency captured by the interests it was supposed to be

controlling. In 1946, the agency merged with the General

Land Office to create the

Bureau of Land Management

1383

Also included in the bill was the phrase “pending final

disposal,” which implied that these grazing lands would not

necessarily be retained in federal ownership. This phrase was

included because many thought the lands would eventually

be transferred to the states or the private sector and because

it lessened opposition to the law. The uncertainty introduced

by this phrase made management of the grazing lands more

difficult, and it was not eliminated until passage of the

Federal Land Policy and Management Act

in 1976.

The grazing fees charged to ranchers were initiated at a

low level, based on a cost-of-administration approach rather

than a market level approach. This has led to lower grazing

fees on public lands than on private lands. Typically, three-

fourths of the fees go to the local advisory boards and are

used for range improvement projects.

[Christopher McGrory Klyza]

ESOURCES

OOKS

Dana, S. T., and S. K. Fairfax. Forest and Range Policy. 2nd ed. New York:

McGraw-Hill, 1980.

Foss, P. O. Politics and Grass. Seattle: University of Washington Press, 1960.

Peffer, E. L. The Closing of the Public Domain: Disposal and Reservation

Policies, 1900–1950. Stanford: Stanford University Press, 1951.

Technological risk assessment

see

Risk assessment

TED

see

Turtle excluder device

Tellico Dam

In an effort to put people back to work during the Great

Depression, several public works and

conservation

pro-

grams were set in motion. One of these, the

Tennessee

Valley Authority

(TVA), was established in 1933 to protect

the Tennessee River basin, its water,

soil

, forests, and

wild-

life

. TVA initiated many projects to meet these agency goals,

but also to provide employment to this impoverished area

and to slow the emigration of the region’s youth. Many of

the projects completed and operated by TVA were

dams

and reservoirs along the Tennessee River and its tributaries.

In 1936 one such project site was identified on the lower

end of the Little Tennessee River. This proposal for Tellico

Dam was reviewed, but it was abandoned because the cost

was too high and the returns too low. The project was

reconsidered in 1942, and plans were drawn up for its con-

struction; however, World War II halted its development.

Environmental Encyclopedia 3

Temperate rain forest

Two decades passed before the Tellico Dam project

became active again. By this time, there was some opposition

to the dam from local citizens, as well as from the Tennessee

State Planning Commission. Opposition grew through the

mid-1960s and congressional hearings were held to study the

economic and environmental factors of this project. Supreme

Court Justice William O. Douglas even visited the site to

lend his support to the Eastern Band of the Cherokee Indian

Nation, whose land would be inundated by Tellico’s

reser-

voir

. Congress, however, approved the project in 1966 and

authorized funds to begin construction the following year.

After construction started, opponents of Tellico Dam

requested that TVA prepare an

Environmental Impact

Statement

(EIS) to be in compliance with the

National

Environmental Policy Act

of 1969. TVA refused because

Tellico Dam was already authorized and under construction

before the Act was passed. Local farmers and landowners,

whose land would be affected by the reservoir, joined forces

with conservation groups in 1971 and filed suit against TVA

to halt the project because there was no impact statement.

The court issued an injunction, and construction of Tellico

Dam was halted until the EIS was submitted. TVA complied

with the order and submitted the final EIS in 1973. That

same year the

Endangered Species Act

was signed into

law, and two ichthyologists from the University of Tennessee

made a startling discovery in a group of fishes they collected

from the Little Tennessee River.

They discovered a new

species

of fish, the

snail

darter

, later scientifically described and named Percina ta-

nasi. Its scientific name honors the ancient Cherokee village

of Tanasi, a site that was threatened by Tellico Dam. The

state of Tennessee also takes its name from this ancient

village. The snail darter’s common name refers to the small

mollusks that comprise the bulk of its diet. In January 1975,

the U.S.

Fish and Wildlife Service

was petitioned to list this

new species as endangered. Foreseeing a potential problem,

TVA transplanted snail darters into the nearby Hiwassee

River without consulting with the Fish and Wildlife Service

or the appropriate state agencies. Two more transplants of

specimens in 1975 and 1976 brought the number of snail

darters in the Hiwassee to over 700. Meanwhile, in October

1975, the snail darter was placed on the federal

endangered

species

list, and the stretch of the Little Tennessee River

above Tellico Dam was listed as

critical habitat

TVA worked feverishly to complete the project, in

obvious violation of the Endangered Species Act, and also

prepared for the ensuing court battles. A suit was filed for

a permanent injunction on the project, but this was denied.

An appeal was immediately made to the U.S. Court of

Appeals, which overturned the decision and issued the in-

junction. TVA then appealed this decision to the Supreme

Court, which, to the surprise of many, upheld the Court of

1384

Appeals ruling, but with a loophole. The Supreme Court

left an opening for the U.S. Congress to come to the aid of

Tellico Dam. In 1979, an amendment was attached to energy

legislation to exempt Tellico Dam from all federal laws,

including the Endangered Species Act. President Carter

reluctantly, because of the amendment, signed the bill. In

January 1980, the gates closed on Tellico Dam,

flooding

over 17,000 acres (6,885 ha) of valuable agricultural land,

the homes of displaced landowners, the Cherokee’s ancestral

burial grounds at Tanasi, and the riverine

habitat

for the

Little Tennessee River’s snail darters.

Fortunately, Tellico Dam did not cause the

extinction

of the snail darter. During the 1980s, snail darter populations

were found in several other rivers in Tennessee, Georgia,

and Alabama, and the transplanted population in the Hi-

wassee River continues to thrive.

[Eugene C. Beckham]

ESOURCES

OOKS

Ono, R., J. Williams, and A. Wagner. Vanishing Fishes of North America.

Washington, DC: Stone Wall Press, 1983.

Wheeler, W. B. TVA and the Tellico Dam: 1936–1979: A Bureaucratic Crisis

in Post-Industrial America. Knoxville: University of Tennessee Press, 1986.

Temperate rain forest

A temperate rain forest is an evergreen, broad-leaved, or

coniferous forest

which generally occurs in a coastal

cli-

mate

with cool to warm summers, mild winters, and year-

round moisture abundance, often as fog. Broad-leaved tem-

perate forests are found in areas including western Tasmania,

southeastern

Australia

, New Zealand, Chile, southeastern

China, and southern Japan. They often have close evolution-

ary ties to tropical and subtropical forests.

Temperate conifer rain forests are more cold-tolerant than

broad-leaved rain forests and are rich in mosses while lacking

tree ferns and vines. The original range of the temperate

conifer rain forest included portions of Great Britain, Ire-

land, Norway, and the Pacific Coast of North America. The

Pacific Northwest (PNW) rain forest extends from Northern

California to the Gulf of Alaska and is the most extensive

temperate rain forest in the world. The eastern boundary of

the PNW forest is sometimes set at the crest of the most

western mountain range and sometimes extended further

east to include all areas in the maritime climatic zone, which

has mild winters and only moderately dry summers. These

forests are dominated by Douglas fir (Pseudotsuga menziesii),

western hemlock (Tsuga heterophylla), sitka spruce (Picea

sitchensis), western red cedar (Thuja plicata), coastal

red-

woods

(Sequoia sempervirens), and associated hardwoods

Environmental Encyclopedia 3

Teratogen

and conifers. In the absence of harvesting, these forests

are regenerated by small wind storms and very infrequent

catastrophic disturbances.

The PNW forests are noteworthy in many ways. Of

all the world’s forests, they have the tallest trees, at 367 ft

(112 m), and areas with the highest

biomass

(4,521 Mt

per ha). On better sites the dominant

species

typically live

400 to 1,250 years or more and reach 3–13 ft (1–4 m) in

diameter and 164–328 feet (50–100 m) in height, depending

on site and species.

The natural temperate rain forest is generally less bio-

diverse than its tropical counterpart, but still contains a rich

flora

and

fauna

, including several species that are unique

to its

ecosystem

. Preservation of temperate rain forests is

a global

conservation

issue. Humans have virtually elimi-

nated them from Europe and left only isolated remnants in

Asia, New Zealand, and Australia. In North America, size-

able areas of natural rain forest still exist, but those not

specifically reserved are predicted to be harvested within 25

to 50 years.

The same pressures that previously converted most of

the natural temperate rain forests to plantations and other

land uses still threaten the remaining natural forests. There

is the desire to harvest the massive trees and huge timber

volumes before they are lost to insects or wind blow. There

is also the desire to replace slow-growing natural forests with

younger forests of fast-growing species. Those who favor

preservation cite the connection between intact rain forests

and high salmon/trout production. They note that the re-

placement forests, being simpler in structure and species

composition, cannot offer the same biological diversity and

ecosystem functioning. Also extolled are the aesthetic, spiri-

tual, and scientific benefits inherent in a naturally function-

ing ecosystem containing ancient massive trees. See also Bio-

diversity; Clear-cutting; Deciduous forest; Deforestation;

Forest Service; Tropical rain forest

[Edward Sucoff and Klaus Puettmann]

ESOURCES

OOKS

Adam, P. Australian Rainforests. Oxford: Clarendon Press, 1992.

Franklin, J. F. “Pacific Northwest Forests.” In North American Terrestrial

Vegetation, edited by M. G. Barbour and W. D. Billings. Cambridge:

Cambridge University Press, 1988.

Tennessee Valley Authority

The idea for the Tennessee Valley Authority (TVA) emerged

with the election of Franklin D. Roosevelt as President of

the United States, and it became one of the major symbols

of his “New Deal” policies designed to rescue the country

1385

from the social and economic problems of the Depression

of the 1930s. TVA activities have included improved naviga-

tion, flood control, production of electricity (and its distribu-

tion to small towns and rural areas),

fertilizer

production,

soil conservation

and stabilization, reforestation, improved

transportation

facilities, and recreational sites.

The TVA was established when Roosevelt signed the

Implementing Act in May of 1933. Within a few months

of its passage, the Norris Dam and the town of Norris,

Tennessee were under construction and the controversy be-

gan. Early opponents labeled it “socialistic” and un-Ameri-

can, contrary to the American ideal of private enterprise.

The most enduring criticism has been that TVA is too

single-minded in its emphasis on power production, espe-

cially after hydro-capacity was exhausted and the agency

turned first to

coal

and then to

nuclear power

to fuel its

power plants

. TVA has most recently been criticized for

being too concerned about profit-making and too little con-

cerned about a project’s environmental impacts, such as

air

pollution

created by generating plants and effects on

endan-

gered species

The Tennessee Valley Authority has, however, ef-

fected change in the intended region. Nearly all of the re-

gion’s farms now have electricity, for example, compared to

only 3% in 1933, and the area has been growing economi-

cally. It is now closer to the nation’s norms for employment,

income, purchasing power, and quality of life as measured

by jobs, electrification, and recreational facilities. A clean-

air plan was initiated in 1998 to cut 170,000 tons of toxic

emissions from TVA’s coal-fired plants yearly. See also Tel-

lico Dam

[Gerald R. Young Ph.D.]

ESOURCES

OOKS

Creese, W. L. TVA’s Public Planning: The Vision, The Reality. Knoxville:

University of Tennessee Press, 1990.

Nurick, A. J. Participation in Organizational Change: The TVA Experiment.

New York: Praeger Publishers, 1985.

RGANIZATIONS

Tennessee Valley Authority, 400 W. Summit Hill Dr., Knoxville, TN USA

37902-1499, (865) 632-2101, Email: tvainfo@tva.gov

Teratogen

An environmental agent that can cause abnormalities in a

developing organism resulting in either fetal death or con-

genital abnormality. The human fetus is separated from the

mother by the placental barrier, but the barrier is imperfect

and permits a number of chemical and infectious agents to

pass to the fetus. Well known teratogens include (but are

Environmental Encyclopedia 3

Terracing

not limited to) alcohol, excess vitamin A and retinoic

acid

the rubella

virus

, and high levels of

ionizing radiation

Perhaps the best known teratogenic agent is the drug thalid-

omide, which induced severe limb abnormalities known as

phocomelia in children whose mothers took the drug. See

also Birth defects; Environmental health; Mutagen

Terracing

A procedure to reduce the speed at which water is removed

from the land. Water is directed to follow the gentler slopes

of the terrace rather than the steeper natural slopes. Terrac-

ing is usually recommended only for intensively used, eroding

cropland in areas of high-intensity rainfall. Terraces are

costly to construct and require annual maintenance, but are

feasible where

arable land

is in short supply or where

valuable crops can be grown. In order to become self-suffi-

cient in food production, ancient civilizations in Peru often

constructed terraces in very steep, mountainous areas. Today,

in Nepal, people living in the foothills of the Himalayas use

terraces in order to have enough land available for food

production.

Territorial sea

Territorial sea is the part of the ocean that a nation controls.

For centuries, countries had different opinions about who

owned the seas. In 1609, Dutch statesman Hugo Grotius

said that all nations should have access to the oceans. Most

countries wanted territorial rights.

Methods for measuring boundaries included a 1702

recommendation from Cornelius van Bynkershonk. He pro-

posed that a nation had the right to the area that could be

protected by cannons located on land.

During the twentieth century, an international law

defined territorial sea and three other coastal zones. The

1994 United Nations

Convention on the Law of the Sea

treaty defined territorial sea as the area extending up to 12

nautical miles (13.8 statute miles) from a nation’s shoreline.

A nation’s territorial sea consists of the ocean surface,

the airspace above the sea, and the seabed below. Within

this area, the nation has the exclusive rights to

natural

resources

, as well as rights for fishing, shipping, and navi-

gation.

The U.N. had discussed coastal boundaries since 1958,

and nations met numerous times before approving the treaty

in 1994. The United States claimed its 12-mile territorial

1386

sea in 1988 when President Ronald Reagan signed proclama-

tion 5928.

[Liz Swain]

Territoriality

The attempt by an individual organism or group of organisms

to control a specified area. The area or territory, once con-

trolled, is usually bound by some kind of marker (such as a

scent or a fence). Control of territory usually means defense

of that territory, primarily against other members of the same

species

. This defense, which may or may not be aggressive,

typically involves threats, displays of superior features (e.g.,

size or color), or displays of fighting equipment (e.g., teeth,

claws, antlers). Actual physical combat is relatively rare. A

songbird establishes its territory by vigorous singing and will

chase intruders away during the mating and nesting season.

A leopard (Panthera pardus) marks the boundaries of its

territory with urine and will defend this area from other

leopards of the same sex. Territoriality is found in many

organisms, probably including humans, and it serves several

purposes. It may provide a good nesting or breeding site

and a sufficient feeding or

hunting

area to support offspring.

It may also protect a female from males other than her mate

during the mating season.

Tertiary sewage treatment

see

Sewage treatment

Tetrachloroethylene

Tetrachloroethylene is a manufactured chemical used for

dry cleaning

and metal degreasing. It is also used in the

manufacture of other

chemicals

and for textile finishing

and dyeing. Tetrachloroethylene has been produced com-

mercially since the early 1900s. At room temperature, tetra-

chloroethylene is a nonflammable colorless liquid. It evapo-

rates easily and has a sharp, sweet odor similar to chloroform,

which most people can smell at a level of about one part

per million (ppm). Other names for tetrachloroethylene are

perchloroethylene, PCE, tetrachloroethene, and “perc".

Results of animal studies using high levels of tetrachlo-

roethylene indicated that it can cause liver and kidney dam-

age. Exposure to very high levels of tetrachloroethylene was

toxic to the unborn pups of pregnant rats and mice. The

offspring of rats exposed to high levels of tetrachloroethylene

during pregnancy exhibited changes in behavior. Since tetra-

chloroethylene has been shown to cause liver tumors in mice