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XIII. Glossary



"A" horizon - the surface layer or topsoil; the dark and generally loose and crumbly layer which contains higher amounts of organic matter
Acid Rain - precipitation that is more acidic than normal, usually caused by emissions of sulfur dioxide or nitrogen oxides (Air)
Acre - a piece of land containing 43,560 square feet. (Example: a parcel 150 feet wide and 290.4 feet long is one acre)
Adaptation - the process of making adjustments to the environment
Aggregates - hard materials such as sand, gravel, or crushed stone, used for mixing with a cementing material to form concrete; or used alone as fill
Air exchange - process by which plants can remove chemicals from the air and produce "clean" oxygen
Air Pollution - any particles or gases that are in the air, but not part of the air's natural composition (Air)
Aquaculture - raising fish on a farm
Aquifer - geologic formation which contains usable amounts of groundwater that can be accessed from a well or spring
Assimilation - process through which plants absorb ammonia and nitrate into their roots from soil or water (Land Use and Natural Hazards)


"B" horizon - subsoil; a light colored, dense layer which contains higher amounts of clay
Best Management Practices (BMP) - mandatory and voluntary practices farmers and others use to reduce erosion and prevent or control non-point source pollution (Agriculture)
Biodegradable - capable of being broken down by air, water, and bacteria
Biodiesel - a conventional diesel fuel mixed with biologically derived oils in order to cut down on the use of fossil fuels (Energy)
Biodiversity - many varieties of plants and animals (Forestry and Wildlife)
Biofuels - a conventional gasoline fuel mixed with biologically derived alcohols in order to cut down on the use of fossil fuels (Energy)
Biological diversity (or biodiversity) - the variety and complexity of species present and interacting in an ecosystem and the relative abundance of each
Biomass - the total weight (mass) of all living matter in a particular habitat or area
Biome - geographic area characterized by certain types of plant and animal communities that contains smaller ecosystems (Forestry and Wildlife)
Biota - the animal and plant life of a region or period
Biotechnology - the use of technology to create bigger and better plants and animals
Boreal - pertaining to the arctic and Antarctic tundras (Forestry and Wildlife)
Brownfield - a term used to classify abandoned or under-used plots of land or buildings (Land Use and Natural Hazards)


"C" horizon - parent material
Cambium - a thin layer of living dividing cells just under the bark of trees; this layer gives rise to the tree's secondary growth
Carbon Cycle - the combined processes, including photosynthesis, decomposition, and respiration, by which carbon as a component of various compounds cycles between its major reservoirs (Energy)
Carrying capacity - a wildlife management term for an equilibrium expressed by the availability of habitat components and the number of animals in a given area. In general ecological usage, carrying capacity is the dynamic equilibrium established between a life form and its environment. It is frequently expressed as a number indicating the population of any animal a given area can support. Carrying capacity varies throughout the year. The population number varies from year to year, depending upon conditions within the habitat such as rainfall. There may be a difference between the ecological carrying capacity of a given area and the cultural carrying capacity of an area. The cultural carrying capacity is the number of a given species of animal that the human community will tolerate. This number is generally lower than the actual carrying capacity of the land
Cellulose - a complex carbohydrate that constitutes the chief part of the cell walls of higher plants and yields fiber for many products
Clear-cut - a method of harvest in which all trees in a given area are removed, and the area is then replanted or allowed to regenerate; this method is usually used with shade-tolerant species
Climate - the average weather for a region. This includes temperature, precipitation and wind.

Climate Change – Significant changes in the weather over an extended period of time. An extended period can be several decades or longer.

Closed-loop recycling - the act of collecting, remaking, and purchasing the remade material which can be used and re-collected again
Cluster Zoning - planning development to be concentrated and dense in some areas, leaving open space and environmentally sensitive lands undisturbed (Land Use and Natural Hazards)
Cogeneration - a process in which an industrial facility uses its waste energy to produce heat or electricity (Energy)
Compost - partially decomposed organic matter
Compound leaf - a leaf that is subdivided into many leaflets; a leaf that is comprised of a single leaf blade is a "simple leaf"
Conifer - a plant that bears its seeds in cones
Conservation - the care and protection (wise use) of natural resources from loss and waste. (Example: actions that prevent soil erosion)
Conservation Easements - arrangement where the owner of a piece of property donates the development rights to that property to the government, thereby preventing development on the land (Land Use and Natural Hazards)
Contaminant - an item that is not recyclable found in a load of recyclables, making the load unable to be recycled
Contour farming - strips of plowed land located next to strips of grassland; a practice used to control water run-off and soil erosion


Deciduous (adj.) - describes a plant that periodically (typically in autumn) loses all its leaves; most North American broadleaf trees are deciduous; a few conifers, such as the larch and cypress, are also deciduous (Energy)
Deforestation - cutting or over-harvesting of trees, in which case the cutting down of trees occurs at a rate that surpasses re-growth (Forestry and Wildlife)
Denitrification - process in which bacteria turn nitrate back into atmospheric nitrogen (Land Use and Natural Hazards)
Diversity - variety; an ecosystem must contain a variety of plant and animal life to be healthy. An ecosystem with few species is not as healthy or dynamic as an ecosystem with a diversity of species
Dump - location where garbage is just dumped; not to be confused with a sanitary landfill where garbage is processed properly


Ecology - interrelationships between organisms and their environment
Ecosystem - a natural unit that includes living and nonliving parts interacting to produce a stable system in which the exchange of materials between the living and nonliving parts follow closed paths; all living things and their environment in an area of any size will all be linked together by energy and nutrient flow
Eelgrass - a rooted underwater grass type plant
Electricity - electric current used or regarded as a source of power (Energy)
Emissions - electrons discharged into the air from a surface
Endangered Species - organisms that face extinction, often because of loss of habitat
Environment - the conditions under which an organism lives
Environmental Education – The process of teaching people about environmental issues and engaging them to become active thinkers and problem solvers to improve their environment.
Environmental Literacy – is the term given to people who use their knowledge about the environment to make decisions and recognize the benefits and the trade-offs made to the environment.
Enviroshopping - a strategy used to make wiser shopping decisions that result in less trash being produced
Erosion - wearing down or washing away of soil and land surface by the action of wind, water, or ice (Water)
Escarpment - a long cliff or steep slope facing in one direction that separates two relatively level surfaces; produced by erosion or faulting
Eutrophication - the buildup of nutrients in freshwater lakes and ponds that leads to an increase in algae growth (Forestry and Wildlife).


Fecal coli form - bacteria that live in the intestines of humans and animals and become infectious when released through feces (Water)
Feed - food given to farm animals for growth, energy, and nourishment. Example: hay, corn, and oats
Fertilizer - plant food applied to the soil for plants to use for nourishment and growth (Water)
Fiber - plant or animal products used to make clothing, paper, homes, and furniture. Example: cotton, timber, and wool
Fossil Fuel - ancient underground deposits of organic matter, such as coal or oil (Energy)


Generator - a machine that converts mechanical energy into electrical energy (Energy)
Geology - the study of the earth and its history, and the processes and forces which are constantly changing its face
Geothermal Reservoirs - underground pools of water heated by the earth (Energy)
Grass strips - strips of grass between cultivated areas that are left to control water run-off
Green Building Design - process of using "green" features such as recycled materials and energy efficient heating systems when planning buildings (Green Building)
Green Roof - relatively flat roof with plants growing on it; the plants serve as a natural source of insulation (Energy)
Greenfield - open, natural, or agricultural lands that provide habitats for wildlife, ecosystem benefits, timber and food production, and aesthetics of a community (Land Use and Natural Hazards)
Greenhouse - structure designed to collect heat from the sun's rays (Green Building)
Greenhouse Gases - any of the atmospheric gases that contribute to the greenhouse effect, i.e., global warming (Energy)
Groundwater - water beneath the earth's surface, often between saturated soil and rock, which supplies wells and springs (Water)
Growth Management - using government policies to plan development in a community (Land Use and Natural Hazards)


Habitat - living area that includes the resources necessary to support wildlife (Forestry and Wildlife)
Hardwood - a deciduous or broadleaf tree; also applies to the wood from such trees
Hazardous material - an item that is harmful to the environment
Heartwood - the older, harder, nonliving central portion of wood of some trees that is usually darker, denser, less permeable, and more durable than the surrounding sapwood; many trees do not form a true heartwood
Horizon - a layer of soil with similar physical and chemical properties
Hydric - characterized by, relating to, or requiring an abundance of moisture (Water)
Hydrophytic - adapted to grow in water (Water)


Igneous - describes a rock or mineral that solidified from molten or partly molten material
Impervious surfaces - surfaces that water cannot penetrate (Land Use and Natural Hazards).
Indoor air pollution - an invisible or odorless form of gaseous chemicals emitted from furnishings and objects and trapped in poorly ventilated buildings; includes tobacco smoke, dust, paint thinner, cleaners, pesticides, radon gas, smoke from wood burning fireplaces, and chemicals from personal care products; chemicals used in the manufacturing of furniture, paint, carpeting, ink on printed materials, plastic, and dry cleaning solutions that are emitted and can cause headaches, drowsiness, and irritation of the eyes, nose, and throat
Infiltration rate - the rate that rainfall soaks into the soil surface
Interdependencies - the relationships of wildlife to one another and with the various elements of their environment



Karst - describes the topography formed over certain rock types by dissolution. It is characterized by sinkholes caves, and underground streams


Latex - a sap from trees; used to make rubber or plastic products such as tires, gloves, and paint
Land Trust - non-profit organizations that work to conserve land by purchasing or accepting donations of land or conservation easements (Land Use and Natural Hazards)
Leaching - the loss of materials caused by water carrying them deeper into the soil profile
Leaf litter - a layer of decaying plant matter (such as leaves, twigs, grasses, etc.) found on top of the soil
Litter - garbage disposed of incorrectly or any waste that is out of place.
Loam - a soil texture which consists of equal acting parts of sand, silt, and clay; generally comprised of about 40% sand, 40% silt, and 20% clay


Macroinvertebrate - aquatic organisms without backbones that are visible without the aid of a microscope. They are often studied to help determine water quality in streams.
Magma - naturally occurring molten rock
Meaningful Watershed Educational Experience (MWEE) - An investigative or experimental project that engages students in thinking critically about the Bay watershed
Metamorphic - describes any rock derived from pre-existing rocks in response to large changes in temperature, pressure, or other environmental factors
Methane - an odorless, colorless, flammable gas, CH4, the major constituent of natural gas, that is used as a fuel and is an important source of hydrogen and a wide variety of organic compounds (Energy)
Mineral - a naturally occurring inorganic (non-living) substance having an orderly internal structure and characteristic chemical composition and other physical properties
Mixed-Use Development - occurs when buildings for different purposes (such as homes and stores) are located in the same area (Land Use and Natural Hazards)
Mottles - spots or blotches of colors different from the main subsoil color


Natural Lighting & Cooling - the use of the sunlight indoors through building design instead of relying on artificial lighting, as well as design and technology that limit the need for air conditioning (Green Building)
Natural Play Area – A planned outdoor space that integrates natural components from nature into a spot that encourages children to play independently or with their families.   Examples can include logs that can be used for balance beams, natural materials such as sticks and brush to make forts, sunflower houses, etc.
Nitrification - the formation of nitrite (NO2-) and then nitrate (NO3-) as bacteria get their energy from ammonia (Land Use and Natural Hazards)
Nitrogen Fixation - the process in which atmospheric nitrogen is converted into nitrate by bacteria in the soil, water, or in the roots of some plants (Land Use and Natural Hazards)
Non-Point Source Pollution - a form of pollution with an unidentifiable specific origin of release (Water)
Non-Renewable Resources - resources that are in finite supply (Energy)
Nutrient - substance assimilated by organisms that promotes growth (Water)


Old growth forests - forests containing trees that are often hundreds, sometimes thousands, of years old; examples include forests of Douglas fir, western hemlock, giant sequoia, and coast redwoods in the western U.S.
Organic matter - dead and decaying plants, animals (Energy)


Parent material - the layer of very little weathering from which other soil layers develop
Particulates - small particles of dust and soot that may be found in the atmosphere (Air).
Passice Solar Homes - homes that are positioned to face southward and passively collect the sun's warmth for heat (Energy).
Ped - the smallest unit of soil
Percolation - the seeping of surface and groundwater through soil and subsurface strata (Agriculture).
Permeability - the rate at which water moves down through the subsoil
Photosynthesis - the process by which chlorophyll-containing tissues of plants use light and carbon dioxide from the atmosphere to produce glucose and oxygen; the process by which plants clean the air by taking in pollutants and gases through their leaves and roots and convert them to harmless substances
Plateau - an elevated area of relatively flat land. It is often limited on at least one side by an escarpment, or an abrupt drop to lower ground
Plutonic - describes igneous rocks formed deep beneath the earth's surface
Point Source Pollution - a form of pollution in which the specific origin of release into the environment is identifiable (Water).
Pollution - the addition of unwanted substance to or the alteration of the environment in a way that adversely affects human health or living systems. Pollutants may be biodegradable, non-biodegradable, or slowly degradable.
Pollution prevention - the reduction or elimination of pollutants prior to removing off-site for recycling, treatment, or disposal. P2 (as it is called) can include substitution of different raw materials, reduction of toxic chemical use, and increased recycling or treatment of wastes. Companies often find reduced costs for raw materials, energy, pollution control, and waste disposal, while fewer pollutants are discharged into the air, water, or land. Preventing pollution improves the environment today and may help prevent tomorrow's problems.
Proffers - agreements and modifications developers make to protect the environment in order to get a permit to build a new subdivision, malls, office buildings, etc. (Land Use and Natural Hazards).
Property Rights - legal ownership of the rights to engage in a certain activity (Air).
Pulp - fibrous material prepared from wood, recovered paper, cotton, and grasses by chemical or mechanical processes; used in making paper or cellulose products
Pulpwood - timber that is cut and made into pulp for paper and other products
PV (Photovoltaic) Cells - small cells or panels capable of producing a voltage when exposed to radiant energy, especially light (Energy).


Quinine - a drug used to cure and prevent malaria that comes from Peruvian bark


Radioactive Elements - any materials of, exhibiting, or caused by radioactivity (Energy)
Recharge - the replenishment of groundwater or an aquifer with surface water (Water)
Recycling - practice of reusing materials for new purposes (Energy)
Reforestation - the renewal of forest cover by natural regeneration or the planting of seeds or seedlings
Renewable Energy - energy that comes from a source that is constantly renewed; e.g., the wind keeps blowing, the sun keeps shining; water continuously flows in a river (Energy)
Renewable Resource - a natural resource that may be replenished through natural cycles. The sun, wind, wetlands, forests, and croplands are examples of renewable resources (Energy)
Reservoir - natural or artificial pond or lake used for the storage and regulation of water (Energy)
Resin - a substance from trees used to make varnish, lacquers, inks, and plastics
Retrofitting - to substitute new or modernized parts or systems for older equipment (Energy)
Riparian buffer - a zone of vegetation along a river or stream corridor that offers wildlife habitat and helps absorb runoff from the land during storm events
Runoff - water lost by surface flow
Rural Area - area with a low population and building density (Agriculture)


Saltwater intrusion - occurs when groundwater supplies are depleted to the extent that coastal waters infiltrate local aquifers
Sapwood - the younger, softer, living, or physiologically active outer portion of a tree's wood that lies between the cambium and the heartwood and is more permeable, less durable, and usually lighter in color than the heartwood. The tree's water and nutrient needs are transported within the sapwood
Secchi Disk – A black and white circular disk attached to a rope used to measure water quality. It is dropped into water to measure turbidity.
Sedimentary - describes a layered rock resulting from the consolidation (cementing) of sediment
Seedling - a young tree grown from a seed up to a small sapling
Segregated use - zoning by allowable land use function (Land Use and Natural Hazard)
Selective cutting - the cutting of intermediate-aged, mature, or diseased trees in an uneven-aged forest stand, either singly or in small groups. This encourages the growth of younger trees and maintains an uneven-aged stand
Shelter wood cutting - the removal of the understory of a forest so that younger saplings can grow in the shade of older and larger trees
Sick building syndrome - term used to describe the effects of high levels of indoor air pollution
Side effects - term used to describe conditions resulting from (or reactions to) exposure to health hazards, toxins, chemicals, and drugs
Silt - soil deposits caused by water run-off; one of the three particle sizes found in soil, between sand and clay in size
Silviculture - management and cultivation of forests
Skidder - a large machine that drags harvested wood from the forest floor to a loading area
Slope gradient - the rise or fall of the land
Smart Growth - development that protects natural resources while creating healthier human habitat (Land Use and Natural Hazard)
Smog - mixture of pollutants in the air that reduces visibility and can have negative effects on health and the environment (Air)
Soil profile - a cross-section cutting down through the different soil layers or horizons
Soil structure - the manner in which individual soil particles are grouped together
Soil texture - the relative proportion of sand, silt, and clay found in a soil; the feel of the soil
Solar Energy - our ability to convert the sun's power into electricity (Energy)
Sprawl - the resulting spread of developed areas when metropolitan areas grow and expand at the fringes, pushing development into rural areas (Agriculture)
Subsidize - to provide money, or another incentive, to encourage people to engage in a particular activity, such as buying energy-efficient appliances (Air)
Subsoil - a soil layer under the topsoil and above the bedrock
Succession - used here to describe forest communities; the natural evolution (or cycle) of birth, growth, maturity, and death
Surface Water - water that exists in bodies on the Earth such as rivers, lakes, ponds, oceans (Water)
Sustainable Agriculture - a production and distribution system that minimizes the negative impacts on health, safety, wildlife, water quality and the environment, as well as optimizing use of available resources (Agriculture)
Sustainable Development - a production and distribution system that minimizes the negative impacts on health, safety, wildlife, water quality and the environment, as well as optimizing use of available resources (Agriculture)
Sustainability - has enough resources and small enough impact to be used for a long time (Energy)
Sustainable use - managing resources so that they produce continuously, unimpaired by periodic harvests


Tannin - chemical used to tan leather; found in many trees
Temperate - area between tropical and polar zones, characterized by seasonal weather changes (Forestry and Wildlife)
Terracing - making a long pile of earth with sloping sides and a flat top; usually done along rivers to control flood waters
Timber cruise - a survey of a forest or forest stand to mark trees to be harvested
Topographic - referring to the shape of the surface (natural features) of the land, determined by elevation, relief, and land forms (Land Use and Natural Hazards)
Topography - the general description of a land surface including its relief and the position of natural and man-made features
Topsoil - the upper layer, "A" horizon of soil in which plants grow; usually richer in plant food than the subsoil; the plowed layer
Tributary - a stream that flows into a larger stream or other body of water (Water)
Tropical - type of forests found in an area near the equator, receives direct sunlight all year so temperatures are warm (Forestry and Wildlife)
Turbine - a device with propeller blades and an axle turned by water, wind, or steam (Energy)


Urban Area - area with a higher population and building density (Agriculture).



Water pollution - sewage, industrial chemicals, heavy metals, and household cleaners are examples of materials commonly discharged into streams and rivers. In addition, chemicals from the air dissolved in rainwater, pesticides, and fertilizers leached from the land run off into water
Watershed - geographic area in which water, sediments, and other materials drain into a common body of water (Water)
Weathering - all physical and chemical changes produced in rocks and soils by the forces of climate
Windbreak - a row of trees which serve as protection from the wind
Wetland - land areas that contain hydric soils and hydrophytic plants and are saturated with water for a portion of every year (Water)


Xylem - the complex woody tissue of higher plants that includes systems for transporting water storing nutrients, and structural support