A
agroforestry growing both tree and food crops on the same piece of land.

asset(s) something with market value, including financial assets, physical assets, and natural assets.

B
biodiversity the maintenance of many different interrelated species in an ecological community.

biomass energy supply from wood, plant, and animal wastes.

C
certification the process of certifying products that meet certain standards, such as certifying produce grown using organic farming techniques.

clear-cut the process of harvesting all trees within a given area.

D
desalination the removal of salt from ocean water to make it usable for irrigation, industrial, or municipal water supplies.

discount rate the annual rate at which future benefits or costs are discounted relative to current benefits or costs.

E
ecological complexity the presence of many different living and nonliving elements in an ecosystem interacting in complex patterns; ecosystem complexity implies that human impact on ecosystems may be unpredictable.

ecosystems management a system of resource management that stresses long-term ecosystem sustainability.

F
flow the quantity of a variable measured over a period of time, such as the flow of a river past a given point measured in cubic-feet per second.

freshwater runoff the amount of freshwater that flows across a given area in a period of time, including water usable for human water supplies and flood waters.

full pricing the inclusion of both internal and external costs in the price of a product.

G
groundwater overdraft the withdrawal of water from an underground aquifer at a rate greater than the recharge rate.

I
institutional failure the failure of governments or other institutions to prevent resource overexploitation, or the use of policies that promote resource overexploitation and environmental damage.

L
logistic curve an S-shaped growth curve tending toward an upper limit.

M
mean annual increment (MAI) the average growth rate of a forest; obtained by dividing the total weight of timber by the age of the forest.

microirrigation irrigation systems that increase water use efficiency by applying water in small quantities close to the plants.

monoculture an agricultural system involving the growing of the same crop exclusively on a piece of land year after year.

O
optimum rotation period the rotation period for a renewable resource that maximizes the financial gain from harvest; determined by maximizing the discounted difference between total revenues and total costs.

P
property rights the set of rights that belong to the resource owner, such as a landowner’s right to prohibit trespassing.

public good(s) goods available to all (nonexclusive), whose use by one person does not reduce their availability to others (nonrival).

R
recharge of aquifers the refilling of groundwater reservoirs through seepage of surface and subsurface water through the earth’s strata.

resilience eosystem capacity to recover from adverse impact.

S
social sustainability the maintenance of social structure and traditions, for example among indigenous peoples.

stable water supply the quantity of water available to a region for human use on a continual basis.

stock the quantity of a variable at a given point in time, such as the amount of timber in a forest at a given time.

subsidies government assistance to an industry or economic activity; subsidies can be direct, through financial assistance, or indirect, through protective policies.

T
tragedy of the commons the tendency for common property resources to be overexploited because no one has an incentive to conserve the resource, while individual financial incentives promote expanded exploitation.

U
under-pricing prices of goods or services below the price that would result from taking full social costs into account.

use value the value that people place on the use of a good or service.

W
water-abundant and water-scarce areas areas of the world where stable water supplies are either ample or limited; water scarcity has been defined as less than 1,000 cubic meters per capita of renewable supply.

water cycle the cycle of evaporation and precipitation that continually supplies fresh water.