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  • Glossary
| Last Updated:13/10/2017



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A forest where animals can roam without fear of man.


Non-living parts of the environment


 Relating to or dealing with perceptions of beauty; the philosophy dealing with beauty and with judgements or perception of beauty; also esthetic.


 The small living organisms, ranging from minute arthropods and seeds to microscopic fungal spores and bacteria, that are suspended in the atmosphere.


 1. Life processes occurring in the presence of free oxygen.

2. Applied to soil organisms that can live only in the presence of oxygen and to conditions in which free oxygen is available.

Aerial Strip Census

 A census of wildlife taken from both sides of an aircraft flying along specified lines. Sampling techniques are used to compute the results.

Aerial Photograph

 1. A photo graph of the Earth's surface taken (either directly downward or obliquely) from an aeroplane.

2. Aerial photograph. Photograph taken from an aerial platform (usually an aeroplane), either vertically or obliquely.

Aeration, Soil

 The process by which air and other gases in the soil are renewed. The rate of soil aeration depends largely on the size and number of soil pores and on the amount of water clogging the pores. A soil with many large pores open to permit rapid aeration is said to be well aerated, while a poorly aeration soil either has few large pores or has most of those present blocked by water.

Adverse Impact

 An effect that causes harmful interference (beyond limits of acceptable change) with the structure or functioning of a person, place, ecosystem, or object.

Adventitious Bud

 A bud from any part of the stem, leaves or roots that is not connected with the strands of bud-bearing tissue arising from the axis of the leaves.

Advance Reproduction/ Advance Regeneration

 True seedlings or sprouts of the tree species that occupy the overstory existing as part of the understory vegetation. The root systems of sprout advance reproduction are usually older than the stems, are relatively large, and are capable of supporting much greater stem growth than the root stems of true seedlings.

Advance Growth

 Seedling, sapling and pole of species of the overwood that have been established naturally in a forest before regeneration felling are started. 


 The process of passing a period of hot season or prolonged drought in an inactive state. It can also be stated as the state or condition of torpidity or dormancy induced by heat and dryness of summer as opposed to hibernation.


 Sexually mature; an animal that has contributed to new individuals to a population.

Adaptive Management

 An approach to natural resource management wherein actions are designed and executed to achieve objectives, but also effects are monitored for the purpose of learning and adjusting future management actions, thereby improving the efficiency and responsiveness of management.


 The result of the process of  long-term evolutionary adjustment of a population to environmental changes, short-term physiological/behavioural responses compensating for environmental changes. Frequently a short-term behavioural or physiological response, if it is generally adaptive, will be reinforced by genetic adaptation that ensures the longevity of the short-term response.


 Capable of undergoing inheritable (and/or non-heritable) strutural or functional changes in response to environmental changes that could otherwise impair life processes.


 The ability to alter structure or function in response to changes in the environment in such a way that fundamental life processes can continue to cope with (or continue to function in) an uncertain environment.


 A measure, course of action, or treatment that is undertaken to directly or indirectly, produce, enhance, or maintain forest and rangeland and related rural land outputs or achieve administrative or environmental quality objectives.


 The extent to which the pH value of a solution falls below 7.

Acid Soil

 Soil with a low pH, less than 7.0 but practically less than 6.6.

Acid Rain

 Atmospheric stocks of sulphur dioxide (SO2), nitrous oxide(NO2) accumulate primarily from coal and heavy oil fired for power generation. As a result, acid rain occurs through two principal processes. In dry deposition, particulate matter is physically deposited, subsequently taking acidic form in conjunction with surface water. wet deposition is characterised by acidic substances, particularly sulphuric and nitric acid, being formed in the atmosphere, and subsequently being deposited through rain precipitation or simply movements of moist air.

Acid or Sour Humus

 Humus resulting from decomposition under an aerobic condition.

Acid Deposition

 1. It involves the atmospheric deposition of sulphur dioxide(SO2), nitrogen oxide(NO2), ammonia (NH3). Acid wet and dry deposition has effects on water, soil and forests. (Stanners and Bourdeau, 1995).

2. Precipitation and dry particulate fallout with low pH linked to other components of air pollution.


 Conformance to a recognizable standard,  can often mean the number of bits is computer word available in a given system. The statistical meaning of accuracy is the degree with which an estimated mean differs from the true mean.

Accuracy Assessment

 Comparison of a classification with groundtruth data to evaluate how well the classification represents the real world.


 1. Adjustment to environmental change by an individual. The physiological adjustment or increased tolerance showh by an individual organism to environmental change.

2. Adaptation to a different climate.

3. A genetically determined characteristic that enhances the ability of an individual to cope with its environment.

4. The process(es) whereby populations, species, or individuals (or part of individuals), change in structure, form, and/or function in such a way as to better survive under given environmental conditions.

5. Evolutionary process by which an organism becomes fetted to its environment.

6. A reversible change in the morphology or physiology of an organism in response to environmental change.

Access Time

 A measure of the time interval between the instant that data are called from storage and the instant that delivery is complete.

Accelerated Erosion

 Abnormally rapid erosion in an environment disturbed mainly by man. Not in vogue.


 1. The number of organisms in a population, combining density within inhabited areas and number and size of inhabited areas.

2. It refers to the total number of a particular species in an area.

Abundance, Species

 An estimate of the total number of individuals of a species in a defined area, population, or community. (Confusion between abundance and density can be avoided if density is viewed as abundance per unit of area or volume).

Abundance, Relative

 The frequency of  encountering an organism in a given time and place relative to the frequency of encounter in another time or place. Typically the smaller divided by the larger number, thus a proportion.

Abundance, Index of Relative

 Any expression of relative abundance, e.g, a useful approximation of the total number of individuals of a species relative to time or space.


 The division of real world phenomena into individual, distinct items.

Absorptive Capacity

 Also Known as assimilative capacity. The ability of the environment to assimilate waste products from the economy. Limits to this capacity may be determined locally, regionally or globally. To the extentthat waste emissions exceed the absorptive capacity of the environment, pollutants accumulate and damage results.

Absolute Geo-reference

 The referencing in space of the location of a point using a predefined coordinate system such as latitude and longitude or a national grid.

Age, Exploitable

 The age at which an individual tree of crop attains the size or stage of growth required to fulfil the management objects.

Age, Crop

 The age of a regular crop corresponding to its crop diameter.

Age, Average

 The arithmetic mean age of a population or group.

Age Ratio

 Age ratio is a proportion of young to adults, suggesting a measure of productivity. This provides an indication of population density where numbers cannot be readily counted as among rabbits and ducks.

Age Gradations

 Normal Series of a complete series of age gradation from the seedlings to the mature stage in proper proportions.

Age Gradation

 An age class with one year as the interval. Loosely used sometimes as synonymous with age class.

Age Distribution

 Individuals of a population classified according to age classes or periods such as pre-reproductive or sub-adult, reproductive, and postreproductives. An age pyramid is a diagram of the proportions within each age class of a population.

Age Composition

 1. An array of age classes. 

2. The arrangement of age classes in a population which describes the relative strengths of the age classes. It is synonymous with age structure.

Age Classification

 The division of a crop according to differences in age; or the allotment of woods to age class.

Age Class Distribution

 The local occurrence, or proportionate representation, or different age class in a forest.

Age Class Distribution, Normal

 A complete series of age class in such proportions as will permit equal volumes from annual or periodic fellings under the given rotation and silvicultural system.

Age Class

 One of the intervals into which the range of age of trees growing in a forest is divided for classification or use; also the trees falling into such an interval age gradation.


 Biochemical or physical changes occurring in seeds, bulbs, tubers and fruits after harvesting when ripe in the ordinary way; often necessary for subsequent germination or growth.


 The establishment of forest cover on land not previously forested. Afforestation may be necessary, for example, to increase the net capacity of the Earth's forests to absorb carbon dioxide (CO2) and other greenhouse gases.


Water-borne deposit 


 For plants, the uptake of carbon-dioxide

Alpine Area

The part of a mountain above the tree line, but below the permanent snow. 


Simple rootless plants that grow in sunlit waters. The decomposition or breakdown of dead algae generally affects water quality adversely by reducing levels of dissolved oxygen. Algae serve as food for fish and small aquatic animals. 


 (Sustainability) an ecologically based farming system, that, through the integration of trees in farms, increases social, environmental and economic benefits to land users.


High-pressure atmospheric closed circulation whose relative direction of rotation is clockwise in the Northern Hemisphere, counterclockwise in the Southern Hemisphere, and undefined at the Equator. Also known as high-pressure area. 


The gaseous envelope surrounding a planet or celestial body.