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Old-Growth Forest

1. Future old growth forest: Forests contiguous to old growth forests that: (1) exhibits some but not all old growth characteristics, (2) occurs in direct association with and as an integral part of an old growth forest, and (3) has the capacity to protect old growth forest areas because of their forest characteristics and location.
http://www.massforesters.org/old.htm

2. (Canada - BC) - Forests on the coast > 250 years old; and forests in the interior > 140 years old for most tree species, and > 120 years old for lodgepole pine and deciduous species.
http://www.natareas.org/abstr18.htm

3. (Canada - BC) Forest that contains live and dead trees of various sizes, species composition and age class structure that are part of a slowly changing but dynamic ecosystem. Old growth forests include climax forests, but do not exclude sub-climax or even mid-seral forests. The age and structure of old growth varies significantly by forest type and from one biogeoclimatic zone to another. (Wells, et al. 1998)

4. (Canada) A stand dominated by mature or overmature trees that has not been significantly influenced by human activity. The stand can contain various ages and species of vegetation.
http://www.nrcan.gc.ca/cfs/proj/sci-tech/arena/gloss_e.html#26

5. (Finland) A forest stand exceeding the regular cycle by 20 years. Lauri Karvonen 24.4.2000. Guidelines for Landscape Ecological Planning.

6. (Foret ancienne, rodal maduro). A forest dominated by mature organisms that have originated naturally from those endemic to the forest or its surrounds, in which the genetic, species and structural diversity have not been significantly changed by human activity. Forestry Chronicle 70(6):669 1994.

7. (Philippines) Forest predominantly stocked with mature trees with less than 25 percent of the mature stand volume removed by cutting.
http://www.nscb.gov.ph/ru12/DEFINE/DEF-ENV.HTM

8. (Primary, Original) Forests that have never been clear cut and that have little or no evidence of past human activity. Such forests may have been grazed, experienced limited exploitation of valuable tree species, and their floors may have been burned by Amerindians and European colonists (Duffy and Meier 1992).

9. (Timber) - Timber from a mature, naturally established forest (Georgia Forestry Commission).

10. (USA - USFS - Monongahela NF) - Stands with large, mature, or overmature trees comprising a plurality of the stocking... usually having a multi-layered canopy in trees of various age classes... includ[ing] dead trees and relatively large amounts of decaying material on the forest floor. USDA FS Monongahela National Forest, West Virginia (1986).
http://wvnvm.wvnet.edu/~rlanden/oldgrth.htm

11. (USA-Massachusetts) - An area of contiguous forest that (1) shows no evidence of significant human, post-European disturbance that originated on site, (2) has a significant component of older trees that are greater than fifty percent of the maximum longevity for that particular species, (3) is at least five acres in size, and (4) has the capacity for self-perpetuation, or (5) has the characteristics of a forest which, when found in combination together, are indicative of an old growth forest and which otherwise meets the criteria established by regulation by the Secretary.
http://www.massforesters.org/old.htm

12. (USA-Nevada) "Old growth" refers to stands of essentially undisturbed virgin timber on which less than 25 percent of the volume has been removed by cutting, fire or other causes. Source: NRS 528.019
http://www.leg.state.nv.us/web/99NRS/NRS-528.html

13. (USA-USFS) The USFS has developed Old-Growth definitions for each of the major forest types found in the United States. These are available from the Regional Offices of the US Forest Service. A generic definition is as follows: Ecosystems distinguished by old trees and related structural attributes. Old growth encompasses the later stages of stand development that typically differ from earlier stages in a variety of characteristics which may include tree size, accumulations of large dead woody material, number of canopy layers, species composition, and ecosystem function. Description - The age at which old-growth develops and the specific structural attributes that characterize old growth will vary widely according to forest type, climate, site conditions, and disturbance regime. For example, old-growth in fire-dependent forest types may not differ from younger forests in the number of canopy layers or accumulation of down woody material. However, old-growth is typically distinguished from younger growth by several of the following attributes: 1) large trees for species and site, 2) wide variation in tree sizes and spacing, 3) accumulations of large-size dead standing and fallen trees that are high relative to earlier stages, 4) decadence in the form of broken or deformed tops or bole and root decay, 5) multiple canopy layers, and 6) canopy gaps and understory patchiness. Old-growth is not necessarily "virgin" or "primeval." Old-growth could develop following human disturbances. USFS 1989.

14. (USA-Vermont) A forest stand in which natural processes and succession have occurred over time undisturbed by human intervention http://www.state.vt.us/anr/fpr/forestry/ucf/glossary.htm Vermont Forest Resource Plan.

15. (Russia) Old-growth forests are forests originated through natural successions and have not experienced significant human impact over a long period of time. Under significant human impact we understand: clearcutting or intensive selective logging; large scale human-induced fires; intensive and regular application of chemicals such as pesticides, herbicide, fertilizers, etc.; severe industrial pollution; forest reclamation; intensive recreation, etc. Under the long period of time we understand the time, which exceeds the lifetime of the dominant tree species for a particular forest type.
http://www.forest.ru/eng/old-growth/index.html

16. (Victorian forests) - Forest which contains significant amounts of its oldest growth stage in its upper stratum and has been subjected to any disturbance, the effect of which is now negligible.
http://www.rfa.gov.au/documents/oldgrowth/oldgrow.html#E11E3
(Woodgate et al. (1994).

17. A classification of forest stands that describes an ecologically mature ecosystem. Where information is not available for ecological classification, age or size of dominant trees, or both, are used. (Bolsinger and Waddell 1993)

18. A climax forest that has never been disturbed by man. The old growth forests can be classified as per the age and disturbance criteria.
http://www.biodiv.org/Forests/Glossary.html

19. A forest characterized by growth displaying successional stages that occur only after a relatively long period of time without a catastrophic disturbance. In Minnesota, old-growth forests probably develop after 125-150 years without a catastrophic disturbance (adapted from Old-growth Forests in Minnesota. A Preliminary Report, Minnesota DNR Natural Heritage Program).
http://www.greatplains.org/resource/1999/natural/natural.pdf

20. A forest dominated by mature organisms that have originated naturally from those endemic to the forest or its surrounds, in which the genetic, species and structural diversity have not been significantly changed by human activity.
http://www.forestry.utoronto.ca/ac_staff/emeritus/My%20Webs/english.htm

21. A forest dominated by mature trees that has not been significantly influenced by human activity" (CCFM 1997: 124).
http://www.fraserinstitute.ca/publications/critical_issues/2000/env_indic/section_07.html

22. A forest or stand that (1) contains at least one, preferably several, tree species that have attained an average age of 150 years or more in the mature specimens; (2) has gone undisturbed by human activity for a time interval sufficient for the establishment of old-growth characteristics, and; (3) contains a density of at least 8 mature trees in the 150 year-old age bracket per acre. Leverett (1991).
http://wvnvm.wvnet.edu/~rlanden/oldgrth.htm

23. A forest relatively old and relatively undisturbed. NOTE: (1) The term "old" varies by the species or group of species in a stand. (2) Some individuals believe old growth to be an uncut, virgin forest with very little man-made disturbance, while other individuals believe an old growth forest can be created by limiting future disturbance and creating certain characteristics evident in uncut virgin stands and thus termed a managed old growth forest.
http://weber.u.washington.edu/~robh/S-7/EcolGlos.html

24. A forest stand usually at least 180-220 years old with moderate to high canopy closure; a multi-layered, multi-species canopy dominated by large overstory trees; high incidence of large trees, some with broken tops and other indications of old and decaying wood ("decadence"); numerous large snags; and heavy accumulations of wood, including large logs on the ground. From: Kathy_Jope@nps.gov  (Kathy Jope) also http://www.studyweb.com/Agriculture/

25. A forest that contains live and dead trees of various sizes, species, composition, and age class structure. Old-growth forests, as part of a slowly changing but dynamic ecosystem, include climax forests but not sub-climax or mid-seral forests. The age and structure of old growth varies significantly by forest type and from one biogeoclimatic zone to another.
http://www.for.gov.bc.ca/pab/publctns/glossary/O.htm
http://www.for.gov.bc.ca/pab/publctns/frrra/app-c.htm

26. A forest that contains live and dead trees of various sizes, species, composition and age-class structure. The age and structure of old growth varies significantly by forest type and from one biogeoclimatic zone to another.
http://www.interfor.com/glossary/glossary24.html

27. A forest that has not undergone a stand-replacing disturbance such as logging or fire, such that succession has not occurred.
http://www.eresourcesystems.com/Help/Glossary/glossary.html

28. A forest that is ecologically mature and has been subjected to negligible unnatural disturbance such as logging, roading or clearing.
http://www.rfa.gov.au/dfa/other_info/attachd.html

29. A late stage of forest succession. Although the specific characteristics of old-growth stands vary with species composition and history, some commonly expected attributes in mesic forests on productive sites include-an abundance of large trees at least 180 to 200 years old; a multi-layered, multi-species canopy dominated by large overstory trees with moderate to high closure; numerous trees with broken tops, snags, and large logs.
http://www.rmrs.nau.edu/publications/rm_gtr_295/glossary.html

30. A mature forest which has not been disturbed by human activity. Also known as virgin forest. An increasingly rare, and increasingly valued, element of the wilderness. The lumbermen see it as something else, as evidenced in this not-so-subtle definition from an industry web site: Old Growth Forest: Forest stands in which the dominant cover types are mature or over-mature trees that have reached their maximum size. No harvest has occurred among these large, old trees and dead and fallen trees are as common as standing trees. Boundary Waters Compendium Glossary.
http://www.rook.org/earl/bwca/lists/glossary/

31. A natural progression of forest growth without evidence of man's influence. Sydney Haskell, Carmanah Forestry Society. (Wells, et al. 1998)

32. A post-rotational forest http://www.ameteam.ca/glossary.htm

33. A primary or a secondary forest which has achieved an age at which structures and species normally associated with old primary forests of that type have sufficiently accumulated to act as a forest ecosystem distinct from any younger age class. UNEP/CBD/SBSTTA 2001

34. A stand of mature or overmature trees relatively uninfluenced by human activity. The stand can contain multiple layers of tree canopies, and various ages and species of vegetation.
http://www-env.ccm.emr.ca/schoolnet/issues/borealnet/n_glos/glos.htm and
http://atlas.gc.ca/legacy/schoolnet/issues/borealnet/n_glos/glos.htm

35. A very old and complex forest community, usually at least 200 years old, characterized by a mixture of species, trees of varied size and age, snags, and extensive amounts of wood on the forest floor.
http://www.nps.gov/olym/edgloss.htm

36. An ecosystem distinguished by the presence of populations of old trees that is not necessarily in late successional condition or tree from evidence of human activity (Spies 1997).

37. An undisturbed forest with trees that are more than 200 years old. It is characterized by fallen trees, trees with broken tops and mature and dying trees.
http://www.nbs.gov/features/kidscorner/glossary.html and
http://biology.usgs.gov/features/kidscorner/glossary.html

38. Ancient forests. http://www.nrdc.org/sitings/lookup/teraa.html

39. Any ecosystem composed of dominant and codominant trees that are mature.
http://fscus.org/html/standards_policies/us_regional_standards/archives/ozark_ouachita4.html

40. Ecologically mature and have been subjected to negligible human-induced disturbance such as logging, roading and clearing or, if subject to any disturbance, the effect of which is now negligible. Oldgrowth forests are usually dominated by trees which exhibit late-mature or senescent growth stages in the upper stratum.
http://www.rfa.gov.au/rfa/vic/east/raa/esfm/gloss1.html

41. Ecologically mature forest that has been subject to negligible levels of disturbance such as logging, roading and clearing. The definition focuses on forest in which the upper stratum or overstorey is in the late mature or overmature growth phase.
http://www.rfa.gov.au/dfa/other_info/glossary.html

42. Ecologically mature forest where the effects of disturbances are now negligible.
http://www.rfa.gov.au/documents/oldgrowth/oldgrow.html#E11E3

43. Ecosystems distinguished by old trees and related structural attributes. Specific attributes vary according to forest type, climate, site conditions, and disturbance regime.
http://www.safc.org/resources/glossary.htm#definitions

44. Ecosystems distinguish by old trees and related structural attributes. Old-growth forests are characterized by larger tree size, high accumulations of large dead woody material, multiple canopy layers, species composition, and ecosystem function. The structure and function of an old-growth ecosystem will be influenced by its stand size and landscape position and context.
www.superiornationalforest.org/july4thstorm1999/Appendix%20B.doc

45. Forest conditions often including multiple canopy layers, variety in tree sizes and species, variety of tree ages including mature trees, and standing and dead woody material.
http://www.ci.boulder.co.us/bmp/Plan/glossary.htm

46. Forest having the following structural characteristics: 1. An abundance of old trees, recognizable by the asymmetrical shapes, relatively long trunks free of low branches (i.e., in-forest as opposed to open-grown shapes), deeply furrowed or plated bark, signs of heartwood decay, large prominent root structures, flattened crowns with protruding dead limbs, large thick limbs, and trunks often showing a twist that develops with age; 2. Fallen logs in all stages of decomposition, crisscrossing the forest floor and lying in and across stream beds, covered by moss and lichens; 3. Plentiful snags (standing dead trees); 4. Canopy gaps, large and small, formed from trees that have fallen; 5. Undulating forest floor, expressed in randomly scattered pits and mounds where trees have fallen over and decomposed; 6. Majority of tree species that fall into the late successional class and a conspicuous absence of multiple-stemed trees; 7. Minimal of signs of human disturbance. http://www.canadian-forests.com/fsc-glossary.html and Eastern Old-Growth Forests: Prospects for Rediscovery and Recovery (M.B. Davis (Ed.) 1996. Island Press, Washington, DC).

47. Forest in which the upper stratum is ecologically mature and has been subjected to negligible unnatural disturbance such as logging, road-building and clearing.
http://www.epa.nsw.gov.au/soe/95/28.htm

48. Forest stand dominated by trees reaching natural death; the last stage in forest succession.
http://biotech.chem.indiana.edu/search/dict-search.phtml

49. Forest stand dominated by trees reaching natural senescence; the last stage in forest succession.
http://www.habitat-restoration.com/paeglos.htm

50. Forest stands well beyond the rotation age for managed forests. Canadian Pacific Forest Products Ltd. (Wells, et al. 1998).

51. Forest that contains live and dead trees of various sizes, species, composition and age class structures. Old growth forests, as part of a slowly changing but dynamic ecosystem, including climax forests but not sub-climax or mid-seral forests.
http://www.luco.gov.bc.ca/lrmp/diamond.htm#60

52. Forest that has a significant proportion of the oldest discernible growth stage(s) in its overstory and negligible structural evidence of disturbances.
http://www.privateforestry.org.au/glos_o-z.htm

53. Forest that is ecologically mature and has been subjected to negligible unnatural disturbance such as logging, roading and clearing. The definition focuses on forest in which the upper stratum or overstory is in the late mature to overmature growth phases. (The National Forest Policy Statement (Commonwealth of Australia 1992) identified.
http://www.rfa.gov.au/documents/oldgrowth/oldgrow.html#E11E3 )

54. Forest which has not had significant unnatural disturbances altering its content or structure since European settlement.
http://www.schools.wafa.org.au/terms.htm

55. Forest with uninterrupted growth of more than 175 years (mid-latitudes).
http://www.yorku.ca/faculty/academic/cblanche/nats2200/n22oldgrowth.html

56. Forests having a long, uninterrupted period of development...substantially free of human influences or natural disturbances... Whitney (1987).
http://wvnvm.wvnet.edu/~rlanden/oldgrth.htm

57. Forests that either have never been cut or have not been cut for many decades. Forests characterized by a large percentage of mature trees.
http://outreach.missouri.edu/mowin/Resources/glossary/glossaryo.html

58. Forests which have never been logged or developed.
http://www.themouth.org/forest/oldgro.html

59. Forests with some very old trees. These forests have not been disturbed by major hurricanes, fires, or human actions in the last 200 to 250 year.
http://omega.cc.umb.edu/~conne/joel/definition.htm

60. Generally, a forest stand that has reached a stage of extreme maturity.
http://www.dnr.state.mi.us/wildlife/Landowners_Guide/Introduction/Glossary.htm

61. Individual trees that are beyond the age of biological maturity, or stands that contain old growth trees as well as some large snags, and logs on the ground.
http://www.sfrc.ufl.edu/Extension/ssfor11.htm

62. Later stages in forest development that are often compositionally and always structurally distinct from earlier successional stages. Franklin and Spies 1991.

63. Later stages of forest development that are often compositionally and always structurally distinct from earlier stages. Old-growth forests contain trees that are large for their species on a site. In addition, old growth is usually charactertized by a variety of tree sizes, abundant large snags and logs, and a developed, but patchy understory. Old-growth typically exhibits high diversity in structural attributes due to varied stand disturbance histories, variable plant species mixes among sites, and interactions with adjacent stands. Structural characteristics are dynamic and old-growth stands do not always contain all of the attributes used to describe them. However, forests that most clearly match the full range of structural features for old-growth will most likely provide the full array of associated functional characteristics. (Mike Chapel, California Board of Forestry) Source: Beardsley_Debby/r6pnw_portland@fs.fed.us

64. Mixed-mesophytic old-growth, includes large trees, basal area, diverse (native) understories, windthrow mounds, snags, woody debris, etc. Martin (1992).
http://wvnvm.wvnet.edu/~rlanden/oldgrth.htm

65. Old forests often containing several canopy layers, variety in tree sizes and species, trees at least 180 to 220 years old, and standing and dead woody material.
http://www.umpqua-watersheds.org/glossary/gloss_o.html

66. Old forests valuable in nature conservation terms have usually greatly exceeded the regeneration ages stipulated in forestry data. The trees are normally of varying sizes and species, and form multiple canopy layers, although spruce forest at a late successional stage also qualifies. Old stumps or other minor traces of human activity do not necessarily reduce the conservation value of a forest. Old age and competition have increased the amount of natural removal, and often also the amount of damage naturally suffered by the trees. The Working Group on the Protection of Old Forests on State Lands in Southern Finland

67. Old forests which often contain several canopy layers, variety in tree sizes and species, decadent old trees, and standing and dead woody material.
http://www.ci.boulder.co.us/openspace/Forest/forestgloss.htm

68. Old growth and ancient forests are essentially the same thing. "Ron Muir" muir@forestry.auburn.edu

69. Old growth forests can be loosely described as forests that look largely as they would appear if Europeans had not settled North America. They are forests that have suffered little or no logging or grazing.
http://www.earthisland.org/oldgrowth/faq.html

70. Old growth, virgin forest -- (forest or woodland having a mature or overmature ecosystem more or less uninfluenced by human activity)
http://www.notredame.ac.jp/cgi-bin/wn?forest 
Forests which have never been logged or developed.
http://www.taconic.net/sequoiainternet/forest/oldgro.htm

71. Old multi-story forest - a forest stand with moderate to high canopy closure-a multi-leveled and multi-species canopy dominated by large overstory trees; high incidence of large trees, some with broken tops and other indications of old and decaying wood; numerous large snags; and heavy accumulations of wood, including large logs on the ground. 
http://roadless.fs.fed.us/documents/feis/glossary.shtml

72. Old-growth forests are ecologically mature and have been roading and clearing or, if subject to any disturbance, the effect of which is now negligible. Oldgrowth forests are usually dominated by trees which exhibit late-mature or senescent growth stages in the upper stratum.
http://www.rfa.gov.au/rfa/vic/east/raa/esfm/gloss2.html

73. Old single story forest - single canopy layer consisting of large or old trees. Understory trees are often absent, or present in randomly spaced patches. It generally consists of widely spaced, shade-intolerant species, such as ponderosa pine and western larch, and high frequency fire regimes.
http://roadless.fs.fed.us/documents/feis/glossary.shtml

74. Old-growth forest i.e. ancient forest means a natural-state (or close) forest where the amount of dead wood is tens of cubic meters per hectare. Ilkka Hanski (1999) Helsingin Sanomat

75. Old-growth forests are natural forests with pronounced variations in the ages of the trees, multiple-layered vegetation, and a great abundance of old trees and large pieces of dead wood in different stages of decay. Swedish FSC standard

76. Old-growth forests contain threatened ecosystems and species, or endemic species. They can also be large landscape-level forests capable of supporting natural ecological patterns. The Taiga Rescue Network

77. Old-growth stands must include at least six trees per acre that are more than 30 to 32" in diameter and more than 200 years in age. The stands must have multilayered canopies (except within mixed evergreen forests) and hold minimal amounts of large standing snags more than 20 " in diameter and fallen logs at least 24" in diameter. 1986 Old-Growth Definition Task Force of the Forest Service interim definition.
http://www.woodrow.org/teachers/biology/institutes/1992/old_growth.html

78. Old-growth tree. The closest scientific description is that it's a tree that is beyond its pathological rotation age--or simply a tree living beyond its maturity.
http://www.accessatlanta.com/news/business/old_definition.html

79. Original, intact forest land that has not yet been significantly degraded by people.
http://www.ran.org/ran/info_center/factsheets/basicfacts.html

80. Relatively old and relatively undisturbed by humans. Hunter (1989).
http://wvnvm.wvnet.edu/~rlanden/oldgrth.htm

81. Stands in primary or secondary forests that have developed the structures and species normally associated with old primary forest of that type have sufficiently accumulated to act as a forest ecosystem distinct from any younger age class.
http://www.biodiv.org/programmes/areas/forest/definitions.asp

82. Stands in which the relic trees have died and which consist entirely of trees which grew from beneath the canopy. Oliver and Larson 1996.

83. Stands in which the relic trees have died and which consist entirely of trees which grew from beneath... and which have developed in the absence of allogenic processes". Transition old-growth "contains some trees which began after the initial disturbance and also large and numerous younger trees of allogenic origin". Oliver and Larson (1996) and Leverett (1996).
http://wvnvm.wvnet.edu/~rlanden/oldgrth.htm

84. Stands regenerated by natural succession, with a substantial amount of old trees and deadwood, and often with an uneven age structure.
http://www.forest.ru/eng/old-growth/definitions.html

85. Stands that are "overmature, past the point of maximum growth, etc. Leverett (1996). http://wvnvm.wvnet.edu/~rlanden/oldgrth.htm

86. Stands with a high percentage (>50%) of the canopy trees over half of the maximum life span of the representative trees, a few trees near the maximum life span, no recorded history or discernible signs of human disturbance, a "late successionary" species composition, and a set of characteristics associated with mature, nature-managed forests. Leverett (1996).
http://wvnvm.wvnet.edu/~rlanden/oldgrth.htm

87. Stands with canopy trees usually 150 years old or older but no fixed percentage, trees need not be near maximum life span, but forest must possess a set of characteristics associated with mature forest. Leverett (1996).
http://wvnvm.wvnet.edu/~rlanden/oldgrth.htm

88. The (usually) late successional stage of forest development. note 1 - old-growth forests are defined in many ways; generally, structural characteristics used to describe old-growth forests include (a) live trees; number and minimum size of both seral and climax dominants, (b) canopy conditions: commonly including multilayering, (c) snags: minimum number of specific size, and (d) down logs and coarse woody debris: minimum tonnage and numbers of pieces of specific size. note 2 - old-growth forests generally contain trees that are large for their species and site and sometimes decadent (overmature) with broken tops, often a variety of tree sizes, large snags and logs, and a developed and often patchy understory. note 3 - stand age, although a useful indicator of old growth, is often considered less important than structure because (a) the rate of stand development depends more on environment and stand history than age alone, and (b) dominants are often multiaged. note 4 - due to large differences in forest type, climate, site quality, and natural disturbance history (e.g. fire, wind, and disease and insect epidemics), old-growth forests vary extensively in tree size, age classes, presence and abundance of structural elements, stability and presence of understory. note 5 - the minimum area needed for an old-growth forest to be a functional ecological unit depends on the nature and management of surrounding areas; small areas often do not contain all old-growth elements. note 6 - an old-growth forest is commonly perceived as an uncut, virgin forest with very little human-caused disturbance; some believe that the time taken for stands to develop old-growth structure can be shortened by silvicultural treatments which the area occupied by each species per unit area is estimated by eye. note - this method is contrasted with the weight method - synonym ocular plot estimate, plot estimate method, square-foot method (Helms 1998). From: tnygren@juno.com (Harold T Nygren)

89. The forest-state that stretches from the time of dominant stand height growth cessation, through to and including the stable forest climax. Western Canada Wilderness Committee. (Wells, et al. 1998).

90. The old growth forests have been described by the adjective primeval, ancient, wilderness, virgin, pristine while in forester's terminology they are called as over-matured, decadent, and senescent, old growth. The old growth forests may be defined as a climax forest that has never been disturbed by man. The old growth forests can be classified as per the age and disturbance criteria.
http://glossary.eea.eu.int/EEAGlossary/O/old-growth_forest

91. The seral stage after mature, which is the potential plant community capable of existing on a site, given the frequency of natural disturbance events. In forests of the Pacific region, old growth often begins around age 200 and continues until a stand replacing event takes place. Depending on the frequency and intensity of disturbances, and site conditions, old-growth forest will have different structures, species compositions, and age distributions.
http://fscus.org/html/standards_policies/us_regional_standards/archives/pacificnorthwest3.html

92. Those mature and over-mature forests which occupy sites which have not previously been impacted by the hand of man. Fletcher Challenge Ltd. (Wells, et al. 1998).

93. Timber stands with the following characteristics: large mature and over-mature trees in the overstory, snags, dead and decaying logs on the ground, and a multi-layered canopy with trees of several age classes.
http://rredc.nrel.gov/biomass/states/bio_glossary/glossary.html
and
http://www.eren.doe.gov/biopower/glossary.html#F and 
http://bioenergy.ornl.gov/faqs/glossary.html#T

94. To most people "old growth" means big trees. The U.S. Forest Service definition is "a forest with trees 200 years or older, snags (standing dead trees), and down woody debris on the forest floor."
http://www.forestinfo.org/Glossary.htm

95. Uncut virgin forest; a forest that has not undergone a stand-replacing disturbance such as logging or a crown fire, such that succession has not occurred.
http://www.fw.vt.edu/zedaker/3364/ecolterms.html

96. Undisturbed primary forest, typically diverse in species and age of constituents, and is a result of competition and long-time natural selection International Dendrological Research Institute Glossary -
http://world.std.com/~jegan/idriglossary.html

97. Virgin and old, second-growth forests containing trees that are often hundreds, sometimes thousands, or years old.
http://www.gsu.edu/~mstnrhx/ecogloss.htm and http://ecology.org/biod/library/glos_NS.html

98. Virgin timber.
http://rredc.nrel.gov/biomass/forest/tim_glossary/t_glossary.html#O

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