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Biotemperature refers to all temperatures above freezing, with all temperatures below freezing adjusted to 0 °C, as plants are dormant at these temperatures. Holdridge's system uses biotemperature first, rather than the temperate latitude bias of
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communities. Merriam observed that the changes in these communities with an increase in latitude at a constant elevation are similar to the changes seen with an increase in elevation at a constant latitude.
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Holdridge life zone classification scheme. Although conceived as three-dimensional by its originator, is usually shown as a two-dimensional array of hexagons in a triangular frame.
250:'s life zones, and does not primarily use elevation. The system is considered more appropriate to the complexities of tropical vegetation than Merriam's system.
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sagebrush desert, yet both are classified as Upper
Sonoran. However it is still sometimes referred to by biologists (and anthropologists) working in the
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of the northwestern USA. He tried to develop a system that is applicable across the North
American continent, but that system is rarely referred to.
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181:. Much more detailed and empirically based classifications of vegetation and life zones now exist for most areas of the world, such as the
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This system has been criticized as being too imprecise. For example, the scrub oak chaparral in
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Ricketts, Taylor H.; Dinerstein, Eric; Olson, David M.; Loucks, Colby J.; et al. (1999).
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The life zones that
Merriam identified, along with characteristic plants, are as follows:
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The
Canadian and Hudsonian life zones are commonly combined into a Boreal life zone.
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335:"Ecological Regions of North America: Toward a Common Perspective"
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Terrestrial
Ecoregions of North America: a Conservation Assessment
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ratio of annual potential evapotranspiration to mean total annual
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The life zones
Merriam identified are most applicable to western
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published a life zone classification using indicators of:
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shares relatively few plant and animal species with the
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in 1889 as a means of describing areas with similar
298:. Vol. 1. Infobase Publishing. p. 961.
27:Concept was developed by C. Hart Merriam in 1889
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147:Arctic-Alpine (alpine meadows or tundra):
342:Commission for Environmental Cooperation
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195:Commission for Environmental Cooperation
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369:. Radford University. Archived from
234:annual precipitation (logarithmic)
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191:list of North American ecoregions
89:Lower Sonoran (low, hot desert):
143:Rocky Mountains bristlecone pine
99:Upper Sonoran (desert steppe or
296:Encyclopedia of World Geography
323:. Washington DC: Island Press.
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275:Köppen climate classification
121:Transition (open woodlands):
137:Hudsonian (spruce forest):
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187:World Wide Fund for Nature
129:Rocky Mountain Douglas fir
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65:, being developed on the
40:concept was developed by
363:"Holdridge's Life Zones"
183:list of world ecoregions
127:Canadian (fir forest):
344:. 1997. Archived from
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294:McColl, R.W. (2005).
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391:Biogeographic realms
207:Holdridge life zones
32:Altitudinal zonation
367:Geology class notes
260:Biogeographic realm
67:San Francisco Peaks
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16:(Redirected from
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221:Leslie Holdridge
139:Engelmann spruce
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193:defined by the
185:defined by the
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113:Colorado pinyon
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42:C. Hart Merriam
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229:biotemperature
205:Main article:
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123:ponderosa pine
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30:Main article:
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179:United States
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133:quaking aspen
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91:creosote bush
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75:Cascade Range
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63:North America
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371:the original
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346:the original
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227:mean annual
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117:Utah juniper
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172:Great Basin
95:Joshua tree
18:Biotic zone
281:References
270:Ecoregion
219:In 1947,
201:Holdridge
189:, or the
162:Criticism
109:scrub oak
105:sagebrush
101:chaparral
38:life zone
385:Category
254:See also
248:Merriam
176:western
168:Arizona
71:Arizona
57:Merriam
302:
149:lichen
50:animal
349:(PDF)
338:(PDF)
265:Biome
153:grass
46:plant
300:ISBN
81:List
73:and
48:and
36:The
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