Systems: Comparative Treeline Environments

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Systems Comparative Treeline Environments

• Maritime, temperate
• Continental temperate
• Arctic
• Equatorial

Identification of key phases in plant
establishment survival A. Reproduction Seed
formation B. Seed germination C. Seedling
establishment D. Growth Development E.
Survival and persistence (species
replacement) F. Asexual reproduction (layering)
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Universal explanations for treelines

• Growing season too short for adequate carbon gain
• Growing season too short for adequate foliar
  development
• Growing season determined by July minimum air
  temperature or soil temperature
• Late spring frosts in Snowy Mountains

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Arctic Treeline Environments - 1
Summer in the Brooks Range Above summer snow,
to right spruce seedling. Pictures from Linda
Brubaker
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Arctic Treeline Environments - 2
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Arctic Treeline Environments -3
Growth limitations Growth limitations at
subarctic tree lines include long periods of
summer daylight vs. winter darkness the
continual presence of permafrost. Soil
temperatures may be as important as wind.
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Continental, temperate treelines
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Continental, temperate treelines
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Maritime, temperate treelines
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Maritime, temperate treelines
Role of snowpack Root growth Shoot
growth Nutrients Water
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Maritime, temperate treelines - global climate
change
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Equatorial or tropical Treelines
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Equatorial or tropical Treelines