April 17

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April 17 Optional field trip See announcement
by Biology club to meet 9 AM on campus,
or Meet at 930 at Coalton Cr.
Trailhead. (McCaslin and Coal Cr. Rd, south of
Superior)
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C4 grasses not only out-compete C3 species in
this environment, they create a positive feedback
IN GREAT PLAINS

• High fire frequency
• low N availability,
  high light, low water
• C4 grass species dominance (high CN, high NUE),

High NPP
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Data from Jenny
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• Fire effects
• species composition
• survivorship
• seed bank response
• b) resource availability
• 1. Light
• 2. Moisture
• 3. Nutrients
• a. volatile elements
• b. ash elements

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Note impact of both fire and grazing on shading
of the canopy!
grazed
ungrazed
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Grazing 1) lowers probability of fire (lower
fuel load) 2) lowers intensity, amount of fuel
loss of fire 3) Removes the canopy to enhance
light on the surface 4) deposits N onto soil
rather than into atmosphere (makes N
more available to plants) 5)neutral/reduces C
input to soil!
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Why the bias against the word grassland?
desertification
forestation
Deserts Grassland
Forests
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Google hits Forest 240 million (forest
ecosystems 14.7 million) Desert 108 million
(!) (desert ecosystems 1.5 million) Grassland
4.9 million (grassland ecosystems 0.4 million)
prairie 50 million, rangeland 1.4
million Deforestation 3.5 million Forestation
1.0 million Desertification 1.6
million Grasslandification
10 Grassification 884 (a 4/20 issue)
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letter in Daily Camera 9/21/04
Weve got some educating to do!!!
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The Smokey the Bear Mantra DROWN THEIR
BUTTS CRUSH THEIR BUTTS DROWN THEIR BUTTS CRUSH
THEIR BUTTS
Remember, only you can prevent fire suppression!
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Successional changes in nutrient cycling depend
on element. Essential and limiting elements are
retained most strongly in mid-succession
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Fires occur frequently in the boreal forest
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Taiga forest of Alaska
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The taiga as the perfect example to show the
interactions of climate, topography, parent
material, biota, and time since formation. The
climate potential for permafrost Topography
south vs north facing slopes critical Parent
material effects of glacial flour,
permafrost Biota control on microclimate Time
fire and flood set the historical range of
variability (HRV)