49 Cards in this Set
| Front | Back |
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soil development: What are driving variables?
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climate
parent material
topography
Land use
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soil development:
What are State Variables
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vegetation, animals, microbes & soil structure, chemistry, fertility
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characteristics of soil
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properties and profile develop with depth
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Where is ecosystem species diversity its highest
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95% of diversity is in the soil
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why are soils important?
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-soils are alive
-95% of diversity
-forests can only be sustained if soils are
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What is soil made out of?
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Air 20-30%
water 20-30%
Mineral 45%
Organic 5%
soils ar often half pores
all chemical reactions occur in organic material
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What is the size ratio of minerals: clay slit and sand
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clay small
slit medium
sand big
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Why does mineral and organic size matter?
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Determines the size of surface area
the capacity of soil to hold water
-sands don't hold as well as clay and clay holds more of it
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Importance of soil pores
macropores?
compaction?
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macropores drain with gravity and provide space for organic organisms and plant roots
compaction causes water loss and the ability to absorb less water
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What are the important elements/nutrients for plant growth? (5)
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-Nitrogen:good of enzymes, proteins, DNA
-Phosphorus: lipids, ATP, DNA
-Potassium: activating enzymes,
salt levels
-Calcium: cell wall
-Magnesium: chlorophyl, enzymes
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How do nutrients increase growth?
(fertilizers)
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more nutrients (fertilizer) increases tree growth more leaves and more growth/leaf
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how to test and interpret nutrient dependency in plants
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comparing nutrients and having test areas and control areas of different values
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NPP
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Net primary production
=gpp-R
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R
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how much respiration occurred
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GPP
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Gross Primary production
sum of all photosynthesis done in the system
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carbon balance
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the amount of carbon put out by humans minus the amount taken up by the earth
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How much solar energy goes into the biomass?
Where does it go?
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about 50%
foliage= 10-31%
wood r=4-25%
root production and respiration 25-62%
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Production ecology equation
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resource * fraction captured*efficiency of conversion*fraction to component
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efficiency of larger tree resource use vs. smaller tree use
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smaller trees are less efficient at using resources (less photosynthesis or more allocation away from wood)
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CAI
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current annual increment
(volume growth rate for current year or between measurement periods)
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MAI
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mean annual increment (average volume growth rate over entire life of stand)
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define
succession
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observed process of change in species structure of an ecological community
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arguments against succession
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1. succession is not a process
2.the specifics of ecosystem change are unpredictable and influenced by numerous legitimate process that vary in importance over time
3. On-the-ground evidence of succession is rare
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trends in forest change:
common trends
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long lived conifers can survive after aspen die
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trends in forest:
size of deviations from the trends
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aspen-conifer stand shifts conifer about 1/3 of the time
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What is the importance of riparian ecosystems?
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most diverse, productive and important ecosystems
-plant richness of 20-80 species per .1 ha
-about 48% of birds only net here
-flood mitigation and erosion control
-economic value of sport fishing
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changes in river flows impact on vegetation
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-changes in plant communities through space and time
-soil nitrogen patterns
-plant diversity
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absence of floods on the cottonwood
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stresses out seedlings & causes adults to grow deeper roots to access water tables
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What are rapid ways for trees to die?
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wind
insects
fire
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difference between disturbance vs stress
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disturbance= less predicable more rapid
stress= more predictable more chronic
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are all disturbances the same?
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NO
different causes, effects, and extent
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probability od disturbance
if we have a 10,000 area and each year 100 ha burns then...
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odds of a fire in a given area each year is 1%
the average interval (time between fires at a given area) is 100 yr
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Bark beetles mass attack:
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kill the tree or be killed by the tree
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bark beetles go from an endemic to an epidemic why?
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an attack on a few trees to warm temperatures and droughts enabling tree death
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winds effect on soil
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pit mounds by tree roots being pulled out of ground
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beetle effects on soil
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wetter soil not much impact on nutrient release
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fire effects on soil and nutrients
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causes nutrients to turn to gas and ash and be lost
wet soil is safer & ground fires are fires effecting soil most
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tree mortality from beetles is about equal to that of fires true or false
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true
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What is fire? What about energy release?
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some organic compounds break into small pieces and evaporate (vaporize or volatilize) These gases rise, and then mix
with
oxygen
and
combust
releasing
energy
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wood vs. charcoal
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wood burns easier at 500 F
while charcoal won't burn unless its 1100F
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ground fire
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burning organic soil layer
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surface fire
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burning fuels a few m above surface
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crown fire
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burning canopy
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passive crown fire (torching)
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surface fire ignites individual trees from below
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Active crown fire
(running)
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crown fire spreads from tree to tree
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erosion with fire
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usually increase a bit after fire sometimes a lot
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hydrophobic areas after a fire
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usually higher than the control
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fire regime
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usually summarized by frequency and severity (variance also important)
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fire regime extent, intensity & severity
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extent-size of fire
intenisty- energy released from fire
severity-impact of a fire
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F 311: EXAM 1