NREM 301NREM 301Forest Ecology & SoilsForest Ecology & Soils
Nutrient CyclingNutrient Cycling
Field Quiz Today – Be Field Quiz Today – Be Prepared for WetPrepared for Wet
Day 25Day 25November 11, 2008November 11, 2008
Soil DepthSoil Depth
Summit (linear)Summit (linear)Shoulder (convex)Shoulder (convex)
BackslopeBackslope (linear)(linear)
ToeslopeToeslope
(concave)(concave)FootslopeFootslope(linear)(linear)
Ice TransportedIce TransportedGlacial TillGlacial Till
Residual BedrockResidual Bedrock
ColluvialColluvial
Alluvial Alluvial
Soils – Parent Material – Topography in Central Iowa
LesterLesterHaydenHayden
StordenStorden
TerrilTerrilColandColand
SpillvilleSpillville
Slope Position &Shape
Field QuizField Quiz
L – litter (Oi)L – litter (Oi)
H – humus (Oa)H – humus (Oa)
F – fermentation (Oe)F – fermentation (Oe)
MorMor – Oi (L)Oi (L) Oe (F)Oe (F) Oa (H)Oa (H)
Mull – Oi (L)Mull – Oi (L) Oe (F)?Oe (F)?
ModerModer – – Oi (L)Oi (L) Oe (F)Oe (F) Oa (H)?Oa (H)?
Soil & FF horizons, texture, structureSoil & FF horizons, texture, structure
Kinds of FF’sKinds of FF’s
ConiferConiferAcidAcid
Low C/NLow C/NDeciduousDeciduous
BasicBasic
ThalwegThalweg
Bend – deep poolBend – deep pool
Riffle – shallow, Riffle – shallow, turbulent flowturbulent flow
Run – fast smooth flowRun – fast smooth flow
IslandIsland
Riparian ZoneRiparian Zone
Habitat Habitat UnitsUnits (page 13-14) (page 13-14)
River Continuum Concept
Heterotrophic/Allochthonous
Autotrophic/Autochthonous
TermsTerms
EcologyEcology
EcosystemEcosystem
CommunityCommunity
PopulationPopulation
EcotoneEcotone
Vertical & Vertical &
Horizontal StratificationHorizontal Stratification
Landscape EcosystemLandscape Ecosystem
Group Activity - Group Activity - please use this picture to define and please use this picture to define and provide examples of each of the terms.provide examples of each of the terms.
Lake ecosystem – the biotic & abiotic factors that Lake ecosystem – the biotic & abiotic factors that interact to create the functioning lake system.interact to create the functioning lake system.
Fish/invertebrates = animal communityFish/invertebrates = animal communityAquatic plants – plant communityAquatic plants – plant community
All individuals of sunfish = the sunfish populationAll individuals of sunfish = the sunfish population
All individuals of duck weed = duckweed populationAll individuals of duck weed = duckweed population
Floating mat ofFloating mat ofplants – ecotoneplants – ecotonegradation between gradation between aquatic and forest.aquatic and forest.
Vertical Stratification – various canopies in forestVertical Stratification – various canopies in forest
Horizontal StratificationHorizontal Stratification lake, floating plant mat, forestlake, floating plant mat, forest
Landscape Ecosystem = Landscape Ecosystem = northern lake/bog ecosystemnorthern lake/bog ecosystem
Differences between plant typesDifferences between plant types
DecurrentWeak Apical
Control
1 3 years
Many Years
ExcurrentStrong Apical
Control
1 3 YearsMany Years
Bud Activity & Tree Shape
P 5 - HandoutP 5 - Handout
TangentialTangentialWallWall
Xylem Cell WallsXylem Cell Walls
RadialRadialWallWallRaysRays
44
33
33
22
RadialRadialWallWall
TangentialTangentialWallWall
Outside WallOutside WallCallus/CambiumCallus/Cambium
What wall produced the callous?
Yearly Shoot Growth Patterns
Determinate growthDeterminate growth – terminal bud stays active with strong control
Indeterminate growthIndeterminate growth – no true terminal bud – weak control or maybecome a floral bud or abort
Determinate Indeterminate Result of IndeterminateP 5 - HandoutP 5 - Handout
VA MycorrhizaeVA Mycorrhizae
EctomycorrhizaeEctomycorrhizae Special Soil FungiMycorrhizal Fungi
Mycorrhizae = symbiosis between fungi and root.
Fungi receives carbon from plant,plant gets a 10-100X increase in absorbing root surface area.
EctomycorrhizaeBasidiomycetes & Ascomycetes* spores wind & water dispersed* 2,100 species of fungi in NA* most conifers, willow, aspen, oak, hickoryEndomycorrhizae (VA)Phycomycetes – spores below ground* most widespread, associate with * most plant families including crops* most deciduous trees
(P 10 – Handout)
Fruit on what kind of shoots?
Short Shoot
Short ShootLong Shoot
Bud Growth Patterns
Fixed Growth – one annual flush
Free Growth – continuous growth
Fixed
Free GrowthMany Riparian Species P 4 - HandoutP 4 - Handout
Recurrent Growth (Southern Pines)
Epicormic Branch
Adventitious bud
What is the name for this kind of branch & what kind of bud gives rise to it?
How do forest stands respond to disturbance?
Stand DevelopmentModel
Disturbance where original species still present on site.
Disturbance where all species have been removed.
What kind of species is A?
Shifting Mosaic Steady State Model
Gap Succession
Forbs/Shrubs/SeedlingsForbs/Shrubs/Seedlings
Even-agedEven-agedSingle SpeciesSingle Species
Older Trees Older Trees DieDie
Create Gaps – Create Gaps – MixedMixed
SpeciesSpecies
Whole Area MixOf Different AgedGaps – Uneven-agedMixed Species
Site changes: moresunlight, some compaction
Any species can seed in if seed can get there
All can germinate & start to grow
Mainly shade intolerant will capture site at the beginning
Rate of change depends on longevity of species
Site changes: loss of OM structure but soil still fertile
Any species can seed in if seed can get there light seeded grasses & forbs
If well established & if fire occurred then could keep woody plants out
Length of grass stage depends on fire
Site changes: new material, no bio- logical legacies
Only “pioneer” species can get established
Next seral stage depends on rate of modification of site by pioneers
FacilitationTolerance Inhibition
Succession PathwaysSuccession Pathways
Diagram the general nutrient cycle for an ecosystemGroup ActivityGroup Activity
Show:
a)Inputs (how do nutrients get
into an ecosystem)
b) Outputs (how are nutrients
lost from the ecosystem)
c) Internal Cycling (how do
nutrients move around in the
ecosystem
Think of nutrients cycling in an ecosystem box
Page 525 Textbook
GeochemicalGeochemical
BiogeochemicalBiogeochemical
BiochemicalBiochemical
General NutrientGeneral NutrientCycleCycle
Ability of fresh OM to be incorporated into the soil helps
dictate rate of cycling
Oi (L)Oi (L)
Oe (F)Oe (F)
Oa (H)Oa (H)
Mineral soilMineral soil
Histisol Organic SoilHistisol Organic Soil
BogsBogs
1. Northern or high elevation climates2. Water source – precip – bowl
with not other in or outputs
3. Anaerobic water
4. Low pH < 5
5. Slows decomposition
6. Sphagnum moss
FensFens
1. Similar locations
2. Water source is
groundwater or stream –
moving into & out of fen
3. Higher pH
4. More nutrients
5. More plant diversity
Two Concave Depression Sites
Salt FlatSalt Flat FenFen
Both within about 10 miles of each other – one is at about 6,000 ft the other at 9,000 ft elevation
What reasons cause the difference you see?
Group ActivityGroup Activity
pH very basicpH very basic pH very acidpH very acid
Low precipitation, high ET Higher precipitation, lower ET, morePlant growth – conifers dominate
Fall is here and the leaves are falling off of the trees Group ActivityGroup Activity
These leaves play an important role in maintaining the organic matter in the soil. How do you think they become part of the OM?
Please use this figure to expand your answer
Group ActivityGroup Activity
B) What % of the aspen leavesare C, H, O and ash?
A) What % of the aspen leavesis water?
Lignins & phenolic compounds
Cellulose
Sugars, starches & simple proteins
Hemicellulose
Fats, waxes, etc.
Crude proteins
C) Rank the compounds from fastest decomposition to slowest.
Sugars, starches & simple proteinsCrude proteinsHemicelluloseCelluloseFats, waxes, etc.Lignins & phenolic compounds
Rapid decomposition
Slow decomposition
Composition of typicalComposition of typicalgreen plant materialgreen plant material
Soil Meso & Microfauna
Over 1000 species in a single m2 of forest soil
Many of the world’s terrestrial insect
species are soil dwellers for at least some stage of their life-cycle
A single gram of soil may contain millions of individuals and several thousand species of bacteria
A typical, healthy soil might contain:
a) several species of vertebrate
animals – moles, shrews, etc.
b) several species of earthworms,
c) 20-30 species of mites,
d) 50-100 species of insects,
e) tens of species of nematodes,
f) hundreds of species of fungi
g) thousands of species of bacteria
and actinomycetes.
Soil – a very complex ecosystem – 1,000’s of organisms that are critical to global cycles. The most densely packed ecosystem on the planet.
Macrofauna - > 2 mm – termites, ants, earthworms, beetles, etc. – can dig through soil & create structures for their movement and habitat (burrows, galleries, nests, etc.)
Mesofauna – 0.2-2mm – collembolas, acarids – live in air-filled pores
Microfauna - <0.2mm – protozoa, nematodes, rotifers – live in water-filled pores
C) What are the three major steps of decomposition?
Group ActivityGroup Activity
A) What is meant by the term detrital food web?
B) How is this food web similar, different from the traditional terrestrial food web?
Soil (Detrital) Food Web
Decomposition
1. OM is oxidized to water & CO2
2. Heat energy released
3. Nutrients released(mineralized)
4. Resistant compounds produced by
organisms
C/N
C/N = 30:1
C/N = 120:1
C/N = 300:1
Dry Plant OM 42% = C 1-2% = N
1. Microbes need 8 C for 1N to build cells
2. Need 16 C for Rs
3. Need C/N = 24/1
4. If OM > 24:1 microbes take N from NO3 in soil5. So lack of N can slow decomposition
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