Transcript Black Oak- White Oak Forest

Black OakWhite Oak
Forest
Manistee National Forest
* Outwash plain dominated by Jack Pine to the west
* Northern hardwood forest to the east
Land Form
• Kamic Hills
• Formed by
Wisconsin
Glaciation approx.
8000-9000 years
ago
Parent Material
• Ice contact material
• Derived from outwash
stratified drift laid down
by previous Illinoian
glaciation (128,000 yrs.
ago)
Ecosystem overview:
Northern Oak Relationships:
Soil Profile
Oe/i/a2-0 cm; intact and partially decomposed Quercus rubra, Acer rubrum, Q.
alba leaves; abrupt smooth boundary.
A
0-3 cm; black (7.5 YR 2.5/1) loamy sand, weak fine subangular blocky
structure; very strongly acid; abrupt smooth boundary.
E
3-6 cm; dark gray (7.5YR 4/1) loamy sand; weak medium subangular
blocky structure; very strongly acid:, abrupt smooth boundary.
BS1
6-14 cm; brown. (7.5YR 4/4) sand; single grain; moderately acid;
diffuse smooth boundary.
BS2
14-26 cm; strong brown (7.5YR 5/8) sand; single grain; moderately
acid; diffuse smooth boundary.
C
26 cm; dark yellowish brown (10YR 5/8) sand; single grain;
moderately acid.
Soil Profile
Northern Oak Soil Profiles
-10
0
Depth (cm)
10
Fine Young Entisols
Duripan Duripan
Bt Boys
Oe/i/a
Oe/i/a
A
Oe/i/a
A
E
E
Bs
E
Bs2
Bs
20
A
Bs
30
C
40
C
50
60
C
Soil Texture
Group
% sand
% silt
Fine Young
Entisols
91.15
Duripan Duripan
90.93
5.56
Bt Boys
76.94
17.40
Average
86.34
8.87
3.64
% clay
In lab
In situ
sand
loamy sand
sand
loamy sand
5.21
3.51
5.60 loamy sand loamy sand
4.77
Bulk Density, AWC and OM
• Bulk Density:
1.08 g/cm3
• Available Water Content:
0.23 cm3 H2O/ cm3 soil
• Organic Matter Content:
2.06 %
Soil pH, CEC & base saturation
pH
Using H2O:
4.62
Using CaCl2:
3.46
CEC
(cmolc/ kg)
% Base
Saturation
1.19
13%
Soil Profile Summary
•
Soil Texture: Sand (76-91%)
Silt (3-17%)
Clay (3-5%)
- Affects Db and AWC
• Lowest CEC and base saturation
• Non-calcareous; acidic
• Soil horizons shallow and not well
developed
Soil Profile Summary
• Texture= Sand (90-92%)
Clay (3.5%) & Silt ( 5-5.5%)
Non-calcareous; Acidic
* Well-developed forest floor
* Soil Horizons shallow & not very
developed
*
Plant Profile
Predominant Overstory plants
Quercus alba, Quercus rubra, Acer rubrum
Understory plants included
Pinus Strobus, Sassafras albidum, Hamamelis
virginiana
Groundcover plants included
Pteridium aquilinum, Carex Pensylvanica,
Gaylussacia bacata
Plant Factors Influencing Soil
• Slow Decomposition
• Nutrient Poor Litter
• High Content of
Organic Acids
NO and NH Nutrient Pools
NO & NH Nutrient Pools
3000
2500
2000
NH Ecosystem
1500
NO Ecosystem
1000
500
0
(Mg/ha)
(kg
N/ha)
C
N
Above
Above
Ground Ground
Mg ha-1 kg N ha- Mg ha-1 kg N ha1
1
C
N
C
N
Forest
Floor
Forest
Floor
Soil
Soil
Nitrogen Exchange
• Nitrogen is often a limiting factor in the
productivity of terrestrial ecosystems.
• Microbial activity fixes organic nitrogen
into forms that are available to plants
• plants use fixed nitrogen to manufacture
organic compounds,
• N returns to the microbes tied in organic
compounds forming plant litter
Nitrogen Exchange
N cycling is controlled by:
• Litter production, above and below ground
• Litter chemical composition
• Microbial community numbers and types
• Temperature and moisture affecting the
activity of microorganisms
Role of Organic Matter (Carbon)
• Carbon supplied by plant litter limits
microbial growth
• Amount of N released during
decomposition reflects the “quality” of
organic matter
The Connection
Plant and microbial
activity within terrestrial
ecosystems is tightly
linked through the
exchange of C and N
Chemistry
• N is released from OM by heterotrophic soil
organisms (bacteria,fungi, actinomycetes) in
the form of ammonia
• R-NH3 + H2O  R-OH + NH4+
• Ammonia can then be assimilated by plants,
participate in ion exchange reactions or…
Chemistry
…it can be oxidized by chemoautotropic
bacteria to form nitrate
2 steps:
• NH4+ + 11/2 O2  NO2- + H2O + 2H+
• NO2- + 1/2O2  NO3-
Nitrifying Bacteria
• Only 3 genera carry out the first step, and
only 1 genera carry our the second
• All nitrifying bacteria are
– strictly anaerobic and
– intolerent of low soil pH
• Thus, their activity is restricted in acidic
conditions like the northern oak ecosystem
N and C Exchange in the
Northern Oak Ecosystem
•Microbial biomass is very small
•Thus, so is the specific microbial respiration rate,
indicating the relative efficiency of the microbial
community to convert organic C to biomass.
(higher = less efficient)
site
microbial biomass
spec resp
units
g C/g
mg/g/d
NH
117.09
215.04
NO
20.84
556.34
N and C Exchange in the
Northern Oak Ecosystem
•The low biomass of microorganisms contributes
to a small amount nitrogen produced.
•The acidity of the site may contribute to the very
low amount of nitrate.
site
incub NH4+
units
ug N/g soil
incub NO3-
NH
31.67
27.35
NO
23.27
0.32
N and C Exchange in the
Northern Oak Ecosystem
•The ratio of C respired to N mineralized indicates
the litter quality of a site.
•A high ratio indicates a good substrate for
microbial growth, but little N released where it can
be assimilated for plants.
Site
C respired:N mineralized
NH
7.16
NO
11.11
How does it all fit together?
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Fire from west burns through NO forest
burn quick release & loss of nutrients
Vegetation = response to /100yr disturbance
Less nutrients in oak litter  slow decomp.
Canopy less dense  site drier than NH
Less water  less weathering of soil