Black Oak- White Oak

Forest

Manistee National ForestManistee National Forest

* Outwash plain dominated by Jack Pine to the west* Northern hardwood forest to the east

Land FormLand Form

• Kamic Hills

• Formed by Wisconsin Glaciation approx. 8000-9000 years ago

Parent MaterialParent 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 ProfileSoil ProfileOe/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 ProfileSoil ProfileNorthern Oak Soil Profiles

Oe/i/a Oe/i/a Oe/i/aA A

A

E

E

E

Bs

Bs

Bs

C

C C

Bs2

-10

0

10

20

30

40

50

60

Fine Young Entisols Duripan Duripan Bt Boys

Dep

th (c

m)

Soil TextureSoil Texture

Group % sand % silt % clay In lab In situ

Fine Young Entisols

91.15 3.64 5.21sand loamy sand

Duripan Duripan 90.93 5.56 3.51 sand loamy sand

Bt Boys 76.94 17.40 5.60 loamy sand loamy sand

Average 86.34 8.87 4.77    

Bulk Density, AWC and Bulk Density, AWC and OMOM

• Bulk Density: 1.08 g/cm3

• Available Water Content:

0.23 cm3 H2O/ cm3 soil

• Organic Matter Content: 2.06 %

Soil pH, CEC & base Soil pH, CEC & base saturationsaturation

pHpHUsing H2O:

4.62Using CaCl2:

3.46

CECCEC(cmolc/ kg)

1.19

% Base % Base SaturationSaturation

13%

Soil Profile SummarySoil 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 SummarySoil 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 ProfilePlant 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 Plant Factors Influencing SoilSoil

• Slow Decomposition• Nutrient Poor Litter• High Content of

Organic Acids

NO and NH Nutrient PoolsNO & NH Nutrient Pools

0

500

1000

1500

2000

2500

3000

(Mg/ha) (kgN/ha)

Mg ha-1 kg N ha-1

Mg ha-1 kg N ha-1

C N C N C N

AboveGround

AboveGround

ForestFloor

ForestFloor

Soil Soil

NH Ecosystem

NO Ecosystem

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 respunits g C/g mg/g/dNH 117.09 215.04NO 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+ incub NO3-units ug N/g soilNH 31.67 27.35NO 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 mineralizedNH 7.16NO 11.11

How does it all fit How does it all fit together?together?

• 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