1 / 15

Dynamics of the Northern Hardwood Ecosystem

Dynamics of the Northern Hardwood Ecosystem. Yuqiong Hu, Jeff Plakke, Sharon Shattuck, Erin Wiley. Introduction: Field Review. -Moraine deposits composed of old outwash plains -Abrupt, hilly topography -higher latitude and elevation cooler temperatures. -Sandy soil

sparr
Download Presentation

Dynamics of the Northern Hardwood Ecosystem

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Dynamics of the Northern Hardwood Ecosystem Yuqiong Hu, Jeff Plakke, Sharon Shattuck, Erin Wiley

  2. Introduction: Field Review -Moraine deposits composed of old outwash plains -Abrupt, hilly topography -higher latitude and elevation cooler temperatures -Sandy soil -Well-developed profile -Bh horizon -Overstory dominated by Acer saccharum -Many mesic indicators Conclusion: Most important factors influencing this site are topography and climate. Topography leads to fire suppression and climate influences soil moisture.

  3. Results: Physical Properties • Average texture, based on Textural Triangle= Sand • AWC= 0.14 cm^3 H2O/cm^3 soil

  4. Results: Chemical Properties • pH • Water pH: 5.31 • CaCl2 pH: 4.66 • Organic Matter: • Organic Matter: 3.26% • Organic Carbon: 1.63% • CEC and Base Saturation • CEC: 3.87 cmol charge per kilogram • Base Saturation: 96.4%

  5. Results: Biological PropertiesMicrobial Biomass and N-Mineralization

  6. Results: Biological PropertiesBiomass and Nitrogen Pools

  7. Discussion: Physical PropertiesTexture • Sandy texture (87% sand) • Cannot hold moisture well • low surface area: volume ratio • Because parent material and texture are similar to Northern Oak site, there must be another driver for ecosystem development

  8. Discussion: Physical Properties Available Water Content (AWC) • AWC Relatively low, but higher than site on similar parent material. Why? • Physiography and Climate • Parent material= sand • Higher elevation, higher latitude influences snowmelt • Lower Solar Penetration due to high Basal Area • Organic Matter • Field evidence: • Presence of Bh horizon in soil profile indicates organic matter breakdown.

  9. Discussion: Chemical PropertiespH and Organic Matter • pH: What controls it? • Litter quality • Microbial activity (because pH is acidic, fungi are primary decomposers in this ecosystem) • Parent Material (soil buffering capacity) • Organic Matter • Low in soil compared to O.M. pool in overstory; indicates high rate of decomposition • Increases water-holding capacity • Field evidence: Bh horizon indicates high amount of O.M. in system

  10. Discussion: Chemical PropertiesCEC and Base Saturation • CEC and Base Saturation • CEC somewhat low due to parent material • Sand= low CEC • Higher than site on similar parent material due to higher O.M. content • Base Saturation: Indication of large nutrient pool • Lack of Fire • Young, relatively unweathered Parent Material

  11. Discussion: Biological Properties Microbial Activity and Nitrogen Cycling • Litter Production high + litter accumulation low = high Microbial Biomass -“look up, look down” • Litter Quality is high = high C:N ratio • N mineralization = NH4+lots of “Goodies” • Nitrification is high • Nitrobacter spp. NH4+NO3- • Potential for nutrient loss through leaching NO3- (highly mobile, sandy soils, water movement) after a disturbance (decreased plant uptake).

  12. Discussion: Biological Properties Biomass and Nutrient Pools • Aboveground Biomass is highest “look up…” • drives N mineralization and Nitrification through litter decompostion • Belowground Nitrogen Pool is Highest • Forest floor is lowest for both “…look down.” = high rate of decomposition. “what about the roots?”

  13. DISCUSSION & SYNTHESIS: Climate evapotranspiration snowpack moisture Rate of microbial activity Nutrient pool Litter quality Plant community Litter Quantity

  14. DISCUSSION & SYNTHESIS: Topography Disturbance Regime Plant community Nutrient Pool Litter quantity pH Litter quality Rate of Microbial Activity

  15. Questions?

More Related