ic.ucsc.edu Sytsma 2005 Attiwill et al. 1993.

ic.ucsc.edu

Sytsma 2005

Attiwill et al. 1993

Attiwill et al. 1993

Janse et al. 1997

How does phosphate that stored in forest vegetation and soils move into lakes?

• Leaching and transport of soluble orthophosphate through ground or surface waters

• Transport of soil particles by erosion

• Transport of organic material (*)

Sytsma 2005

“For the 10 to 30 year old forests, three out of four study areas had lower landslide densities than found in mature forest, and two of four had reduced erosion volume. For the 31 to 100 year old forests, three out of four study areas had both lower landslides and erosion volume as compared to mature forests. Therefore, for the most erosion prone landscapes, these results also indicate that 10 to 30 year old forests have a 75 percent chance of having a lower landslide density than mature forests. In a similar light, 31 to 100 year old forests have a 75 percent chance of having both lower landslide density and erosion (sediment delivery to channels) as compared with mature forests.”

ODF, 1996

Understory Vegetation Tree Foliage

Forest Floor Uptake and Return

Cole & Rapp, 1981

Sytsma 2005

USDA Forest Service

USDA Forest Service

USDA Forest Service

USDA Forest Service

USDA Forest Service

ODF 1996

ODF 1996

“For the 10 to 30 year old forests, three out of four study areas had lower landslide densities than found in mature forest, and two of four had reduced erosion volume. For the 31 to 100 year old forests, three out of four study areas had both lower landslides and erosion volume as compared to mature forests. Therefore, for the most erosion prone landscapes, these results also indicate that 10 to 30 year old forests have a 75 percent chance of having a lower landslide density than mature forests. In a similar light, 31 to 100 year old forests have a 75 percent chance of having both lower landslide density and erosion (sediment delivery to channels) as compared with mature forests.”

ODF, 1996

Google Maps

Possible Research Opportunities

• Road density vs. phosphorus loading

• Road densities can be obtained from aerial photographs.

• It may also be possible to determine when road systems were built by looking at old aerial photographs.

• Recently harvested or permanently cleared land area vs. phosphorus loading

• ODF maintains data for all harvest operations in Oregon. It may be possible to monitor a lake long-term to see if phosphorus loading changes as harvest activity increases or decreases in the watershed.