Forest Ecology Soil

 Time to Get Dirty

Soils  For this presentation we are going to be ‘borrowing’ some information from the Oregon Envirothon

Soil is …...an integral part of a larger ecosystem affecting both land and affecting both land and water processes

Soil is … an ecosystem unto itself a complex, 3-dimensional habitat

5 functions of soil

The five factors of soil formation  Climate  Organisms  Topography/relief  Parent Material  Time Soil = f(cl,o,r,p,t) Passive Factors Active Factors

Landscape positions

A soil profile

Soil profile Soil horizons

OOAAEEBBCCRROOAAEEBBCCRR The “Master” horizons surface horizon made of Organic matter surface horizon, mineral soil high in organic matter subsurf. horizon light in color due to leaching subsurf horizon, can be high in clay least weathered (and deepest) of all the soil horizons bedrock

O horizon

 Minerals  Organic matter  Water  Air Soil has four components mmm m m m O O w w w a a a

The four components of soil:

Influence of Texture SandSiltClay Water-holding capacity Aeration Drainage Nutrient retention LowMediumHigh GoodPoor Medium SlowVery slowHigh LowMedium

Less Greater Compaction

Soils  Notice the affect of compaction  Can you name some ways soil can become compacted?  Equipment  Rain  Livestock

Soils  Living things and their size difference

Relative Sizes

Soil  Let’s look at some more information  Rocks are the parent material for soil formation  Soil management  Logging practices have changed over the past few decades to help manage the soil and soil compaction.  More hi-lead logging is done and logs are suspended in the air to prevent them from dragging on the ground

Soils  Ground logging has changed to leave more brush where machines are operating to reduce compaction  If skid trails are used, the number is minimized to reduce compaction and run off

Soil  Erosion  Most erosion results form road building in the forests  Proper road building techniques reduce erosion  Recent studies from OSU have shown that the 1 st year after harvest, soil is more likely to erode than before harvest  However, after the 1 st year, soil is more stable than before harvest

Soil  How is it more stable?  Before harvest  Large conifer trees  Little brush  Lot’s of open ground  After harvest  Lots of brush  Little open ground

Soil Review