Forest EcologyForest Ecology

SoilSoil

Forest EcologyForest Ecology

Time to Get DirtyTime to Get Dirty

SoilsSoils

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

Soil is …Soil is …

...an integral part of a ...an integral part of a

larger ecosystemlarger ecosystem

affecting both land and affecting both land and

water processeswater processes

Soil is …Soil is …

an ecosystem unto itself an ecosystem unto itself

a complex, 3-dimensional habitata complex, 3-dimensional habitat

5 functions

of soil

1

54

3

2

The five factors of soil formationThe five factors of soil formation

ClimateClimate OrganismsOrganisms Topography/reliefTopography/relief Parent MaterialParent Material TimeTime

Soil = f(cl,o,r,p,t)

Passive Factors

Active Factors

Landscape positionsLandscape positions

A soil profile

Soil profile

Soil horizons

O O

AA

EE

BB

CC

RR

The “Master” horizonsThe “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 Minerals Organic matter Organic matter WaterWater AirAir

Soil has four componentsSoil has four components

mm

mm

mm mmmm

mm

O

O

w

ww

a a

a

The four components of soil:

Influence of TextureSand Silt Clay

Water-holding capacity

Aeration

Drainage

Nutrient retention

Low Medium High

Good PoorMedium

Slow Very slowHigh

HighLow Medium

Less GreaterCompaction

SoilsSoils

Notice the affect of compactionNotice the affect of compaction Can you name some ways soil can Can you name some ways soil can

become compacted?become compacted? EquipmentEquipment RainRain LivestockLivestock

SoilsSoils

Living things and their size differenceLiving things and their size difference

Relative Sizes

http://commtechlab.msu.edu/sites/dlc-me/zoo/zdrr0101.html

SoilSoil

Let’s look at some more informationLet’s look at some more information Rocks are the parent material for soil Rocks are the parent material for soil

formationformation Soil managementSoil management Logging practices have changed over the Logging practices have changed over the

past few decades to help manage the soil past few decades to help manage the soil and soil compaction. and soil compaction.

More hi-lead logging is done and logs are More hi-lead logging is done and logs are suspended in the air to prevent them from suspended in the air to prevent them from dragging on the grounddragging on the ground

SoilsSoils

Ground logging has changed to leave Ground logging has changed to leave more brush where machines are operating more brush where machines are operating to reduce compactionto reduce compaction

If skid trails are used, the number is If skid trails are used, the number is minimized to reduce compaction and run minimized to reduce compaction and run offoff

SoilSoil

ErosionErosion Most erosion results form road building in the Most erosion results form road building in the

forestsforests Proper road building techniques reduce erosion Proper road building techniques reduce erosion Recent studies from OSU have shown that the Recent studies from OSU have shown that the

11stst year after harvest, soil is more likely to erode year after harvest, soil is more likely to erode than before harvestthan before harvest

However, after the 1However, after the 1stst year, soil is more stable year, soil is more stable than before harvestthan before harvest

SoilSoil

How is it more stable?How is it more stable? Before harvestBefore harvest

Large conifer treesLarge conifer trees Little brushLittle brush Lot’s of open groundLot’s of open ground

After harvestAfter harvest Lots of brushLots of brush Little open groundLittle open ground

Soil ReviewSoil Review