forest harvest effects on temperature of small headwater streams

Forest harvest effects on temperature of small headwater streams

with and without riparian buffers

Steven M. Wondzell, Jack E. Janisch, William J. Ehinger, and Peter A. Bisson

With help from:Alex Foster, Shannon Claeson, and Jeff Rickleffs

Janisch, J. E., Wondzell, S. M., and Ehinger, W. J. 2012. Headwater stream temperature: Interpreting response after logging, with and without riparian buffers, Washington, USA. Forest Ecology and Management 270:302-313.

CapitolForest

WillapaHills

GOOGLE

EARTH

Area: 1.1 - 7.6 haWinter Q: 0.1 - 9.6; x = 2.1 l/sSummer Q: 0.0 - 1.8; x = 0.3 l/s

Temperature sensors at each wier

So…… for tiny headwater streams?

Does forest harvest increase stream temperature?

Do riparian buffers limit temperature increases?

Tpredicted = -0.23 + 1.18*Tcontrol + 1.33*sin(2πj/365) + 1.59*cos(2πj/365) + є

r2 = 0.9166

CapitolForest

WillapaHills

WILLAPA HILLS

ELFL

ControlContinuous

Clearcut

LORI

ControlContinuousPatchClearcut

MCCO

ControlContinuousPatch

SPLT

ControlContinuous

Clearcut Clearcut

CAPITOL FOREST

MOSH

ControlContinuousPatch Patch

ROTT

ControlContinuous Continuous

Clearcut

SESA

ControlContinuous

Clearcut

TAGS

ControlContinuousPatch PatchClearcut

Descriptive variablesElevation

AreaAspect

GradientDepth

Canopy+Topographic densityWetted channelWetland area

Streambed texture

No direct measurement of Shade

Descriptive variablesElevation

AreaAspect

GradientDepth

Canopy+Topographic densityWetted channelWetland area

Streambed texture

?

• Some treated streams were significantly warmer, but… • On average, temperature increases were small• Trend did not match expectations for treatments, • Responses within treatments were highly variable

• Temperature responses were correlated with streambed texture, wetlands, and length of stream

• Surface area exposure• Amount of hyporheic exchange

Results Summary:

So…… for tiny headwater streams?

Does forest harvest increase stream temperature?

Do riparian buffers limit temperature increases?

WS03 - 1996 FLOOD