Instream wood transport, and effects of forest harvest on geomorphology and fish, in northern Minnes...
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Instream wood transport, and effects of forest harvest on geomorphology and fish, in northern Minnesota streams. Eric Merten Jacques Finlay* Heinz Stefan* Lucinda Johnson Raymond Newman Bruce Vondracek.

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Instream wood transport, and effects of forest harvest on geomorphology and fish, in northern Minnesota streams

Eric Merten

Jacques Finlay*

Heinz Stefan*

Lucinda Johnson

Raymond Newman

Bruce Vondracek

This work was funded by the Minnesota Department of Natural Resources Section of Fisheries, the Minnesota Forest Resources Council, the National Council for Air and Stream Improvement, the U.S. Forest Service, Minnesota Sea Grant, Minnesota Trout Unlimited, and the Minnesota Environment and Natural Resources Trust Fund as recommended by the Legislative Citizen Commission on Minnesota Resources.


Forest harvest effects on the Pokegama Creek system: 1997 to 2007

http://www.youtube.com/watch?v=up7-xHm6jlA

Ecohydraulics of wood transport in north shore streams


Pokegama sampling help 2007

Andy Arola

Daryl Arola

Brenda Asmus

Jason Bronk

Ryan Carlson

Jacquelyn Conner

Bill Coates

Carrie Dorrance

Sue Eggert

Art Elling

MaryKay Fox

Jo Fritz

Sarah Harndin


Pokegama sampling help 2007

Nat Hemstad

Becca Hunt

Deacon Kyllander

Marty Melchior

Steffen Merten

Mateya Miltich

Brittany Mitchell

Erik Mundahl

Elliot Nitzkowski

Ian Phelps

Lisa Pugh

Jeff Rice

Jeremy Steil

Sandy Verry

Dustin Wilman

Jason Zwonitzer


April Bebault 2007

Ryan Carlson

Tracy Close

Levi Drevlow

Jo Fritz

Ryan Johnsen

Nicole Rath

Marty Rye

Nathan Schroeder

Rachael Stanze

Dustin Wilman

Wood

sampling

help

>6km surveyed every 10m

Rachael ongoing discharge data, Tracy Close sharing data




  • Merten (1999) found significant fine

  • sediment increase after harvest

  • Hemstad, Merten, and Newman (2008) found fine sediment levels persisted for several years

  • Hemstad and Newman (2006) found more eroding banks and fine sediment 0-2 years after harvest in the catchment


Experimental design Practices (BMPs) for timber harvest (1996)

  • Pre-harvest sampling in summer 1997

  • Forest harvest in winter 1997-1998

  • Post-harvest sampling summer 1998

  • through summer 2000

  • Natural recovery of sites

  • Post-harvest sampling in summer 2006

  • through summer 2007


  • Analysis Practices (BMPs) for timber harvest (1996)

  • Repeated measures ANOVA using all

  • data from all sites

  • Tests for overall differences between

  • years, throughout the study area

  • Can not determine the causes of the

  • differences


FOREST HARVEST Practices (BMPs) for timber harvest (1996)


C Practices (BMPs) for timber harvest (1996)

FOREST HARVEST


D Practices (BMPs) for timber harvest (1996)

FOREST HARVEST


, p= 0.05 Practices (BMPs) for timber harvest (1996)

, p= 0.05

, p= 0.00

, p= 0.03


Pokegama summary
Pokegama Summary Practices (BMPs) for timber harvest (1996)

  • Canopy cover and eroding banks

    recovered nine years after harvest

  • Sediment inputs still present nine years

    after harvest, flushed in fall of 10th year

  • Years with warmer air temperatures may

    exacerbate effects of open canopy and fine

    sediment


Ecohydraulics of wood transport in streams: Practices (BMPs) for timber harvest (1996)

empirical models from the north shore

of Lake Superior in Minnesota


Why study wood transport? Practices (BMPs) for timber harvest (1996)

If a wood piece is exported from a stream reach, it no longer provides

geomorphic or ecological functions there


Plunge pools Practices (BMPs) for timber harvest (1996)

Lateral migration

Habitat complexity

Invertebrate substrate

Leaf litter retention

Transient storage

Hyporheic exchange


Needs for wood transport studies Practices (BMPs) for timber harvest (1996)

Research questions for this project

Data collection

Data analysis

Results and discussion


Needs for wood transport studies Practices (BMPs) for timber harvest (1996)

Location: managed forests in the interior U.S.


Needs for wood transport studies Practices (BMPs) for timber harvest (1996)

Location: managed forests in the interior U.S.

Design: high resolution but still a field study


Needs for wood transport studies Practices (BMPs) for timber harvest (1996)

Location: managed forests in the interior U.S.

Design: high resolution but still a field study

Predictors: examine relative importance of all known mechanisms


Needs for wood transport studies Practices (BMPs) for timber harvest (1996)

Research questions for this project

Data collection

Data analysis

Results and discussion


Mobilization Practices (BMPs) for timber harvest (1996)

Entrapment


Needs for wood transport studies Practices (BMPs) for timber harvest (1996)

Research questions for this project

Data collection

Data analysis

Results and discussion


~2000 hours sampling on nine streams Practices (BMPs) for timber harvest (1996)


Nine streams between Practices (BMPs) for timber harvest (1996)

Duluth and Silver Bay


Bankfull widths ranged from 3.3 to 25.1 m Practices (BMPs) for timber harvest (1996)


963 pieces measured and tagged, many variables measured Practices (BMPs) for timber harvest (1996)

4,190 m of stream surveyed every 10 m


Braced against a live tree Practices (BMPs) for timber harvest (1996)

Saldi-Caromile et al. 2004


Needs for wood transport studies Practices (BMPs) for timber harvest (1996)

Research questions for this project

Data collection

Data analysis

Results and discussion


HEC-RAS model Practices (BMPs) for timber harvest (1996)


HEC-RAS model Practices (BMPs) for timber harvest (1996)


Drag force ≈ Practices (BMPs) for timber harvest (1996)(U 2/2) ρw Cd AN + (U 2/2) ρw Cf ASAcos3 θ

Lift force ≈ U 2/2 Clp ANcos θ + U 2/2 Clg ANsin θ

Braudrick and Grant 2000


“What factors determine whether or not a piece is mobilized/entrapped?”

Multiple logistic regression with mobilization as the response variable

-shows which variables are important for mobilization

Multiple logistic regression with entrapment as the response variable

-shows which variables are important for entrapment


Needs for wood transport studies mobilized/entrapped?”

Research questions for this project

Data collection

Data analysis

Results and discussion


Needs for wood transport studies mobilized/entrapped?”

Location: managed forests in the interior U.S.

Design: high resolution but still a field study

This study examined individual pieces in the field at a fine spatial scale

and at a < 1-year temporal scale

Predictors: examine relative importance of all mechanisms

This study examined more and better predictors than any previous study


Variables retained in the final model for mobilization; mobilized/entrapped?”

n = 865 pieces of wood.

Overall model p < 0.001 and Nagelkerke’s r2 = 0.39


Variables retained in the final model for mobilization; mobilized/entrapped?”

n = 865 pieces of wood.

Overall model p < 0.001 and Nagelkerke’s r2 = 0.39


Variables retained in the final model for mobilization; mobilized/entrapped?”

n = 865 pieces of wood.

Overall model p < 0.001 and Nagelkerke’s r2 = 0.39


Variables retained in the final model for entrapment; mobilized/entrapped?”

n = 344 pieces of wood.

Overall model p < 0.001 and Nagelkerke’s r2 = 0.25


Keep sediment out mobilized/entrapped?”

Keep streams cool

Promote more wood

Conclusions

[email protected]


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