Historical creation of early seral habitat fire wind bugs
Download
1 / 17

Historical Creation of Early Seral Habitat: Fire, Wind, Bugs - PowerPoint PPT Presentation


  • 124 Views
  • Uploaded on

Historical Creation of Early Seral Habitat: Fire, Wind, Bugs …. Fred Swanson USDA Forest Service Pacific Northwest Research Station. Early seral – definition issues. And we thought we have problems with old growth definitions! Easy to talk about the archtype Dimensions for definition:

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Historical Creation of Early Seral Habitat: Fire, Wind, Bugs ' - doli


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Historical creation of early seral habitat fire wind bugs l.jpg

Historical Creation of Early Seral Habitat: Fire, Wind, Bugs

Fred Swanson

USDA Forest Service

Pacific Northwest Research Station


Early seral definition issues l.jpg
Early seral – definition issues

And we thought we have problems with old growth definitions!

Easy to talk about the archtype

Dimensions for definition:

  • Precursor system

  • Temporal - persistence

  • Spatial – patch size, location in environmental gradients

  • Disturbance regime context


Creating early seral l.jpg
Creating early seral

  • Many disturbance types

  • Few types commonly create big patches

  • Many processes create fine patterns


Controls on disturbance effects l.jpg
Controls on disturbance effects

  • Selective of vegetation structure class

  • Selective of species

  • Spatial heterogeneity – of disturbance process, of affected ecosystem

  • Species dominating post-disturbance

  • Persistence of effects of disturbance – biotic legacies, dispersal, soil properties change


Disturbance processes in pnw l.jpg
Disturbance processes in PNW

Big patch

  • Fire

  • Forest cutting

  • Volcanic – tephra vs.

    lava flows

    Small patch

  • Landslides – fast

  • Landslides – slow

  • Wind

  • Bugs

  • Root rot


Non forest openings l.jpg
Non-forest openings

large

Mount St. Helens

Blast zone – planted

Mount St. Helens

Blast zone - unplanted

Mount St. Helens

Primary succ. zone

Lava

flows

Patch

size

Wildfire

Clearcuts

fast (Yang et al) slow

Xeric

meadows

Mesic meadows

Canopy

gap

small

0

50

100

tropics

Persistence of early seral (yrs)


Root rot wind bugs l.jpg
Root rot, wind, bugs

  • Part of ecosystem disturbed

  • Species ready to occupy the site

    After Phellinus weiri Holah et al. (1997) observed:

  • Coast Range – shrubs dominate site

  • Cascades – hemlock dominates site

    After Bull Run windthrow – hemlock dominates

    (Sinton et al 2000)




Slide12 l.jpg

Stand-Replacing Disturbance

Fires

Harvests


Slide13 l.jpg

Stand-Replacing Disturbance in Western Washington, 1972-2004

Fires Harvests

1972-1977

1977-1984

1984-1988

1988-1992

1992-1996

1996-2000

2000-2002

2002-2004

Volcanic eruption


Age class distributions in coastal oregon l.jpg

Early seral

Age Class Distributions in Coastal Oregon

Source: various CLAMS analyses (Spies et al. 2007)


What we don t know l.jpg
What we don’t know

  • Character of pre-management early seral habitat

  • Character of current plantations we might call early seral


Real complex early seral more or less probably less l.jpg
“Real”, complex early seral – …More or less? Probably less!

  • Lack of cultural burning

  • Fire suppression

  • Reduced federal harvest

  • Forest encroachment in mesic meadows

  • Practices to hasten conifer canopy closure

  • Regime-scale effects – is there cumulative loss of structural complexity and biotic diversity over multiple cuttings?

    But, does harvest do the early seral creation job? Do we have more wildfire?


Closing thoughts l.jpg
Closing thoughts

Next steps:

  • Synthesize existing knowledge of early seral condition and function

  • Confer about management options and impediments

  • Integrate thinking/management across landscapes and all age classes

  • Address geographic variation

    What are the similarities/differences with development of old-growth science, policy, and management?


ad