Early Seral Ecosystem Creation And Dynamics

1. Early Seral Ecosystem Creation and Dynamics Thomas Spies PNW Research Station

4. His ES High Severity Fire Mixed-Severity Fire

7. Disturbances that create early seral ecosystems vary in their effects on ecosystem structure Structural Element Wind Fire Landslide Clear cut/Burn Canopy foliage X X X X Standing Trees X x X X LWD X X/ x Understory vegetation X X X Forest Floor X X X OM Soil x X x Roots x

8. 0 20 Low Mod High Tree Canopy Closure (%) Dead and Live Biological Legacies Wildfire Windthrow Landslide Early Seral Based on What Remains Retention Systems

9. Blowdown, Bull Run Watershed

10. HOH Fire Tillamook Fire High Severity Wildfire Yacolt Burn

11. Landslides in Coast Range Photo by Rob Pabst

12. Long-lived early seral related to land-use history and site conditions

13. Early Seral on Intensively Managed Forest Land

14. Gap Disturbances

15. Gap Height Diameter/Ht Ratio = 1.0 Diameter/Ht Ratio = 0.5 Gap Size Effect Dense Conifer Forests ES plant species begin to appear ES plant species infrequent

16. Gap diameter/canopy ht ratio Number of Gaps Most natural gaps are too small for early successional conditions

17. Fire as a gap process in dry, fire-prone forests

18. Historical dynamics of fire and succession in Ponderosa Pine R. Van Pelt Time Zero 20 yrs 40 yrs 60 yrs 80 yrs Fire Suppression

19. ES ES ES ESES Successional Pathways ES

20. ES ES ES

21. Early seral creation in the Biscuit Fire

23. Historical Range of Variability Oregon Coast Range % of Landscape Early Seral: 10-25% Old Growth: 35-60% % of Landscape Probability

24. Wildfire Conversion of Old Forest to Early Successional 1993-2003 Percent Loss of Older Forest on a Decadal Basis By Province Based on Moeur and Spies et al. 2005 3.1 % ( incl BB and DL) 3.6 % 3 % 9.5 % 2.3 % 0.4 % 0 % 0 % 0 % 1.4 % 0 %