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Forest Ecological Relationships: Teakettle and Plumas Lassen Administrative Study

Forest Ecological Relationships: Teakettle and Plumas Lassen Administrative Study. Malcolm North, Sierra Nevada Research Center, Davis, CA mpnorth@ucdavis.edu. What does the information gathered over the last 10 years of Sierran ecological studies suggest for managing forests?

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Forest Ecological Relationships: Teakettle and Plumas Lassen Administrative Study

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  1. Forest Ecological Relationships: Teakettle and Plumas Lassen Administrative Study Malcolm North, Sierra Nevada Research Center, Davis, CA mpnorth@ucdavis.edu

  2. What does the information gathered over the last 10 years of Sierran ecological studies suggest for managing forests? • Processed-centered restoration • Historic diameter distribution • Historic spatial patterns • What is the seral development (shrub response, future tree composition) of treated stands?

  3. What influences the ‘health’ of current and treated forests? • In fire suppressed mixed conifer, limited water is a primary driver of many ecological processes • Treatments that reduce stand density, significantly increase water availability, BUT increases in slash and litter can stall process recover • Fire jumpstarts most processes, boosts environmental and habitat heterogeneity, and significantly increases biodiversity

  4. What is process-centered restoration? (courtesy of Don Falk, Tree Ring Lab, UA) • Ecological processes are placed at the center of restoration design • A range of process values estimated (based on suitable reference) • Composition and structure are varied as needed to bring process within targeted range, or left to equilibrate on their own Falk 2006; Cortina et al. 2006

  5. Proceed Centered Restoration: Methods • Begin with bracketed estimates of (a) fire regime and (b) individual fire events under historical conditions • Model effects of structural treatments on fire behavior and effects across a range of prescriptions • Set structural prescription to achieve process target values • Test model on the ground and adapt (courtesy of Don Falk, Tree Ring Lab, UA) Covington et al. 2001; Fulé et al. 2004; Falk 2006

  6. Model assumptions and conditions (90th – 95th percentile wx) • Modeling in FVS 6.31, Nexus 2.0, Behave+ • 32-48 km hr-1windspeed @ 6 m • Slope 5% • Surface fuel moisture: • 1 hr fuels 3-8% • 10 hr 4-10% • 100 hr 5-12% • Live fuel moisture 80-100% • Fuel models 9-10 Fulé et al. 2004; Falk 2006 (courtesy of Don Falk, Tree Ring Lab, UA)

  7. Target (reference) values for key fire behavior and effects (response) variables • Primarily surface fire, occasional torching OK • Overall flame height  2 m • Headfire spread rate  3 - 4 m min-1 • Fireline intensity  1000 km m-1 • TI  40 km hr-1, CI  65 km hr-1 • Percent mortality by size class •  2% overstory trees ( 40 cm dbh) •  80% saplings and understory trees ( 15 cm dbh) Agee 1993, Sackett and Haase 1996, Pyne, Andrews et al. 1996

  8. Structural (input) variables • Thin progressively across a range of maximum thin diameters: unthinned – 40 cm (16 in). This alters: • Tree density (stems ha-1) • BA (m2 ha-1) • Crown base height distribution (m) • Crown bulk density (kg m-3) • Size distribution (dbh, cm) Graham et al. 2004; Peterson et al. 2005

  9. Proportion of response by max diameter thinned

  10. Current diameter distribution in fire-suppressed mixed conifer

  11. Before 1865, tree death and recruitment is pulsed by fire and El Nino events Fire

  12. Diameter distribution at Teakettle after treatments compared to 1865 245 Pretreatment Burn/no thin 205 Unburned/understory thin 165 Burn/Understory thin Unburned/Overstory thin 125 Burn/overstory thin 85 1865 Reconstruction Density (# of stems/ha) 30 20 10 0 0 25 50 75 100 125 150 25 cm dbh size classes Diameter distribution

  13. Carbon Storage and Rate of Accretion

  14. Pretreatment Forest Highly Clustered

  15. 1865 Reconstruction Slightly clustered Random

  16. Overstory Thin (similar to DFPZ) Clumped Regular

  17. White fir and incense cedar produce far more seed than pines

  18. NB-NT: No burn/no thin NB-UT: No burn/understory thin NB-OT: No burn/overstory thin B-NT: Burn/no thin B-UT: Burn/understory thin B-OT: Burn/overstory thin

  19. Canopy Openness Effects on Understory Vegetation Cover Herb Canopy Openness PercentCover 80 Canopy Cover 40

  20. Stanislaus Tuolomne Experimental Forest Methods of Cutting Plot 1929 Historic forests probably had higher shrub cover Some studies suggest shrubs are important habitat for birds and small mammals For Jeffrey or ponderosa pine, if sapling is established, shrub may not reduce survival However sugar pine may need forest canopy for early growth How much shrub cover and how distributed?

  21. Summary I: Some suggestions from recent ecological research Put fire back into the system whenever possible. Where fire can’t be used, thin stand to control intensity of inevitable wildfire Trees should not be evenly spaced after thinning Different treatments by species—not uniform diameter limits

  22. Summary II: Some suggestions from recent ecological research Need to mix it up at multiple scales—leave some dense clumps, some gaps Plant pine seedlings to overcome natural seeding, shrub competition, and limited mineral soil and direct sunlight We still don’t know exactly how stands are going to develop in DFPZs, SPLATs or other fuels’ treatments

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