creating and maintaining multi-strata stands is fvs wrong?
DESCRIPTION
Creating and Maintaining Multi-Strata Stands Is FVS wrong?. GMUG 11/15/2013 Weikko Jaross. 9/22/2014. DRAFT subject to change. 1. The case study location Generally observed patterns What is a multi-strata stand? Design parameters Concluding remarks. The Focus of this talk. 2. - PowerPoint PPT PresentationTRANSCRIPT
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Creating and Maintaining Multi-Strata Stands
Is FVS wrong?
GMUG 11/15/2013Weikko Jaross
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• The case study location
• Generally observed patterns
• What is a multi-strata stand?
• Design parameters
• Concluding remarks
The Focus of this talk
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• Lands held in fiduciary trust
• Sustainable harvest unit
• 1997 State Trust Lands HCP
• ~255k forested acres
• 3,595 FVS ready stands
Case Study Location
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The Olympic Experimental State Forest has a long term vision of achieving the dual objective of producing commodities and ecosystem functions from old forest stands.
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Current Patterns
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A view of an OESF landscape having continuous forest cover
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Harvest Patterns
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Examples of Variable Retention Harvesting and Variable Density Thinning
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Regeneration Patterns
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RandomUniform Clumped
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Storm Driven Patterns
– Winter storm months (October-March)
– Pacific low pressure centers (cyclones)
– Typical endemic storms • wind gusts 18-26 m/s (~40-60 mph)
• minor damage to stands
– Exceptional catastrophic storms• wind gusts 33+ m/s (~70+ mph)
• 100+ mph along coast • extensive damage to stands
January,1993 “Inaugural Day Storm”
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Forest Level Patterns
Natural regeneration processes occupy a continuous range of post disturbance scales from gap-phase to large openings with retention
Common silvicultural systems practice narrowly defined scales and patterns.
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Conceptual Strata
Sapling SawPole Large Tree
> 120’
80 – 120’
30 – 80’
< 30’
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> 15 30”+ tpa
& > 2 strata
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• Sustain the dual objective at the stand scale
• Build upon previous growth modeling efforts
• Emulate patterns by balancing harvest with growth
• Achieve key strategies for each stratum
1. manage regeneration toward a target condition
2. manage the mid-story to a target stand density
3. manage the overstory to achieve stand development
Can a one-size fits all approach work?
Design Parameters
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FVS Code
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FVS Code Cont.
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Scenarios•ABA79•ATA15•ATA17
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FVS Code Cont.
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Regeneration is managed to a target density of established mid-story cohorts
• At 30-years post-harvest
• representative tree species
• 129 trees per acre
• 12 to 50 feet tall trees
• clustered in lower density plots
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Ideal 30-Year Cutting Cycle
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Stands Cut
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Volume Removals
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?
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Forest Level (multi-strata)
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Forest Level (big trees)
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Stand Level (multi-strata)
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?
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Stand Level (big trees)
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Stand Level (Multi-Strata and Big Trees)
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Not enough big trees
Not enough strata
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ATA17 Scenario
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Over Time
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ATA15 Scenario
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Over Time
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ABA79 Scenario
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Over Time
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• The simulation techniques do better than no-management at the forest and stand levels.
• Managing the overstory crown cover to a basal area target performs best in terms of the dual objective.
• Long term, the standardized removals are not well matched to stratum level accretion.
Results Summary
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• FVS was sensitive to the parameters for – regeneration assumptions – stratum level target retention levels– minimum harvest levels– cutting cycles
• Lower minimum harvest levels resulted in – stands having more consistent re-entry patterns– fewer multi-strata stands– fewer large trees
• Multi-strata approaches are similar to the group selection examples in the FVS documentation.
General Observations
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So, is FVS wrong?
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• The overstory results are consistent with others’ modeling work.
• The concept of managing each stratum to specific targets seems to make sense.
• Is the growth in each stratum realistic?
• Can FVS predictions apply to broader scales and patterns?
• Validation methods and data must exist ??
My Thoughts
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Time for Questions?
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