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1 5/9/2015 Creating and Maintaining Multi-Strata Stands Is FVS wrong? GMUG 11/15/2013 Weikko Jaross DRAFT subject to change1
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2 2 The case study location Generally observed patterns What is a multi-strata stand? Design parameters Concluding remarks The Focus of this talk DRAFT subject to change
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3 Lands held in fiduciary trust Sustainable harvest unit 1997 State Trust Lands HCP ~255k forested acres 3,595 FVS ready stands Case Study Location DRAFT subject to change3 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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4 Current Patterns DRAFT subject to change4 A view of an OESF landscape having continuous forest cover
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5 Harvest Patterns DRAFT subject to change5 Examples of Variable Retention Harvesting and Variable Density Thinning
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6 Regeneration Patterns DRAFT subject to change RandomUniform Clumped
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7 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” DRAFT subject to change
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8 Severity vs. Freq Patterns Summarizing weather buoy data off shore of the Columbia River. (Jaross and Read, 2005) DRAFT subject to change
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9 Climate Patterns Northwest Windstorms by Cliff Mass, Department of Atmospheric Sciences, University of Washington Special to Northwest Science & Technology, Winter 2005. http://nwst.org/ NW catastrophic storms occur when sea surface temperatures transition between El Nino and La Nina. (Mass, 2005) NW catastrophic storms make landfall on a 20 to 40 year return interval. ~120-year rotations with gap phase regeneration (Agee, 1993) DRAFT subject to change
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10 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. DRAFT subject to change
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11 Conceptual Strata SaplingSawPoleLarge Tree > 120’ 80 – 120’ 30 – 80’ < 30’ DRAFT subject to change > 15 30”+ tpa & > 2 strata
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12 12 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 DRAFT subject to change
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13 FVS Code DRAFT subject to change13
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14 FVS Code Cont. DRAFT subject to change14 Scenarios ABA79 ATA15 ATA17
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15 FVS Code Cont. DRAFT subject to change15 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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16 Ideal 30-Year Cutting Cycle DRAFT subject to change16 1 2 34 56789 10
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17 17 Stands Cut DRAFT subject to change
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18 18 Volume Removals DRAFT subject to change ?
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19 19 Forest Level (multi-strata) DRAFT subject to change ?
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20 20 Forest Level (big trees) DRAFT subject to change
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21 21 Stand Level (multi-strata) DRAFT subject to change ?
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22 22 Stand Level (big trees) DRAFT subject to change
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23 23 Stand Level (Multi-Strata and Big Trees) DRAFT subject to change Not enough big trees Not enough strata
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24 24 ATA17 Scenario DRAFT subject to change Over Time
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25 25 ATA15 Scenario DRAFT subject to change Over Time
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26 26 ABA79 Scenario DRAFT subject to change Over Time
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27 27 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 DRAFT subject to change
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28 28 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 DRAFT subject to change
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29 29 So, is FVS wrong? DRAFT subject to change
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30 30 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 DRAFT subject to change
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31 31 Time for Questions? DRAFT subject to change
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