Comparisons of DFSIM, ORGANOIN and FVS

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Comparisons of DFSIM, ORGANOIN and FVS

• David Marshall
• Olympia Forestry Sciences Laboratory
• PNW Research Station
• USDA Forest Service
• Growth Model Users Group
• August 10, 2005

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Model Comparisons

• Based on work done while testing ORGANON version
  8.

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Model Comparisons

• Part 1 Out of the Box
• Part 2 Plot Comparisons
• Part 3 Density Regimes

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Model Comparisons

• Part 1
• Out of the Box

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Model Comparisons Part 1

• Will Focus on 4 Models
• DFSIM
• Forest Vegetation Simulator (FVS)
• ORGANON
• TreeLab
• Does not suggest these are the best
• Represent the heart of the DF region
• DFSIM, FVS and ORGANON are widely used
• Available for free on the internet

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Model Comparisons Part 1

• DFSIM version 1.4
• Curtis and others 1986 (revised 1999)
• Stand Model (annual)
• http//forsys.cfr.washington.edu/dfsim/
• FVS-PN (RV 01.11.2005)
• US Forest Service, Forest Management Service
  Center
• Tree Model (10-year increment - default)
• http//www.fs.fed.us/fmsc/fvs/index.php
• ORGANON SMC version 7 and 8 (pre-release)
• Hann and others at Oregon State University (1988
  - 2004)
• Tree Model (5-year increment)
• http//www.cof.orst.edu/cof/fr/research/organon/
• TreeLab
• Turnblom and students at the University of
  Washington (2001)
• Stand Model (annual)
• http//www.cfr.washington.edu/research.smc/treelab
  /Website/TreeLab_home.htm

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Model Comparisons Part 1Out of the Box

• Out of the Box projections
• Models
• DFSIM
• TreeLab
• ORGANON
• FVS
• Site Index 121 feet
• Planted to about 450 trees per acre
• Trees List at 14 years
• Growth to 64 years

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Model Comparisons Part 1 Out of the Box

• 14 - 64 years
• Site Index 121 feet
• Planted (450 tpa)

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Model Comparisons Part 1 Out of the Box

• 14 - 64 years
• Site Index 121 feet
• Planted (450 tpa)

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Model Comparisons Part 1 Out of the Box

• DFSIM
• Default maximum RD 70
• Curtis suggests higher (seems to like RD about 80)

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Model Comparisons Part 1 Out of the Box

• DFSIM
• Default maximum RD 70
• Curtis suggests higher (RD about 80)
• ORGANON
• Default SDImax 520
• Some evidence suggest lower (480)

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Model Comparisons Part 1 Out of the Box

• DFSIM
• Default maximum RD 70
• Curtis suggests higher (RD about 80)
• ORGANON (version 7)
• Default SDImax 520
• Some evidence suggest lower (480)
• FVS has extensive growth modifiers
• Default SDImax (maximum BA) 950
• Growth multipliers for
• Basal area growth
• Mortality
• Height growth
• Crown change

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Model Comparisons Part 1FVS Adjustments
SDImax Growth Multipliers Growth Multipliers Growth Multipliers Projection at 54 years (4 cycles) Projection at 54 years (4 cycles) Projection at 54 years (4 cycles)
SDImax BAI MORT CR TPA BAPA CR
950 1.0 1.0 1.0 242 431 0.56
800 1.0 1.0 1.0 202 370 0.56
950 0.7 1.0 1.0 305 394 0.56
950 1.0 1.1 1.0 230 404 0.56
950 1.0 1.0 2.0 283 410 0.34
650 0.7 0.8 2.0 254 276 0.34
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Model Comparisons Part 1 Out of the Box

• DFSIM
• Default maximum RD 70
• Curtis suggests higher (RD about 80)
• ORGANON
• Default SDImax 520
• Some evidence suggest lower (SDImax 480)
• FVS has extensive growth modifiers
• Default SDImax (maximum BA) 950 (lower to 650)
• Growth multipliers for
• Basal area growth (0.7x)
• Mortality (1.1x)
• Height growth (1.0x)
• Crown change (2.0x)

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Model Comparisons Part 1 Models Modified
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Model Comparisons Part 1 Models Modified
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Model Comparisons Part 1 Models Modified

• Looked at only the default 10-year time step for
  FVS.
• Different time steps might have different
  properties (TIMEINT keyword).

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Model Comparisons

• Part 2
• Plot Comparisons

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Model Comparisons Part 2 12 Stands

• 12 Stands (Plantations)
• 5 Oregon
• 4 Washington
• 3 British Columbia
• Initial Tree List
• Site Index Start of Period
• 10-year net change

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Model Comparisons Part 2 12 Stands
Mean Min. Max. SD
Total Age 28.6 18 40 7.0
Site Index 128.5 96 158 19.5
TPA 331.5 192.0 566.0 103.9
SDI 233.7 85.5 322.5 76.7
CR 0.64 0.45 0.88 0.13
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Model Comparisons Part 212 Stands

• WARNING
• Because of the small number of plots, this should
  not be considered a validation of the models.

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Model Comparisons Part 212 Stands
10-Year Change (Actual Predicted) 10-Year Change (Actual Predicted) 10-Year Change (Actual Predicted) 10-Year Change (Actual Predicted) 10-Year Change (Actual Predicted) 10-Year Change (Actual Predicted) 10-Year Change (Actual Predicted)
Trees Trees Basal Area (net) Basal Area (net) Crown Ratio Crown Ratio
Mean (/acre) SD (/acre) Mean (ft2/ac) SD (ft2/ac) Mean SD
DFSIM 19.8 41.5 -5.1 17.0
TreeLab 18.7 38.6 -3.2 18.1
ORGANON V7 SMC -14.2 17.9 -4.5 12.2 -0.04 0.05
ORGANON V8 SMC -10.0 17.8 -3.9 11.8 -0.05 0.05
FVS PN -13.3 20.2 -40.4 38.9 -0.14 0.06
FVS Modified PN -2.4 19.9 -3.7 24.3 -0.07 0.06
- TPA under predict mortality
- BA/AC over predict net growth
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Model Comparisons Part 212 Stands

• Mortality
• DFSIM and TreeLab over predicted
• ORGANON and FVS under predicted
• Basal Area Growth
• All over predicted but
• Heavily influenced by 3 youngest plots
• ORGANON tended to be the least variable
• FVS needed lots of tweaking
• Small Sample Size

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Model Comparisons

• Part 3
• Density Regimes

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Model Comparisons Part 3Density Management
Projections

• Models
• DFSIM
• TreeLab
• ORGANON (SDImax480)
• FVS-PN
• FVS-PN modified

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Model Comparisons Part 3Density Management
Projections

• 3 Planting Densities and PCT (220 tpa)
• Site Index 121 feet
• Starting Age 14 years
• Project to 54 years

• Models
• DFSIM
• TreeLab
• ORGANON (SDImax480)
• FVS-PN
• FVS-PN modified

Stand TPA BA QMD SDI
A 310 16.3 3.1 47
B 452 24.5 3.2 71
C 689 53.8 3.8 145
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Model Comparisons Part 3Density Management
Projections
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Model Comparisons Part 3Density Management
Projections
Decrease average tree size with increasing
growing stock Thinning increased tree size
Increasing merchantable volume with increasing
growing stock SMALL increase from thinning in
DFSIM and ORGANON V8 and small decrease in FVS
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Model Comparisons Part 3 Density Management
Projections
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Model Comparisons Part 3Density Management
Projections
How did they get there?
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Model Comparisons Part 3Density Management
Projections
FVS may require different calibrations?
ORGANON 8 may not need maximum size-density on
(Monserud)
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Model Comparisons Part 3Density Management
Projections
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Conclusions
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The End