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

Model Comparisons Based on work done while testing ORGANON version 8.

Model Comparisons Part 1 – “Out of the Box” Part 2 – Plot Comparisons Part 3 – Density Regimes

Model Comparisons Part 1 “Out of the Box”

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

Model Comparisons – Part 1 DFSIM version 1.4 –Curtis and others 1986 (revised 1999) –Stand Model (annual) – FVS-PN (RV ) –US Forest Service, Forest Management Service Center –Tree Model (10-year increment - default) – ORGANON SMC version 7 and 8 (pre-release) –Hann and others at Oregon State University ( ) –Tree Model (5-year increment) – TreeLab –Turnblom and students at the University of Washington (2001) –Stand Model (annual) –

Model Comparisons – Part 1 “Out 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

Model Comparisons – Part 1 “Out of the Box” years Site Index 121 feet Planted (450 tpa)

Model Comparisons – Part 1 “Out of the Box” years Site Index 121 feet Planted (450 tpa)

Model Comparisons – Part 1 “Out of the Box” DFSIM –Default maximum RD = 70 –Curtis suggests higher (seems to like RD about 80)

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)

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

Model Comparisons – Part 1 FVS Adjustments SDImaxGrowth MultipliersProjection at 54 years ( 4 cycles ) BAIMORTCRTPABAPACR

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)

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).

Model Comparisons Part 2 “Plot Comparisons”

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

Model Comparisons – Part 2 12 Stands MeanMin.Max.SD Total Age Site Index TPA SDI CR

Model Comparisons – Part 2 12 Stands WARNING Because of the small number of plots, this should not be considered a validation of the models.

Model Comparisons – Part 2 12 Stands 10-Year Change (Actual – Predicted) TreesBasal Area (net) Crown Ratio Mean (/acre) SD (/acre) Mean (ft 2 /ac) SD (ft 2 /ac) MeanSD DFSIM TreeLab ORGANON V7 SMC ORGANON V8 SMC FVS PN FVS Modified PN TPA = under predict mortality- BA/AC = over predict net growth

Model Comparisons – Part 2 12 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

Model Comparisons Part 3 “Density Regimes”

Model Comparisons – Part 3 Density Management Projections Models –DFSIM –TreeLab –ORGANON (SDImax=480) –FVS-PN –FVS-PN modified

Model Comparisons – Part 3 Density 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 (SDImax=480) –FVS-PN –FVS-PN modified StandTPABAQMDSDI A B C

Model Comparisons – Part 3 Density 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

Model Comparisons – Part 3 Density Management Projections

How did they get there?

Model Comparisons – Part 3 Density Management Projections FVS may require different calibrations? ORGANON 8 may not need maximum size-density on (Monserud)

Model Comparisons – Part 3 Density Management Projections

Conclusions

The End