• Include thinning in YIELD table output.
  • Modify SVSVIEW output to follow database directory
  • Verify matching volumes – FpsCrus, FpsXpnd, FpsVols
  • Cause Mixed species Timber label in STAND to create mixed species DBHCLS records if none exist.
  • Adjust SVS crown width output based on FPS libraries
  • Replaced all YPX and ZPX functions with IMSL routines


January: 5.2
  • Modified tree list generator for growth map (FPSLoad2)
  • Insert defect into trees distributed to growth map
  • Add command line arguments
  • Modify taper to store initial difference from Library in TX() array, then add to ACCX(Isp,D,H,Stem) for use.
  • Also add outputs for “.D” and “.C” in DBHCLS and STAND.
  • Move DelRows to LOADX2 (Bug with < 4.1 tpa)
  • Remove rounding from STAND, YIELD and DBHCLS inserts
August: 5.3
  • Add Net Present Value calculation to yields
November: 5.3b
  • Revise thinning to single tree iterations (slower).
  • Cut/Leave ratio takes smallest trees possible
  • Spacing control takes smallest dbh within highest CSI
  • Last species in Species.Lib now available (bug fix)
  • Increase precision on output to include dbh classes with frequency > 0 rather than > 0.04 trees/hectare for all live, dead and cut trees.


March: 4.2
  • Add GISLINK table to database.
  • Set logic for GIS, Net, Buffer & Report acres.
  • Stop if ODBC connection fails.
July: 4.3
  • Update to FPSPATH & FPSDATA directory search
  • Separate small tree growth model from input routine
  • Small tree growth may now be invoked at any time.
  • Duplicate V4.30 in 32-bit Fortran PowerStation
November 5.1
  • Write out thinning records to DbhCls and Stand
  • Modified Map Generator for > 5000 trees/hectare
  • Modified YIELD table generator to not delete new rows


  • Modify slip function for better interpolation control.
  • Build in new mortality surface in Species.Lib.
  • Build in new fertilizer surface in Species.Lib.
  • Change all CCF displays to CSI displays & reports.
August: 4.12
  • Add thinning by spacing criteria
  • Modify tree list generator in LOADX so not to loose trees.
  • Separate the small tree growth from LOADX logic.
  • Modify the thinning logic – below, above, d/D, spacing
  • Have the thinning routine call VIEWX.

1995: 4.X

march 4.00
  • Computer simulation of tree and stand growth dynamics on a periodic basis using using individual tree measures of density for uniform to clumpy spatial patterns.
april 4.01
  • 4.0.1 Pop up tabular report after graphics display
  • Refine small-tree treelist input procedure
  • Pause to review tabular report rather than error code 0
May 4.02
  • Change report age (Rag) test to (Tag.le.Rag.le.Tag2) instead of (Tag.lt.Rag.le.Tag2) for initial stand reports before any growth update.
June 4.03
  • Zero out window Stems/Area (SPA) before summation.
  • Set Growth percent limit to 999.9 for format restrictions.
  • Show Mai/Pai graph for total age unless by calendar year.R
  • Revise clumpiness algorithm in stem map procedure.
  • Fill SPA(500,500) both ways for random thinning selection.
  • Use CSI basal area ratio weighting by distance (mod. Hegyi)
  • Verify comparisons to SPS Version 2.1 and Bulletin 201.

1981: 3.X

  • Computer simulation of tree and stand growth dynamics on a periodic basis using Boris Zeide’s two-point site curves.
  • This was an individual tree growth model using only stand-level measures of density (basal area, stand density index and Crown Competition Factor (CCF)).

1975: 2.X

  • Computer simulation of individual tree growth dynamics including both tree and stand level statistics on periodic basis.
  • Growth model increment in 20-foot height steps looking backward for number of years by site class to achieve growth step.
  • Growth model was internal Weyerhaeuser Growth Simulator project to validate High Yield Forest – Target Forest Yield projections.
  • Individual trees could be in any spatial configuration from uniform to random to clumped using individual tree density.


1972: 1.X

  • Computer simulation of individual tree growth dynamics including both tree and stand level statistics on annual basis.
  • Growth model increment is in one year steps displaying entire bole and crown profile.
  • Growth model was PhD thesis project.
  • All trees were assumed to be uniformly spatially distributed.