USDA Forest Service

Pacific Southwest Research Station
Pacific Southwest
Research Station

800 Buchanan Street
Albany, CA 94710-0011
(510) 883-8830
United States Department of Agriculture Forest Service. USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.

Research Topics Forest Management

About this Research:
Participating Programs
  • Ritchie, Martin W.; Powers, Robert F. 1993. User's guide for SYSTUM-1 (Version 2.0): A simulator of growth trends in young stands under management in California and Oregon. Gen. Tech. Rep. PSW-147. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. 45 p.
Related Links



SYSTUM-1 is a prototype simulator designed to simulate growth of young plantations in northern California and southern Oregon (Ritchie and Powers 1993-1.4MB). This is the result of a cooperative effort to produce a simulator geared towards young stand forecasts and the particular problems presented in simulating systems with both trees and shrubs. Data for parameter estimation were provided by private landowners, as well as the Forest Service and Bureau of Land Management.

Current Version Number:2.14 Download Now (281 K)
Note: Version 2.14 might require administrative privledges to run correctly depending on your operating system. Contact Martin W. Ritchie with questions. If the download works correctly it will install the associated files under "C:\systum1" - folder.

Requirements: This is a legacy program which operates under DOS. User's must open a DOS window to operate. The software is no longer being updated.

Changes from Version 2.02 to Version 2.14:Version 2.14 has an option to output 3 different FVS-type files: WESSIN, SORNEC, and Klamath. The only differences between these three different files is in the species conversions. The actual format of the file is the same regardless of the variant of FVS.

The read format for these files is:

  1. Plot number........................... I4
  2. Record number......................... I3
  3. Expansion factor (trees per acre)... F6.0
  4. Tree history (always 1)............... I1
  5. Species Code (two letter char.)....... A3
  6. Diameter at breast height (inches).. F4.1
  7. Total tree height (feet)............ F3.0
  8. Crown Ratio Code (integer 1-9)........ I1

A companion file is also written out with the FVS treelist file. This companion file is a FVS keyword file and it contains the basic keywords necessary for a FVS run. It is likely that the user will need to modify this file for an actual run with the user's specification. I recommend that users specify the file name with an extension of .KEY.

We have also modified the default SDI maximum for ponderosa pine to 365.

Additional Downloads

SYSTUM-1 DLL Download DLL Now
Note: Users of the DLL are on their own; we do not provide any support for users of the DLL. The DLL was created by Jeff Hamann at Oregon State University. The DLL self-extracting zip file includes a spreadsheet with an example macro for executing the simulator. The DLL files should be placed in the Windows System directory. The spreadsheet should be placed in some working directory where the user has data presumably.


Martin W. Ritchie
Last Modified: Jun 1, 2018 11:45:33 AM