DFSIM with Economics

Version 1.4

DFSIM (Douglas-fir Simulator) is a managed stand growth and yield simulator for coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii). It was developed in the 1980s from remeasured plot data contributed by many organizations in the Pacific Northwest. It is designed to project the development of stand with at least 80 percent basal area in Douglas-fir and produces yield tables for managed stands with include the effects of initial spacing, precommercial thinning, commercial thinning and fertilization. The DFSIM model also contains an economics option that allows users to estimate present net worth of the simulated regime.

Downloading and Installing DFSIM

Download DFSIM version 1.4

Download the file DFSIM14.ZIP above and place it into a folder. The DFSIM model and associated files are downloaded as a small ZIP (compressed file) that is about 150K in size. The files can be uncompressed with available programs such as WINZIP (http://www.winzip.com) and the contents copied into a DFSIM folder

Running DFSIM

The DFSIM model is a DOS program so needs to be run from a DOS window. In Windows 2000, for example, use the "Start" button and select "Programs", "Accessories" and "Command Prompt". You can then navigate to the folder where DFSIM is stored by using the CD (Change Directory command). If DFSIM were in a DFSIM folder:

c:\WINNT\System32>cd\
c:>cd dfsim

To run dfsim:

1. Make the DFSIM input file by running the SIMIN2 program:

c:>DFSIM>simin2

2. Run DFSIM

c:\DFSIM>dfsim

By default the output goes to the screen. You can send it to an output file by running it this way:

c:\DFSIM>dfsim > outfile

where "outfile" is the output file name of our choice.

Changes from version 1.3

· Allows simulations to begin with as few as 75 trees per acre.
· Provides for simulations beyond 100 years.
· Thinning will not be done if trees per acre are less than 50.
· All stand statistics for BH ages less than 84 years are the same as version 1.3, but for ages 84 years and above the mortality estimates are adjusted to require asymptotic relative densities.
· Lorey's height has been removed from the output tables.

DFSIM References

Curtis, R.O.; Clendenen, G.W.; DeMars, D.J. 1981. A New Stand Simulator for Coastal Douglas-fir: DFSIM user's guide. USDA Forest Service, Pacific Northwest Forest and Range Experiment Station, Portland, OR. General Technical Report PNW-GTR-128. 79 p.

DFSIM (Douglas-fir Simulator) is a new managed stand simulation program for coast Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii. It was developed from remeasured plot data contributed by many organizations in the Pacific Northwest. DFSIM is based on more extensive data and is considerably more flexible than previous whole-stand simulators for the species. It produces yield tables for managed stands which included estimates of effects of initial spacing, precommercial thinning and commercial thinning, and nitrogen fertilization. Topics discussed include basic data, simulator construction and operation, limitations of the program, and potential for future development. The program is available from the authors on request. A subsequent publication will present DFSIM yield tables for a number of management regimes.

Curtis, R.O.; Clendenen, G.W.; Reukema, D.L.; DeMars, D.J. 1982. Yield Tables for Managed Stands of Coastal Douglas-fir. USDA Forest Service, Pacific Northwest Forest and Range Experiment Station, Portland, OR. General Technical Report PNW-GTR-135. 182 p.

Yield tables generated by the stand simulation program DFSIM (Douglas-fir Simulator) are presented for a number of possible management regimes. These include "normal" yield tables for stands planted or precommercially thinned to 300 and 400 trees per acre; tables for commercially thinned stands with and without prior commercial thinnings; and tables illustrating the effect of fertilization with nitrogen. Guides are presented for number of trees to be planted or left after precommercial thinning and expected time of first commercial thinning.

Curtis, R.O. 1987. Levels-of-Growing-Stock-Cooperative Study in Douglas-fir: Report No. 9 - Some comparisons of DFSIM estimates with growth in the levels-of-growing-stock study. USDA Forest Service, Pacific Northwest Forest and Range Experiment Station, Portland, OR. Research Paper PNW-RP-376. 34 p.

Initial stand statistics for the levels-of-growing-stock installations were projected by the Douglas-fir stand simulation program (DFSIM) over the available periods of observation. Estimates were compared with observed volume and basal area growth, diameter change, and mortality. Overall agreement was reasonably good, although results indicate some biases and a need for revision of the upper density limit in the DFSIM program.

Fight, R.D.; Chittester, J.M.; Clendenen, G.W. 1984. DFSIM With Economics: A financial analysis option for the DFSIM Douglas-fir Simulator. USDA Forest Service, Pacific Northwest Forest and Range Experiment Station, Portland, OR. General Technical Report PNW-GTR-175. 22 p.

A modified version of the DFSIM Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) growth and yield simulator, DFSIM WITH ECONOMICS, now has an economics option that allows users to estimate present net worth at the same time a silvicultural regime is simulated. If desired, the economics option will apply a volume adjustment multiplier in yields used in the analysis to reflect application of small-plot research results to average operating conditions or to account for genetics or other local conditions. It can also account for salvage of mortality. Prices can be entered as a table of values or as an equation that can vary with diameter. Logging costs can be entered as a table or can be generated internally for a short-span cable system. Logging costs can vary by diameter and volume harvested. Other harvest-related costs can be included on a per acre bases and also on a unit volume basis. Prices and costs can be trended using an annual percentage rate of change that is applied for a 50-year period.

 

For Additional Information

David D. Marshall
USDA Forest Service
Pacific Northwest Research Station
Olympia Forestry Sciences Laboratory
3625 93rd Avenue SW
Olympia, WA 98512
360-753-7673
dmarshall@fs.fed.us