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Why do I get strange aspen growth predictions when I enter data that
includes trees with diameters less than 9.1 cm?
The aspen growth model is for trees 9.1 cm and above. Model predictions
are unstable for aspen trees less than 9.1 cm. Avoid inputting
trees below this threshold.
Can STIM be installed on a central server to be used by multiple
users over a network?
No, it cannot. STIM currently has to be loaded onto each user's
PC.
After I have grown a stand to age 90, for example, can I 'backup'
to age 45 and grow it again with different parameters?
No, you can only grow a stand forward from the current age, i.e., the
last record in the yield output window. You must generate an identical
new stand, then grow it to age 45 before you can change the parameters
of interest.
Are there any plans to calibrate STIM for other species or treatments?
The Canadian Forest Service developed the hemlock and trembling aspen
models and subsequently transferred the models to the Ministry of Forests.
The Ministry currently has no plans for further STIM developments, but
it is giving consideration to STIM as it continues to develop a growth
and yield modelling strategy for BC.
Each model has on-line help accessible from within the Windows interface.
The on-line help virtually duplicates the hardcopy manual. The manuals:
are available for download in electronic format from our Growth
and Yield Software Registration and Download page
For more information about STIM see pubs/References
Current the Ministry resources only provide for distribution services.
Resources for user support services and staff familiarity with the models
are minimal but we will try to answer user questions to the extent that
we are able. Direct questions to: Mario
Di Lucca.
In addition, the private consultant (Jim
Flewelling) who was involved with the original development of these
models is willing to answer questions about model construction and behavior
(please note that he receives no payment from the Ministry for this).
Currently no STIM training is available
Bonnor, G.M; R.J. De Jong; P. Boudewyn and J.W. Flewelling. 1995. A
guide to the STIM growth Model. Canadian Forest Service,
Pacific Yukon Region, Information Report BC-X-353. 38 pp.
De Jong, R.J.; A. A. Zumrawi; P. Boudewyn and J.W. Flewelling. 1995.
STIM User's Manual (for
Windows) Ver 2.2a (Hemlock) FRDA Report No. 237. 25 pp.
De Jong, R.J.; A. A. Zumrawi; P. Boudewyn and J.W. Flewelling.1996.
STIM User's Manual (for
trembling aspen) Ver 3.0 FRDA Report No. 253. 25 pp.
Forest Productivity Councils of British Columbia, 1991. A
guide to growth and Yield Models of the Pacific Northwest, British
Columbia Ministry of Forests, Inventory Branch, Victoria, 25 pp.
Hynk, D.M.; Scott, W.; Leon, R.M. 1988. Some important aspects in
the development of a managed stand growth model for western hemlock.
In. A.R. Ek; S.R. Shifley; and T.E. Burk, Eds. Forest Growth Modelling
and Prediction, USDA For. Serv., Gen. Tech. Rep. NC-120. pp. 9-21.
Snowdon, B.D. 1995. An evaluation of STIM, a western hemlock growth
model, using WinTIPSY as a benchmark. British Columbia Ministry
of Forests, Silviculture Branch, Unpublished. Report, Victoria, 35 pp.
Hardcopies of all four STIM related reports mentioned above can be
requested from: Publications, Canadian Forest Service, Pacific
Forestry Centre, 506 West Burnside Road, Victoria, B.C. V8X
1M5.
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