1. General Model Information

Name: Valentine's Pipe Model


Main medium: terrestrial
Main subject: forestry
Organization level: organism, population, biocoenosis
Type of model: not specified, ordinary differential equations
Main application:
Keywords: forest, growth simulation, carbon balance, stand growth, pipe-model, self thinning rule, loblolly pine, silviculture, pruning


Dr. Harry T. Valentine
Northeastern Forest Experiment Station
Louis C. Wyman Forestry Sciences Lab
271 Mast Road
PO Box 640
Durham, NH 03824-9799

Phone: 603- 868-7671
Fax: 603-868- 7604
email: hvalentine/ne_du@fs.fed.us
Homepage: http://svinet2.fs.fed.us:80/ne/durham/4104/people/valentine.html



Source of abstract: Pipestem homepage, USDA Forest Service, Northeastern Research Station

Pipestem is a model of carbon allocation and growth that applies to even-aged, mono-specific stands of trees. A detailed description of Version 2 of the model can be found in Canadian Journal of Forest Research, 27:817-830 (1997). Pipestem has been calibrated for loblolly pine in Virginia and North Carolina.

Pipestem projects the growth and development of a model stand over time. The rate of growth of the model stand is defined as the difference between the rates of production and loss of dry matter. Dry matter is measured in units of carbon (C) and the rate of growth per unit land area is measured in units of C/ha/year. The rate of production of dry matter is defined as the difference between the rate of production of C substrate and the rate of consumption of C substrate through maintenance and constructive respiration. These metabolic rates also have dimensions of units of C/ha/year. Version 2.2 affords yearly adjustment of the rate of production of C substrate to account for the increasing concentration of atmospheric carbon dioxide.

Dry matter is divided into foliar, fine-root, and woody components. Carbon-allocation rules based on pipe-model theory are used to divide the dry-matter production into new foliar, fine-root, woody-root, and woody-stem tissue in proper proportions for functional balance. Losses of dry matter result from the turnover of foliage and fine roots, the death and self-pruning of branches associated with crown rise, and the death of trees associated with self-thinning. The latter two processes are driven by the production of dry matter. Version 2.2 affords the removal of dry matter through silvicultural thinning and pruning.

In addition to information about the carbon balance and the production of loss of dry matter, Pipestem also furnishes total basal area (m^2/ha), average tree height (m), average height to the base of a crown (m), and tree density (1/ha) on an annual basis. Estimates or measurements of these four variables (ordinarily obtained from a real stand of age one or older) suffice to initialize the model. Version 2.2 furnishes dominant tree height in addition to the other variables.

Version 2 of Pipestem runs under DOS and Windows 3.1, 95, and NT. Version 2.2 runs under Windows 95 and NT. The kernel of the model also is available as a Fortran subroutine for incorporation into other programs.

II. Technical Information

II.1 Executables:

Operating System(s): Version 2 of Pipestem runs under DOS and Windows 3.1, 95, and NT. Version 2.2 runs under Windows 95 and NT. The kernel of the model also is available as a Fortran subroutine for incorporation into other programs.

II.2 Source-code:

Programming Language(s): FORTRAN (Microsoft)
Pipestem download page: http://www.fs.fed.us/ne/durham/4104/products/products.htm

II.3 Manuals:

II.4 Data:

III. Mathematical Information

III.1 Mathematics

III.2 Quantities

III.2.1 Input

III.2.2 Output

IV. References

Valentine, H.T.; T.G. Gregoire; H.E. Burkhart and D.Y. Hollinger 1997. A stand-level model of carbon allocation and growth, calibrated for loblolly pine. Canadian Journal of Forest Research 27:817-830 (1997).
Valentine, H.T.; T.G. Gregoire; H.E. Burkhart and D.Y. Hollinger 1997. Projections of growth of a loblolly pine stand under elevated temperatures and carbon dioxide. pp 341-352. In: The Productivity and Sustainability of Southern Forest Ecosystems in a Changing Environment. Edited by R.A. Mickler and S. Fox. Springer-Verlag, Ecological Studies Series 128, (1997)
Valentine, H.T. 1997 Height growth, site index, and carbon metabolism. Silva Fennica 31:3, 251-263 (1997)
Robinson, A.P., T.G. Gregoire, and H.T. Valentine 1997. Cut-off importance sampling of bole volume. Silva Fennica 31:2, 153-160 (1997)
Gregoire, T.G. and H.T. Valentine 1996. Sampling methods to estimate stem length and surface area of tropical tree species. Forest Ecology and Management 83:229-235
Gregoire, T.G.; H.T. Valentine and G.M. Furnival 1995. Sampling methods to estimate foliage and other characteristics of individual trees. Ecology 76:4, 1181-1194 (1995)
Gregoire,T.G. and H.T. Valentine 1995. A sampling strategy to estimate the area and perimeter of irregularly shaped planar regions. Forest Science 41:3, 470-476 (1995)
Valentine, H.T.; A.R. Ludlow and G.M. Furnival 1994. Modeling crown rise in even-aged stands of Sitka spruce or loblolly pine. Forest Ecology and Management 69:189-197 (1994)
Valentine, H.T.; V.C. Baldwin, Jr.; T.G. Gregoire and H.E. Burkhart 1994. Surrogates of foliar dry matter in loblolly pine. Forest Science 40:576-585 (1994)
Valentine, H.T., G.M. Furnival, and T.G. Gregoire 1991. Confidence intervals from single observations in forest research. Forest Science 37:1, 370-373 (1991)
Valentine, H. 1988. A Carbon-balance Model of Stand Growth: a Derivation Employing Pipe-Model Theory and the Self-thinning Rule. Annals of Botany 62, 389-396.
Valentine, H. 1985.Tree growth models: Derivations employing the pipe-model theory. Journal of Theoretical Biology 117, 579-585.
Valentine, H. 1987. A Carbon-Balance Model of Stand Growth: A Derivation Employing the Pipe-Model Theory and the Self Thinning Rule. IIASA WP-87-056 .

V. Further information in the World-Wide-Web

VI. Additional remarks

V. This model could be used to study the effects of pollution and other elements of global change on foliage which alters the rate of substrate production, and acidifying soils on feeder root turnover.

Similar ideas as in Valentine´s model are employed in the tree and stand growth models SIMFORG and TRAGIC

Last review of this document by: Juergen Bierwirth Tue Feb 23 16:31:15 CET 1999
Status of the document:
last modified by Tobias Gabele Wed Aug 21 21:44:47 CEST 2002

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