1. General Model Information

Name: Photosynthesis and Evapotranspiration

Acronym: PNET

Main medium: air+terrestrial
Main subject: biogeochemistry, forestry
Organization level: landscape
Type of model: not specified
Main application:
Keywords: forest, leaf area, photosynthesis, transpiration,evapotranspiration, drainage, wood production, foliage productionfine roots production, generalized, lumped-parameter model, photosynthesis,evapotranspiration, net primary production


John D. Aber
Natural Resources Ph.D. Program
Forest Ecosystem Analysis
Complex Systems Research Center
Morse Hall
University of New Hampshire
Durham, NH 03824-3525

Fax: 603 862- 0188
email: john.aber@unh.edu
Homepage: http://www.aber.sr.unh.edu/



The PnET family of models provide a nested set of modular approaches to simulating the carbon, water and nitrogen dynamics of forest ecosystems. Though primarily a temperate forest canopy model, work is currently underway to generalize PnET and produce a simple, alternative model applicable to all terrestrial ecosystem types.

The current version is programmed in Visual Basic and uses a set of graphical user interfaces to allow easy access to data files required to run the models, and rapid development of new files for additional sites. The distribution package contains example files which will allow the user to run each version of the model using data acquired at the Harvard Forest and Hubbard Brook experimental forests and a subset of the VEMAP continental U.S. data.

Author of the abstract:

Complex Systems Research Center, University of New Hampshire

II. Technical Information

II.1 Executables:

Operating System(s): DOS

II.2 Source-code:

Programming Language(s): VISUAL BASIC

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

Aber, J.D., and C.A. Federer. 1992. A generalized, lumped-parameter model for photosynthesis,evapotranspiration and net primary production in temperate and boreal forest ecosystems. Oecologia (1992) 92: 463-474.

Aber, J.D., S.V. Ollinger, C.A. Federer, P.B. Reich, M.L. Goulden, D.W. Kicklighter, J.M. Melillo and R.G. Lathrop, Jr. 1995: Predicting the effects of climate change on water Yield and Forest Production in the Northeastern U.S. Climate Research, 5:207-222.
(PnET II: Introduction to the monthly time-step foliar nitrogen driven version of PnET.P )

Aber, J.D., Reich and M.L. Goulden 1996: Extrapolating leaf CO2 exchange to the canopy: a generalized model of forest photosynthesis validated by eddy correlation. Oecologia, 106:257-265.
( Description of the intantaneous, daily time-step version of PnET. )

Aber, J.D., S.V. Ollinger, C.A. Federer and C. Driscoll. 1997: Modeling nitrogen saturation in forest ecosystems in response to land use and atmospheric deposition. Ecological Modelling, 101:61-78.
( Description of the monthly time-step version of PnET which includes a complete nitrogen cycle. )

V. Further information in the World-Wide-Web

VI. Additional remarks

Global change implications:The model has been used to study global climate change (Aber and Federer, 1992). This study found that elevated temperature and a 25% reduction in precipitation could increase water stress and reduce carbon storage. The PnET model was executed for ten temperate and boreal forest ecosystems in this study.
Last review of this document by: J. Bierwirth: 06. 03. 2001 -
Status of the document:
last modified by Tobias Gabele Wed Aug 21 21:44:47 CEST 2002

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