The source code to the PnET terrestrial ecosystem model is open and freely downloadable. As it has, and continues to be, developed with public funds we feel that it is our obligation to make it available to the community. We hope this approach has the additional benefit of fostering community development of the model. We do ask that any professional presentations and papers which use PnET reference the original authors of the model.

The suite of PnET models (PnET-Day, PnET-II， PnET-CN，PnET-Daily, and PnET-SOM) are available in different source code versions. The original version of the model is programmed in Visual Basic. It has a graphical user interface and makes an excellent teaching tool. This version of the model runs natively on Windows platforms.

We have also developed a new version of the model in the MATLAB programming language. As the MATLAB environment provides I/O operations and graphics together with data and statistical analysis tools, our hope is that the PnET code can be simplified and become more flexible in the handling of each simulation or experiment's specific requirements. MATLAB is available for Windows, Macintosh and Linux.

PnET-BGC is an extention to PnET-II, developed at Charlie Driscoll's lab at Syracuse University, which adds element cycling and interaction in the soil and provides estimates of these solutes in water runoff. This fork of the PnET model is based on the Visual Basic code base. External Link References and download information can be found here.

PnET-Database is an Excel file compilation of PnET applications from literature. This compilation can facilitate new users to learn and run PnET as a reference and developers to do model comparisons to improve PnET. A database framework has been created and a dozens of cases have been already entered into the database. We will update the compilation periodically. PnET users and developers are encouraged to contribute their own data into it.