NetLogo Models Library:
IABM Textbook/chapter 3/Fire Extensions

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Fire Simple Extension 1

If you download the NetLogo application, this model is included. You can also Try running it in NetLogo Web

ACKNOWLEDGMENT

This model is from Chapter Three of the book "Introduction to Agent-Based Modeling: Modeling Natural, Social and Engineered Complex Systems with NetLogo", by Uri Wilensky & William Rand.

• Wilensky, U. & Rand, W. (2015). Introduction to Agent-Based Modeling: Modeling Natural, Social and Engineered Complex Systems with NetLogo. Cambridge, MA. MIT Press.

This model is in the IABM Textbook folder of the NetLogo Models Library. The model, as well as any updates to the model, can also be found on the textbook website: http://www.intro-to-abm.com/.

WHAT IS IT?

This project simulates the spread of a fire through a forest. It shows that the fire's chance of reaching the right edge of the forest depends critically on the density of trees. This is an example of a common feature of complex systems, the presence of a non-linear threshold or critical parameter. This model extends the Fire Simple model by adding a PROBABILITY-OF-SPREAD.

HOW IT WORKS

The fire starts on the left edge of the forest, and spreads to neighboring trees. The fire spreads in four directions: north, east, south, and west.

Unlike the original model, this model allows the user to modify the PROBABILITY-OF-SPREAD. As a result, the spread of the fire is probabilistic and affected by this slider.

HOW TO USE IT

Click the SETUP button to set up the trees (green) and fire (red on the left-hand side).

Click the GO button to start the simulation.

The DENSITY slider controls the density of trees in the forest. (Note: Changes in the DENSITY slider do not take effect until the next SETUP.)

The PROBABILITY-OF-SPREAD slider affects how the fire spreads from patch to patch.

THINGS TO NOTICE

Compare this model to the FIRE-SIMPLE model. When the PROBABILITY-OF-SPREAD is low, how are the results different? When the PROBABILITY-OF-SPREAD is high how are the results different?

THINGS TO TRY

Try setting up and running a BehaviorSpace experiment (see Tools menu) altering the PROBABILITY-OF-SPREAD to analyze the percent burned at different tree density levels.

What is the difference between 100% density and 55% probability-of-spread, and 55% density and 100% probability-of-spread? Why do those yield so different results?

RELATED MODELS

Fire Simple, Fire, Percolation, Rumor Mill

CREDITS AND REFERENCES

This model is a simplified version of:

• Wilensky, U. (1997). NetLogo Fire model. http://ccl.northwestern.edu/netlogo/models/Fire. Center for Connected Learning and Computer-Based Modeling, Northwestern University, Evanston, IL.

HOW TO CITE

This model is part of the textbook, “Introduction to Agent-Based Modeling: Modeling Natural, Social and Engineered Complex Systems with NetLogo.”

If you mention this model or the NetLogo software in a publication, we ask that you include the citations below.

For the model itself:

• Wilensky, U. (2006). NetLogo Fire Simple Extension 1 model. http://ccl.northwestern.edu/netlogo/models/FireSimpleExtension1. Center for Connected Learning and Computer-Based Modeling, Northwestern Institute on Complex Systems, Northwestern University, Evanston, IL.

Please cite the NetLogo software as:

• Wilensky, U. (1999). NetLogo. http://ccl.northwestern.edu/netlogo/. Center for Connected Learning and Computer-Based Modeling, Northwestern University, Evanston, IL.

Please cite the textbook as:

• Wilensky, U. & Rand, W. (2015). Introduction to Agent-Based Modeling: Modeling Natural, Social and Engineered Complex Systems with NetLogo. Cambridge, MA. MIT Press.

COPYRIGHT AND LICENSE

Copyright 2006 Uri Wilensky.

This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License. To view a copy of this license, visit https://creativecommons.org/licenses/by-nc-sa/3.0/ or send a letter to Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA.

Commercial licenses are also available. To inquire about commercial licenses, please contact Uri Wilensky at uri@northwestern.edu.

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