Glossary of wildfire hazard and risk (2019)
This glossary of wildfire hazard and risk terminology is maintained by Pyrologix. Initial development of an earlier version was assisted by Matthew P. Thompson at the Rocky Mountain Research Station.

Understanding stochastic wildfire simulation results (2014)
This document provides awareness-level information about stochastic wildfire simulation systems by describing their inputs and outputs, along with a simplified description of how they work. This report was prepared by Joe Scott of Pyrologix for the USDA Forest Service Washington Office.

Summarizing contemporary large-fire occurrence for land and resource management planning (2014)
When it comes to wildfire management planning, the recent past may be a guide to the near future. This whitepaper describes an analysis process for summarizing contemporary historical wildfire occurrence for a designated portion of the landscape. This document was prepared by Joe Scott of Pyrologix for the USDA Forest Service Washington Office.

Introduction to Fire Behavior Modeling (2012)
This report provides a foundation upon which to build fire behavior modeling experience gained during an apprenticeship under a master or journey-level fire behavior modeler.

Fuel model help file
This document is a compiled help file (.chm). Save it to your computer and then simply double-click on the NewFuelModels.chm file to open it. Modern versions of Windows may require an extra step to properly view the help file. If you are having trouble opening the file once it’s been downloaded, refer to this Microsoft Help page.

The help file describes characteristics of the new fuel model set, its development, and its relationship to the original set of 13 fire behavior fuel models. To assist with transition to using the new fuel models, a fuel model selection guide, fuel model crosswalk, and set of fuel model photos are provided. The content of the help file mirrors the related General Technical Report.

Updated spreadsheet for comparing fuel models (2023.1) 
Although the original CompareModelsFour.xls spreadsheet continues to serve its purpose of simply comparing the fire behavior predicted for different fuel models, our public and private sector colleagues asked for a few additional features, which are now incorporated into this “S495” version. These added features include: the inclusion of fuel model numbers in addition to fuel model codes, the addition of a simple model of wind adjustment factor for each fuel model or for different canopy cover values, conversion of the X-axis to the 20-ft wind speed from the midflame height, and the inclusion of Rothermel’s crown fire rate of spread as a “fuel model” on the chart. An intrepid user will also be able to add custom fuel models to the list.

In 2022 an update to Microsoft Excel caused the drop-down lists to behave poorly. The _2023.1 version linked above works around that issue by moving the graph to a regular worksheet rather than a dedicated graph page.

Nexus 2.1

NEXUS 2.1 is crown fire hazard assessment software that links separate models of surface and crown fire behavior to calculate indices of relative crown fire potential. Use NEXUS to compare crown fire potential for different forest stands, and to compare the effects of alternative fuel treatments on crown fire potential. NEXUS includes several visual tools useful in understanding how the operational surface and crown fire models used in the United States interact.

Crown fire hazard assessment and behavior prediction is an emerging science. In NEXUS we have linked existing models of surface and crown fire behavior to produce a system to assess the potential for crown fires at the stand level. In 1998 the modeling system was initially implemented in a Microsoft Excel spreadsheet. At the time the authors envisioned a short life-span for NEXUS as other more established programs incorporated similar modeling capabilities. In 2001 we updated the spreadsheet and produced an online user’s guide, but still did not envision a long life. In 2003, we obtained funding to re-code NEXUS as a stand-alone computer program, finally shedding the Excel spreadsheet interface. In 2014 the National Park Service funded the update of Nexus to version 2.1, enabling the software to work on computers running Windows 7 and 8 operating systems.

Installation file
The NEXUS2 installation file is nexus2.1.exe. Save this file to your machine and install from there; admin rights required. Alternatively, you may download the NEXUS21.zip archive which contains the installation program plus the associated readme.txt and releasenotes.txt files.

No Warranty
Because NEXUS 2.1 is licensed free of charge, there is no warranty for the program, to the extent permitted by applicable law. Except when otherwise stated in writing, the copyright holders and/or other parties provide the program “as is” without warranty of any kind, either expressed or implied, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose. The entire risk as to the quality and performance of the program is with you. Should the program prove defective, you assume the cost of all necessary servicing, repair, or correction.