Rule Ordering Considerations when Editing Landscapes

Be deliberate in the rules you apply when editing landscapes. Edit rules are applied differently in IFTDSS depending on whether the rule is a Default Fuels Treatment / Disturbance Edit Rule or a User Created Edit Rule. Background on this is summarized at the bottom of this page and in the Rule Technical Documentation topic, but first we’ll present each rule and give some examples of how they apply to various fuels planning scenarios.

After applying rules to a given landscape you should always validate that your changes have been made as you intended. If you are unsure of the effect of the rules you apply, consider saving a version of your landscape after each edit to allow for easy comparison of the changes made by each edit rule you apply.

Applying Default Fuels Treatment / Disturbance Edit Rules

Default Fuels Treatment / Disturbance Rules are applied based on the order in which you add them to your editing session. If multiple Default Fuels Treatment / Disturbance Rules are used within one editing session, they are applied sequentially, meaning that the output from Rule 1 is the input for Rule 2, etc.

See Examples of Applying Default Fuels Treatment/ Disturbance Edit Rules

Rule behavior and example for Default Fuels Treatment/Disturbance edits.
Rule	Example
Default Fuels Treatment / Disturbance Rules are applied based on the order in which you add them to your editing session. If multiple Default Fuels Treatment / Disturbance Rules are used within one editing session, they are applied sequentially, meaning that the output from Rule 1 is the input for Rule 2, etc.	You want to represent a thin, followed by a prescribed fire. To do this, first create and add a rule to thin (Rule 1), then create and add a rule for a low severity wildland fire in the same editing session (Rule 2).

Applying User Created Edit Rules

A specific attribute for a given cell can only be changed once per editing session. It is the first edit of an attribute for a cell that affects the change. Subsequent rules that prescribe changes to a cell that has already been changed by a previous rule in the same editing session are ignored.
Attributes are considered separately when applying User Created Edit rules. For example, a rule that modifies fuel model for a particular cell does not preclude canopy cover or another fuel attribute from being modified by a subsequent rule.
When applying multiple User Created Edit Rules, the selection criteria cannot be contingent on another change that is being made in the same editing session.

See examples of applying User Created Edit Rules

Rule behavior and examples for user created rules.
Rule	Example
A specific attribute for a given cell can only be changed once per editing session. It is the first edit of an attribute for a cell that affects the change. Subsequent rules that prescribe changes to a cell that has already been changed by a previous rule in the same editing session are ignored.	You have a landscape with a treatment unit that overlaps with a Northern Spotted Owl activity center. You’d like to change the fuel model within one of the treatment units from TU5 to TL9 and within the activity center from TU1 to TU5. Within the area of overlap between the activity center and treatment unit, the fuel model change listed first in the editing session will be retained.
Attributes are considered separately when applying User Created Edit rules. For example, a rule that modifies fuel model for a particular cell does not preclude canopy cover or another fuel attribute from being modified by a subsequent rule.	Across your landscape you would like to change all of the area shown as fuel model GS2 to fuel model TU1 and make changes to the canopy characteristics. A user created edit rule that only changes GS2 cells to TU1 will still leave all the GS2 canopy data. To change the fuel model and canopy data, specify GS2 as the attribute you would like to change, select TU1 as the attribute you would like to replace it with, then use the + add row button to add canopy attributes and specify your chosen values for them.
When applying multiple User Created Edit Rules, the selection criteria cannot be contingent on another change that is being made in the same editing session.	An edit session contains User Created Edit Rules to set fuel model GS2 to TU5, then edit the canopy base height to 1 meter for TU5. The result will be all original GS2 set to TU5, but these newly set TU5s will still have the original GS2 canopy base height, the 1 meter canopy base height is applied to all the original TU5s.

Applying Both Default and User Created Rules

Default Fuels Treatment/Disturbance Edit rules are always applied first, followed by User Created Edit rules.
When Default Fuels Treatment / Disturbance Edit rules and User Created Edit rules are applied to areas that do not spatially overlap (i.e., are applied to spatially distinct Landscape Masks) all rules will be retained.
When Default Fuels Treatment / Disturbance Edit rules and User Created Edit rules are applied in separate editing sessions, the outputs resulting from the first editing session will become the inputs to the next editing session

See examples of applying both Default and User Created Rules

Rule behavior and examples when default and user created rules are mixed.
Rule	Example
Default Fuels Treatment/Disturbance Edit rules are always applied first, followed by User Created Edit rules.	You want to change fuel model TU1 to fuel model TU5 in your landscape, then run a high severity wildfire. IFTDSS will reorder your rules so that the wildfire is implemented first, then if the fire resulted in any fuel model TU1s they will be changed to TU5s. The effect of fuel model TU5 is not incorporated into the high severity wildfire scenario. If this is your intention, this would need to occur in two separate edit sessions
When Default Fuels Treatment / Disturbance Edit rules and User Created Edit rules are applied to areas that do not spatially overlap (i.e., are applied to spatially distinct Landscape Masks) all rules will be retained.	You want to thin/masticate in one unit and change fuel model TU5 to TL9 in another unit. This is accomplished by applying the Default Rule, thin/masticate, to one landscape mask and applying a User Created Edit Rule that changes fuel model TU5 to TL9 to another landscape mask within one editing session in the Landscape Edit or Develop Treatment Alternatives dialogues.
When Default Fuels Treatment / Disturbance Edit rules and User Created Edit rules are applied in separate editing sessions, the outputs resulting from the first editing session will become the inputs to the next editing session	You decide to lightly thin/pile burn your landscape. After looking at the results, you then decide to apply a low intensity wildfire (prescribed fire). The landscape resulting from the thin/pile burn will become the inputs to low intensity prescribed fire.

Rule Ordering Background (full documentation available in the (Editing Rule technical documentation)

It is important to understand the intricacies of how landscape edit rules are applied to a landscape. There are 2 ways in which landscape edits are implemented on the landscape. The first is the Default Fuels Treatment / Disturbance Edit rules that use the LANDFIRE Lookup (LFLU) and Fuel Model Lookup (FMLU) tables. The second is User Created Edit Rules. Rules are applied top to bottom in the list, first by Default Fuels Treatment / Disturbance Edit rules, then by User Created Edit Rules. The Default Fuels Treatment / Disturbance Edit rules are ALWAYS applied BEFORE the user define User Created Edit Rules.

The LFLU tables can only be used when Existing Vegetation Type (EVT), Existing Vegetation Height (EVH), and Existing Vegetation Cover (EVC) are present in your landscape data, as this is what is used for conversion in the LFLU tables based on the type, intensity and timing of treatment and disturbance. When a user applies a User Created Edit Rule that modifies the fuel model, stand height or canopy cover for a given landscape cell, the EVT, EVH, and EVC are set to 0 for that cell, which precludes the use of LFLU for future edits. Since LFLU can no longer be used the IFTDSS team has developed a second set of lookup tables called the Fuel Model Lookup (FMLU) tables . The FMLU tables are less accurate because they are a generalization of the LFLU tables. This generalization was necessary because there are many more values for EVT than there are Fuel Models (for more detail, see Editing Rule Technical Documentation).

The actual effect of the rules do differ between Default Fuels Treatment / Disturbance Edit rules and User Created Edit Rules. For Default Fuels Treatment / Disturbance Edit rules, note that the output (if any) from the previous rule is always the input to the next rule in the list. When starting to apply User Created Edit Rules the first fuel model attribute change applied to a cell is the edit that will be reflected in the resultant landscape. It’s important to note that each fuel attribute (fuel model, canopy cover, canopy height, canopy bulk density, and canopy base height) for a cell is treated separately, so although a cell may be locked due to an edit for fuel model, any of the other attributes may be modified by a subsequent rule.

Once your rules are defined and ordered correctly, you need to make sure that your resulting landscape reflects your intended changes.