APPENDIX C – USE OF THE SIMPPLLE MODEL 

USE OF THE SIMPPLLE MODEL IN DEVELOPING RMP ALTERNATIVES 

General Overview 

Simulating Patterns and Processes at Landscape Scales 

(SIMPPLLE) is a computer modeling program that 

simulates vegetation patterns and processes emphasizing 

the dynamics of landscaped level change. It was 

developed for the USDA Forest Service, Region 1 as a 

management tool. SIMPPLLE’s purpose is to help 

provide an understanding of the dynamics of where 

processes will occur across a landscape. The SIMPPLLE 

model has been utilized by the Beaverhead-Deerlodge 

National Forest during their Forest Plan Revision and 

during the BLM’s Dillon Field Office Resource 

Management Plan revision. 

SIMPPLLE was selected for use by the Butte Field 

Office (BFO) because it is both spatially and temporal 

explicit, meaning that landscape level vegetation change 

can be explored in relation to location and neighboring 

vegetation communities, as well as change within these 

communities over time. The SIMPPLLE model was 

used to: (a) simulate future vegetation changes caused 

by various disturbance processes at multiple landscape 

scales, (b) show trends in vegetative communities over 

the next 50 years as a result of fire suppression, (c) 

simulate historic vegetative conditions by running the 

model over 500 years with variables such as fire, insect 

and disease activity, (d) simulate management treatment 

alternatives for their impact on disturbance processes 

and the attainment of desired conditions defined at the 

landscapes scale, and (e) to provide a basis for 

identifying the probability of disturbance processes and 

vegetation conditions. 

Vegetation Layer 

At the time the Resource Management Plan revision 

began the Butte Field Office lacked a current 

comprehensive GIS vegetation layer for the planning 

area. This vegetation layer was needed in order to 

determine the existing condition, calculate potential 

treatment acres and to conduct effects analysis. It was 

determined that the existing Forest Service Potential 

Natural Vegetation (PNV) layer was not adequate for 

our purposes due to the small size and scattered 

ownership of BLM lands within the planning area. 

A Vegetation Subgroup was established and tasked with 

creating this digital vegetation layer and using it to run 

the SIMPPLLE model. This subgroup consisted of 

seven members: two foresters, a wildlife biologist, a 

fire/fuels specialist, a soil scientist, a riparian/range/ 

special status plants specialist, and a GIS specialist. 

Ssurgo soil survey data was obtained from the Natural 

Resources Conservation Service (NRCS) for BLM 

managed and private lands within the Butte Field Office 

for Jefferson, Broadwater, Lewis and Clark, Gallatin, 

and Deerlodge counties. As a majority of these lands 

were determined to be grasslands it was assumed that 

potential vegetation was the same as the existing 

situation. As a result of Silver Bow County not having a 

completed Ssurgo soil survey completed the soil 

scientist for the Butte Field Office generated a 

vegetation map for the county based on his extensive 

knowledge of the area. Park County also did not have a 

published county soils survey, so a Potential Natural 

Vegetation coverage obtained from the US Forest 

Service (Fire Sciences Laboratory, Rocky Mountain 

Research Station, 2001) was used to fill in any data 

gaps. This data layer was also used to fill any data 

omissions on the Gallatin National Forest. 

Soil and vegetation data relating to national forest lands 

was obtained from both the Beaverhead-Deerlodge and 

Helena National Forests. Forest Service soil data was 

used in conjunction with Forest Service stand data to 

determine potential natural vegetation Forest Service 

timber stand data was merged with the county soil 

survey data. 

The county soil surveys lumped grassland and sagebrush 

habitat as grasslands. To map sagebrush habitat, our 

special status plants specialist created a map depicting 

sagebrush. Ssurgo soil survey data from NRCS for 

BLM and private lands in the Butte Field Office for 

Jefferson, Broadwater, Lewis and Clark, Gallatin, and 

Deerlodge Counties was queried for polygons which 

show big sagebrush as part of the characteristic 

vegetation. This map was then merged with the 

vegetation map the BFO Soil Scientist created for Silver 

Bow County. Professional knowledge and data collected 

by the Northwinds contractor were used to check and fill 

in gaps. Park county and Beaverhead county were not 

included due to incomplete soil survey data. 

The BLM has detailed forest stand data that was merged 

into the vegetation data. A crosswalk was developed to 

move the forest stand data from the existing database, 

Forest Vegetation Information System (FORVIS), to the 

vegetation coverage. The crosswalk included data for 

the following attributes: cover class, density, habitat 

type, size class, species type, dominant vegetation, and 

potential vegetation. This crosswalk then allowed data 

required to run the SIMPPLLE model to be extracted 

from the vegetation coverage. 

Butte Draft RMP/EIS 711 
Appendix C 

Encroachment for grasslands was mapped using 

orthophotos to run the model. Encroachment for 

sagebrush polygons was not mapped by the time the 

model was run (7/05) but was mapped in August, 2005 

in the vegetation coverage. Discuss how acres of 

treatment would be identified between encroachment in 

grassland and sagebrush. 

Agriculture, Urban and Mining lands were mapped 

using orthophotos for Deerlodge, Silver Bow, Jefferson, 

Lewis and Clark and Broadwater Counties and merged 

into the vegetation coverage. In Park and Gallatin 

Counties, agriculture lands were mapped using the FS 

Potential Natural Vegetation Grid. 

All polygons less than eight acres in size were merged 

with adjacent polygons. 

To run the SIMPPLLE Model, large polygons were 

broken down to polygons less than 250 acres in size. 

Insect and disease from the 2003 survey flights was 

provided by the Forest Service was added to the 

SIMPPLLE model database in an attempt to accurately 

represent the existing ground condition. The model was 

able to break out and summarize data for the 7 major 

watersheds in the field office. 

SIMPPLLE Process 

1. Gathering Data 

Jimmie Chew and Chris Stalling started working with 

the Butte Resource Management Plan group in 2003. 

Discussion at this first stage centered on the data 

requirements for running a landscape analysis using the 

SIMPPLLE model. Data needs for running SIMPPLLE 

included a GIS coverage (ArcInfo format with polygon 

topology), with attributes of species, size class, and 

density for each vegetation polygon, as well as some 

way to stratify the vegetation (i.e. habitat group). Other 

optional attributes that enhance SIMPPLLE simulations 

and representation of the landscape include land 

ownership, a code indicating the presence or absence of 

roads, fire management zones, prior landscape processes 

(i.e. insect disease and activity), and a “special area” 

field that can be filled with anything the user decides 

would help to logically represent the landscape. An 

ArcInfo Digital Elevation Model (DEM) for the same 

spatial extent as the vegetation coverage is necessary to 

create a neighbor file, which, when paired with a 

vegetation file derived from the ArcInfo coverage, loads 

into SIMPPLLE to create a landscape ready for 

simulation (a file with the .area extension). 

Managers must also consider the size of the area that 

will best represent their goals. Since SIMPPLLE is a 

landscape level, process driven, spatially explicit 

simulation model, vegetation as it is represented on the 

entire landscape will influence and be influenced by the 

processes that cause change over time and space. In 

order for all vegetation polygons to be included in 

SIMPPLLE simulations, a contiguous landscape must be 

used with all polygons populated with vegetation 

information including water and nonforest conditions 

including rock and agriculture. This initial datagathering step was accomplished by the Butte Field 

Office (BFO) working with a contractor, Dave Highness 

from Tetra Tech. 

2. Cross-walk and Data Loading 

Once the BFO had pulled this information together and 

discussed the approach to building a cross-walk from 

their data into SIMPPLLE attributes with Chris Stalling, 

they put together their first cut. The SIMPPLLE User’s 

Guide describes the attributes and can be downloaded 

from 

http://www.fs.fed.us/rm/ecology/publications/simpplle/. 

Several errors were found by BFO personnel, and they 

worked through editing and resolving these errors with 

Chris Stalling. Errors are expected to be found a 

majority of the time following a cross-walk to 

SIMPPLLE attributes; the cross-walk is iterative and 

subject to expert knowledge of the most likely 

vegetation expected at specific locations on the 

landscape. Once the initial vegetation attributes were 

examined by the BFO, discussion followed with Jimmie 

Chew and Chris Stalling about whether specific 

vegetation pathways should be developed for the Butte 

landscape in order to improve model behavior; several 

nonforest pathways were then adjusted. 

Analysis of initial model behavior was accomplished by 

considering the landscape as current and looking at 

vegetation change over several decades, or time-steps, as 

they are represented in the SIMPPLLE environment. 

Further analysis was accomplished on a representation 

of historical landscape conditions by running 

simulations out for several hundred years without fire 

suppression and then saving the “new” landscape as one 

example of the historical Butte landscape. From this new 

starting point, SIMPPLLE simulations were run and the 

output was compared to that obtained from the current 

condition. Users have the option to make multiple 

landscape representations so that various approaches to 

stratification can be tested such as breaking the 

landscape by ownership, or by differences in the special 

area field. 

3. Adjusting the Vegetation 

An initial iteration of a SIMPPLLE landscape 

representation provides managers with the opportunity 

to consider how well the vegetation is being modeled. 

Further adjustment of vegetation states as well as other 

aspects of vegetation change was accomplished by the 

BFO with some interaction by telephone and in meetings 

in Butte. Resultant files that augmented model behavior 

were developed for vegetation pathways, vegetation 

regeneration, and conifer encroachment. Further 

comparisons of current and historical conditions were 

made similar to the earlier iteration. 

712 Butte Draft RMP/EIS 
Use of the SIMPPLLE Model 

4. Processes 

Fire is the most extensive process on the Butte landscape 

and time was spent working on fire behavior with 

Charles Tuss. Files were developed to augment this 

behavior including better representations for fire 

occurrence, fire management zones (fire history based 

on data that can be provided from PCHA), and fire 

spread. Analysis of model behavior was conducted in a 

meeting at the BFO with Jim and Chris by running 

simulations of current and historical landscapes. Model 

behavior was analyzed using output comparisons as 

described above. 

5. Alternative Development 

Charles worked with Jim in Missoula at the RMRS to 

develop management plan alternatives for the BFO. 

They discussed model treatment logic in SIMPPLLE and 

how to alter that logic for simulation. Jim added a 

“cutting” treatment for the WUI, dropped the follow-up 

treatment to “group selection,” changed the “density 

change” logic for “commercial-thinning” (added density 

of 2 along with 3), and made changes to the follow-up 

treatment for “encroachment-thin-and-burn” and 

“ecosystem-thin-and-burn.” Jim and Charles also made 

changes to allow selection of JUSC for cutting. They 

ended up with treatment schedules for the RMP 

alternatives. Variables that where considered in 

development of the treatment schedule for alternative 

development were: 

1. Sleeping Giant and Sheep Creek WSA/ACEC, 

Elkhorn WSA, Black Sage WSA, Humbug 

Spires WSA, – no acres were identified for 

treatment in these areas 

2. We considered the effects of treatment in 

designated semi-primitive areas (including 

ROS and VRM categories). 

3. Recreation sites and lands adjacent to 

recreation sites were taken into account. 

4. Adjacent land ownership and management was 

taken into account. 

5. Access to lands for treatment was considered. 

Including the existing road system. 

6. Budget was NOT used during identification of 

acres for treatment. 

7. Urban interface was taken into consideration 

and a “heavy-handed” approach was used in 

these areas. These areas were not identified for 

“ecosystem restoration.” The Wildland Urban 

Interface Communities at Risk Hazard 

Assessment, 2004 – (The Helena Valley) was 

used as a tool for assessment. 

8. Past treatments (logging and fire) as well as 

past wildfires were considered. 

9. Topographical features (including rocky and 

steep sites) were taken into account. 

10. Wildlife habitat including elk winter range, 

corridors, security habitat and habitat for 

sensitive species was considered. 

11. We addressed errors in the vegetation coverage 

and made corrections based on professional 

knowledge of the area. 

12. We used the Simpplle Model historical 

reference for each major watershed to guide us 

in determining the number of acres treated. 

Riparian – 

Polygons which had FORVIS data were selected from 

the BFO vegetation layer. It was assumed that if the 

polygon had FORVIS data it was/is forested. The BFO 

riparian layer was then queried for FAR reaches. The 

FAR selection was then clipped based on the FORVIS 

selection to get a forested FAR riparian shapefile. The 

clipped selection had repeated lengths which rendered 

acreage calculations impossible. The forested FAR 

riparian shapefile was then buffered by 200 feet. The 

buffer shapefile was converted to a coverage to produce 

an estimate of forested FAR riparian acres. This 

procedure was repeated for NFU and PFC reaches to get 

forested riparian acres for those as well. 

Forested Riparian 

FAR 3,037 acres or 63 Miles 

NFU 937 acres or 19 Miles 

PFC 3,725 acres or 77 Miles 

To get grass/shrub riparian acres, the FAR, PFC and 

NFU selections were summarized to get total lengths for 

each. These figures were used to derive acres by 

multiplying the total length by 400 feet (200ft buffer on 

each side) and dividing by 43,560. Forested riparian 

acres were subtracted to get “wide grass” acres. This 

figure was converted to square feet and divided by 400 

to get back to lineal feet. The resulting figure was 

multiplied by 200 feet (100ft buffer on each side) and 

divided by 43,560 to get back to “narrow or actual” 

grass/shrub riparian acres as follows: 

Grass/Shrub Riparian 

FAR 1,228 acres or 51 miles 

NFU 499 acres or 21 miles 

PFC 1,703 acres or 70 miles 

Each FAR reach was reviewed and an estimation was 

made as to whether the reach could be treated or not 

through a fuels project, a forestry project or a prescribed 

burn project. This estimation was based on whether the 

reach was in a forested polygon, and the riparian 

coordinator’s personal knowledge of each reach. 

Notations were made as to whether reaches had such 

Butte Draft RMP/EIS 713 
I 

II 

Appendix C 

problems as roads, altered flows, small land ownership, 

historical mining etc. Some of these determinations were 

based upon the riparian coordinator’s personal 

knowledge of each reach-the riparian coordinator has 

visited approximately 75% of the reaches. The riparian 

coordinator also made an estimation whether reaches 

could be treated (or are being treated) by grazing 

practices, exclosures, AML reclamation etc. These 

reaches were then intersected with the FAR buffer 

polygon to derive acres. 

FAR Treatable Acres 

Fuels/forestry/prescribed burns 1,966 acres 

AML reclamation, grazing, exclosures, weed treatment 

 689 acres 

Limited treatment forested due to roads, ownership etc. 

 1,072 acres 

Limited treatment grass/shrub due to roads, mining, etc. 

 542 acres 

PFC Maintenance riparian acres 

The riparian coordinator then went through each PFC 

reach and made an estimation as to whether the reach 

may be treated or not through a fuels project, a forestry 

project or a prescribed burn project to maintain the 

functioning condition of the reach. This estimation was 

based on whether the reach was in a forested polygon, 

whether the reach was in a WSA, whether the reach was 

along a major river (all major rivers were excluded from 

treatment—i.e. Yellowstone, Missouri, Jefferson, etc.) 

and personal knowledge of the riparian coordinator. The 

resulting reaches were then intersected with the PFC 

buffer polygon to derive acres. 

PFC Maintenance Acres 

Fuels/forestry/prescribed burns 1,789 acres 

6. Simulation Output and Reports 

Once SIMPPLLE was behaving in an acceptable 

manner, simulations for current with no management, 

historical, and current with management treatments 

applied were run. Macros for Excel are used with model 

output to display data trends and some time was spent 

working with the RMRS to put together displays. These 

include current trends and historical range of variation. 

Watershed FAR Treatable 

-Forest 

FAR Limited 

TreatmentForest 

FAR TreatableGrass/Shrub 

FAR Limited 

TreatmentGrass/Shrub 

PFC MainForest 

Yellowstone 0 0 0 21 48 

Big Hole 774 129 111 267 633 

Upper Missouri 575 472 297 154 859 

Jefferson 593 471 278 71 249 

Gallatin 0 0 0 29 0 

Upper Clark Fork 24 0 3 0 0 

Blackfoot 0 0 0 0 0 

Total 1,966 1,072 689 542 1,789 

Watershed FAR Forest 

Total 

NFU Forest 

Total 

PFC Forest 

Total 

FAR 

Grass/Shrub 

NFU Grass 

Shrub 

PFC 

Grass/Shrub 

Yellowstone 0 0 62 21 0 267 

Big Hole 903 0 1,207 378 37 614 

Upper Missouri 1,047 595 1,699 451 310 549 

Jefferson 1,064 342 665 349 153 273 

Gallatin 0 0 0 29 0 0 

Upper Clark Fork 24 0 0 3 0 0 

Blackfoot 0 0 92 0 0 0 

Totals 3,038 937 3,725 1,231 500 1,703 

714 Butte Draft RMP/EIS