VEGETATION IN THE GRAVELLY LANDSCAPE Joe Casey, BLM
Al Kyles, FS
Kevin Suzuki, FS
Bob Brannon, MtFWP
This report on vegetation covers the following subjects:
 
    I. EXISTING VEGETATION and CONDITION  
      A. Cover Types  
      B. Forest Stand Structure  
      C. Uniques Species and Threatened, Endangered and Sensitive Plant Species  
      D. Noxious Weeds  
      E. How Natural And Human Disturbance Has Affected Vegetation  
      F. Ecological Concerns for the Gravelly Landscape  
      G. Relationship to Ecological Concerns at a Larger Scale
 
    II. VEGETATION POTENTIAL  
      A. Nonforested Habitat Type Groups   
      B. Forested Habitat Type Groups
 
    RELATED APPENDICES   
    APPENDIX C - Detailed description of habitat type groups  
    APPENDIX E - Resolving resource conflicts - a description of risks and tradeoffs  
    APPENDIX G - Opportunity for vegetation treatments, by ownership, ELU, veg class  
 
I. EXISTING VEGETATION and CONDITION

A . Cover Types

Cover types represent dominant species or life forms occupying the landscape today. Cover types in the Gravelly Landscape were described using information from several sources. First, to determine basic vegetative cover landscape wide, vegetation was classified using satellite imagery and mapping called "GAP analysis". GAP analysis was done by Rolle Redmond at the University of Montana prior to 1996. This level of information was most useful on lands for which we have limited or nonexistent vegetation data collected. Prior to this analysis, land managers have not had a complete look at vegetation distribution and condition across all ownerships. This has left a void in assessing the cumulative impacts of management actions.

The GAP analysis was based on satellite images of northern Idaho and western Montana taken in the early 1990's. One of these satellite images contained all of the Gravelly Landscape. It had over 50 groups of image classifications (spectral classifications) of which 29 were applicable to vegetation in the Gravelly Landscape. These 29 groups were further pared down to 10 groups to simplify the vegetation classification and data associated with this process. The GAP analysis of the satellite imagery was improved in 1997 with a second interpretation of aspen and range types, completed through the Remote Sensing Applications Center in Salt Lake City, Utah. This second interpretation improved the accuracy of aspen, sage and grassland mapping using additional ground truthing in the southwest portion of the Landscape. The final 13 groups mapped for the entire Gravelly Landscape area are listed in Table 1 and displayed on Map #12 in the map appendix.

A second source of much more specific information came from Bureau of Land Management (BLM) and Forest Service electronic data bases. While not displayed here, maps are available for specific forest cover types and stand structures on both BLM and FS land. In addition, the Timber Stand Management Reporting System provides detailed data on for all Forest Service lands.

A brief summary of the vegetation shows the dominant cover type is grass/sage which occurs on almost 75% of the Landscape. The next largest vegetation group is conifer forests which make up about 20% of the area. The third largest cover type is agricultural land at about 4%. The remaining area is riparian, rock, wet meadows, water, urban or developed areas. This information is expanded in Tables 1 and 2 and Figures 1 and 2.

Table 1. Basic Vegetation Cover Types Mapped for the Gravelly Landscape
 
Vegetative Map Legend Description
Agricultural  Hay meadows, alfalfa fields, grain fields, etc.
Grass/Shrub  Foothills grasslands, Disturbed grasslands, Montane parks.
Dry Grass  Upland grasses-herb communities below 6800 ft elevation
Moist grass  Upland grass-herb communities from 6800 to 9200 ft elevation
Alpine grass  Upland grass-herb communities above 9200 ft elevation
Mesic Upland Shrub Wet upland sites dominated by shrubs.
Douglas-fir  Lower slope conifer tree canopy that begins at the grass/sage/conifer edge and extends upward.   

Mostly Douglas-fir with some lodgepole pine or Rocky Mountain juniper. 

Lodgepole pine  Mid slope conifer tree canopy that is mostly lodgepole pine with some limber or whitebark pine and extends upslope to about 7800' elevation. 
Subalpine fir complex Generally the upper reaches of the coniferous forest above 7800' with either subalpine fir or subalpine fir mixed with other conifer.
Water  Large enough bodies of water to show at the landscape scale.
Rock  Rock, barren alpine tundra, other mixed barren land.
Urban and some subdivisions Towns, some subdivisions, etc.
Riparian*  Stream bottoms, river corridors, and associated vegetation such aspen patches, willows, spruce, etc.
On National Forest System lands, there is additional site specific data pertaining to coniferous stands of timber and other vegetation. This information, combined with local knowledge of a given area, was used to correct some of the questionable classifications of vegetation from the satellite imagery at the landscape level. The BLM has similar data or that extrapolated from aerial photography on its major land blocks, but limited data on its more isolated tracts. The Natural Resources Conservation Service (NRCS) and Montana Department of Natural Resources and Conservation (DNRC) also have more specific data, based on surveys and aerial photography. This data is limited to specific parcels or ownerships. Gathering the vegetation classification information from satellite imagery was the basis for classifying the vegetation on any remaining federal, State of Montana and private lands. Again, local knowledge was used to adjust any classifications that were obviously in error.

Satellite imagery has its limitations. When information is grouped to improve accuracy, the maps tend to reflect the dominant vegetative types. Specific smaller parcels can be lost and potential for errors in classification of small tracts increases. This ecosystem analysis is the broad view from a distance and has some limitations.

Finally, unique vegetation types such as sensitive, rare or endangered plant communities cannot be easily denoted on mapping at the landscape level. However, where this information is available, it is incorporated. Any potential project level work affecting these resources would be analyzed through the NEPA process using more specific available data.

The ownership jurisdiction and approximate acreage in the Gravelly Landscape is shown in Table 2.
 

Table 2. Acres by Jurisdiction and Vegetative Type
 
Jurisdiction % of Landscape Total  

Acres

Agricultural Grass/ Shrub Mesic Douglas-fir Lodgepole Sub- alpine Water Riparian Rock Urban
US FWS 1.94 38,000 0 31,400 0 2.200 600 2,000 200 1,600 0 0
Forest Service 23.88 468,000 0 232,000 600 47,000 97,000 76,300 200 5,000 10,000 0
Bureau of Land Management 21.43 420,000 0 306,000 1,000 37,000 30,000 40,000 100 1,700 4,200 0
Bureau of Reclamation 0.05 1,000 0 1,000 0 0 0 0 0 0 0 0
Mt Fish Wildlife & Parks 0.92 18,000 0 17,200 0 200 200 0 0 400 0 0
Mt Dept. of Natural Resource Conservation 12.55 246,000 900 225,000 50 9,150 6,000 3,500 0 800 600 0
Private 39.23 769,000 77,000 621,000 4,000 26,000 16,000 4,200 200 19,000 500 1,100
Total Acres 1,960,000 77,900 1,415,400 5,550 121,350 149,600 126,000 700 28,100 15,300 1,100
Percent 100% 3.97% 73.21% 0.28% 6.19% 7.63% 6.43% 0.04% 1.43% 0.78 0.06%
 
 
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B. Forest Stand Structure

Forest species and stands structures were described using satellite imagery and improved on FS lands using TSMRS data, See Map #13. Table 3 and Table 4 display their distribution across the Gravelly Landscape.

Table 3. Distribution of Forest Species
 
Forest Species 
% of Forested Cover 
Douglas-fir 
29 % 
Lodgepole pine 
37% 
Subalpine fir 
31% 
Aspen and Conifer mix 
<3% 
The stand structures of these species were described as:
 
Infant  = seedling to sapling size trees, from 1 to 20 years of age
Juvenile  = pole size or uniform stands, undifferentiated, from 20 to 80 years old 
Gold  = older mature stands, generally have more than one layer of foliage in the canopy, dominant trees older than 80 years
 

Aspen and conifer mix were not discussed separately on the basis of stand structure because of the difficulty of mapping these very small stands.

Distribution of these structural classes by species across the landscape are described in Table 5 below.
 

Table 4. Distribution of Structural Classes
 
Species  Infant or colonization  Juvenile  Gold  TOTAL 
Douglas-fir  548 acres (0.5%)  32,521 (29%)  78,493 (70%)  111,562 
Lodgepole and subalpine fir  4,032 (1.5%)  58,851 (22.5%)  200,662 (76%)  263,545 
Aspen/Conifer  110 (1%)  2969 (26%)  8430 (73%)  11,509 
The proportion of Gold to the Juvenile and Infant structures across all species groups ranges from 4:1 in the subalpine fir group to nearly 3:1 in the Douglas-fir group. There are three significant changes in the distribution of structural classes in recent history, even since the first aerial photos were available in 1945.

1. The decline of aspen from the landscape is readily apparent from its present condition. This early seral species is dying off because it cannot maintain a competitive edge without disturbance in the forest canopy. As it dies off, it is being replaced by more shade tolerant conifers instead of young aspen seedlings. While the species has probably never been a dominant feature in the landscape, a study in the southwest portion of the Gravelly Mountains shows a 47% decline in aspen coverage between 1945 and 1963.

2. The existing Gold portion of the Douglas-fir Group has a large cohort of understory trees less than 100 years old. Historically, the low elevation dry Douglas-fir stands took on the character of open savannah-like stands with an abundance of forage underneath. Low intensity ground fires cleaned out these stands periodically, fire-proofing the large old trees remaining. This change in conditions represents three significant threats to the continued existence of these stands:
 

3. The current situation places a large percentage of all species in the condition (dominated by mature/overmature age classes) most prone to large scale disturbance. Continuing in this direction ecologically has the potential of increasing the severity of events that will "reset" the successional clock in these groups. This is significant in higher elevation stands where large scale high intensity fires present risks to wildlife security cover, watershed stability, and sensitive fish species. It is also of concern in whitebark pine stands vulnerable to large scale loss to white pine blister rust as well as fire.

4. There is an increase in the areas converting from open grass and sagebrush to the Infant class of Douglas-fir. This is evident in photo comparisons from 1945. The forested stands that come in on these sites are typically unhealthy as they get older. The trees are at the outside of their range and develop problems with competition for nutrients and moisture, leaving them susceptible to pathogens. The conversion of sagebrush habitat to Douglas-fir habitat may represent either a plus or minus to other resources, like wildlife habitat, depending upon the location, amount and duration of this conversion. It does represent some long term fire control problems along urban interface.

For more information about stand structure as it relates to potential vegetation and trends , see Section E, F, and G below as well as Section "II. VEGETATION POTENTIAL".

C. Unique Species and Threatened, Endangered and Sensitive Plant Species

Southwest Montana is a unique and floristically rich corner of the state. The richness of the flora in combination with the climate, geology, topography and elevation range give us a full range of diverse plant communities in the Gravelly Landscape. Plant communities range from the dry valley grasslands to dense conifer forest on the mountain slopes and on to the high alpine tundra on the mountain peaks. Riparian areas offer another whole range of diverse plant communities. The vegetation classification currently being used for this landscape is very generalized and does not reflect the diversity of the area.

Wherever you may go within southwest Montana, whether you are on the valley floor or at the top of one of the mountain peaks, you will come across interesting and unique plant communities. Some areas are managed specifically for these unique array of plant communities. Red Rock Lakes National Wildlife Refuge, managed by the U.S. Fish and Wildlife Service, is a mix of lakes, ponds, marshes and other wetland communities managed for trumpeter swans. The Beaverhead-Deerlodge National Forest maintains three Research Natural Areas (RNA): Cave Mountain, Cottonwood Creek and Cliff Lake. Research Natural Areas are part of a national network of ecological areas designated for research and education and/or to maintain biological diversity on National Forest system lands. A similar network of ecological areas is the BLM Area of Critical Environmental Concern (ACEC). The Dillon Resource Area is looking at designating the Centennial sand dunes under the ACEC network. These sand hills support a variety of uncommon plant communities and provide habitat for four plant species of concern. They are also the highest elevation sand dune habitats in the Northern Rocky Mountains.

Many plant species can only be found growing in this area of the state. In Montana, there are no plant species listed as endangered and only two that are listed as threatened. Of the two threatened species, Ute ladies' tresses, a member of the orchid family, was first discovered in the state in 1994. This species has the potential to be found in the Gravelly Landscape. In Beaverhead and Madison Counties, just over 100 plant taxa are tracked by the Montana Natural Heritage Program as species of concern. Plants are listed as species of special concern based on the plants rarity, threat to survival or due to limited knowledge of the species. The Forest Service and BLM further refine this list to focus on those species known to occur or suspected to occur on public land. Currently, the Beaverhead-Deerlodge National Forest maintains a list of 38 species as sensitive. The BLM Dillon Resource Area lists ten species as sensitive.

D. Noxious Weeds

Noxious weeds are the greatest threat to the overall vegetative diversity and soil productivity in the Gravelly Landscape. A variety of noxious weeds have already established a foothold in the area, spotted knapweed being at the top of the list. Other weed species are found just outside the landscape boundary and have the potential to invade. Disturbed ground provides the best seed bed for weeds to establish by eliminating competition from other native vegetation. Most weed species have evolved to take advantage of this type of situation by being able to germinate and grow in harsh environments. The ground disturbance associated with construction of subdivision roads, house construction, logging and agriculture crops create prime sites for weed invasion. The primary vector for introduction of most noxious weed seed is transport to the area by vehicles, be it car, truck, motorcycle or ATV. Sites occupied by noxious weeds are currently being mapped electronically on FS lands.

E. How Natural And Human Disturbance Has Affected Vegetation

Specialists analyzing vegetation need to understand what kinds of changes occur over time, to know how we got where we are today and what the potential for future vegetation is. The different components of the Gravelly Landscape are by no means static. Sometimes change occurs quickly, such as from floods, fires or landslides. Other times, the changes are slower and more subtle, as from climate changes. Certain types of landscapes are prone to natural disturbances. Portions of the Gravelly Mountains are particularly active geologically; collapsing, shifting and sliding.

A disturbance is an event that changes the trend of ecosystem development; in this case, vegetative development or succession. Disturbances play many roles in ecosystem functioning. One example is flooding. Floods play many roles, including flushing debris and accumulated fine sediment or delivering material for soil development to the flood plains. Natural disturbances that affected vegetation composition, structure and function in the Gravelly Landscape included plant succession, insects, disease and fire.

Humans also have had profound effects on the Gravelly Landscape. Agriculture, timber harvest, mining, livestock grazing, hunting and the exclusion of fire have resulted in changes in succession, disturbance regimes and associated vegetation. Specific activities include construction of roads, introduction of exotic plants or animals, conversion of land to agriculture or other uses. When natural disturbance events are detrimental to humans, we attempt to control them or minimize their effects -- often disrupting the normal functions of the disturbance. In many cases, human activities interact with natural disturbances to produce an entirely new effect. This has been the case with both fire and floods.

There has been considerable discussion and some disagreement between resource specialists on the Gravelly vegetation and wildlife subgroup on the role of disturbance processes in determining the types, condition and potential for change in plant communities in the Gravelly Landscape. The team agrees that human activities have affected vegetation in numerous ways. The team agreed that the effect of both human and natural disturbances on plant communities can be documented since 1940. Each member of the team could not agree, however, on the role and influence of fire, in particular, as a natural disturbance prior to 1940. The disagreement centered on whether evidence of historical fires at specific locations can be used to describe a pattern of fire frequency and intensity across the entire landscape. A primary concern was current fire research specific to southwest Montana (Gruell, Barrett, #need citations) may lead to management for more early seral stages in grass/shrubland or low elevation Douglas-fir. This was viewed as detrimental to other resource uses, such as wildlife.

In order to deal with the two viewpoints and still try to understand what the trends in vegetation development might be, the team developed two scenarios for describing how we got where we are today and what the potential for the future is. These are further described in the following section "II. Vegetation Potential in the Gravelly Landscape" and in Appendix C. The role natural and human disturbances played in our current vegetation patterns is described below in very broad terms. Also refer to page #6 for a detailed description of the magnitude of specific human disturbance factors (logging, mining) within each Ecological Landscape Unit.

Below is a description of the broad vegetation cover types and how they have been affected.
 

F. Ecological Concerns for the Gravelly Landscape

Agency specialists in vegetation ecology and wildlife biology compared the existing condition of vegetation to historical trends and vegetation potential. The team identified six areas of concern they agreed on and one area they did not.

Agency Resource Specialists agree that:

     1) Aspen is declining in health and distribution. Aspen is naturally a small but important component of the landscape. Documented decreases in aspen acres have occurred since the 1940's. Most stands are mature to overmature. The aspen component is becoming smaller due to climate changes, plant succession, grazing by cattle and wildlife, and lack of fire or other disturbance. Loss of aspen would reduce plant species diversity and also represent a loss of key wildlife habitat.

     2) There are more high elevation subalpine fir stands and older stands than ever before. Subalpine fir occupies more sites than it has in the last 50+ years. Lodgepole and whitebark pine stands in many areas are slowly converting to subalpine fir due to insect (mountain pine beetle) or disease (whitepine blister rust) mortality and succession. The trade-offs are as potential for old growth habitat increases, there is less whitebark or lodgepole pine habitat for species reliant on those habitats, and heavier fuel loading occurs (higher risk of high intensity fires).

     3) There is an increase in older mid-elevation lodgepole pine and Douglas-fir stands . Lodgepole pine relies on fire to regenerate young stands. In the absence of fire, existing stands continue to age. Very few young stands of either lodgepole or Douglas-fir occur at mid-elevations. The stand structure of Douglas-fir has also changed from more open grown older trees, to multistoried thicker stands. The benefits are as old growth lodgepole pine habitat increases and Douglas-fir stands become thicker, there is more habitat for forest habitat species and more wildlife security cover. The concerns are heavier fuel loading, risk of high intensity fires, and loss of timber products to insect and disease and natural attrition.

     4) There is an increase in Douglas-fir cover along the grass/sage interface with Douglas-fir. In the absence of disturbances, grass/sage stands on favorable elevation and aspects become occupied by young Douglas-fir trees. This is a natural part of succession to climax, but it is occurring on sites marginal for supporting healthy forest stands. The benefits are some increase in habitat for forest habitat dependent species and additional security cover for big game species. The trade-offs are increasing the fuel loading which means harder to control fires in areas where subdivisions are increasing and loss of sagebrush habitat for sage dependent species, and unhealthy forest stands susceptible to disease.

     5) Riparian vegetation is changing in character. There has been a reduction in composition and distribution of native vegetation with an increase in nonnative vegetation. The concern is this contributes to a loss of stream function and a reduction in wildlife habitat diversity. The benefits are related to human use of the sites, whether they provide forage for domestic livestock, road corridors, or recreation sites.

      6) Grass and sagebrush cover types are changing. Agricultural practices have reduced native grass and sagebrush cover types, converting them to nonnatives through cultivation and planting. The potential for natural processes continuing on these sites is reduced. The benefit is production of food for humans and livestock. The trade-off is a loss of the amount of grass/sagebrush habitat available for wildlife species or a change in the character of the vegetation available. There is also some redistribution of where that habitat occurs.

Agency Resource Specialists do not agree on:

The balance of grass and sagebrush as it is distributed across the landscape. Sagebrush/grassland is a prevalent community across the Gravelly Landscape, more so here than many other landscapes in southwest Montana. The question is whether or not the prevalence of this community type is any different now than it was in the past. Certainly there would be differences when we think of geologic time. There may also be differences, at least in vegetative composition, since European settlement of the west. Though there is even question about this. But, is there a difference in the prevalence of this community type in recent recorded history (the last 350 years)? Undoubtedly, on a small scale there have been short term changes resulting from natural influences such as fire, insects, disease, precipitation, etc. But have these influences been significant on the landscape in magnitude or frequency? There have been changes on some scale and for the short term because of human influences: sagebrush treatment (prescribed fire, spraying, plowing, etc.), grazing, fire suppression, etc. But which of these, if any, have had a major influence on the distribution of this community type?

The sagebrush/grassland community is the one where much of the management controversy exists. However, the questions asked above could apply as well to the other community types discussed. It is important to consider the value of these communities in their current status, ecologically, and from a wildlife habitat perspective, in addition to considering whether or not there is a significant change in their relative presence.

The value of these vegetation communities and recommendations for how they should be managed in the future, recognizing the multiple values to wildlife, recreation, scenic values, and economic uses is continued in Chapter 3. Recommendations for the Future. At that point, trade-offs between the various resource values and uses are discussed, weighed and balanced.

G. Relationship to Ecological Concerns at a Larger Scale

"The Northern Region Overview, October 1998" published by the US Forest Service, Region 1, outlined the following as their number 1 and 2 restoration priorities across the Region based on ecological trends:
 

Aspen 
Priority 1 
Conversion due to conifer encroachment & fire exclusion
Dry Douglas-fir 
Priority 1 
Change in density & aerial extent due to fire exclusion
Whitebark pine 
Priority 1 
Loss to blister rust, fire exclusion, mountain pine beetle
Lodgepole pine 
Priority 3 
Change in age structure pattern due to fire suppression
Sage/grasslands 
Priority 2 
Structural change, loss of grass due to fire exclusion
Groups of upland 
Priority 1 
Interface with dry conifer type & conifer encroachment grass/shrubs(Juniper/sage, due to fire exclusion (majority of big game winter range). 
Bitterbrush/ bunchgrass, etc.
Riparian shrub/graminoid bottoms
Priority blank 
Grazing shifted species composition to upland types due to stream channel changes 
For this region of southwest Montana, Charlie Russell/ Cradle of Mountains Zone, the report note the following plant communities most at risk (types not present in the Gravellys left off this list):
 
      Aspen   
      Whitebark pine  
      Dry Douglas fir  
      Lodgepole pine  
      Upland grass/shrubs  
      Sagebrush/grass  
      Riparian  
      Noxious weeds
 
These communities were considered at risk due to past and potential future loss in aerial extent of the cover type; significant changes in landscape level heterogeneity (fragmentation); significant changes in structure (both density and change in distribution of structural stages); and susceptibility to spread of noxious weeds.

II. VEGETATION POTENTIAL

In order to understand the role of vegetation in the landscape, we need to understand the types of, condition of, and potential for change in the plant communities in the Gravelly Landscape. In the section above, we described the types of vegetation currently occurring and some history related to how those types came about. In this next section, we will describe the makeup and ecology of those types to predict how vegetation might change in the future.

To accomplish this, we look at the physical and biological potential as a base for producing vegetation (mapped as Ecological Landscape Units) and the type of vegetation this base is likely to produce (mapped or described as Habitat Type Groups). Refer back to "Ecological Landscape Units" in an earlier section for a discussion of how physical and biological potential were used to describe basic land units. Literature cited in Appendix C.

HABITAT TYPE GROUPS

The climate and geology of the Gravelly Landscape has led to a mountainous area naturally diverse and fragmented. As a result, there are a great number and variety of plant communities found across the Gravelly Landscape. It would be impossible to describe the composition and ecology of each one in this document. To get a general feel for the vegetation found across the landscape, we have grouped plant communities based on structural and ecological similarities into habitat type groups. Within each habitat type group, a handful of communities generally dominate. These dominant communities will be used to help describe the vegetative structure, successional pathways and ecological impacts for the group as a whole. Information on the many other communities not specifically described is available.

Habitat types help us predict what a site is capable of growing as well as describing what IS growing. Habitat types are classified based on the climax plant community, which is the end result of plant succession and reflects the most meaningful integration of the environmental factors affecting vegetation. Use of the habitat type does not imply that an abundance of climax vegetation occurs in the present landscape. Actually, most vegetation in the landscape reflects some form of disturbance and various stages of succession towards climax. This method of classification, however, does not require the presence of a climax stand to identify habitat type. It can be identified during most intermediate stages of succession by comparing the relative reproductive success of species present with known successional trends and observing the existing undergrowth vegetation (Pfister and others, 1977). Furthermore, use of climax community names in habitat type classification does not imply that management should necessarily be for climax vegetation to optimize vegetation health. The vegetation on a site is only one element used in developing an overall assessment of the landscape's capabilities and societal desires.

Changes in plant communities occur over time as a result of natural processes and intervention by people. There has been considerable discussion and some disagreement between resource specialists on the interdisciplinary team on the role of disturbance processes in determining the types of, condition of, and potential for change in the plant communities in the Gravelly Landscape. This disagreement settles on the role and influence of fire, in particular, as a natural disturbance. The group agreed on the necessity of describing site capability and potential plant communities (using habitat type groups as a descriptor). In order to deal with the two viewpoints, the team developed two scenarios for describing how we got where we are today and what the potential for the future is. Scenario 1 is based on the assumption that plant succession is the controlling influence on potential plant communities, recognizing the obvious disturbances by humans and climate that have been recorded since 1940. Natural disturbance cycles like weather, insect and disease, and fire had less of an influence. Scenario 2 is based on the assumption that natural disturbance cycles, particularly fire, had a measurable effect on the distribution, composition and health of vegetation before settlement of the area by European descendant peoples. This assumption relies on interpreting fire scars, soil changes and historic journals and photos. It also assumes that these records of fire in specific instances can be used to infer a repetitive sequence of fires across the landscape.

The information was developed for both scenarios and compared to the existing condition to identify potential areas of concern, risks and trade-offs. The concerns, risks and trade-offs were weighed along with the various other values of the vegetation resource (soil protection, wildlife habitat, scenery, etc.) to describe a desired future condition of the vegetation resource. This comparison was done by interdisciplinary team representatives from each specialty and discipline and is documented in Chapter 3 - "Integrated Desired Future Condition".

Appendix C contains a detailed description of changes to expect for each habitat type group or subgroup over time, as developed for both the Climax Scenario and the Disturbance Scenario.

Habitat types were derived from USFS East Slope Groups. Forested habitat types were then looked at from the landscape level and categorized into several habitat type "groups". The detailed habitat type group descriptions are broken out by those groups as follows:
 

 

A. NON-FORESTED HABITAT TYPE GROUP
 

 
 
Table 5. DISTRIBUTION OF HABITAT TYPE GROUPS (HTG) BY CLIMATE
AS INDICATED BY ASPECT AND ELEVATION
 
North - cool/wet  East - cool/moist  South - warm/dry 
11,000 ft. +   

ALPINE 

11,000 ft. +   

ALPINE 

11,000 ft. +   

ALPINE 

8,000 - 11,000   

HTG I 

8,200 - 11,000   

HTG I 

8,200 - 11,000   

HTG I 

7,500 - 8,000   

HTG F 

7,500 - 8,200   

HTG F 

7,900 - 8,200   

HTG H 

7,000 - 7,500   

HTG D(&H) 

7,000 - 7,500   

HTG D(&C) 

7,000 - 7,900   

HTG B(&C) 

5,500 - 7,000   

HTG B(&A) 

5,500 - 7,000   

HTG C(&B) 

6,500 - 7,000   

HTG A 

< 5,500   

Nonforested 

< 5,500   

Nonforested 

<6,500 Nonforested
 
   
Infant or Colonization - young seedling or sapling trees less than 20 feet tall 
Juvenile - pole size trees from 20 feet to full grown. 
Gold - mature or overmature trees. 
 
 
Table 6. Characterization of Habitat Type Groups
 
Habitat type group A - warm and very dry. Covers 12,000 acres in this landscape, which is less than 1% but it represents 3% of the forested areas. It is the 6th largest forested HTG. Activities: grazing intensity on elevations below this HTG historically have been moderate to intense in the past 130 years. Stocking levels are considerably lower since the 1960's. With use of finer fuels by livestock, population increases in the valley, and conversion of bottom lands to agricultural production, fires were less likely to reach historic sizes. 
Tree Species Acres of Infant or Coloniz. Acres of Juvenile Acres of Gold
Douglas-fir 30 (less than 1%) 1680 (14%)  3470 (30%)
Other conifers 420 (4%) 2060 (18%)  3670 (31%)
Aspen/conifer 0 (less than 1%)  150 (1%)  210 (2%)
% TOTALS About 4% 33% 63%
Habitat type group B - similar to HTG A in temperature but is not as dry as the lower elev. group. Its the 4th largest forested HTG. More frequently found in the west and north sides of the landscape. Comprises 40,000 acres or about 2% of the area and represents about 10% of the forested area. Activities: Grazing is common but less productive than nonforest types. Insect and disease levels are moderate (scattered bark beetle and spruce budworm in the 1980's). Historic logging was more common than HTG A since the quality of timber is higher. It occurred where there was an opportunity for products like mine timbers, fuelwood, post and poles and barn or house logs. Recent timber harvest took place on private and public land from 1970's to present, but the major activity was in the higher elevation portion of this vegetation type. 
Tree Species Acres of Infant or Coloniz. Acres of Juvenile Acres of Gold
Douglas-fir 269 (less than 1%) 6888 (18%)  14,543 (39%) 
Other conifers 958 (3%) 5708 (15%)  8336 (22%) 
Aspen/conifer 34 (less than 1%) 94 (less than 1%)  525 (1%) 
% TOTALS About 4% 34% 62%
Habitat type group C - warm and moist. It is the smallest of the HTG's at 600 acres. Vegetation is a mix of Douglas-fir on south and west aspects and Douglar-fir/lodgepole pine on north and east aspects. Activities: Some grazing of fine fuels, conversion to agriculture, and subdivision activity has affected this habitat type group in minor ways.
Tree Species Acres of Infant or Coloniz. Acres of Juvenile Acres of Gold
Douglas-fir 13 (2%)  127 (22%)  355 (62%) 
Other conifers 35 (6%)  (0%)  39 (7%) 
Aspen/conifer 2 (less than 1%)  (0%)  (0%) 
% TOTALS 9% 22% 69%
 
Habitat type group D - cool and moist. It is the 3rd largest of the HTG's at 53,000 acres total. Comprises 3% of total land area and 14% of the forested area. Vegetation is a wide variety of conifer and understory species. Activities: there has been little or no major natural disturbances during the last 50 years but some human-caused disturbances. 
Tree Species Acres of Infant or Coloniz. Acres of Juvenile Acres of Gold
Douglas-fir 116 (less than 1%) 7226 (14%)  20,052 (38%) 
Other conifers 833 (2%)  10,105 (19%)  12,657 (24%) 
Aspen/conifer 2 (less than 1%)  735 (1%)  1221 (2%) 
% TOTALS 2% 34% 64%
Habitat type group F - located mostly in the Gravelly and Greenhorn Mts. Typically the lower subalpine/lodgepole pine stands. It is the largest HTG in the landscape, representing almost 8% of the total area, 40% of the forested area. Activities: this HTG has the highest degree of timber harvest . However, this is insignificant landscapewide, with less than 1% of the area in "Infant" (seed sapling) category. Most of these occured in the last 20 years or so. A maximum of 3/4 of the 22% juvenile could be related to harvest in the past 20 to 50 years, up to 25,000 acres over 50 years. The Greenhorn/Gravelly ELU has the highest % at 23% infant/juv trees in this HTG. Periodic beetle epidemics have also had a dramatic effect on existing stand structure. 
Tree Species Acres of Infant or Coloniz. Acres of Juvenile Acres of Gold
Douglas-fir 93 (less than 1%) 14,400 (9%)  31,696 (20%)
Other conifers 825 (less than1%)  19,349 (12%)  84,338 (54%)
Aspen/conifer 40 (less than 1%)  1606 (1%)  4528 (3%) 
% TOTALS 1% 22% 77%
Habitat type group H - generally cooler than HTG F. It is the 5th largest in the area at 21,000 acres, contains 1% of the lands area and 5% of the forested area. Activities: This HTG has been affected by timber harvest, to a lesser degree than HTG F, as much as 3,000 acres over the last 50 years. 
Tree Species Acres of Infant or Coloniz. Acres of Juvenile Acres of Gold
Douglas-fir 0 (0%)  1359 (7%)  3532 (17%) 
Other conifers 228 (1%)  2497 (12%)  11,345 (56%) 
Aspen/conifer 22 (<1%)  257 (1%)  1187 (6%) 
% TOTALS 11% 20% 79%
Habitat type group I - cold and moist with upper subalpine and timberline habitat types. It is the 2nd largest HTG with over 105,000 acres, 5% of the total area and 27% of the forested area. Activities: the existing stands are a result of little or no activity or disturbance during the last 50 years. Lack of fire and the expected increase in white pine blister rust mortality threatens the future of whitebark pine in this HTG. 
Tree Species Acres of Infant or Coloniz. Acres of Juvenile Acres of Gold
Douglas-fir 27 (<1%)  841 (<1%)  4845 (5%) 
Other conifers 733 (<1%)  19,132 (18%) 80,277 (75%) 
Aspen/conifer 10 (<1%)  127 (<1%)  759 (<1%) 
% TOTALS 2% 18% 80
 

Linking Habitat Type Groups to Ecological Landscape Units

Habitat type groups tend to reflect underlying landforms, precipitation, elevation and aspect. These habitat type groups were an important element in defining the Ecological Landscape Units mapped in the Gravelly Landscape. Potential vegetation in these ELU's can be characterized by looking at the distribution of habitat type groups within each ELU. This is portrayed in the following bar graphs and Map #14. Also see "Ecological Landscape Units: in the first section of this Chapter.