16 



Klrby 



The Klrby study area Is about 56,320 acres In size, located 

 southwest of Blrnev between Rosebud Creek and the Tongue River 

 (Flpjure 11). The eastern portion of the study area Is very 

 rufTPiied, with hills rlslnp: 500 feet above the Tongue River to 

 elevations of around 4000 feet. The western portion Is composed 

 of high, less rugged plateaus reaching elevations of 4,700 feet. 

 Ponderosa plne-.lunloer forest with sagebrush or grassland parks 

 cover the rugged eastern portion of the study area (Figure 12). 

 The western portion is primarily covered by grasslands and sage- 

 brush, with small stands of ponderosa pine trees along some of 

 the ridges. Riparian vegetation is poorly developed in the 

 eastern portion of the study area, consisting of scattered cotton- 

 wood trees along the Tongue River and the major creek bottoms. 

 Riparian vegetation in the western portion consists of fairly 

 dense stands of deciduous shrubs and trees in most of the drainages. 

 Agriculture consists of hayfields along the Tonprue River and a 

 few grain fields on the western plateaus. 



Tongue River Dam 



The Tonprue River Dam study area is located northeast of Decker, 

 Montana around the Tongue River Reservoir (Figure 13). It 

 covers about 23,500 acres, extending north from the reservoir 

 along the river for about seven miles. The northern part of the 

 study area is very rugged with hills rising 600 feet above the 

 TonKue River. The southern portion around the reservoir consists 

 of gently rolling hills and wide, flat valleys. Sparse ponderosa 

 pine-Juniper forests with small sagebrush parks cover the rugged 

 northern portion (Figure l4). The southern part of the study 

 area is mainly covered by sagebrush, grasslands, and skunkbush- 

 grasslands. The river bottoms and the shoreline of the reservoir 

 are mainly covered by grasslands. Deciduous tree and shrub 

 riparian habitat is poorly developed, except for dense willow 

 thickets and woodlots at the southern end of the reservoir. Low 

 water levels in late summer expose extensive mud flats which 

 become covered with Runex sp. and other annual forbs. Agriculture 

 consists mainly of hayfields along the Tongue River. Most of 

 the study area is used for cattle grazing. The East Decker and 

 West Decker coal mines lie partially within the study area. A 

 housing development is under construction near the mouth of 

 Spring Creek, within the study area. 



VEGETATION TYPE DESCRIPTIONS 



For the purposes of this study five broad vegetation types were 

 identified. Four of these represent native vegetation and 

 Include ponderosa pine, Juniper, sagebrush-grassland and riparian. 

 The fifth type, agricultural, was defined as those areas where 

 crops were being produced. Not all of these types were present on 

 all seven study areas. See the appropriate study area sections 

 for more detailed discussion concernins: the vegetation types and 

 their Importance within the individual study areas. 



