Douglas-fir Forests
Salish: Cq̓ɫp
Kootenai: Ⱡu

Douglas-fir forests make up about 7% of the riparian zone. These forests often contain some ponderosa pine and Rocky Mountain juniper as well.

Douglas-fir is really not a fir at all. Many things about it are different than the true firs, especially the cones. Because of fire exclusion, this tree has greatly expanded its distribution. Shrubs in the understory include snowberry, Wood's rose, service-berry, Oregon-grape, ninebark, and ocean spray. Forbs include dandelion, common yarrow, spotted knapweed, and wild strawberry.

Juniper and Ponderosa Pine Forests
Salish: Punɫp / Sʔátq͏ʷɫp
Kootenai: ʾakukpⱡuⱡaⱡ / Himu

These two trees are found together throughout the river corridor, especially below Goose Bend. This type of vegetation makes up about 8% of the riparian zone.

Ponderosa Pine Forests
Salish: Sʔátq͏ʷɫp
Kootenai: Himu

Ponderosa pine, pure stands of which occupy about 1% of the river corridor's riparian zone, is the state tree of Montana. It is a very important tree for lumber, growing from 50 to 180 feet tall. On the river it is found by itself, but it also grows with black cotton-wood and juniper and dense shrubs, including red-osier dogwood, serviceberry, and Wood's rose.

It has three needles or sometimes two in each bundle and they are usually 4-7 inches long in tufts at the end of the branches. The cones are 3-6 inches long, broadly rounded at base, tapered to the tip, short and squat; bright green, becoming reddish brown as they get older and armed with small spines. The bark is dark on small trees, cinnamon-brown to orange-yellow, thick and broken into large, flat, irregular “jig-saw puzzle-shaped” plates on old trees.

Paper Birch

Paper birch, which occupies about 1% of the river corridor's riparian zone, grows 60 to 80 feet tall and cannot tolerate shade. It takes over areas after fires and was used in the past to make canoes and baskets.

The leaves are oval or ovate, 2-5 inches long and 1-2 inches wide, usually rounded at the base with the margins toothed. They are dark green and shiny above, yellow-green below.

The bark is creamy white, separating into thin, papery layers, and marked by long, narrow, horizontal, dark, corky lines. The inner bark is orange.

Riparian Shrub Communities

Riparian shrub communities, which occupy about 6% of the riparian zone in the river corridor, are often found near the high water mark along the river.

They most often include sandbar willow, red-osier dogwood, Douglas hawthorn, Wood's rose, western snowberry and Bebb's willow. Willow and dogwood are often found together, and rose is frequently found with hawthorne, dogwood, and snowberry.

Grasses frequently found include redtop bentgrass, reed canarygrass, fowl bluegrass, Kentucky bluegrass, and quackgrass.

Other plants in this community include Canada thistle, hemp dogbane, black medic, Canada goldenrod, loosestrife and poison ivy.

Upland Shrub Communities

Upland shrub communities, which occupy about 22% of the riparian zone in the river corridor, can be found both near the high water mark and a considerable distance inland and above the high water mark.

Shrubs found in upland communities include big sagebrush, rubber rabbitbrush, antelope bitterbrush, oceanspray, and serviceberry.

Bluebunch wheatgrass, cheatgrass, prairie junegrass (Koeleria cristata) and Kentucky bluegrass are the most common grasses, and fringed sagebrush, arrowleaf balsamroot, spotted knapweed, and mullein are the most common forbs.

Dry Herbaceous Communities

Dry herbaceous communities, which occupy about 8% of the river corridor, are often found on steep slopes and rocky banks adjacent to the river. Many of these sites are adjacent to the riparian zone; few are contained within it.

The community includes three types of subcommunities: western wheatgrass with Idaho fescue; bluebunch wheatgrass with rough fescue; and Kentucky bluegrass with quackgrass (this last one is found on disturbed sites). Redtop bentgrass and Canada thistle are found on many of these sites, as is spotted knapweed, common timothy, baltic rush, and prickly lettuce.

Xeric Herbaceous Communities

Xeric means extremely dry, and xeric herbaceous communities are the driest on the river. They are usually found farther from the riparian zone or are on especially fine and dry soils. The dominant species in this community are needle-and-thread grass with red threeawn grass, spotted knapweed, erect cinquefoil, and sand dropseed. Cheatgrass, fringed sagebrush, goatweed, and Kentucky bluegrass are also common.

Many of these species have been introduced, and some are troublesome weeds. Fringed sagebrush is an indicator of intensive cattle grazing, Many of these communities are obviously impacted by grazing and some appear to have been heavily grazed in the 1930's and never allowed to recover. These areas are not significantly impacted by water levels, but are used by geese because of their forage value and proximity to the river.

Black Cottonwood Forest
Salish: Mulš
Kootenai: Kanuⱡ mamaⱡ aqpiʾk

Black cottonwood forests occupy about 2% of the riparian zone of the river corridor. The tree grows up to 120 feet high. It is the largest of our cottonwoods. When mature, its trunk is often free of branches up to one-half its height. It has broad, oval-shaped crowns when grown in open sites. It grows on moist soils along streams and rivers. The leaves are 3-7 inches long and 3-4 inches wide; broad, rounded at base. The bark is smooth and greenish on young stems; becomes gray and sharply furrowed, 1 to 2 inches thick as the tree ages.

Because of the way Kerr Dam was operated for many decades (major reductions in peak flows and rapidly fluctuating water levels), there has generally been a tremendous loss of species like black cottonwood and sandbar willow, which pioneer flooded areas like gravel bars. At the same time species ponderosa pine and Rocky Mountain juniper have expanded.

Cultivated Land

Cultivated land includes pasture lands (lands grazed annually by livestock, alfalfa, grainfields, and lawns. By curtailing peak flows, Kerr Dam has "dewatered" much of the floodplain, and that has led to a tremendous conversion of the riparian vegetation to agricultural land. In addition. many of the wetter shrub types have been changed to herbaceous vegetation because of overgrazing of the riparian zone,

Marsh Communities

Marsh communities on the river can be classified as tall and short. Tall marshes are made up of common cattail, flowering rush, hardstem bulrush, and reed canarygrass. Dominant species in the short marsh include water horsetail, common spikerush, arrowroot, beaked sedge, marestail and a combination of jointed rush and slender spikerush.

Marsh communities are vulnerable to water level fluctuations, yet are critical feeding sites for numerous shorebirds and fish, as well as geese in the late spring.

It is likely that the diversity of marsh habitat was greater on the river before regulation of water levels.

Seasonally Inundated Mudflats and Gravel Bars

Gravel bars and mudflats are found throughout the river corridor. Because of the fluctuating water levels (in spring they are underwater and in fall they are exposed), these areas are, for the most part, unvegetated. Still they provide important habitat for shorebirds and waterfowl.

Mixed Forest Communities

Mixed forests are highly variable in the species they have, but birch and Douglas fir are common together, sometimes with black cottonwood, aspen, and/or Rocky Mountain maple as well. Black cottonwood and ponderosa pine are also frequently found together.

Because of the different species present, these forests are used by many wildlife species and have among the highest diversity of bird life.

Fire Occurrence

Areas within the Flathead River Corridor burned on average about once every 8.5 years prior to the days of fire suppression (the average was 8.5 years but actual fire frequency ranged between 5 to 25 years). Some of those fires were lit by Indian people to clear campsites and improve forage for horses and wildlife. The fires generally did not kill large, mature trees. They were brief, low intensity fires that burned mostly grass and shrubs.

It is difficult to control wildfires within the river corridor because the roads are poor and parts of the corridor don't have any roads. Fuels include grasses and native shrubs (sage and bitterbrush), and open stands of ponderosa pine and juniper. There are lots of important natural and cultural resources along the river, many of which benefit from frequent fires. Prescribed fire is the best way to assure protection and restoration of those resources.