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Plant Life

The Salmon River Canyons is primarily arid grassland mixed with towering ponderosa pines, and along the river’s edge hackberry trees, mountain mahogany and other riparian species.  The river’s canyon is a distinctive vegetative region of the Pacific Northwest.  The semi-arid climate features hot, dry summers and mild, moist winters.  This climatic benefit allows for the longest growing season and most frost-free days of any region in Idaho.  Elevations within the river canyon range from 900 feet to over 5,000 feet, which enables many plant communities to thrive.  Native species common to the Salmon River Canyons include: bluebunch wheatgrass, prickly pear cactus, poison ivy, lupine, arrow leaf balsamroot, western yarrow, wooly mullen, coyote willow, curl leaf mahogany, netleaf hackberry, and ponderosa pine.  

Much of the land surrounding the river has been disturbed by grazing, logging, or fire.  These disturbances have facilitated the invasion of non-native plant species.  Non-native species include: yellowstar thistle, cheatgrass, teasel, and knapweed.  Early settlers also introduced several horticultural species such as apricot, apple and walnut trees. 

Floods, which vary widely in frequency and duration on free-flowing rivers, have created distinct bands of lichen and moss on the canyon walls.  Four distict zones are normally apparent.  The low water zone, which is typically underwater, contains lichen and algae.  The normal flood zone, covered by water only during normal high flow periods, contains whitish-gray lichen and eddy moss.  The high flood zone, covered by water only during extreme high flow periods, contains two types of flood moss.  This zone occurs more consistently than any other.  The extreme flood zone supports terrestrial vegetation and is predominantly barren of any lichen or moss.

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