Aspen Forests 



The highlands of southeastern Idaho contain large stands of aspen. In many of these , 

 heavy grazing has caused valuable understory grasses and broad-leaved herbs to be replaced by 

 a sparse cover of undesirable weeds. Presence of trees limits the seeding method to broad- 

 casting with no preparatory seedbed treatment. In both Utah (Plummer and Stewart 1944) and 

 southeastern Idaho, unproductive aspen ranges have been seeded successfully by broadcasting 

 before or during the time of aspen leaf fall. The layer of leaves adequately covers the seed. 

 Grass species that have performed best on aspen sites have been timothy, orchardgrass , tall 

 oatgrass, meadow foxtail, intermediate wheatgrass , and smooth brome . 



Weedy Openings 



Much of the nonforested part of the higher country in southern Idaho is infested with tar- 

 weed and knotweed. These areas are often gullied and are the source of runoff from snowmelt 

 and from summer storms . 



On many of these sites, the temperature of surface soil fluctuates so greatly each day that 

 seeding trials have not been successful. Except on some tarweed areas, further study is needed 

 before we can make sound recommendations for seeding. 



Tarweed often dominates high-altitude openings to the near-total exclusion of other spe- 

 cies. In eastern Idaho, where summer rainfall is quite dependable, tarweed ranges have been 

 improved by seeding; but no good seeded stands have been established in tarweed areas in 

 western Idaho. Germination of tarweed seed is nearly complete each spring; hence it can be 

 eliminated for 1 or more years by shallow cultivation or by spraying with 2,4-D in spring be- 

 fore seeds develop. Seeding should normallybe done in early spring when tarweed is eliminated. 

 Where spring seeding is not feasible, tarweed areas may be cultivated or sprayed with 2,4-D in 

 the spring and seeded in the fall. 



Smooth and mountain bromes , timothy, 

 meadow foxtail, orchardgrass, intermediate, 

 pubescent, and slender wheatgrass , and tall 

 oatgrass are adapted for seeding on tarweed 

 sites. 



Figure 11. --Seeding this lodgepole 

 pine bum has protected topsoil 

 from erosion and provided feed 

 for livestock and elk. Valley 

 County. 



