The effect of removal of moss and low-growing shrubs on the growth of the tussock-forming cotton sedge Eriophorum vaginatum was studied at Eagle Creek in central Alaska. Shrubs and/or moss were removed from heavily infested tussocks with greater or lesser amounts of self-shading. Removal of moss produced little effect. Removal of shrubs resulted in an increase in the irradiance at the tussock surface and increases in tussock temperatures on afternoons of clear days. Tussocks with less self-shading also received more irradiance and showed higher temperatures. Tussocks from which shrubs had been removed produced many more daughter tillers and had smaller adult tillers than did the controls. Tussocks with less self-shading produced more daughter tillers than tussocks with more self-shading. Shrub removal caused increases in concentration of potassium in tillers, but did not change the concentration of nitrogen, phosphorus, magnesium, calcium, total nonstructural carbohydrates, and micronutrients. The results of the experiment indicate that shrub removal did not greatly affect the nutrient regime of the tussocks. Instead, most of the results of shrub removal can be attributed to alterations of the radiation regime of the tussocks. Increased tiller production probably resulted from changes in light quantity, light quality, or the direct effect of increased temperatures in the meristematic region. The combination of shading by shrubs and self-shading may have important effects on the vegetative demography of E. vaginatum and on macro- and microsuccession in tussock tundra.