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Pinyon-juniper woodlands are encroaching on thousands of hectares of sagebrush steppe. Decreased fire frequency favors proliferation of pinyon-juniper woodlands and subsequent decline in desirable understory species. Woodland encroachment increases tree cover and produces hazardous canopy fuel loads that contribute to severe crown fires. Crown fires can produce high amounts of heat that kill desired vegetation which increases erosion potential and degrades wildlife habitat, and threatens life and property in wildland urban interfaces. Mechanical shredding converts canopy fuels into small woody debris, distributed in patches. Shredding changes wildfire dynamics from a potential crown fire to a more controllable surface fire.  We measured untreated, shred, and shred + burn treatments on 40 different sites throughout Utah (587 subplots). Fuels were measured on 30-meter transects within 30 X 33 m subplots. Shredding trees reduced large-diameter fuels to primarily 10 hour fuels (6.4-25.4 mm diameter). The shred treatment did not alter standing shrub biomass, but increased herbaceous biomass relative to untreated subplots two-fold at low tree cover and eight-fold at high tree cover (P < 0.01). Compared to shred subplots, the shred + burn treatment decreased woody biomass three-fold for low tree cover and ten-fold for high tree cover, while herbaceous biomass increased two-fold at low to moderate tree cover. Mechanical shredding is a valuable tool for reducing canopy fuels to aid in controlling fire, and generally stimulates a positive understory response. Although this study did not measure soil heating and plant mortality, burning shredded fuels may cause lethal soil heating longer than that of a fire in a historic sagebrush steppe community. Prescribed burning could be used in cool-weather, high-moisture conditions to safely remove surface fuels and prevent lethal soil heating and plant mortality.