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Piñon and juniper trees are masticated or shredded to reduce fuels and encourage understory growth. We measured hydrologic, soil, fuel, and vegetation responses to shredding in Utah in a series of both designed and post-hoc studies conducted over the last 7 years on one to 44 sites.  Shredded debris increased infiltration in interspaces with gravelly loam soil and 15% slope (1 site).  Shredding increased time of soil water availability in spring and summer by up to 6 weeks in stands with high pre-treatment tree cover (4 sites).  Shredding also increased N supply rate by 4.7 times in stands with high pre-treatment tree cover (4 sites), probably due to decreased tree use of N and increased time of available soil water. Shredded debris increased P concentrations and microbial biomass across a range of pre-treatment tree cover (44 sites), while decreasing N mineralization and nitrification in surface soils where pre-treatment tree cover was < 45%.  Both bluebunch wheatgrass and cheatgrass seedlings had greater production on shredded than untreated microsites (3 sites).  Shredding converted canopy fuels to 1 and 10 hour woody debris (44 sites).  Shrub cover was unaffected by shredding but perennial herbaceous cover was increased, even for plots with high pre-treatment tree cover (44 sites).  Sites that are seeded after shredding especially had high perennial grass cover where pre-treatment tree cover was high.  Shredding has the advantage of placing canopy fuels on the ground, which lessens fire spread and benefits suppression.  It also leaves sagebrush and other shrubs, while increasing perennial herbaceous cover.  It may also increase cheatgrass cover on some susceptible sites.   Treating these susceptible sites will be most successful when they have high initial cover of perennial grasses or are seeded to promote perennial plant use of the soil water and nutrient resources made available from tree shredding.