Utah juniper (Juniperus osteosperma) expansion in the west has resulted in increased wildfires and has led land managers to search for effective fuel control methods. Mechanical mastication using a large, rotating drum with carbide teeth mounted on a tractor allows managers to selectively control trees throughout much of the year. Because tractors typically weigh 16,300 kg or more, they may compact soils during the mastication procedure. Compaction may increase the bulk density of soils which may increase surface runoff and erosion. We investigated soil compaction and hydrologic responses from mastication on a gravelly loam soil with a slope of 15% on the Onaqui Mountains of Utah.  Rain simulations were conducted on 4 uncompacted and 4 compacted microsites (juniper mound, shrub mound, interspace with grass, and bare ground interspace). Rain simulations were applied at 2 rates: 6.4 and 10.2 cm per hour. Runoff and sediment were collected from 20 pre-treatment (all uncompacted) plots and 40 post-treatment (20 uncompacted and 20 compacted) plots. Bulk density samples, compaction, ground cover, soil stability, and microtopography were measured. Preliminary results indicate that tracked soils are more compacted than non-tracked soils.