Mechanical mastication that converts standing shrub and small tree fuels into compact surface fuels is thought to moderate fire behavior and, thus, is widely used as a method to reduce fire hazard. Whether standard fuel models can be used to predict the resulting fire behavior and effects in these fuel beds is poorly understood. Prescribed burns in masticated fuels were used at two sites in northern California to study effects on fire behavior and residual trees. Custom fuel models provided a better prediction of fire behavior variables than standard fuel models. Under wildfire conditions, computer simulations using the custom models predict that mastication may be useful as a tool for moderating fire behavior but does little to ameliorate fire effects. This works shows managers that further reducing the masticated material with prescribed burns could help better achieve the objectives of reducing fire hazard while improving resilience of the remaining stand to wildfire.