Forest managers use mastication to grind or shed vegetation to remove competition, prepare a site for natural or artificial regeneration, or release sapling-sized trees; or they use mastication to convert ladder fuels to surface fuels and enhance decomposition of biomass. However, determining the best mastication configuration within the context of management objectives and site limitations is challenging. This report synthesizes our current knowledge on mastication as a forest management tool. We found that excavators, skid steers, and tractors can all be carrier machines and different types of vertical and horizontal cutting heads exist that can be front-end mounted or boom mounted, each with its own advantages and disadvantages. We provide a summary on the ecological effects from mastication. We found that there were several studies on plant and soil impacts, but limited information on impacts to wildlife habitat. Although costs of mastication widely vary depending on machine size, the physical setting, size and configuration of pre-treatment biomass, and operator skill, mastication does have market and non-market benefits. Depending on the management objective, if mastication is an option, then a thorough site evaluation should consider slope, nonnative species invasions, vulnerability of soils to erode or compact, and treatment costs.