Due to increasing use of wood products for energy production, recycling of wood ash as an alternative to deposition on landfills is of high interest. Using wood ash in forest road construction to improve mechanical stability has been recently suggested as feasible recycling option. To investigate the environmental impact of this implementation, a two-year field experiment, a column experiment and a water extraction experiment were conducted all including application of grate ash (GA) and fluidized bed ash (FBA). Analysing the leaching waters, surface runoff water and sub-road soil samples of the field experiment on an acidic and an alkaline forest soil, respectively, revealed that wood ash application is generally environmentally acceptable. However, changes in leachate composition were seen in all experiments. The highest impact of wood ash was found in the acidic forest on the GA treated site. Here Al, As, Fe, Mn, Ni, Co, Cu, Mo, pH und NO2- showed initial ‘flush events. In addition a column experiment simulating the forest road set-up was conducted in the laboratory treating pure soil with an ash-soil mixture on top with artificial rainwater. Three test soils of different pH were used. Due to the additional soil layer the direct ash-derived input of contaminants was diminished. Here mainly secondary mobilisation and ion exchange reactions caused increase of some characteristics, including Al, Cd, Co, Pb and Zn on the acidic soil, As, Fe, Mo, PO4, SO4, pH, EC und DOC on the neutral soil and Ni, Cu und SO4 on the alkaline soil. In conclusion more alkaline soils of higher clay and silt content were able to cope better with the impact of wood ash. The wide range of soils differing in buffer capacity should be considered in the establishment of thresholds for wood ash application in forest roads.