Wild deer have been increasing in abundance and distribution in Wales. Species present are Fallow, Roe, Red and Muntjac. Previously there has been no comprehensive research into assessing deer impacts in Wales. Research shows that overabundance of wild deer can have negative impacts on land-use activities including forestry, agriculture and conservation. Landowner questionnaires, vegetation and deer surveys carried out identify that whilst deer are currently not a significant issue nationally in Wales there are regional and deer species specific issues. The baseline data identifies that whilst negative deer impacts in Wales are increasing there is still capacity for deer to increase in abundance and provide a positive contribution within the Welsh countryside. Fallow are the most common species that have an impact, particularly in south and west Wales. Developing roe populations also have potential to add to the negative deer impacts across Wales. Results indicate that mid Wales will be the next region that will develop negative deer impacts. Increases in deer distribution and abundance is occurring at a greater rate than previously estimated. In woodlands managed for conservation, the research illustrates the value of small, short term exclosures and use of landscape level deer and impact evaluation methodology. Results highlight the usefulness of vegetation assessments, browsing indices and indicator plant species to monitor deer impacts. Deer are one component of woodland and it is important factors affecting deer are considered within a landscape framework. Research data has been used to formulate a conceptual model for assessing risks of wild deer in Wales becoming a problem in woodlands managed for conservation. The model establishes that in addition to land-use type and habitat preference by deer the other key factor that needs to be addressed to reduce the deer risk is the early implementation of a deer management plan, particularly monitoring.