In flammable shrublands fire size often depends on local management. Policy and land use change can drastically alter fire regimes, affecting livelihoods, biodiversity, and carbon storage. In Ethiopia, burning of vegetation is banned, but the burn ban is more strongly enforced inside the Bale Mountains National Park. We investigated if and how policy and land use change have affected fire regimes inside/outside the park. The park was established in 1969, and both studied areas have been part of a new REDD+ project since 2013. Our hypothesis is that burnt heathland stands are nonflammable and act as fuel breaks, and hence that reduced ignition rates leads to larger fires. To quantify change we analyzed remote-sensed imagery from 10 fire-seasons between 1968 and 2017, quantifying sizes of resprouting Erica stands and recording their postfire age. To elucidate underlying mechanisms of change we interviewed 41 local smallholders. There was a five order of magnitude variation in patch size (< 0.01- > 1000 ha). A significant interaction was found between year and site (inside/outside park) in explaining patch size, indicating that the park establishment has affected fire size. Inside the park there was a tendency of patch size increase and outside a clear decrease. Especially the largest fires (> 100 ha) increased in numbers inside the park but not outside. Respondents confirmed that large fires have increased in frequency and attributed this mainly to lack of fuel breaks and the fact that fires today are ignited in a more uncontrolled manner later in the dry season. Outside the park respondents explained that fires have become smaller because of increased ignition and intensified grazing. Both situations degrade pasture and threaten Erica shrub survival. For flammable ecosystems, REDD+ fire-exclusion policies need updating, and in this case complemented with a community-based fire management program making use of the vivid local traditional fire knowledge.