Rhizosphere effects of tree species - Large reduction of N2O emission by saplings of ash, but not of beech, in temperate forest soil

► Ash saplings reduced N2O efflux of a forest soil which was not solely explainable by plant N uptake. ► Under ambient N availability, N2O emissions were reduced by 94% compared to root-free soil. ► Under high N availability ash saplings lowered N2O emissions even by 98%. ► The suppression of N2O release by ash roots was larger than the stimulating effect of N addition. ► In contrast, N2O emissions were not significantly affected by beech saplings.