Ionic liquids are synthetic compounds with melting temperatures lower than 100 °C and with high ability of modification of their physical and chemical properties from changes in their chemical structure. Although the number of applications in the last years has been continuously increasing, their effects on the different terrestrial ecosystems have been scarcely studied. In this work, the effects of the ionic liquid ethylammonium nitrate (EAN), the aluminum nitrate salt (Al(NO3)3), and the saturated mixture of both components on the germination of three forest species were studied. Different doses, from 0% to 10% weight, of the three treatments were applied at seeds of three different forest species (Eucalyptus globulus Labill, Pinus radiata D. Don, and Pinus sylvestris L.) and the germination of these seeds was continuously monitored for 35 days. The results showed that the addition of ionic liquid, salt, and mixture provoke the reduction of germination for all the species. Concentrations of 5% and higher incite the total inhibition of the germination of all species for all the treatments, with the EAN treatment being the most harmful.