We have analysed several edaphic and nutritional factors influencing the soil conservation in 19 native temperate forests dominated by Quercus robur L. in Galicia (north-western Spain). Oak forests represent the climax communities in the study area. Show a high variety of vascular plants and commonly occurs in mixed stands, known as “fragas”, along with other tree species as Castanea sativa Mill., Betula alba L., Corylus avellana L., and often Taxus baccata L. Other oak species that hybridize easily between them may also could be present, e.g., Quercus petraea (Matts.) Lielb., and Quercus pyrenaica Willd. These forests are especially vulnerable because of the anthropic impacts to which they are exposed. Poor soil conditions and nutrient removal due to forest fires, in addition to the application of unsuitable management rotations, could limit tree nutrition and influence the conservation of these ecosystems. So, we have described the soil type on which the stands are located and their main edaphic properties. Also, we have assessed the nutritional status from the result of foliar analysis. Most soils are acidic or highly acidic and all are rich in organic matter. The foliar analysis showed that the most important limitations for the oak forests were normally the low concentration of macronutrients, even in some soils there were also deficient level of nitrogen. These deficiencies may to be linked to the low availability of these nutrients in the soil. Such restrictions may reduce the possibilities of conservation of these ecosystems, something that should be considered in future silvicultural treatments aimed to their sustainable protection and management.