The growth and survival of forests in the future, especially in the peripheral and transition areas of ecosystems, such as the Moldavian oak forests, depend directly on temperature changes and the amount of atmospheric precipitation. The purpose of this paper is to determine the potential impact of climate aridization on native species - oaks (Quercus robur, Q. petraea, Q.pubescens) in correlation with ecological niche for these species and identifying the vulnerability zones of forests versus the drought (reproduced by various values of the DeMartonne Index). It has been determined that mesophilic oak specie, during the vegetation period, in the central and southern part of the country, under more dry, more arid conditions of development, will feel changes in the sensitivity to water scarcity, changes in the compositional structure of the respective ecosystems and chorological displacements of the species (limiting the growth area of the Quercus robur, Q. petraea and advancing of Q.pubescens to the central part of country).