THE IMPACT OF CLIMATE ARIDIZATION ON OAK STANDS IN THE REPUBLIC OF MOLDOVA (CASE STUDY)

The forests of the Republic of Moldova are composed predominantly by mesophilous deciduous tree species, the most valuable specie are oaks, located at the limit of their natural area. The growth and survival of forests, especially in the peripheral and transition areas of ecosystems, such as the oaks stands of country, also depend on the variety of the thermal and pluviometric regime, which has changed over the last decades in the context of climate aridization. The estimation of the mesophilic tree species exposure to regional climate aridization is shown by the simultaneous use of a set of eco-metric indices: Forest Aridity Index (FAI), De Martonne Index (IM), Ellenberg Coefficient (EQ), and Beech Tolerance Index (Q(BTI)). For areas occupied by oaks (within 2 major natural reserves from central part of Moldova), have been indicated FAI values equal to 6.5-7.5; IM values between 30.0-35.0; EQ values ranging from 30.0-38.0; and Q(BTI) values around 15.0 units, favourable for the mesophilic oak forests development. This fact indicates that during the vegetation period of mesophilic trees, in the central part of the Republic of Moldova, in more arid conditions of development, through modification of oak sensitivity to the water deficit, changes will occur in the compositional structure of ecosystems and the chorology of species. The study results are of particular interest in the sustainable management of the national forestry sector.