Climate change is expected to increase instability of several ecosystems and a rising concern for tree biologists is the decline in genetic diversity of tree populations affecting forest health and resilience under changing environmental conditions. Understanding the population diversity and its inherent dynamics is the cornerstone in conservation, genetic improvement and sustainable utilization of tree genetic resources. The accelerated change of climatic conditions, altered land use patterns, habitat fragmentation and land degradation can significantly affect population demography. Hence, information on patterns of genetic diversity change, and the potential association between environmental heterogeneity and genotypes are essential for selecting adaptive seed sources for ecological restoration programs and designing seed transfer guidelines, as well as on planning in situ and ex situ conservation strategies.