Trees are unique in terms of development, sustainability and longevity. Some species have a record lifespan in the living world, reaching several millennia. The aim of this review is to summarize the available data on the genetic and epigenetic mechanisms of longevity in forest trees. In this review, we have focused on the genetic aspects of longevity of a few well-studied forest tree species, such asQuercus robur,Ginkgo biloba,Ficus benghalensisandF. religiosa,Populus,WelwitschiaandDracaena, as well as on interspecific genetic traits associated with plant longevity. A key trait associated with plant longevity is the enhanced immune defense, with the increase in gene families such asRLK,RLPandNLRinQuercus robur,the expansion of theCC-NBS-LRRdisease resistance families inFicusspecies and the steady expression of R-genes inGinkgo biloba. A high copy number ratio of thePARP1family genes involved in DNA repair and defense response was found inPseudotsuga menziesii,Pinus sylvestrisandMalus domestica. An increase in the number of copies of the epigenetic regulatorsBRU1/TSK/MGO3(maintenance of meristems and genome integrity) andSDE3(antiviral protection) was also found in long-lived trees. CHG methylation gradually declines in theDAL 1gene inPinus tabuliformis, a conservative age biomarker in conifers, as the age increases. It was shown inLarix kaempferithat grafting, cutting and pruning change the expression of age-related genes and rejuvenate plants. Thus, the main genetic and epigenetic mechanisms of longevity in forest trees were considered, among which there are both general and individual processes.