For many, the terms aging, maturation and senescence are synonymous and used interchangeably, but they should not be. Whereas senescence represents an endogenously controlled degenerative programme leading to plant or organ death, genetiC aging encompasses a wide array of passive degenerative genetiC processes driven primarily by exogenous factors (Leopold, 1975). Aging is therefore considered a consequence of genetiC lesions that accumulate over time, but by themselves do not necessarily cause death. These lesions are probably made more severe by the increase in size and complexity in trees...