Of longevity, budwood age, and young rootstock

General Fruit Growing
1

intriguing findings…when growing long-lived fruit crops such as lanzones which may take 12 to 30(!) years to start fruiting, airlayering is the only option, because grafting mature stems to young rootstock prolongs the juvenile period by at least two years.
the sidenote was just as intriguing—when an old(but disease-free) avocado tree has finally lost its capacity to regenerate, its budwood will be rejuvenated by grafting to a seedling.

evidently, by grafting to seedling rootstoc, the budwood from heirloom and disease-prone/short-lived varieties were maintained over hundreds of years, and with each grafting, may even ‘regress’ to some degree of ‘juvenility’.

2

There is nothing in that article that indicates these findings can be generalized to other genera or tribes (families) of plants.

3

you betcha! But still intriguing nonetheless, i mean, if you have an excellent but already declining avocado tree(as long as it is disease-free), all you need to do is take budwood and could rejuvenate by grafting to a seedling.