From what I understand (to save time let's agree that this qualification applies
to all of what follows), there are certain plants that have a finite lifespan
built into them: they go to seed and then they die. (Incidental question: does
such a lifespan always coincide with a single solar year?) Then there are
animals, who have decrepitude built into them instead: it can't be put off
indefinitely, and once it starts, it continues until the animal is too feeble to
survive.

Please comment on anything that's incorrect so far.

My main question is: What about trees? I can't recall ever hearing of a tree
that died of old age. They continue growing throughout their lives, but is there
anything about perpetual growth that necessarily leads to death? (Incidental
question: How does a tree's growth rate change over the course of its life?)
Obviously something will get them eventually, just because life is a gamble and
every lucky streak has to end. But, in principle, could a tree live forever?

Any help greatly appreciated.

Peace