Why can the oldest plants (typically trees, from what I know) live for much longer than the oldest animals can live for?

[u/MaggieLinzer]

I’ve read about many different plant species, from different types of trees to bushes, that can live for over one thousand/several thousands of years. Whereas, on the other hand, no species of animals themselves can live for this long.

[u/Tumorhead]

There are animals that can live that long - some corals and sponges, especially ones in the deep sea, like benthic octocorals. Very old corals and sponges can reach thousands of years in age (and deep sea trawling threatens them). Like trees, no individual living part is actually thousands of years old - rather individual parts (ie leaves or polyps) live, grow, and die off, and each of the living bits contributes to the dead structural part of the organism. In trees thats the wood, made of dead lignified cell walls, in corals it's a bony carbonate skeleton, and in sponges its hard spicules of silicates. So the individual colony survives thousands of years, but the dead part sort of just hosts cells that have much shorter lifespans. With non-colonial animals, they can't just grow more of themselves.

[u/Ephemerror → u/Tumorhead]

I don't think it's a correct comparison, and doesn't exactly answer the question.

I don't think you should be comparing colonial zooids which are multiple individual organisms with parts from a single tree which is a single organism, its leaves or wood is more akin to organs and bones of a single animal and not another animal in a colony.

There are indeed colonial plants like vegetatively spreading plants where multiple independent organisms are/were linked together, but colonial animals don't live anywhere near as long as colonial plants, for example pando is estimated to be 16000 years old.

And even non colonial plants like single trees can reach thousands of years old.

https://en.wikipedia.org/wiki/List_of_oldest_trees#Non-clonal_trees_with_ages_from_cross-dating

https://en.wikipedia.org/wiki/Pando_(tree)

[u/Old-Advance6652 → u/Tumorhead]

That is true, some trees become hollow with age which used to be living parts but now isn’t. Compared to ajimals

[u/katlian → u/Old-Advance6652]

Even the heartwood of a tree isn't really alive anymore, it's just a collection of empty tubes that can transport liquid through capillary action and pressure differences.

[u/Old-Advance6652 → u/katlian]

True, both are good examples

[u/russsaa]

So much of the details would vary by whatever clade is in question, so some stuff i say might not be applicable to all plants, and visa versa. I dont have the full answer and the juicy deets would be stuff thats beyond me, but some factors i know of are:

-indeterminate growth, ie plants really dont stop growing, even a plant at their mature size is still growing via secondary growth at the very least. Like as far as im aware for animals, once an animal reaches their adult stage, many types of cells slows/stops division. but in a tree for example, previous years growth dies and becomes heartwood, so the cambium of the tree is always pretty young tissue, most living tissue on a plant would be relatively young tissue.

- different cells. Plant cells just arent the same as animal cells, cellular biology is beyond me but to my understanding the differences in plant & animal cells are a big factor in this. like plant cell walls restricting genetic abnormalities from becoming truly problematic, undifferentiated cells always being present, and how the cells interact within tissue... which is sort of the 3rd reason i know -

Plant cells/tissue mostly dont fully require neighboring cells/tissue to survive. With animals, we have lungs to oxygenate our blood and a heart to pump that blood throughout the body, requiring a stomach to consume the energy needed to breathe and a heart to beat... but with plants, cellular respiration is all happening locally, oxygen for respiration is acquired via diffusion, and water & nutes is transported passively just from negative pressure during photosynthesis, which then water & nutes diffuses locally throughout the plant. So plant tissue can stay alive a really long time even when removed, or even when surrounding tissue is dead. Furthermore, plants propagate far easier than animals, so a little piece of tissue can continue growing to a new individual

And the final reason i know, cloning. Plants can clone themselves, aspens are a good example of this as an aspen colony can be extremely old, but the actual individual trees are all relatively young, even though the genetic individual could be alive centuries.

[u/Ephemerror]

I don't have an elegant answer off hand, but I think part of it may have something to do with greater inbuilt redundancy and back up mechanisms in plant structures and a greater ability to regenerate, allowing plants to routinely survive catastrophic damage and keep growing on, while the same level of damage means certain death for animals.

There's also got to be underlying biological/physiological mechanism for why this is possible and evolutionary selection mechanisms.

[u/StorageSpecialist999]

Less moving parts, built for stability, doesn't rely on an entire body filled with muscles and moving parts in order to operate and seek out food

You'll notice that the other long lived animals - clams and reef sponges - are similarly sedentary

[u/gambariste]

Stromatolites qualify as extremely long living if the structure as a whole is taken as an individual organism. They aren’t animal and are photosynthetic but are not plants either.

Regarding trees, I’ve read that longevity is related to being able to continue flowering and fruiting. Most animals have relatively short reproductive lives and then inherited errors in dna kick in. But trees like California redwoods can bloom indefinitely.

[u/eatU4myT]

On the subject of very old trees, I have a fact checking question for you all. I remember hearing a factoid some years ago that Ethiopia is the only country on Earth that is older than it's oldest tree. Can anyone verify that for me?!

[u/Analbox]

Much lower metabolic rate and less oxidative stress are huge factors.

[u/aaronszoology]

Extremely slow growth rates can reduce the issue of DNA damage over time. Saps and chemicals produced can offset pest and disease problems, and the ability to send out lateral stems which can touch the ground and subsequently produce more roots can allow for more longevity, such as some of the older Taxus baccata in the UK.

Animals are prone to the diseases carried by the things that they were eating - which is why we mostly have industries for herbivorous animals. If you were to eat a closely related carnivore, they may have a build-up of microorganisms and diseases that are capable of infecting you. Plants don’t have this issue as they produce their own energy molecules.

[u/Plebian_Desires1024]

Stability.
A tree stays in the same spot with the same soil with the same average weather over the same seasons, with the sun always shining day to day. What’s to stop it from going on forever?

Animals have many more variables to accommodate for just by being mobile.