Plant life span questions

[amcoffeegirl]

I was reading some advice being given on another forum and they stated that every plant has a life span. I don’t believe that. I think if a plant is given good growing conditions that it will just keep growing.
If it has no pests or health issues would a tree just die from old age?
What are your thoughts on this?
Plants can die for a lot of reasons but can old age be one of them?

 

[PiñonJ]

Plants have lifespans, as do most other organisms. Your assumption that good growing conditions would cause them to live longer is not supported by the evidence. The oldest known trees live in some of the harshest conditions. According to Wikipedia, the oldest living Bristlecone is just over 5000 years old. I’m guessing their slow growth is part of what lets them live so long. Clonal colonies are another story. According to the same article, the Pando aspen clone is estimated at 80,000 years, but the individual trees get old and die.

 

[Dav4]

Ultimately, genetics determine longevity. Good horticulture and favorable growing conditions can extend life, but everything dies eventually.

 

[Cadillactaste]

The shrub called a sand cherry has a very short life span. They just weaken and become supseptible to things. Watched one wither and die in the neighbors landscape that I admired for years prior to planting one in my own yard. I had no clue. Flowering almond is also short lived.

I just had a treatment last spring to my front tree to help it store energy than push new growth in hopes to prolong its life span. We had planted it for our son...when he was born. Explained to the nursery of the reason to plant the tree. Grimmy enlightened me it has a short lived tree. 12-15 years he said for the flowering purple plum. My son is 21... So we have been fortunate it's still standing. But it did have die back when we had that acrtic spell in 2013-14 and then 2014-15. They say the life span is 20 years. So...it's frustrating.

 

[WNC Bonsai]

Here is a great refernce on lifespans of common trees in Virginia but it should apply to the same species in similar zones.

Lifespans of Common Trees in Virginia

Source: Loehle, C. (1988). "Tree life history strategies: the role of defenses." Canadian Journal of Forest Research 18(2): 209-222.

Common Name Scientific Name Average Lifespan Maximum Lifespan

Ash, Green Fraxinus pennsylvanicum120 175

Ash, White Fraxinus americana260 300

BasswoodTilia americana100 140

Beech, American Fagus grandifolia300 400

Birch, GrayBetula populifolia50?

Birch, Paper Betula papyrifera100 140

Birch, Sweet Betula lenta150 250

Birch, YellowBetula alleghaniensis150 300

BoxelderAcer negundo75 100

CatalpaCatalpa speciosa100?

Cedar, Eastern redJuniperus virginiana150 300

Cherry, BlackPrunus serotina100 250

Chestnut, AmericanCastanea dentata100 300

CucumbertreeMagnolia acuminata80 250

Cypress, BaldTaxodium distichum600 1800

Dogwood, Flowering Cornus florida125?

Elm, American Ulmus americana175 300

Elm, Slippery Ulmus rubra200 300

HackberryCeltis occidentalis150 200

Hemlock, EasternTsuga canadensis450 800

Hickory, BitternutCarya cordiformis175 200

Hickory, Mockernut Carya tomentosa200 300

Hickory, Pignut Carya glabra200 300

Hickory, Shagbark Carya ovata250 300

Holly, American Ilex opaca100 150

Locust, Black Robinia pseudoacacia60 100

Honeylocust Gleditsia triacanthos120?

Magnolia, Southern Magnolia grandiflora80 120

Maple, RedAcer rubrum130 300

Maple, Silver Acer saccarinum100 125

Maple, Sugar Acer saccharum300 400

Mulberry, Red Morus rubra125?

Oak, Basket Quercus michauxii100 200

Oak, Black Quercus velutina100 225

Oak, BlackjackQuercus marilandica100?

Oak, Chestnut Quercus prinus300 400

Oak, Live Quercus virginiana200 300

Oak, Northern Red Quercus rubra200 400

Oak, Overcup Quercus lyrata300 400

Oak, Pin Quercus palustris100 150

Oak, Post Quercus stellata250 450

Oak, Scarlet Quercus coccinea80 180

Oak, Southern Red Quercus falcata200 275

Oak, Water Quercus nigra175 175

Oak, WhiteQuercus alba300 600

Osage-orangeMaclura pomifera75 300 +

Pecan Carya illinoensis300?

PersimmonDiospyros virginiana60 80

Pine, Loblolly Pinus taeda100 300

Pine, ShortleafPinus echinata200 300

Pine, Table MountainPinus pungens100 200

Pine, Virginia Pinus virginiana100 200

Pine, WhitePinus strobus200 450

Poplar, BalsamPopulus balsamifera100 150

Tulip–PoplarLiriodendron tulipifera250 450

SassafrasSassafras albidum100 500

Spruce, BluePicea pungens150 350

SweetgumLiquidambar styraciflua200 300

Tupelo, Black Nyssa sylvatica250 600

Walnut, Black Juglans nigra150 250

Willow, BlackSalix nigra70 85

 

[WNC Bonsai]

Sorry that the formatting wasn’t preserved but you should be able to figure it out. Gotta love those bald cypress and hemlock!

 

[Wires_Guy_wires]

I found that when plants are grown in vitro, with the right adjustments, their life span can be extended by at least fourteenfold. That takes a bi-monthly transfer though, so it's expensive and time consuming.

There are still mutations taking place though, meaning that it's unlikely that the genetic makeup is still the same as fourteen lifespans earlier. Eventually, those mutations take place in genetic regions that the plant needs to function normally, that's when they wither and die.

Imagine a copy of a copy of a copy of a copy of a copy (and so on). At some point, the loss is too great to function.
The speed at which this happens differs greatly among individual plants of the same species and even the same cultivar.

 

[Starfox]

I think the question is more 'Can bonsai techniques extend the lifespan of certain tree species?'.

No doubt some species of trees in the wild or planted out in a garden can and do have shorter life spans and it's probably safe to say that the reason one tree may die early could be entirely different to the reason another may, so if one can work out the reasons why they do then that is a good start.

It's a question that often gets raised with Australian natives as there are quite a number of species that are well known for their short life spans of around 20 years or so and what I have read the trees basically outgrow their root systems and ability to get all that energy up into the limbs. In theory the action of keeping a tree small, healthy, contained and regularly pruned should extend the lifespan. It sounds logical at least.

And there is anecdotal evidence of some trees in peoples collections that have outlasted their wild cousins considerably so the theory may hold some water. I'm not sure anyone is out there sciencing this though and seeing as western bonsai is still relatively young pursuit we may have to wait a few decades before it becomes clearer.

I do think we can extend their lives with techniques, maybe not indefinitely but somewhat at least and I also feel that you shouldn't let a so called short lifespan detract on wanting to own a particular species.

 

[peterbone]

Most trees die because the feeder roots get further and further from the trunk of the tree. If you prune the roots regularly then they can in theory live forever. There may be other limiting factors such as genetic mutations but I think it would be a very long time before that has an effect. Some trees such as Birch have a relatively short lifespan because they have reduced ability to heal themselves and fight disease. They compensate by propagating themselves over large distance and in high numbers. One reason why Birch is used less as bonsai.

 

[Gustavo Martins]

All you need to know

https://www.fs.fed.us/psw/publications/groover/psw_2017_groover001.pdf

 

[Anthony]

Our varieties of casuarina are supposed to live for 50 years.
Which is why we don't grow them.
As our Bonsai growing age approaches 40 years, we now wonder
if the Gmelina will also die.
Life span is supposed to also be around 50 years,

To helplessly watch "children" die -------- most depressing.

My family range is 100 to 90 years, I am just 55. Knock on
wood.

Never really thought about out living some of the Bonsai.
Good Day
Anthony

 

[peh3]

Makes me wonder if rooted cuttings start at the age of the original tree or if they have their own age...

 

[Wires_Guy_wires]

Makes me wonder if rooted cuttings start at the age of the original tree or if they have their own age...

The age of the original tree in most cases. We make good use of that with grafting and similar techniques.

 

[amcoffeegirl]

I find this very interesting and I am proud of the way this conversation is progressing.
I have heard that trees have a life span before but I’ve never really given it much thought.
I just find the studies fascinating- honestly.
Most may think it’s boring but I enjoy learning.

 

[Leo in N E Illinois]

@Gustavo Martins
Thank you for the link to the detailed research on aging in trees. For those who do not want to read the whole article here is a highlight or two from the conclusions.

<quote> Trees do not have a strictly programmed time of senescence, in contrast to monocarpic species that senesce after flowering and producing seeds (Munné-Bosch, 2008). In fact, there has been speculation that trees may to some degree defy the forces that limit life span in most species (Ally et al., 2010). It has been hypothesised that senescence and limited life span may be the result of natural selection, which, in most species, is most effective during youth when reproductive capacity is greatest. In trees, however, perennial growth can result in larger bodies carrying more numerous reproductive structures and may also provide benefits to wind-based pollen or seed dispersal through greater height growth. Thus, there is potentially a large benefit to delaying senescence to enable larger growth of persistent woody bodies. <snip>

The article goes on, but the key point, lifespan in trees is open ended, without the strict defined limits one would encounter with monocarpic species (what we think of as conventional annual plant species). While there are average ages, there are no bright line limits. Individuals can vary from the average by significant numbers of years, sometimes an order of magnitude or more longer lifespan than the average lifespan.

So it is safe to say that for bonsai purposes, any tree that is listed as being capable of living more than 20 years will have a good chance at outliving one or two generations of bonsai artists.

On the other hand, how many trees, of long lived species have we killed in our collections at some age less than the average life span? I know I have killed my share of long lived species. If a tree makes it in my collection past 5 years it has beaten the odds. My best record is to keep a single tree healthy for about 38 years, then it wasn't healthy because of something I did, not the tree's biology. Then it died. In general as bonsai artists, most of us really do not have to worry about the tree's life span. We need to worry about whether we can provide consistent care long term enough to get through a decade.

Worrying about the life span of a tree is a trivial concern in most situations, except perhaps if you are a member of a multigenerational bonsai nursery family and are planning for bonsai sales 50 and 100 years from now.

 

[penumbra]

Some plants not on the list have surprisingly short lifespans, such as Mimosa and Redbud. These two spring to mind because I have outlived the ones planted when I was young. Redbuds are about 30 to 40 years, but I flagged some in tree conservation that were at least 80 years old if not older. In fact, I was the cause of a developer to lose 4 parking spaces at an office complex because I would not allow clearing equipment near a large old redbud. I outlived many Mimosa trees but the one I planted in my yard 30 years ago is doing very well. Domestication has added many years to some trees and shortened the lifespan of others.
And then all of these figures are based upon average life spans. Consider that a pet rabbit might live 14 years and that the average lifespan of a wild rabbit is measured in weeks. So yes, absolutely, some bonsai can be expected to live longer than their wild counterparts.

 

[amatbrewer]

@Gustavo Martins
In general as bonsai artists, most of us really do not have to worry about the tree's life span. We need to worry about whether we can provide consistent care long term enough to get through a decade.

Worrying about the life span of a tree is a trivial concern in most situations, except perhaps if you are a member of a multigenerational bonsai nursery family and are planning for bonsai sales 50 and 100 years from now.

That is good information, especially for new and/or aspiring Bonsai artists. A while back when I started thinking about getting back into Bonsai, I asked about a particular species of tree that I was fond of (and very prevalent), and was advised to not bother due to its 'short life span of around 20-30 years'. I foolishly listened and it was not until a number of years later that inspiration struck again. I would be much further along in my Bonsai journey had I ignored that advice.

 

[penumbra]

Our varieties of casuarina are supposed to live for 50 years.
Which is why we don't grow them.
As our Bonsai growing age approaches 40 years, we now wonder
if the Gmelina will also die.
Life span is supposed to also be around 50 years,

To helplessly watch "children" die -------- most depressing.

My family range is 100 to 90 years, I am just 55. Knock on
wood.

Never really thought about out living some of the Bonsai.
Good Day
Anthony

This brings to mind a post a short time back when the topic was who the caretaker would be when you pass. As year #70 closes in I have someone in line for my bonsai, another in line for my rare succulents, another for my Japanese prints, another for my Chinese jade etc.

 

[rockm]

This takes a bit of "original" non-animal (look it up) centric thinking....Trees are plants, obviously. Tagging them with this kind of "longevity" thing misses how they operate.

There is a theory (and I can't put my finger on the documentation at this point) that trees don't really die from old age, as much as they succumb to simple physics. It takes x amount of years until the tree's genetically programmed capabilities can't operate because they're overtaxed by distance, height, depth of growth. The most recent outer growth encasing a tree isn't as old as the dead inner wood.

The taller a tree gets and the more its roots spread out, the more energy the tree expends getting and sustaining resources from those outlying (And most actively growing) areas. Long, thick, woody roots closer to the trunk are very inefficient at finding and exploiting nutrients in the soil. Those thick woody roots are highways for the younger, active feeder roots at the end. Same for the top growth. At some point, the tree physically can't pump water high into its crown, or draw nutrients back to the tree's main body.

All the while, the tree is basically regenerating itself entirely (growth rings anyone) every year or so. In other words, trees are kind of like coral reefs, where living tissues regenerate over a dead core.
With bonsai, we kind of short circuit that "aging" process forcing more efficient roots closer to the core of the plant and keep foliage closer to the roots.

 

[penumbra]

Interesting. Plants do have the ability to regenerate their telomeres. Apparently juvenile cells are continually created in the meristem.