Tree Senesence

[Jim1NZ]

I was after views and opinions on tree senescence. What triggers it, why do tree senesce?

Age related, environment related, reproduction related, height related, mass related???

What do you think...

 

[Stumper]

Age related, environment related, reproduction related, height related, mass related???


Yes. And over pruning related.

 

[smokechase II]

Stress related events such as; repeated droughts, beetles getting it on....

 

[Jim1NZ]

Interesting...

So no one thinks it is any one factor over the other?

 

[Shaun Bowler]

What the hell are you talking about, professor?

Is what you are asking called Suddden limb drop?

 

[treeseer]

Senescence just means aging, so no there's not one over others, many factors can work to age a tree, just as a person. Like Stumper, I see it often as anthropogenic (that's a word for the professor that means "human-caused").

I've seen maples decline in cities. Authorities had no clue wtf was going on, so they called it "early senescence". This was a big word used to sustain their authority even tho on this subject they were totally ignorant. The causes are often girdling roots, bad soil, bad air, and other anthropogenia.

Jim ya gotta get more specific if you want an intelligent answer; otherwise you get crap like this post.

 

[Jim1NZ]

Yea, tree senescence is the process where a tree declines before death. Often a tree will die back, growth will come to a stand still, and the tree will produce excessive seed as a last ditch reproduction effort before giving up the ghost.

It seems when expenses become greater than there tree can afford it starts to senesce.

Was just wondering if anyone had ever looked into it?

 

[Ekka]

The trees sheer size and ability to respond to injuries, insects, disturbance, drought etc diminishes as the vascular system depletes of nutrients, water sugars etc. On large mature trees the foliage ratio is a lot higher than a juvenile, the demand on resources is a lot higher.

Trees are unable to just move to a better spot, the area where they've been parked for 100 years may be getting depleted. Droughts etc have impact. Factors contribute and not in all cases do the trees actually have to be over mature and old.

You do get premature senesence.

Here's some links might help you out

http://www.savatree.com/pages/timel...ticles_treehealth/timelytips_tracingtree.html

http://www.publish.csiro.au/paper/FP03236.htm

I believe good PHC will prolong the declining period, but best to have a continual program of care even when the tree appears healthy.

 

[treeseer]

Eric reading that leaf link reminded me of how many nutrients there are in leaves, and most of these get scraped away like trash! I'm going to tune up my leaf shredder for the fall season and take it to more jobs and bring the kids so they can use it during cleanup.

I think the first step in PHC has to be reversing the stupid things people do to trees, and leave them to function like they're programmed to. The trees want their leaves back!

 

[Jim1NZ]

Cheers Ekka

I am thinking there are two types of senescence, the first being premature senescence from environmental factors eg, drought, compaction, poor arboricultural practice..., and harmful organism attack.

I was thinking there is also traditional form of senescence which is growing old before death. This form of senescence is age related. You may ask why banzai plants or pollarded trees can last longer than the same species would do normally though. Well i think by changing the plants form, structure or reproduction system constantly, the tree is 'tricked' into believing its a different age.

So are trees given a certain amount of time? Why can a bristle cone pine grow in excess of 10,000 years then?

Thoughts???

 

[Ekka]

Jim

Excellent point.

And the reason why is because Bonzai's are nipped and pruned including roots on a regular basis. Frankly, the amount of TLC they receive along with the environment they're usually kept in far surpass the regular neglect of a street or yard tree.

Why cant a bristle cone pine live 10,000 years then/

Because it reaches maturity after a nominal time, and generally speaking smaller trees reach their full size quicker ... how many years does it take for those big Californian Redwoods to reach their size?

Now I figure once the tree has reached maturity (like a young vigorous tree climber at your age) then an enjoyable stable period comes a long but lifes knocks abound, injuries, insects and all that bull????. The whole system is so large and requires huge resources and the growth has slowed immensely.

Also, the species susceptability to degenerate from pathogens makes a difference ... ficus trees can take a lot of abuse but perhaps some pines not.

 

[Jim1NZ]

Gold stuff Eric, i like your thinking

... how many years does it take for those big Californian Redwoods to reach their size?

I takes 3000 years for these trees to reach their full size, but what attacks them? How come they can live for 3000 years and not being touched, then all of a sudden start to decline?

Yea i agree with this as well...

Also, the species susceptibility to degenerate from pathogens makes a difference ... ficus trees can take a lot of abuse but perhaps some pines not.

I am starting to decide on a theory, what do you think about an income and expenditure relationship with senescence. A tree will grow and prosper as long as possible until attack, until environmental conditions etc become to expensive to afford, a tree will then trigger senescence and start to decline. This also explains early senescence, a tree under large amounts of stress once mature, will fight as long as possible to stay alive, but when those expenses of growth, repair, reproduction etc get to great, the tree will then seance.

 

[Jim1NZ]

Trees have mechanisms that determine the ratio of their resources that are allocated for growth and defense. As the tree gets larger more and more of the trees resources are needed to 'protect' the tree from being consumed by the waiting multitude of organisms in the environment. Resources that are used for defense are not available for growth.

Eventually the tree can longer protect it's huge storage of 'food' and the environment consumes the tree and recycles it.

All types of stress subtract from the trees growth and defense resources.

Dan Nelson

Great stuff thanks.
I agree, this is along the same lines of my income and expendature theory dont you think?

 

[Shaun Bowler]

Thanks. I learned. I will share this with my Co-workers.

 

[Jim1NZ]

Good stuff Shaun

 

[smokechase II]

Do you believe this?
A large Pine is hit by lightning. The heating of the moisture in the wood cells causes a rapid expansion explosion and a spiral open wound down the stem. Pitch flows to scab over this wound, but wait, the beetle armies have learned to locate a chemical odor in that pitch and move in for the kill. Sadly, our majestic Pine senesces at too young an age and with one last gasp does two things for the good of the order. 1) Puts out its best cone crop ever and 2) Emits a chemical to warn his wingmen that its time to fight off beetles with all you've got. The trees may not talk to you, but they do converse with each other.
Epilogue: A White Fir nearby, that has a substantial rotten core soaking wet in cattle urine, attracts a ground to bottom of the cloud strike and starts a fire that is blamed on President George Bush. This fire then burns up all the trees in sight. Negating that superb cone crop and supporting a huge fire contractor business structure that doesn't really care about the price of gas.
Sorry Jim1NZ, but this is the kind of rambling that you'll get from the likes of us when you fail to more precisely define discussion parameters at the start of a new thread.

 

[Jim1NZ]

Yea, well i always thought that was an interesting theory, but is hard to say trees are programed to die when they can live for 10,000 years.

I totally agree with that as a means of future survival, trees must adopt to their environment, so they must for the new combinations (if stronger), and select the best traits to secure the future survival of their species

Great input Dan, cheers

 

[Jim1NZ]

Do you believe this?
A large Pine is hit by lightning. The heating of the moisture in the wood cells causes a rapid expansion explosion and a spiral open wound down the stem. Pitch flows to scab over this wound, but wait, the beetle armies have learned to locate a chemical odor in that pitch and move in for the kill. Sadly, our majestic Pine senesces at too young an age and with one last gasp does two things for the good of the order. 1) Puts out its best cone crop ever and 2) Emits a chemical to warn his wingmen that its time to fight off beetles with all you've got. The trees may not talk to you, but they do converse with each other.

I totally agree, Eculaypt trees are well known to produce these auxins.

Dont know about the rest of it though

There is no factual evidence that states this is how it is or isn't. I was interested in others opinions in the matter as a whole. If you don't want to participate don't, i don't care.

 

[Kneejerk Bombas]

Because of limitations of the trees genetics.

Death is natures way of making room for the new combinations(next generation) of genes mother nature is watching and it's these new combinations that will compete for survival and carry the dead trees genetics into the future. Death is the cosmic gardeners weeding and breeding program.

There is also evidence that senescence is genetically programed into all living things. Evolutionary advantages could be the reason.

If senescence is ever understood at the genetic level human life extension may become a reality and that is really exciting.

Dan

You've mentioned trees dying as eing a genetic thing before. I don't understand.
I always thought a tree lives on until something comes along and kills it. For example a small young tree is unlikely to get hit by lighting, but a mature tree with its crown sticking out of the top of the forest is.
If you consider all the things that can cause a tree to die, it makes sense that eventually they sucumb. Some in a short time, others after thousands of years.
If you were to take a cutting off that 3000 year old tree, its life starts over, and has statistically the same chance of living as any other tree. The genetics haven't failed it somehow.

 

[Jim1NZ]

Its not one thing or another, it is compounding factors which are to blame. Genetics does still play a part in senescence though, for example, the stages in the life of a tree are controlled by genetics.

You cant say it is all harmful organisms which causes senescence to occur either, they may lead to or trigger senescence but no tree would grow long enough to senesce.