That question was asked by a friend of mine who is going for her PhD... I remember hearing some definition about the organization within the structure of the tree from Shigo.. Anyone have that or something better...
Good question about what constitutes death in a perennial, compartmented, and responsive organism! I do remember Dr. Shigo talking about the loss of communication between root and shoot, as Daniel remembers. "Communication" here is in an older sense, not just of messages being sent and received, but as the network that allows the flow of matter and energy (which of course, are the same thing).
For me, the handy definition depends on the application. From a clinical, practical point of view, the first year it produces no buds/leaves makes sense as Tom and Bucknut describe. That shows an individual organism-wide failure.
As a demonstration years ago, i did a time series of observations of cells and chemistry in the foliage of a fraser fir....which had been cut as a Christmas tree. So a child would recognize that tree as being as "good as dead", even if the foliage had plenty of living chloroplasts while having declining nutrition and certainty of death.
Death of particular cells/tissues is built into the functional design as immature secondary xylem mature, they die in order to function.
As a pathologist i do encounter trees that from a common-sense evaluation would be reckoned as dead, about which the tree is unaware. Buds or root/stump suckers can keep coming! So with clonal species like many Populus, stems die while the collective continues!
I am very interested in this topic. We have a Cottonwood tree that looked pretty rough last year, and now this year so far it's losing bark it does have bud though but it's losing bark on a lot of the upper limbs.
We would really like the street to live given the position in our property that it occupies.
I believe have witnessed death by these definitions,
Then mycorrhizae connects for others to tap resources,
Then fully symbiotic at some point sprouts where was dead season or so later.
>>Even fallen trees bases obliterated, even fallen branches in rich more tropical environment of Florida, seems life re-ignited after candle went out by any normal measure.
Trees changed the planet, an ultimate survivor and harmonizer with Nature , sets up mutual environments, and makes way thru many things.
My imageries of align-meant and pure inline as mantra are partially to depth of a life view.
I think this planet is only marginally more habital than other planets on the big scale.
Temp extremes, ultra-violent radiation , crushing gravity, oxidation etc. rain down and around.
Life I think must be organized or aligned enough to face this onslaught pouring downward and all around.
Stand tall organized in contiguous column strength , best chance of life going on.
>>cosine is this inline columnSine, I think of as columnSine, or to your cos(cause/cosine)
But the more beaten over, non-contiguos chain, the more sine expousre (the non of cosine) the more leveraged strikes of the hail of forces incurred, until pulled down to composting back.
Life definition therefore must encompass grafts, transplants from cadavers and other re-ignitions of system parts still in fresh enough order to carry and conduct thru and pass back life flow thru sound circuitry.
In trees, when can't conduct water thru, dry wood where capillaries are probably violated or blocked is out of this arranged order. Then ports of give and take can't mechanically conduct sharing of life flow.