On 01/05/2016 6:17 PM, Leon wrote:
On 1/5/2016 6:15 PM, OFWW wrote:
On Tue, 5 Jan 2016 09:00:09 -0800, Electric Comet
wrote:


interesting shot showing the fires during the life of the tree

http://media.eurekalert.org/multimed.../20963_web.jpg

Did you know that tree rings do not show years, but show rainy
seasons?



I always understood rings represent years, size of rings represent the
climate for that year. Do you have a reference by any chance?

The US FPL Wood Handbook --
http://www.fpl.fs.fed.us/products/publications/several_pubs.php?grouping_id=100

See chap 3 for botany lessons. Short version is, in temperate climates
such as most of the US, there is an annual growth and dormant season and
so the growth rings can be associated with that yearly cycle. How
prevalent they are is basically determined by the variety of the tree
itself, spacing is related to environmental and local conditions. But
it makes note that this is a temperate-zone characteristic and so to
refer them as "annual rings" isn't necessarily accurate; use the term
"growth rings" or "growth increment" instead.

OTOH, in many tropical woods it's essentially impossible to visually
detect growth rings altho I note in the 2010 edition it includes the
following: "... continuing research in this area has uncovered several
characteristics whereby growth rings can be correlated with seasonality
changes in some tropical species (Worbes 1995, 1999; Callado and others
2001)."

Shorter version is R. B. Hoadley's Understanding Wood, Taunton
Press...although I don't believe it's been revised; there's certainly
little to fault for a US audience and domestic woods on the subject
albeit it's not a botany textbook, either (nor, of course, is the
Handbook, but it is in more depth than Hoadley).

--