08, 2002 17:42 PDT
recent emails about "ancient" trees and clones brings
to mind a
favorite question I like to ask students in my Ecology of New
Growth class - "What part of a 300 year old tree is 300
years old?" The
following discussion usually leads to a discussion of the fact
living part of a tree, where cells are dividing and expanding,
isn't in the
middle, it's on the margins! Like our own faces, the part
presented to the
world is pretty young. The old stuff is hidden down pretty deep.
So what actually does tree age really mean? Certainly tree age
what we recognize as a single organism (is it?) has persisted in
spot for a long time, recording in its rings a record of growth
chemical and other (?) signatures of past events. The cellular
of the meristems in the original seedling continue to fix carbon
accumulate biomass and grow. Branch structure and bark form
age, too, so perhaps those dividing cells aren't doing the same
elders did or they are responding to a different environment.
And the soil
under that tree IS truly old, having been more or less
undisturbed for as
long as the tree has occupied the air space above.
So what we are impressed by (or at least I am) is not the AGE of
per se, but the timespan of a continuous unbroken record of
living - and
dying - of a single plant genotype in one place - I seem to
process, not a product. Whew. Too much something in dinner
So I guess we will continue to search for and wrangle over the
tree --- which is of course more than just old wood!
Really enjoy your posts.
09, 2002 04:48 PDT
said Larry! We know that our human bodies change completely
couple of years too. Still looks like the same person, but
material. Yet, the silent observer within, the one who keeps
anew all the time, is always there, unchanged. I suggest that
true of all beings. Perhaps some of those same particles that
part of those old Trees are now part of us, and vice versa.
cellular memory explains some of our kinship with the great old
the Forest? Seeing Bob do his little dance when he finds one
with no doubt!