On 01/09/2016 10:05 PM, Martin Eastburn wrote:
I'd say growing seasons is the soft more alive ring area
and the hard ring is the winter very slow growing.
Generally true altho specifics again vary by species.
I can't suggest strongly enough to actually go read Hoadley or Chapter 3
of FPL Handbook or the like but from the latter--
"In temperate portions of the world and anywhere else with distinct,
regular seasonality, trees form their wood in annual growth increments;
that is, all the wood produced in one growing season is organized
together into a recognizable, functional entity that many sources refer
to as annual rings. Such terminology reflects this temperate bias, so a
preferred term is growth increment, or growth ring (IAWA 1989). ...
Woods that form distinct growth rings, and this includes most woods that
are likely to be used as engineering materials in North America, show
three fundamental patterns within a growth ring: no change in cell
pattern across the ring; a gradual reduction of the inner diameter of
conducting elements from the earlywood to the latewood; and a sudden and
distinct change in the inner diameter of the conducting elements across
the ring (Fig. 3€“5). These patterns appear in both softwoods and
hardwoods but differ in each because of the distinct anatomical
differences between the two.
Non-porous woods (or softwoods, woods without vessels) can exhibit any
of these three general patterns. Some softwoods such as Western
red-cedar (Thuja plicata), northern white-cedar (Thuja occidentalis),
and species of spruce (Picea) and true fir (Abies) have growth
increments that undergo a gradual transition from the thin-walled
wide-lumined earlywood cells to the thicker-walled, narrower-lumined
latewood cells (Fig. 3€“5B). Other woods undergo an abrupt transition
from earlywood to latewood, such as southern yellow pine (Pinus), larch
(Larix), Douglas-fir (Pseudotsuga menziesii), baldcypress (Taxodium
disticum), and redwood (Sequoia sempervirens) (Fig. 3€“5C). Because most
softwoods are native to the north temperate regions, growth rings are
clearly evident. Only in species such as araucaria (Araucaria) and some
podocarps (Podocarpus) does one find no transition within the growth
ring (Fig. 3€“5A). Some authors report this state as growth rings being
absent or only barely evident (Phillips 1948, Kukachka 1960).
Porous woods (or hardwoods, woods with vessels) have two main types of
growth rings and one intermediate form. In diffuse-porous woods, vessels
either do not markedly differ in size and distribution from the
earlywood to the latewood, or the change in size and distribution is
gradual and no clear distinction between earlywood and latewood can be
found (Fig. 3€“5D). Maple (Acer), birch (Betula), aspen/cottonwood
(Populus), and yellow-poplar (Liriodendron tulipifera) are examples of
diffuse porous species.
This pattern is in contrast to ring-porous woods wherein the transition
from earlywood to latewood is abrupt, with vessel diameters decreasing
substantially (often by an order or magnitude or more); this change in
vessel size is often accompanied by a change in the pattern of vessel
distribution as well. This creates a ring pattern of large earlywood
vessels around the inner portion of the growth increment, and then
denser, more fibrous tissue in the latewood, as is found in hackberry
(Celtis occidentalis), white ash (Fraxinus americana), shagbark hickory
(Carya ovata), and northern red oak (Quercus rubra) (Fig. 3€“5F).
Sometimes the vessel size and distribution pattern falls more or less
between these two definitions, and this condition is referred to as
semi-ring-porous (Fig. 3€“5E). Black walnut (Juglans nigra) is a
temperate-zone semi-ring-porous wood. Most tropical hardwoods are
diffuse-porous; the best-known commercial exceptions to this are the
Spanish-cedars (Cedrela spp.) and teak (Tectona grandis), which are
generally semi-ring-porous and ring-porous, respectively.
Few distinctly ring-porous species grow in the tropics and comparatively
few grow in the southern hemisphere. In genera that span temperate and
tropical zones, it is common to have ring-porous species in the
temperate zone and diffuse-porous species in the tropics. The oaks
(Quercus), ashes (Fraxinus), and hackberries (Celtis) native to the
tropics are diffuse-porous, whereas their temperate congeners are
ring-porous. Numerous detailed texts provide more information on growth
increments in wood, a few of which are of particular note (Panshin and
deZeeuw 1980, Dickison 2000, Carlquist 2001).
The Redwoods would grow a foot or more on every rain or heavy fog.
After a fair rain, you could stand outside and hear the wood swell.
We had one near the house that was maybe a 30" sapling (diameter) and
as it grew upward the trunk rotated. The lower limbs were trimmed off
the deck only to have new ones sweep inward towards the house. Not all
did that and I think the wood might be beautiful if cut, but have no
idea on strength with twisted grain.
....
Botanically, softwoods are gymnosperms or conifers; their seeds are not
enclosed in the ovary of the flower. Anatomically, softwoods are
nonporous (they do not contain vessels). Softwoods are usually
cone-bearing plants with needle- or scale-like evergreen leaves. Some
softwoods, such as larches and baldcypress, lose their needles during
autumn or winter.
One can see/hear similar phenomenon in cornfield in hot weather if have
adequate moisture; one can almost see it actually grow. If it takes a
redwood 2000 yr more or less to get 300 ft, though, that's only an
average of under 2" per year. Reminds me of what Mark Twain said of the
length of the Mississippi River if one took the claims of it's
lengthening on an annual basis to their logical conclusion!
I've visited the redwoods both coastal and the giants numerous times but
haven't had the opportunity to spend a full day or more at a given spot...
--