by Dr. Herbert G. Baker, 1965
It's always the fate of a lecturer in a series like this to look at the
audience and see a real expert on the subject in the audience, and I see
Bill Libby sitting there. And when I will have to leave to catch my plane
I'll hand the fielding of the questions over to him and you'll see he'll
do a much better job than I shall. Well, this talk, indeed, this series
of talks is going to deal with the redwoods of California. And the first
talk is intended to put these redwoods in their context, the historical
context, as well as the botanical context.
Nowadays we recognize the existence of three separate genera of redwood.
We think of them as three separate genera because we have reason to believe
that they represent the end points of three long lines of separate evolution.
Most of the species in those lines are now extinct. The three which remain
are the ones we know as Metasequoia, Sequoia and Sequoiaderdron. Each of
these genera nowadays consists only of one single species. In the genus
Metasequoia, it is Metasequoia (glyptostroboides). In the genus Sequoia,
Sequoia sempervirens. And in the genus Sequoiadendron, Sequoiadendron gigantea.
And these three species are respectively the dawn redwood, Metasequoia (glyptostroboides),
the coast redwood, Sequoia sempervirens, and the Sierra redwood, or big
tree, Sequoiadendron gigantea.
Metasequoia, of course, is the most recently recognized of this group. And
does have, indeed, a very strange history, having first been recognized
as a fossil by a Japanese botanist in 1941. And, subsequently being found,
also while World War II was in progress, as a wild tree in a single valley
in central China. Metasequoia (glyptostroboides), the dawn redwood, which
is the only one of the redwoods now not found living as a wild plant in
California. Well, it's easy to distinguish the dawn redwood, Metasequoia,
from the other two because the dawn redwood is deciduous. You've probably
noticed all these short twigs bearing leaves have been dropping off whilst
I've been holding this up. Metasequoia (glyptostroboides) is a deciduous
tree. The other two are evergreen. Furthermore, Metasequoia has its leaves
arranged along the twigs in opposite pairs, whereas in Sequoia, along the
twig. Metasequoia is a native of China, the other two are natives of California.
Metasequoia is also a considerably smaller tree than the others, seldom
apparently reaching above about 100 feet in height. Whereas, both of the
other trees are capable of topping 300 feet.
Well it's pretty clear why Metasequoia is in another genus than the others.
But it's not clear to the outsider why these two trees Sequoiatendron and
Sequoia should be separated generically. And, indeed for most of the 100
years that they have been known to science, they were not separated generically.
They were kept together in the genus Sequoia.
But as more and more careful studies have been made of these trees and particularly
as botanists have used their microscope to peer into the developing seed,
they have seen significant differences between these two kinds of trees
so significant that there should be two different genera recognized.
For us, however, the most important thing is not whether they are placed
in two separate genera, but whether we can tell them apart. And on most
occasions when we meet a redwood tree in the wild, there is not much difficulty
in telling them apart. When we see them in a state of nature, we do not
have too much difficulty because the coast redwood we find only in areas
in a narrow strip running parallel with the Pacific Coast generally within
the range of the summer fogs. The Sierra redwoods on the other hand is confined
to the western slope of the Sierra Nevada and as a consequence, one wouldn't
have much difficulty because of ones geographical position in telling which
kind of redwood tree one was looking at.
Nevertheless the rangers of the State Division of Beaches and Parks every
now and again have reports made to them by hikers or hunters or others who
prowl around the wild places of California, that there are Sierra redwoods
growing amongst the coast redwood trees. Part of the trouble in this case
seem to come from the appearance of one of the trees. The Sierra redwood
has adpressed leaves, little scale leaves which are adpressed along the
branches. The coast redwood has leaves which stand out from the branches
in two rows, so-called distichous arrangement. This is clear enough in the
way of a difference. But at the bases of each one of these branches and
in the branches which are borne high up on the trees or on young trees,
there is often is a tendency for the coast redwood leaves to be arranged
along the stem in a manner very much reminiscent of the arrangement in the
Sierra redwood. And it's probably this which occasionally gives rise to
stories of Sierra redwoods growing in coastal regions.
But there is a very definite separation of the distribution ranges of these
two species. The coast redwood running along near the coast form southern
Oregon down to the Golden Gate, appearing again in the San Francisco Peninsula
and the Santa Cruz Mountains and appearing once again south of Monterey
Bay for a distance down into the Santa Lucia Mountains. The coast redwood
also occurs in eastern Sonoma County and western Napa County and is native
in the Oakland Hills. In the Santa Lucia Mountain area the distribution
of coast redwood is a series of valleys at right angles to the coast line.
This gives you the general idea of the distribution of the two trees.
The Sierra redwood has adpressed scale-like leaves. Whereas in the coast
redwood there are scale leaves adpressed at the base of the branches but
then there is an alternate arrangement of leaves which stand out from the
There are other differences between the species. The cones of the Sierra
redwood are considerably larger, being two to three inches long compared
with a single inch or even slightly less in the case of the coast redwood.
The cone scales of the Sierra redwood are more numerous - about 35 to 40
in each cone compared with 25 or so in the coast redwood, and each cone
scale in the cones of the Sierra redwood bears as many as nine seeds upon
it, whereas the less numerous cone scales. In the coast redwood bear smaller
numbers of seeds each, only two to five. Add to this the fact that the sierra
redwood seems to be more regular in producing seeds -- it has a better crop
every year than does the coast redwood. Altogether, there appears to be
a considerably greater seed output per tree of the Sierra redwood than of
the coast redwood.
But the coast redwood has its compensation for this. The coast redwood trees
are able to sprout from a cut stump or from the roots of the tree and achieve
a measure of vegetative reproduction in this way which is not shown by the
Sierra redwood which relies for reproduction to a much greater extent upon
the establishment of seedlings. An interesting difference between the trees
of the coast redwood and the Sierra redwood species is that the seeds ripen
and shed in the same year that pollination takes place in the coast redwood,
whereas, in the Sierra redwood the ripening does not take place until the
season ; after pollination. And in the Sierra redwood cones may hang on
the trees for many years with seeds still inside them.
I've mentioned that all three of the redwoods -- Metasequoia, Sequoia and
Sequoiadendron -- have long fossil histories in which they showed, once,
much more extensive distributions than is the case at the present day. The
genus Metasequoia, the dawn redwoods nowadays in restricted to a single
valley in central China. It has a history which goes back to the Upper Cretaceous
Period, a matter of 110 million years ago. And its history from that time
until the present has been one of continual contraction in its natural range.
From a maximum distribution in the Northern Hemisphere during the beginning
of the Tertiary Period, about 65 million years ago, it has shrunk down to
this single valley in central China. You can see that the dawn redwood was
once quite commonly found in western North America as well as in eastern
Asia. And there are records of the dawn redwood from Greenland and from
Spitsbergen. This is indicative of the fact that the climate in Greenland
and Spitsbergen war distinctly more clement at a time in the past actually
at the beginning of the Tertiary Period when the Metasequoias lived up there.
It seems that the dawn redwood was never native in Europe.
For the coast redwood, the Sequoia, the picture is almost as traumatic.
It too shows a history that reaches back to the Cretaceous Period. And the
genus Sequoia was widespread through the Northern Hemisphere during the
early part of the Tertiary Period, 60 million years ago. But with the cooling
and the drying of the climates of the . Northern Hemisphere which took place
during the Tertiary Period, the genus Sequoia became progressively restricted
to western North America, western Europe, the Himalayas, and Japan. And
then it seems to have been eliminated entirely, everywhere except western
North America, by the onset of the Pleistocene Period, one to two million
years ago, with the glacial advances. In western North America we know that
at the beginning of the Tertiary Period the coast redwood was found in the
region of Alaska and British Columbia.
This was the beginning of the Tertiary Period where a subtropical or even
tropical climate was to be found in California, the present home of the
Coast redwood. At that time it existed considerably farther north and also
existed considerably farther inland. But during the cooling and the drying
of the climate during the Tertiary Period, it gradually became eliminated
from its inland stations. It gradually moved farther south from its Alaskan
and British Columbian stations down into California.
And its journey southward seems to have reached the maximum during the Pleistocene
glacial advances. At that time the coast redwood seems to have reached some
200 miles farther south than its present distribution and has been recorded
from Carpenteria in Santa Barbara County as a fossil.
With the partial recovery of warmth after the Pleistocene glacial episodes,
the coast redwood seems to have retreated northward a little to its present
day distributions where it is located just about on the overlap between
subtropical and warm temperate on the Pacific coast of North America. Its
present range is from the Santa Lucia Mountains in Monterey County along
parallel with the coast to Curry County; the southernmost county of Oregon.
In addition to the latitudinal shifts in the genus Sequoia, it also was
eliminated from its inland localities and persisted as a relic only in the
coastal regions. This seems to have been due to increasing dryness especially
in the summer months from the middle of the Tertiary Period onwards. So
it became extinct in such states as Montana, Idaho, Wyoming, Nevada. It
finally was restricted to the foggy coastal hills of central California.
And during this contraction in region several species of Sequoia appear
to have become extinct leaving us with just the single surviving species,
Sequoia Sempervirens, the coast redwood.
At present it seems that the coast redwood is prevented from expanding its
range by a different kind of limiting factor according to whether you go
to the northern limits, the southern limits, the western or the eastern
limits. According to Forrest Shreve, a famous botanist - the southern limit
of the coast redwoods in the Santa Lucia Mountains is determined by the
severity of the period which is to be experienced between the cessation
of the winter rains and the onset of the summer fogs. There is a dry period
at the beginning of the summer and this gets longer and longer the farther
south you go, In the Santa Lucia Mountains there comes a time when this
becomes too severe for the coast redwood, a tree which likes good moisture
supply. If you have this long dry period between the end of the winter rains
and the beginning of the summer fogs, it is unable finally to grow. It is
noticeable as one goes down Highway 1 south of Big Sur that the redwood
trees become restricted to the bottoms of these valleys or at least to the
valleys themselves which run at right angles from the coast inland. In these
valleys the trees get extra drainage water. They get shelter from the winds
which blow over the area and a higher humidity as a result. But even that
does not suffice to save the redwoods beyond a certain point and so we have
the southern limit to its distribution.
As far as the eastern limits of the narrow coastal strip of coast redwood
distribution are concerned it seems very likely that it is the low rainfall
and particularly the hot winds which sometimes blow off the lands, especially
in the fall which determine the inner limits of this distribution. The Western
limits are pretty obviously imposed by the Pacific Ocean. But even so, the
redwoods do not usually reach right down to the Pacific Ocean. Usually they
are separated from the ocean by a little stretch. And it is to be suggested
that the rainfall on the immediate coast is probably insufficient for them.
It is only when the rain bearing winds are forced up over the mountains
that sufficient rain falls. In addition, the fog cap tends to be on the
mountains rather than on the immediate coast. And, in addition, in all probability
the redwood is susceptible to damage from salt spray.
And then the northern limits of the coast redwoods may very well be set
by severe winter conditions. In Humboldt County the trees on the outsides
of the forests, the edges of the forest, may be damaged by the winter frosts.
But the forest as a whole is protected by the very nature of being a forest.
But further north over the Oregon County line, it has been suggested, that
frost damage becomes more severe and particularly frost damage to young
trees imposes a limit on the northern distribution of the coast redwood.
Certainly, one would imagine, it reduces the competitive power of the coast
redwood so that it is unable to compete with such trees as the Douglas fir
which takes its place farther north and incidentally which also takes its
place at greater elevations farther south.
So we have the probable limits on the distribution of the coastal redwood.
It has been suggested that a rainfall of some 40 inches per year is minimal
for this tree. But in many of the areas where the coast, redwood grows,
the rainfall is considerably less than this. So deficient rainfall can be
compensated for in two ways. Firstly, by increasing the amount of water
supply to the roots. And a tree which grows along the margins of a river
may be able to grow in an area where the rainfall itself is inadequate for
the support of the tree. On the other hand, you can compensate for deficient
rainfall by summer fog. But up on the outer coast range, not only is there
a greater rainfall, but there is also the summer fog. And through the fog
drift, the condensation of fog on the leave, and then dripping onto the
ground or running down the trunk, to the ground, we do have a supplementation
of the natural rainfall. In addition to this, which Oberdoffer, a worker
from San Francisco State College working on the San Francisco Peninsula
has concluded may add as much as the equivalent of 50 inches of rain around
the base of a tree,
The fog also cuts down evaporation and transpiration and cuts down the heating
effect of the sun during the summer months. So this fog is not only a potent
source of water for the trees, but also comes just at the time of the year
when it is most needed, in the dry summer months.
Now the Stanford campus area is inadequately supplied with rain for the
growth of redwoods. But, of course, there is the Palo Alto tree growing
by San Francisquito Creek in the Stanford area well away from the outer
coast range. But it is by the side of the creek. And in the days when San
Francisquito Creek carried more water than it does now, that might have
been a significant aid to those trees in their growth.
This then is the fortunate concatenation of climatic circumstances which
has given us the redwood forests and the associated redwood flora, the sword
ferns under these trees, and the oxalis and other ferns which abundantly
carpet the soil under these great trees in Humboldt County.
Actually, however, despite this long history, it wasn't until the Spanish
explorers came to California that a European or person of European descent
had ever seen a redwood tree. It had to wait until the 18th century for
its discovery even though its history is so tremendously long. But Englishmen,
Sir Francis Drake, did have the opportunity of being the discoverer of the
coast redwood in 1579. Had he not been so obviously a sailor, rather than
an explorer of the land, he might have taken the opportunity whilst the
Golden Hind was being careened in the vicinity of Point Reyes of penetrating
just 10 or 20 miles inland, where he would have seen the coast redwoods
in the area which we now think of as Samuel P. Taylor State Park. But Sir
Francis Drake was deterred by the fog and the cold from making such a journey
and it seems certain that it was through Spanish eyes that the Palo Colorado
or redwood was first seen by Europeans. Father Juan Crespe, the Franciscan
missionary who was the diarist of the Portola expedition, the first expedition
by land up the Pacific Coast, in 1769, recorded the existence of coast redwood
trees when he was in the vicinity of the Pahara River in Monterey County.
And he used the following words, in translation, of course: "The area
is well forested with very high trees of a red color, not known to us. They
have a very different leaf from cedars and, although the wood resembles
cedar somewhat in color, it is very different and has not the same odor.
However, the wood of the trees that we have found is very brittle. In this
region there in a great abundance of these trees and because none of the
expedition recognizes them they are named redwood for their color."
Palo Colorado, of course, in the original Spanish. You remember it was the
Portola expedition which also discovered the Palo Alto tree when they reached
San Francisco Bay.
But the first collection of the coast redwood seems to have been made by
Thadeys Haenke, botanist of the Malaspena expedition in 1791. And it appears
there is at least one tree derived from the seed which he went home still
growing in Spain. The Malaspena expedition was a Spanish financed expedition
but Malaspena, its captain was an Italian, and Haenke, its botanist was
a German. The redwood trees from which they collected seed, in all probability,
grew near Santa Cruz. And indeed most of the early collection of seed which
were sent back to Europe and have given rise to cultivated trees there,
were collected in the Santa Cruz area. Nevertheless, it was a Scot, Archibald
Menzies, who played the role of botanical discoverer, because it was his
specimen sent back to Britain which formed the basis of the botanical description
of the coast redwood tree. In 1794, Menzies collected a herbarium specimen
and for a long time it was unknown just where the collection was made. The
specimen, however, still exists in the British Museum in London and the
story is that one day Professor Willis Jepson of the University of California
here was looking at that herbarium specimen in the British Museum and he
happened to turn the herbarium sheet over and on the back side of the sheet,
it said Santa Cruz, Menzie. It seems that through all the years they'd had
the sheet, nobody had thought of turning it over. Well, this specimen was
carried to Britain in 1795, but a description of it with a botanical name
was not given until 1823 when the name was published by a botanist named
Lambert. And because the material looked to Lambert like the already known
genus taxodium, he called the redwood taxodium sempervirens. It's sometimes
thought that the name sempervirens refers to the long life of the tree,
which indeed may be upward of 2,000 years. But this is not the case. Lambert,
after all, was describing a specimen from a hyberium sheet and he knew nothing
of the longevity of the tree. And he was merely concerned to record that
the tree was evergreen. Sempervirens meant evergreen in distinction to those
taxodium speciea like the bald cypress, taxodium discusum, which are deciduous.
The generic name became changed subsequently because a German botanist,
Steven Endlicher, recognized that indeed it was not a species of taxodium.
And in 1847, he called the coast redwood Sequoia sempervirens, the name
which it still hold today.
Well, generally speaking, early visitors to California knew relatively little
about the coast redwood. And some of them seem only to have seen the trees
from a distance. And I think that at least a part of the reason for this
is the nature of the terrain upon which the coast redwood trees grow. They
do not grow on the south side of the Golden Gate where the Presidio and
the Mission Dolores stand. And as a consequence, persons who landed there
in early times did not come into contact with the redwood trees. Neither
do they occur in the vicinity of Monterey, the other, even more frequent,
point of call for these visitors that came from the sea. And when these
visitors journeyed from Yerba Buena, the old San Francisco, to San Jose
or to Monterey or to Salinas, it was much easier to make the journey by
the Santa Clara valley route which lay through the oak savannah and the
grassland rather than to go through the mountainous areas where the redwoods
grow beneath their fog cap. Thus, when Captain Beechey of His Majesty's
Ship 'Blossom' visited California in 1826, he rode overland from San Francisco
to Monterey. And he was not at all overawed by the redwoods. He merely noted
them in the distance and gave them half a sentence of mention. By contrast
he described poison oak with great forcefulness. And it is quite clear that
this made much more impression on him, as did the fleas which existed in
everyone of the settlements. The little things impressed him much more than
the big ones.
On the other hand, the Sierra redwoods, the only big trees according to
some people, have never failed to impress visitors who see them for the
first time. And in part, I think, the greater impressiveness of the Sierra
redwoods may be traced to the fact that in their case it is the enormous
girth of the trunks readily appreciated against the scale of a human being
which marked them out as utterly different from the other coniferous trees
which grow with them. The girth in the important thing to notice.
The fossil history of Sequoiadendron, the Sierra redwood genus, has not
been worked out with the same completeness as has the fossil history of
the genus Sequoia. But we know it in sufficient detail to understand the
general picture. Once again it appears to have been a progressive contraction
in range for the genus which had its origin in the Cretaceous Period, but
gradually diminished in area; during the climatic changes of the Tertiary
Period. And before the end of the Tertiary Period, about two million years
ago, Sequoiadendron, which had occurred in Europe as well as in Greenland
and in North America, had become extinguished everywhere except in North
At the present time, Sequoiadendron gigantea is found in a series of groves
in a narrow belt running some 260 miles in length on the western slopes
of the Sierra Nevada. The elevation of these groves ranges from about 4,500
feet at the northern limit to about 7,500 feet at the southern limit. The
northernmost grove consisting of about six trees grows on the middle fork
of the American River in to Placer County. And the most southerly grove,
a larger one containing about 100 trees, grows along Deer Creek in Tulare
The climate in these areas is both drier and cooler than that in which the
coast redwood grows. The rainfall is 18 to 60 inches a year, which incidentally
mostly comes in the form of snow. And in these groves Sequoiadendron grows
mixed with other trees. Growing along the side is a much more slender Douglas
Dr. Dan Axelrod of the University of California at Los Angeles, famous paleobotanist,
has shown from the study of fossils that during the Tertiary Period there
were forests of the Sierra redwood in the State of Nevada. But as the rainfall
decreased at the end of the Tertiary Period, the Sierra redwood migrated
westward to the western lopes of the Sierra Nevada. Not only was it becoming
too dry for the Sierra redwood in Nevada, but the winters were also becoming
too cold for this tree. For all that it grows in the mountains of California,
it is known to be damaged seriously by prolonged spells of temperatures
below zero degrees Fahrenheit. The accelerated uplift of the Sierra Nevada
which took place during the end of the Tertiary and the Pleistocene Periods
created still more of a rain shadow on the Nevada side and produced conditions
which were completely unsuitable for the growth of Sequoiadendron. Consequently,
when the Pleistocene Epoch came with its four major ice ages, just over
a million years ago, the Sierra redwood was already restricted to the western
side of the mountain.
So why does it grow on groves on the western side of the mountain, rather
than in continuous forests? It seems to have been the great naturalist John
Muir who put forward the explanation for this a way back in 1875. Muir noticed
that the groves are usually on unglaciated slopes separated by valleys which
were heavily glaciated during the periods of ice expansion, of glacier formation,
in the Sierra Nevada, during the Pleistocene Epoch. And he postulated that
the Sierra redwood trees were wiped out in these valleys by the ice age
that time and have never been able to get back in again. And we generally
accept this view nowadays. We believe that the Sequoiadendron has not spread
back into the valleys in post-glacial times because the valleys are still
too cold in the winter for the trees. Thus we have the Sierra redwood growing
magnificently, to over 300 feet in height, and to an enormous age, certainly
to an excess of 3,000 years in its groves but not apparently being able
to spread out from its groves except where man has planted the trees in
other parts of the world, particularly as a decorative tree in the eastern
United States and in Europe. But it's interesting that this tree is not
completely lacking in genetical variation. A large number of horticultural
forms have been selected from it in cultivation including what I think is
the ultimate, I almost said ultimate insult to the big tree, a dwarf form
of the big tree suitable for growing in rockeries.
With regard to the discovery of the Sierra redwood in the 19th century we
needn't bother to argue too much by whom these trees were first seen. Was
it Joseph Walker in 1833 or John Bidwell or any one of several other hunters
who was the first non-Indian person to see them. The important fact is that
the scientific discovery of the Sierra redwood or big tree dates from 1852
when once again seeds were collected and sent back to England by a collector
named William Lobb. William Lobb had been sent out to California by the
nursery firm of James Vetch to collect seeds of California plants suitable
to grow as decorative plants in the British Isles. Lobb's seed and his specimens
formed the basis of the first botanical description of the tree by the great
botanist John Lindley. Lindley named the tree Wellingtonea gigantea, in
honor of the Duke of Wellington, the Iron Duke, the hero who defeated Napoleon
at Waterloo. The reason was that Wellington had died the year before and
a suitable memorial was needed. And being the giant amongst trees, it was
inevitable that it should be claimed for a domestic hero. Interestingly
enough, that has been its fate subsequently too. After Endlicher established
the genus Sequoia in 1847 he added the Sierra redwood to the coast redwood
in the genus Sequoia and this made the Sierra redwood become called Sequoia
gigantea. But the hero worshippers were not to be outdone and some years
later Sudworth, who felt that American tree. ought to be named after an
American hero, proposed that the name be changed to Sequoia Washingtoniana.
And even this was not enough for one patriotic New Yorker who wanted to
be quite politically and patriotically straightforward about the thing and
call it Americus gigantea. But, alas, all these names are invalid for one
reason or another and we have it now Sequoiadendron gigantea.
But I don't think there's any reason to be sad about this. After, all Sequoia
and Sequoiadendron are both names which commemorate a very great man, a
Cherokee Indian named Sequoia who lived at the end of the 18th century and
the beginning of the 19th century admittedly not in California but in the
territory which is now Oklahoma. In 1821, this self-educated man completed
an alphabet of 86 characters by which the Cherokee language could be written
and printed As a result they were able to have a written law. They were
able to have written newspapers and so on. He was far ahead of his time
in helping his people, and I personally think that it's just as good that
his name should be commemorated in these trees as that of any military hero.
I think these are noble trees and are very well worthy of discussion in
this series of lectures. But whilst we are thinking about the nobility of
the tree, we might make a resolution never to allow this sort of thing to
be done again to them. Nor indeed to allow the sort of situation on the
next slide come about if we can possibly avoid it. If we possibly can, let's
have the situation which in pictured on, the last of these slides. Thank
you very much.
Questions and Answers
QUESTION: I would like to ask, Professor Baker, if it's possible to pinpoint
the southernmost station on the coast of Monterey where the redwood is growing
ANSWER: Unfortunately, I could go there, but I couldn't describe it very
accurately. Dr. Libby, can you pinpoint this?
Dr. Libby: I think it's Salmon Creek, isn't it?
ANSWER: Yes, I think that is the name. Go down Highway 1 anyway and you'll
see it gradually getting harder to spot in the valleys until ultimately
QUESTION: To ask a collateral question to that and that is whether the former
growth that you can see is rather different down there. is that a climatic
ANSWER: Well, again this really is Dr. Libby's question because the is studying
variation in the redwood tree. But I think, in all probability, it's true
to say that the redwood is potentially a very variable tree. If you see
any collection of trees and you look at them carefully, you can see considerable
differences from tree to tree. And superimposed upon this can of course
be the very profound effects of wind trimming and so on. So I imagine the
lower stature of some of these trees is due to direct environmental effects.
However, it's quite striking that in the coast redwood, the biggest trees
are not found in the center of the distribution range gradually tailing
away as you go north and south, but some of the biggest trees are near the
northern limits in Del Norte County and Humboldt County and then down in
the southern area, in the Santa Cruz area. Bill. would you like to add something
Dr. Libby: Nothing beyond the fact that we'll have the answer in 80 or 90
QUESTION: Some of the redwoods that you find on the campus have a very red
bark, whereas if you go up in Humboldt County, they'll be very gray in bark.
ANSWER: Well, I think to some extent this may be due to lichen growth on
the bark. But there is again variation in the amount of the red pigmentation.
I think climatic conditions, greater moisture availability permitting lichen
growth is one explanation at any rate.
QUESTION: You've described the growth patterns of the redwoods. Now, are
they still contracting and dwindling or are they replenishing themselves?
ANSWER: Well, there are ecological questions which I think Dr. Stone in
going to answer in the next lecture. But my impression is that the range
is not decreasing noticeably at the present time. Seedlings of redwoods
only become established in rather special conditions, but they are being
established in sufficient numbers in, I think, up to the limits of the present
QUESTION: Concerning the rates of possible growth of some of these trees,
you mentioned that the California redwoods are sometimes used as ornamentals
in other parts of the world and in the eastern United states. I was wondering
first of all, how well they do there.
ANSWER: Well, I can speak primarily for the British Isles. And in Britain
the Sierra redwood does extremely well. It is especially planted as a park
tree. That is to say on the big estates. Amongst the grassland there will
be scattered trees of the Sierra redwoods. They have kept their conical
shape very well in the 100 years or so that they've been growing in the
British Isles and they're quite a familiar item on the landscape. Now they
do very well. They seem to be climatically quite well suited. But I've never
heard of any seedlings actually making their appearance there. On the other
hand, the coast redwood has not been very successful when introduced into
the British Isles. It seems unable to make a go of it as isolated trees.
They're too subject to damage by the winds and storms. They really need
to be grown in groves. There's been some success with them in groves and
also occasionally as lines of trees. There's an especially famous line of
coast redwood trees at Ascot near London. But because they don't grow well
as tall trees, but they do sprout so easily from the base, there are a number
of redwood hedges in Britain. It has begun to be used as a hedge plant.
Again I think this is rather an insult to such a noble tree. But it lends
itself to hedging rather well. There are, of course, specimen trees growing
in the botanical gardens. And the most interesting situation at the famous
Royal Botanical Gardens at Kew is that they have wasp-waisted redwood trees.
If you see any one of the redwood trees there, you will see the base of
the tree, if this is the lower part of the trunk, is something like this.
And the explanation for this in that on everyone of these trees there is
a little descriptive plaque which says: "The bark of the redwood tree
is extremely soft and may be pushed in with the thumb. The result is that
five feet above the ground all the way around they've been pushed right
QUESTION: is the Metasequoia a drought-resistant tree or does it need a
ANSWER: Oh, yes, I forgot to say something about Metasequoia then. So, I
don't think it's especially drought-resistant. And indeed the ones we grow
up at the garden, we have near a fork of Strawberry Creek, that they get
a good deal of moisture. No, I think their general requirement for growth
in a garden or in on estate are rather similar to those of the coast redwood.
However, Metasequoia is being tried out on an increasing scale as a decorative
tree. The seeds have been obtained from China. There were two lots of collection
of the seeds from China, one by Elmer Merrill of Harvard University, who
made a collection of seeds there and distributed them to gardens all around
the world, and the other by Professor Balph Chaney of this University, who
went on an expedition to China, soon after the rediscovery of the Metasequoia,
an expedition which was financed by the San Francisco Chronicle. And he
brought back some actual trees, I think two living trees, small trees. And
we have them at the botanical garden now. They're growing. We also have
some trees from Merrill's seed. And we can't see any difference between
the way they're going. But the interesting thing is that they have now grown
up to the stage were they are producing seed-bearing cones. Alas, these
cones probably have no good seed in them, because there are no pollen bearing
cones on the tree yet. They go in for the production of seed-bearing cones
before they go in for the production of pollen-bearing cones. But as soon
as the pollen-bearing cones start to form, then we can expect to get some
seed formation in our trees and be greatly able to do selection experiments
perhaps to increase the range of variability. However, it is possible to
propagate Metasequoia quite easily by taking cuttings and rooting those.
Professor Chaney had the botanical garden here in Berkeley make a large
number of such rooted cuttings which he then sent out to places at various
latitudes up into Alaska, scattered generally around North America. The
idea being to find out what was the range of climates within which Metasequoia
could grow. And that experiment really is still in progress.
QUESTION: At what age do they start producing cones, the various varieties?
ANSWER: Well, I'm not very good on this. This is one for the silviculturists.
But I think, it's probably the order of 6o, 70 years for both Sequoia and
Sequoladendron. Isn't it, Bill, sorry to lean so heavily on you.
Dr. Libby: They'll come in much earlier than that under some conditions.
But that's not a bad guess for the average.
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