| Redwoods and Sequoias |
Above: General Grant (click picture to enlarge) - probably the second largest tree in the World (at least it
probably has the second largest voluminous trunk) - second only to the General Sherman tree. Both trees
are species of the giant sequoia, Sequoiadendron giganteum (formerly Sequoia gigantea) - a type of
conifer. This tree is 81.1 metres tall and its diameter at breast height (dbh) is 8.85 metres. General Grant
is shorter but wider than General Sherman which is 83.6 metres tall and has a dbh 0f 8.25 metres, a crown
spread of 33 metres and a trunk volume of about 1473 cubic metres. The photos do not convey the shear
size of this tree. Note the fire scar on this tree. This photo and the ones below were taken in the Sequoia
National Park (of which King's Canyon National Park is now a part) in the Sierra Nevada mountains in
California. The figure of the man on the right is approximately to the same scale.
What is a redwood?
The term 'redwood' is a colloquial term applied to a number of trees around the World (all with redwood)
including the Scot's Pine (Pinus sylvestris) which is altogether a much smaller tree (but with its own unique
character). Commonly the term is applied to three similar looking conifer trees belonging to the cypress
family, these are: Sequoiodendron giganteum, Sequoia sempervirens and Metasequoia glyptostroboides.
The first two are unique to California, whilst the third is found in China. Metasequoia glyptostroboides is
commonly called the dawn redwood and although an impressive tree in its own right (about the size of an
English oak) it is much smaller than Sequoia and Sequoiadendron. Sequoia sempervirens is commonly
known as the coast redwood or simply redwood, whilst Sequoiadendron giganteum is commonly known as
the giant sequoia or simply sequoia. Some people have tried to avoid confusion by using the term sequoia
exclusively for Sequoiadendron and the term redwood for Sequoia sempervirens. However, this is not
strictly botanically correct, since the redwood's Latin name is Sequoia and Sequoiadendron is a redwood
tree! Sequoiadendron literally means 'sequoia tree' so is not so helpful. Sequoiadendron was originally
classified as a Sequoia species, but its mode of development differs and Sequoia giganteum caused a
name clash as it was a name used for a variant of Sequoia sempervirens!
This taxonomical mess is perhaps best resolved as follows: consider Sequoia, Sequoiadendron and
Metasequoia as redwoods and sequoias (they all have very similar bark and other external features) but
use the full names giant sequoia, coast redwood and dawn redwood. (Remember though, that Californians
consider the redwood to be Sequoia sempervirens only and the sequoia to be Sequoiadendron giganteum
only). This is a classic example of why botanists prefer to use Latin names!
Both General Sherman and General Grant are giant sequoias (Sequoiadendron giganteum). The giant
sequoia has a more voluminous and more massive trunk than the coast redwood, but the coast redwood is
generally the taller tree, with its buttressed trunk tapering to a graceful point, in classical conifer fashion,
whereas the giant sequoia maintains a column-like stem for most of its height. Below are more pictures of
giant sequoias - click each picture to enlarge.
probably has the second largest voluminous trunk) - second only to the General Sherman tree. Both trees
are species of the giant sequoia, Sequoiadendron giganteum (formerly Sequoia gigantea) - a type of
conifer. This tree is 81.1 metres tall and its diameter at breast height (dbh) is 8.85 metres. General Grant
is shorter but wider than General Sherman which is 83.6 metres tall and has a dbh 0f 8.25 metres, a crown
spread of 33 metres and a trunk volume of about 1473 cubic metres. The photos do not convey the shear
size of this tree. Note the fire scar on this tree. This photo and the ones below were taken in the Sequoia
National Park (of which King's Canyon National Park is now a part) in the Sierra Nevada mountains in
California. The figure of the man on the right is approximately to the same scale.
What is a redwood?
The term 'redwood' is a colloquial term applied to a number of trees around the World (all with redwood)
including the Scot's Pine (Pinus sylvestris) which is altogether a much smaller tree (but with its own unique
character). Commonly the term is applied to three similar looking conifer trees belonging to the cypress
family, these are: Sequoiodendron giganteum, Sequoia sempervirens and Metasequoia glyptostroboides.
The first two are unique to California, whilst the third is found in China. Metasequoia glyptostroboides is
commonly called the dawn redwood and although an impressive tree in its own right (about the size of an
English oak) it is much smaller than Sequoia and Sequoiadendron. Sequoia sempervirens is commonly
known as the coast redwood or simply redwood, whilst Sequoiadendron giganteum is commonly known as
the giant sequoia or simply sequoia. Some people have tried to avoid confusion by using the term sequoia
exclusively for Sequoiadendron and the term redwood for Sequoia sempervirens. However, this is not
strictly botanically correct, since the redwood's Latin name is Sequoia and Sequoiadendron is a redwood
tree! Sequoiadendron literally means 'sequoia tree' so is not so helpful. Sequoiadendron was originally
classified as a Sequoia species, but its mode of development differs and Sequoia giganteum caused a
name clash as it was a name used for a variant of Sequoia sempervirens!
This taxonomical mess is perhaps best resolved as follows: consider Sequoia, Sequoiadendron and
Metasequoia as redwoods and sequoias (they all have very similar bark and other external features) but
use the full names giant sequoia, coast redwood and dawn redwood. (Remember though, that Californians
consider the redwood to be Sequoia sempervirens only and the sequoia to be Sequoiadendron giganteum
only). This is a classic example of why botanists prefer to use Latin names!
Both General Sherman and General Grant are giant sequoias (Sequoiadendron giganteum). The giant
sequoia has a more voluminous and more massive trunk than the coast redwood, but the coast redwood is
generally the taller tree, with its buttressed trunk tapering to a graceful point, in classical conifer fashion,
whereas the giant sequoia maintains a column-like stem for most of its height. Below are more pictures of
giant sequoias - click each picture to enlarge.
Above: notice the red-brown bark of the giant sequoia (redder in real-life than my camera would
suggest!) though colour does vary. Notice the fibrous nature of the bark - it is very light and spongy to
the touch and comes away in vertical strips (don't try this, especially not on a protected tree in the
National parks!). The lower part of the trunk is somewhat buttressed and often bears nodular growths
(resembling crown galls, not sure what they are though) especially in older trees. The bark at the base
of the tree tends to be more scaly.
suggest!) though colour does vary. Notice the fibrous nature of the bark - it is very light and spongy to
the touch and comes away in vertical strips (don't try this, especially not on a protected tree in the
National parks!). The lower part of the trunk is somewhat buttressed and often bears nodular growths
(resembling crown galls, not sure what they are though) especially in older trees. The bark at the base
of the tree tends to be more scaly.
Above: notice the fluted columnar trunks - a geometry reminiscent of the stone columns in ancient
Greek temples).
Greek temples).
Above: looking into the canopy gives you an idea of the colossal height of these trees - these
trunks are largely straight but taper due to the perspective! The vertically elongated scales of the
bark are more recognisable here as the scales tend to be shorter higher up the tree.
trunks are largely straight but taper due to the perspective! The vertically elongated scales of the
bark are more recognisable here as the scales tend to be shorter higher up the tree.
Above: another colossal fluted and buttressed trunk.
Above: another view of General Grant.
Above: the bark on some giant sequoias is noticeably paler and whiter higher up the tree, especially
on the branches (though this might be an illusion due to the brighter light?). The canopy is
concentrated toward the top of the tree, with about the first 40% of the trunk bearing no branches and
then branches increasing in length up to half-way up the tree and the crown tapers like a broad cone,
which often has a blunt looking tip. Young trees have a more classical Christmas-tree shape with a
conical crown starting low on the trunk. Fallen branches leave scars on the lower half of the trunk,
which are often blackened by fire. This tree is General Grant again.
on the branches (though this might be an illusion due to the brighter light?). The canopy is
concentrated toward the top of the tree, with about the first 40% of the trunk bearing no branches and
then branches increasing in length up to half-way up the tree and the crown tapers like a broad cone,
which often has a blunt looking tip. Young trees have a more classical Christmas-tree shape with a
conical crown starting low on the trunk. Fallen branches leave scars on the lower half of the trunk,
which are often blackened by fire. This tree is General Grant again.
Comparison of giant sequoias and coast redwoods
Giant Sequoia Coast Redwood
Height up to 90 m up to 110 m
Diameter up to 8 m + up to 2 m
Lifespan up to 3200 years up to 2200 years
Bark up to 0.75 m thick up to 0.3 m thick
Female cones about as large as a chicken's egg about as large as a large olive
Seeds about the size of oat flakes about the size of tomato seeds
Reproduction by seed only (sexual) By seed (sexual) or sprout (asexual)
Habitat between 5000 and 9000 feet on the Californian Pacific coastal planes
Mature trees need lots of water Mature trees need lots of water
Only found in California Only found in California
e.g. the Sierra Nevada only in a strip 750 km by 8-75 km
(cool air, heavy rains and fog)
(nutrient poor soils)
Mixed conifer forests Mixed conifer forests
Crown morphology Narrow, conical Broad, conical
The habitat of the giant sequoia is the mixed-conifer zone (5000 to 9000 feet, but most between 5000 and 7000
feet) on the Californian mountains. This habitat receives some 110 cm rain per annum (44 inches pa) and has
cool air and heavy snow in winter. Black oak, parasitic snow plants and other conifers also grow here. Animals
found in this habitat include: the black bear, mountain lion, cougar, raccoon, quail, mule deer, frogs, tarantulas,
rattle snakes, peregrine falcons and the yellow-bellied marmot. The grizzly bear used to occur in these areas
but was hunted to extinction in California. The high tannin content in the thick bark and wood deters insects and
other grazers and reduces microbial decay, such that dead trees take ages to decompose. Only stunted trees
grow above 9000 feet and up to the tree line at about 11 000 feet.
Note: if you meet a cougar then make lots of noise and throw stones and fight back if attacked. If you meet a
bear and the bear approaches then make lots of noise to scare it off and throw stones (some have survived
attack by playing dead and allegedly on one occasion by striking the sensitive nose) try to keep a safe distance
from the bear, though you could not outrun it (you may however, as a Florida naturalist pointed out to me, run
faster than the other guy!). Watch where you step to avoid startling rattlesnakes. The tarantula bite is not
usually life threatening but is allegedly very painful! Check your armpits and private areas for deer ticks at the
end of the day and remove them to avoid contracting Lyme's disease which can cause arthritis.
The habitat of the coast redwood is low altitude (30 to 750 metres above sea level) and damp all the year
round, with cool air, fog and heavy rains (250 cm pa). This heavy precipitation leaches nutrients from the soils
which are therefore nutrient poor. The nutrients are all locked up within the ecosystem's biomass, which means
that fallen dead trees must be recycled and many young trees grow on these rotting carcasses of their
predecessors and sometimes still bear hollow cavities at the base of their trunks in old age (where the former
fallen tree once existed as the roots grew around it). These coastal damp forests are mixed conifer forests with
Douglas-fir, western hemlock, tanoak, madrone, ferns, redwood sorrel and of course mosses and fungi.
The role of fire in the Sierra Nevada forest ecosystems
The mountain forests where the giant sequoia lives accumulate the needles from the various conifer trees
which decay only very slowly. These dry leaves are potential fuel for forest fires. Lightning strikes or intense
heat and careless human activity may initiate forest fires quite easily in the dry summer months and such fires
are a regular occurrence. For about 100 years, and until quite recently, these fires were considered a bad
thing and many were put-out in their early stages. However, this caused more pine-needle fuel to accumulate,
as fewer fires kept the fuel levels down, and so fires are no probably more frequent than in the natural state.
The policy now is to allow these wildfires to burn out naturally but protect habited areas. Although harmful to
those animals that do not manage to escape, the thick bark of the sequoias protect them and usually they
suffer mere scarring as a result and a loss of their leaves, but soon recover. Dead vegetation burnt away
opens up clearings for sequoia seedlings, essential since these seedlings are easily out-shaded and
out-competed by faster growing trees and shrubs (though if they manage to survive they will eventually get
their own back!). Thus fire is an essential part of the natural cycle of these forests and essential for the health
and vitality.
Enemies of the redwoods
Until the age of conservation, pioneers deforested vast areas of redwood forests for timber and to access
minerals such as gold. Apart from humans, mature redwoods have few natural enemies, but wind and lightning
are two such enemies. Eventually, wind may topple even a mature redwood, especially if the soil beneath it
becomes unstable or if humans remove the shelter afforded it by its neighbours, or if it is just too old and
rotten. Trees may topple if one side of the tree becomes heavier (such as if one side is badly damaged or dies
in old age). Many old stories abound of the affects of lightning on redwoods, although these stories cannot be
easily verified. More often than not these trees survive lightning strikes, but occasionally lightning has been
reported to do immense damage to these tall trees. Stories tell of trees in which the uppermost or middle-most
third of the trunk was blasted into tiny fragments, in the latter case the unsupported top-most section plummets
and may split the base of the tree asunder. There are even reports of entire great trees being reduced to
matchwood. Apparently redwoods shatter into cubical fragments when the force is great enough (the wood of
many conifers fragments in this way, in contrast to broad-leaved tree wood that tends to splinter into elongated
shards). Why are these catastrophic strikes so rare? Well, they could be caused by positive lightning which is
about a tenth as rare but ten times more powerful than the more common negative lightning. It may also
depend upon the moisture content of the tree or of its bark. Conifer trees with high resin content are more likely
to explode when struck by lightning as the resin canals conduct electricity better. Birch trees have oils that are
said to conduct electricity well and so are less likely to be damaged by lightning. The wetness of the soil is also
an important factor. Trees rooted in wet soil may suffer tremendous root damage when struck by lightning.
Often trees suffer more internal damage from lightning than is apparent from external appearances.
Wind and old age are apparently the main enemies of the redwood trees, but lightning may be a factor limiting
the height of the tallest trees.
Friends of the redwoods
Many of these trees now reside in National Parks and are protected by rangers (where possible) and hopefully
the future of these magnificent giants is assured for a long time to come. We are indebted to the U.S. National
Park Service for protecting these habitats and providing informative and educational materials.
Giant Sequoia Coast Redwood
Height up to 90 m up to 110 m
Diameter up to 8 m + up to 2 m
Lifespan up to 3200 years up to 2200 years
Bark up to 0.75 m thick up to 0.3 m thick
Female cones about as large as a chicken's egg about as large as a large olive
Seeds about the size of oat flakes about the size of tomato seeds
Reproduction by seed only (sexual) By seed (sexual) or sprout (asexual)
Habitat between 5000 and 9000 feet on the Californian Pacific coastal planes
Mature trees need lots of water Mature trees need lots of water
Only found in California Only found in California
e.g. the Sierra Nevada only in a strip 750 km by 8-75 km
(cool air, heavy rains and fog)
(nutrient poor soils)
Mixed conifer forests Mixed conifer forests
Crown morphology Narrow, conical Broad, conical
The habitat of the giant sequoia is the mixed-conifer zone (5000 to 9000 feet, but most between 5000 and 7000
feet) on the Californian mountains. This habitat receives some 110 cm rain per annum (44 inches pa) and has
cool air and heavy snow in winter. Black oak, parasitic snow plants and other conifers also grow here. Animals
found in this habitat include: the black bear, mountain lion, cougar, raccoon, quail, mule deer, frogs, tarantulas,
rattle snakes, peregrine falcons and the yellow-bellied marmot. The grizzly bear used to occur in these areas
but was hunted to extinction in California. The high tannin content in the thick bark and wood deters insects and
other grazers and reduces microbial decay, such that dead trees take ages to decompose. Only stunted trees
grow above 9000 feet and up to the tree line at about 11 000 feet.
Note: if you meet a cougar then make lots of noise and throw stones and fight back if attacked. If you meet a
bear and the bear approaches then make lots of noise to scare it off and throw stones (some have survived
attack by playing dead and allegedly on one occasion by striking the sensitive nose) try to keep a safe distance
from the bear, though you could not outrun it (you may however, as a Florida naturalist pointed out to me, run
faster than the other guy!). Watch where you step to avoid startling rattlesnakes. The tarantula bite is not
usually life threatening but is allegedly very painful! Check your armpits and private areas for deer ticks at the
end of the day and remove them to avoid contracting Lyme's disease which can cause arthritis.
The habitat of the coast redwood is low altitude (30 to 750 metres above sea level) and damp all the year
round, with cool air, fog and heavy rains (250 cm pa). This heavy precipitation leaches nutrients from the soils
which are therefore nutrient poor. The nutrients are all locked up within the ecosystem's biomass, which means
that fallen dead trees must be recycled and many young trees grow on these rotting carcasses of their
predecessors and sometimes still bear hollow cavities at the base of their trunks in old age (where the former
fallen tree once existed as the roots grew around it). These coastal damp forests are mixed conifer forests with
Douglas-fir, western hemlock, tanoak, madrone, ferns, redwood sorrel and of course mosses and fungi.
The role of fire in the Sierra Nevada forest ecosystems
The mountain forests where the giant sequoia lives accumulate the needles from the various conifer trees
which decay only very slowly. These dry leaves are potential fuel for forest fires. Lightning strikes or intense
heat and careless human activity may initiate forest fires quite easily in the dry summer months and such fires
are a regular occurrence. For about 100 years, and until quite recently, these fires were considered a bad
thing and many were put-out in their early stages. However, this caused more pine-needle fuel to accumulate,
as fewer fires kept the fuel levels down, and so fires are no probably more frequent than in the natural state.
The policy now is to allow these wildfires to burn out naturally but protect habited areas. Although harmful to
those animals that do not manage to escape, the thick bark of the sequoias protect them and usually they
suffer mere scarring as a result and a loss of their leaves, but soon recover. Dead vegetation burnt away
opens up clearings for sequoia seedlings, essential since these seedlings are easily out-shaded and
out-competed by faster growing trees and shrubs (though if they manage to survive they will eventually get
their own back!). Thus fire is an essential part of the natural cycle of these forests and essential for the health
and vitality.
Enemies of the redwoods
Until the age of conservation, pioneers deforested vast areas of redwood forests for timber and to access
minerals such as gold. Apart from humans, mature redwoods have few natural enemies, but wind and lightning
are two such enemies. Eventually, wind may topple even a mature redwood, especially if the soil beneath it
becomes unstable or if humans remove the shelter afforded it by its neighbours, or if it is just too old and
rotten. Trees may topple if one side of the tree becomes heavier (such as if one side is badly damaged or dies
in old age). Many old stories abound of the affects of lightning on redwoods, although these stories cannot be
easily verified. More often than not these trees survive lightning strikes, but occasionally lightning has been
reported to do immense damage to these tall trees. Stories tell of trees in which the uppermost or middle-most
third of the trunk was blasted into tiny fragments, in the latter case the unsupported top-most section plummets
and may split the base of the tree asunder. There are even reports of entire great trees being reduced to
matchwood. Apparently redwoods shatter into cubical fragments when the force is great enough (the wood of
many conifers fragments in this way, in contrast to broad-leaved tree wood that tends to splinter into elongated
shards). Why are these catastrophic strikes so rare? Well, they could be caused by positive lightning which is
about a tenth as rare but ten times more powerful than the more common negative lightning. It may also
depend upon the moisture content of the tree or of its bark. Conifer trees with high resin content are more likely
to explode when struck by lightning as the resin canals conduct electricity better. Birch trees have oils that are
said to conduct electricity well and so are less likely to be damaged by lightning. The wetness of the soil is also
an important factor. Trees rooted in wet soil may suffer tremendous root damage when struck by lightning.
Often trees suffer more internal damage from lightning than is apparent from external appearances.
Wind and old age are apparently the main enemies of the redwood trees, but lightning may be a factor limiting
the height of the tallest trees.
Friends of the redwoods
Many of these trees now reside in National Parks and are protected by rangers (where possible) and hopefully
the future of these magnificent giants is assured for a long time to come. We are indebted to the U.S. National
Park Service for protecting these habitats and providing informative and educational materials.
Above: the whole tree (my camera distorted the perspective too much for these two pictures to
form a montage because I was looking up at quite a steep angle.
form a montage because I was looking up at quite a steep angle.
This sequoia is next to a fallen dead sequoia. As these dead trees rot very slowly, they form rather
strong hollow shells that you can walk through.
strong hollow shells that you can walk through.
A group of sequoias, quite possibly all descended from the same individual.
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