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Welcome to Mariposa Grove of Giant
Sequoias. If you're impressed with these trees in the
parking area, you'll be awed by the larger trees farther
ahead.

These trees, Sequoiadendron giganteum, aren't
the oldest living things. Some individual living specimens
of the ancient bristlecone pine, Pinus aristate, are
more than 4,600 years old! The oldest Giant Sequoias
may exceed 3,000 years.

And Giang Sequouas aren't the tallest living things,
either. The related coastal redwoods, Sequoia sempervirens,
grow higher up to 368 feet (112). These
"Sierra redwoods" top out around 310 feet (94 meters);
the tallest in the Mariposa Grove is about 290 feet (88
meters).

Giant Sequoias don't even have the greatest
basal diameteters. The Montezuma cypress, Taxodium
mucronutum, of Mexico may exceed 50 feet (15 meters).
The largest known Giant Sequoia is just over 40 feet (12
meters) in basal diameter.

So why did these trees capture the attention of
the worl when discovered by western Europeans in the
early 1850's? SImply stated in total volume the Giant
Sequoias are the largest living things known to humans.

On your left as you start into the grove on the tram
road is the Fallen Monarch. Perhaps you've seen this
tree before - in the famouse 1899 photograph of U. S.
Cavalry officers on their horses up on t! Tannic acid in
the wood suppresses the initial growth of fungi and
bacteria, essentially arresting decay. Only when rain and
melting snow have leaches the tanning from the wood
can decay begin. Biologists suspect that this tree had
been down several hundred years before the Cavalry
photograph was taken! For your safety and to help preserve
what remains of the Fallen Monarch, please do not
climb on it.

Notice the Roots of this tree Sequoias don't have
deep tap roots; instead, the roots spread our near the
surface to capture water. While the roots are usually no
deeper than six feet (2 meters), they fan out more than
150 feet (45 meters), providing a stable base to balance
the massive trunk. Staying on the road and trails minimizes
soil compaction that damages these surface roots.

Numerous young Sequoias line the road above
the Fallen Monarch, distinguished by their foliage of
round overlapping scales; distinctive conical profiles
and soft, spongy bark. Strangely, there are few young
Sequoias in the forest. Can you guess why?

To germinate, Sequoia seeds have three requirements
10 some direct sunlight, 2) adequate moisture
and 3) bare mineral soil. Ironically, road construction
creates a perfect seedbed by opening up the forest floor
to sunlight, increasing moisture along the roadsides and
providing bare mineral soil on the road's spoil banks.

But why are young Sequoias so sparse away from
the road? Shortly after these trees were discovered, in a
well-intended effort to protect them, people began suppresing
natural fires. More shade-tolerant trees, such as
white firs, incense-cedars and sugar pines, quickly
spread over the forest floor, reducing sunlight, competing

for moisture and blanketing the minral soil with their
needles and debris. It became impossible for Sequoia
seedlings to get started

Only lightning-caused fires, usually occuring in
late summer, could reduce the competition from other
evergreens and burn away the leaf litter, leaving a thing
layer of nutrient-rich ash over the mineral soil. The heat
from a fire dries someof the ever-present green Sequoia
cones high in the mature trees, causing a shower of
fresh seed to fall after the fire onto a perfectly prepared
seedbed. eginning in November, snowstorms slowly
bury the Mariposa Grove in an ever-deepening white
blanket. As the snowpack melts the following spring,
sunlight, moisture, fresh seeds, ash and mineral soil
combine to create a Sequoia nursery.

This dependency on natural fires for Sequoia
reproduction was not understood until the early 1960's.
By then, 100 years of unburned forest litter and young
evergreens had accumulated, producing a massive fuel
load. Had ligtning ignited a fire under these unnatural
conditions, an intense crown fire could have occurred,
possibly killing even the largest trees. To reduce this
adbnormal fuel supply and promote Giant Sequoia reproduction,
the National Park Service began a series of
"prescribed burns," deliberately set and closely monitored
by rangers during spring and fall. When the forest
returns to a more natural state, these management fires
will probably be discontinued. Then nature can resume
its cycle of ligtning-caused ground fires every seven to 20 years.

At the Bachelor and Three Graces up ahead you
can often find the egg-shaped Sequoia cones. The
crown of a mature Giant Sequoia may bear thousands of
green cones at any one time. Each cone contains about
200 tiny flat seeds, roughly 1/4-inch (1cm) in length and
resembling a rolled oak flake. These female cones grow
on the upper branches. Given this vertical separation,
how do the trees reproduce?

Like most conifers, Giant Sequoias depend on the
wind. Late winter storms bring strong winds that carry
the pollen from the lower branches of one tree to the
upper branches of others, continuing the genetic mixing
necessary for healthy reproduction. This vertical separation
reduces the likelihood that the tree could pollinate
itself. Please remember to leave all cones where you
find them for other visitors to enjoy.

Before you round the curve and see the Grizzly
Giant, stop for a minute and drift back in time. The year
was 1852, and a Mr. Dowd was employed as a professional
hunter, supplying meat to a mining camp some 75
miles north of Yosemite. One day while hunting, he
stumbled upon a grove of giant cinnamon-colored trees
that we know today as Calaveras Big Trees State Park.
Mr. Dowd rushed back to camp, exclaiming that he had
just found giant orange trees easily four times larger
than any trees he had seen before! Mr. Dowd's announcement
was undoubtedly greeted by a hail of unkind
comments about his mental stability. He left the
camp but was not deterred. After an appropriate absence,
he returned, announcing that he had just shot an
enormous grizzly bear and needed five strong men to
help carry the meat back to camp. When the five men
confirmed Dowd's incredible story, the word was out.