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05/24/2006
Red Apes and Chestnuts
Two years ago (columns of 5/5/2004 and 5/12/2004), I wrote
about the American chestnut tree, a wonderful tree that grows to
heights of over a hundred feet and diameters as large as 8 feet. I
find it hard to believe a record 17 feet quoted on an American
Chestnut Foundation Web site! Perhaps I shouldn’t be so
skeptical; according to my 1962 World Book Encyclopedia, the
General Sherman tree in Sequoia National Park in California
measured 36.5 feet in diameter at its base. At any rate, with a
crown that can spread out a hundred feet, the American chestnut
is one big tree. Today, the tallest American chestnut tree is
reportedly a 106-foot-tall specimen in the state of Washington,
where the chestnut blight has not yet reached.
To review, in the 1800s a quarter of all the trees in the forests of
the eastern United States were American chestnuts. There were
billions of them until, in the early 1900s, a fungus known as
chestnut blight arrived here from the Orient. It killed virtually all
of the American chestnuts. New shoots grew from the stumps of
the dead trees but the fungus remained in the roots and killed off
the shoots before reaching the stage where nuts were produced.
The smaller Chinese chestnut tree is immune to the chestnut
blight and, when the extent of the blight’s effects became
apparent, a program of cross breeding the American and Chinese
chestnuts began. The ultimate goal of the cross breeding is to
obtain a nearly pure American chestnut that retains the blight
immunity of the Chinese chestnut. To do this, let’s take one of
the few remaining American chestnut trees and cross it with a
Chinese chestnut. This gives us a 50-50 American-Chinese tree.
Of course, we then have to wait years before 50-50 tree produces
nuts. When we cross that 50-50 specimen with a pure American
chestnut, we get a 75-25 American-Chinese tree. Over the years
this approach has been repeated a sufficient number of times so
that today there is a 94% American-6% Chinese chestnut.
A few American chestnut trees were found that seemed resistant
to the blight. Propagating these chestnuts is another approach to
bringing back the American chestnut. One of the problems is
that the blight takes its time to do its dirty work. It may take
decades before we can be sure we have a true blight-resistant
chestnut. I gather that the current cross breeding plan is to
achieve a 98% American-2% Chinese chestnut and begin
planting these breeds in national forests in the eastern U.S.
This past week saw some very good news. An AP article by
Elliott Minor posted on AOL News and in Sunday’s New York
Times reports that a stand of about a half dozen American
chestnuts undamaged by blight was discovered in the area of
Pine Mountain, Georgia. The tallest tree is about 40 feet tall and
is about 20 to 30 years old. How did these trees escape the
blight? That’s the question forestry experts are trying to answer.
Either the trees are resistant to the blight or something in the Pine
Mountain area is conferring immunity to them. Or did the blight
somehow skip the Pine Mountain area?
The Georgia chapter of the American Chestnut Foundation is
quite excited about the trees, found by biologist Nathan Klaus
while hiking in the Franklin D. Roosevelt State Park near FDR’s
“Little White House” in Warm Springs, Georgia. The chapter
members will add the tall “Klaus tree” to the list of “Mother”
trees to pollinate and propagate. Pollinating the trees isn’t easy.
They have to get up to where the flowers are and pollinate them
with the pollen from the tree being used to cross breed. They
then have to bag the flowers to be sure no other pollen comes
into the picture. The Pine Mountain grove isn’t accessible to a
bucket truck and the tree is too tall to reach the flowers with
orchard ladders but I’m sure these Georgians will find a way.
We’ve revisited the American chestnut. Let’s also revisit animal
intelligence, a favorite topic. In the April Scientific American,
there’s an article titled “Why Are Some Animals So Smart?” by
anthropologist Carel Van Schaik. Van Schaik thinks that certain
orangutans in Sumatra demonstrate the key role that “culture”
plays in developing such intelligence. The orangutans live in an
area near Suaq Balimbing in the Kluet swamp in Sumatra and
differ markedly from orangutans elsewhere.
Typically, orangutans live in relatvely dry areas and tend to be
loners, not sociable apes like chimpanzees or gorillas. In
contrast, the orangutans in the swampy Suaq area are quite
sociable, possibly due to the lush area they inhabit and the fact
they don’t have to struggle as much to find sustenance. (Schaik
describes the hot, sticky insect-ridden environment as great for
the apes but hell for the researchers!) The interesting thing about
these Suaq apes is that, contrary to other wild orangutans,
they’ve created and use tools.
The Suaq tools are used to secure various kinds of food – ants,
termites and especially, honey. The orangutans will watch trees
for signs of bees flying into or out of holes in trees. In other
locales, the red apes just use their mouths and fingers to access
the honey. The Suaq apes select a stick and, holding it in their
mouths, will move it around in the hole, pull it out and suck off
the honey. Captive orangutans take to tool use quite readily, but
wild orangutans have been conspicuous nonusers of tools.
More impressive is another use of a tool by the Suaq apes.
There’s a tree known as the Neesia tree that produces capsules
ranging up to 10 inches long and 4 inches wide. The husk of the
capsule is very tough to open but when the seeds ripen cracks
appear in the husk and rows of seeds the size of lima beans are
exposed. The seeds are quite nutritious (nearly 50% fat) and
they also have attachments that are about 80% fat. The Neesia
plant protects its seeds by surrounding them with razor-sharp
needles that keep orangutans from fully utilizing all the seeds.
The Suag apes, on the other hand, strip the bark off sticks and
again, holding the sticks in their mouths, insert the sticks into a
crack and move the stick back and forth to loosen the seeds.
After that the ape tips the capsule and the seeds fall out directly
into its mouth. The Suaq orangutans are the only ones observed
to do this. Yet, just across a river, also a swampy environment,
are more orangutans that enjoy the Neesia seeds but don’t use a
tool. As a result, they don’t get as much nourishment from the
Neesia as do the Suag apes. The river is so wide that orangutans
cannot swim across. The river effectively has created two
different cultures of red apes.
What is culture? Those who study primates define it as the
ability to learn by observation skills invented by others. In Van
Schaik’s view, the likely scenario is that the two uses of the tools
were invented by a couple of clever Suaq orangutans. Then,
thanks to the sociable nature of the Suaq group and the tendency
to gather together as opposed to going it alone, there was plenty
of opportunity for others to observe and pass along the tool
making and use. The orangutans have the innate ability to create
and use tools, as demonstrated by their rapid acquiring of the
techniques in captivity. In the wild, it apparently takes the social
group to create the culture that gets passed along to its members
and to following generations. Is it our sociability that makes us
humans so smart? If so, what is it that makes us so un-smart at
being sociable on a large-scale basis?
Allen F. Bortrum
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