In remote corners of Sichuan Province,
China, the arrow bamboo is acting strangely. It grows brown
and scraggly with odd grass-like seed heads appearing amidst
the foliage. The giant pandas that have traditionally lived
on the arrow bamboo forest have stopped eating these plants.
The brown-out is spread over a 270,000 square mile area.
The Chinese are working hard to help this rare and endangered
species survive a botanical disaster.
But it happened 60 years ago, and this time it was anticipated.
The arrow bamboo flowers only once in 60 years, and the
moment it goes into flowering mode the pandas won't eat
it any more. This is much like lettuce plants that bolt
to flower in the heat, and the formerly delicious leaves
turn unpleasantly bitter. Like lettuce, bamboo releases
its seed then dies. With bamboo forests, 10 to 20 years
is needed for the stand to grow back again from seed.
In the 1980s other stands of arrow bamboo in a preserve
went to seed and hundreds of pandas died of starvation.
But what did the pandas do a century ago or more when the
arrow bamboo flowered? Experts say there was more wild land
for them to migrate to new stands to feed on. Now, limited
to their preserve, the options are gone. Today the Chinese
are trying to encourage the old migration paths to reestablish
themselves so the pandas will move on to new preserved habitat
in search of alternate food.
This example of the arrow bamboo illustrates one of the
most fascinating facts about this grass-like plant. Few
people have ever seen it flower, which makes these plants
maddeningly difficult to tell apart. It also wreaks havoc
with classification because our binomial system is based
on reproductive structures and flowers. After rare bamboos
flower there can be a rush to reclassify based on analysis
of the blooms.
In most cases, the bamboo we grow in our gardens are clones.
New plants are made from roots and cuttings of a parent
and its parent and so on. This makes them all genetically
identical. When a cutting taken in California is sent to
South Africa, and another cutting of that plant lands in
Australia, each one of these is genetically identical. When
the time to flower comes around, every one of these plants,
no matter where they are on earth, goes to seed at the same
time. This is called "gregarious bamboo flowering"
because they all do it simultaneously because they are all
technically the very same plant.
Bamboo is a wind pollinated flower, so you need a lot of
plants together where pollen grains saturate the air. It
is believed that there is a very good reason for bamboo
to die after it flowers. If you've ever seen a dense bamboo
forest in the wild, you'll find the ground riddled with
rhizomes seeking an open spot to send up a new clum or shoot.
Seed would have little chance of finding an open spot without
competition for limited water from the adults. In other
words, a seedling would not survive without the old stand
dying back to yield open space and moisture to youngsters.
In other Third World countries such as India, gregarious
bamboo flowering is linked to famine. Rats feed voraciously
on the hundreds of thousands of acres of dying bamboo, its
seed and flowers. This causes rapid reproduction in the
rodent population. Higher numbers of pests then turn to
other crops and stored harvests, threatening the human food
supply. The bamboo flowering has become a bad omen in India.
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