Nature & Beasts
Why do whole bamboo forests flower and die in the same year?
- They are often one plant
- Disease
- Drought
The answer is They are often one plant. A stand is usually one connected organism on a clock up to 120 years long.
Because a stand is usually one plant. Bamboo spreads by rhizome, so what looks like a forest of separate stems is often a single connected organism - and it flowers on an internal clock that can run to 120 years, sets seed, and then dies. Plants propagated from the same stock and separated onto different continents will flower in the same year, which means the clock is genetic rather than environmental.
The favoured explanation is predator satiation. Producing seed rarely and then all at once overwhelms whatever eats it: the seed-eaters cannot possibly consume a crop that size, so a fraction survives to germinate. Flowering a little out of step with your neighbours would mean being eaten, which keeps the population synchronised.
In parts of northeast India the consequence is a documented disaster on a schedule. Mautam - roughly, bamboo death - follows the flowering of Melocanna baccifera about every 48 years: rats breed explosively on the seed glut, and when it runs out they move into the fields, and famine follows. It happened in 1862, 1911, 1959 and 2006, and the 1959 episode contributed directly to an insurgency, because the government dismissed the warnings as superstition.