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Hibakujumoku

Hibakujumoku is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Hibakujumoku rather than just read about it. In short: Hibakujumoku (Japanese: 被爆樹木; also called survivor tree or A-bombed tree in English) is a Japanese term for a tree that survived the atomic bombings of Hiroshima and Nagasaki in 1945. The term is from Japanese: 被爆, romanized: hibaku, lit. 'bombed, A-bombed, nuked' and Japanese: 樹木, romanized: jumoku, lit. 'trees and shrubs'.

Hibakujumoku — main illustration
Hibakujumoku — illustration

Key takeaways

  • Hibakujumoku belongs to science; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Hibakujumoku to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Hibakujumoku from memory before moving on to harder problems.

Reference excerpt

Hibakujumoku (Japanese: 被爆樹木; also called survivor tree or A-bombed tree in English) is a Japanese term for a tree that survived the atomic bombings of Hiroshima and Nagasaki in 1945. The term is from Japanese: 被爆, romanized: hibaku, lit. 'bombed, A-bombed, nuked' and Japanese: 樹木, romanized: jumoku, lit. 'trees and shrubs'.

Damage The heat emitted by the explosion in Hiroshima within the first three seconds at a distance of three kilometres from the hypocenter was about 40 times greater than that from the Sun. The initial radiation level at the hypocenter was approximately 240 Gy. According to Hiroshima and Nagasaki: The Physical, Medical, and Social Effects of the Atomic Bombings, plants suffered damage only in the portions exposed above ground, while portions underground were not directly damaged.

Surviving trees in Hiroshima In 2011, the United Nations Institute for Training and Research (UNITAR) in Hiroshima published a report and database detailing the surviving trees in that city. The closest tree, 370m from ground zero of the blast (34.3955° N, 132.4536° E), is a Weeping Willow (シダレヤナギ) on the Motomachi riverbank of the Ōta River. The tree fell at the time of the bombing, but new buds sprouted from the roots. The second closest tree is a Kurogane holly (クロガネモチ) 410m from the hypocenter, which burned down during the bombing, leaving only a stump, but miraculously sprouted in 1949.. In all, in 2011 there were 12 survivor trees within 1000m of the blast, and 48 within 2000m.

Regeneration The rate of regeneration differed by species. Active regeneration was shown by broad-leaved trees. Approximately 170 trees that grew in Hiroshima in 2011 had actually been there prior to the bombing. The oleander was designated the official flower of Hiroshima for its remarkable vitality.

Types of hibakujumoku Hibakujumoku species are listed in the UNITAR database, shown below, combined with data from Hiroshima and Nagasaki: The Physical, Medical, and Social Effects of the Atomic Bombings. A more extensive list, including distance from the hypocenter for each tree, is available in Survivors: The A-bombed Trees of Hiroshima.

List

Surviving trees in Nagasaki Although not as well known as the hibakujumoku in Hiroshima, there are a number of similar survivors in the vicinity of the hypocenter in Nagasaki. Approximately 50 of these trees have been documented in English. The J-pop singer and actor Fukuyama Masaharu, who was born in Nagasaki to survivors of the atomic bomb, has been active in preserving Nagasaki's hibakujumoku. His song "Kusunoki" (クスノキ), from his 2014 album Human, honours the camphor trees of Sannō Shrine. Fukuyama used the song to solicit donations which the city of Nagasaki used to establish the Kusunoki Foundation, dedicated to preserving the trees and teaching the history associated with them.

See also Hibakusha, humans that survived the atomic bombs List of individual trees Ákos Nagy - Hibaku Jumoku - The trees of Hiroshima [被爆樹木]

References

Illustrations

Hibakujumoku: A Eucalyptus bicostata tree at the site of Hiroshima Castle, 740 m from the hypocenter. The tree survived the atomic bombing, while the castle was destroyed.
A Eucalyptus bicostata tree at the site of Hiroshima Castle, 740 m from the hypocenter. The tree survived the atomic bombing, while the castle was destroyed.

Worked examples

Example 1 — a first encounter with Hibakujumoku

Start with the simplest possible case. Write down what Hibakujumoku claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Hibakujumoku before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Hibakujumoku ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Hibakujumoku

In research
Hibakujumoku appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Hibakujumoku in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Hibakujumoku is common in secondary-school and first-year university syllabi. It links to neighbouring topics Atomic bombings of Hiroshima and Nagasaki, Individual trees in Japan, Radiation effects, so understanding it makes those chapters shorter.
In everyday life
Look for Hibakujumoku outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
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How to study Hibakujumoku in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Hibakujumoku means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Hibakujumoku out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Hibakujumoku in simple terms?

Hibakujumoku (Japanese: 被爆樹木; also called survivor tree or A-bombed tree in English) is a Japanese term for a tree that survived the atomic bombings of Hiroshima and Nagasaki in 1945. The term is from Japanese: 被爆, romanized: hibaku, lit. 'bombed, A-bombed, nuked' and Japanese: 樹木, romanized: jumok…

Why does Hibakujumoku matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Hibakujumoku?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Hibakujumoku.

Tags

  • Atomic bombings of Hiroshima and Nagasaki
  • Individual trees in Japan
  • Radiation effects
  • Trees of Japan

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