- Why in news
- On 3 July 2026, the Ministry of Science & Technology announced that a banyan tree in Munger, Bihar, is about 700 years old by radiocarbon dating. It is called the oldest accurately dated banyan.
- What it is
- The Munger Banyan (Ficus benghalensis) is a heritage tree on the ITC campus in Munger, Bihar. Scientists of the Birbal Sahni Institute of Palaeosciences, Lucknow, dated it with a new method for tropical trees. Earlier age estimates for such trees rested on folklore and records.
- Method used
- The team used high-precision radiocarbon dating by Accelerator Mass Spectrometry (AMS) on extracted alpha-cellulose. Results were calibrated against IntCal20 and OxCal software.
- Why not tree rings
- Most tropical broadleaf trees lack distinct annual growth rings. This limits conventional dendrochronology and makes radiocarbon dating necessary.
- Sampling site
- Samples came from wood near the pith of a secondary trunk and an ancient primary branch. The pith holds the earliest wood formed in the juvenile stage of secondary growth.
- Institute
- Dr. Trina Bose of the Birbal Sahni Institute of Palaeosciences, Lucknow, led the work. The institute is an autonomous body under the Department of Science and Technology.
- Radiocarbon basis
- Radiocarbon dating measures the decay of carbon-14 in organic material. It suits material up to roughly 50,000 years old.
Don’t confuse with Dendrochronology vs radiocarbon dating: Dendrochronology counts annual growth rings, which most tropical broadleaf trees lack. Radiocarbon dating measures carbon-14 decay in wood and works without rings.
Don’t confuse with Carbon dating vs other isotope dating: Radiocarbon dating suits organic material of recent age, up to about 50,000 years. Uranium-series and potassium-argon methods are used for much older rocks and minerals.
Science and technology: 57 Prelims questions since 2013; most test the concept behind the news, not the news itself. In Mains, 12 news-triggered questions.
Why it matters
- Gives a scientific protocol to date heritage trees, replacing folklore-based age estimates.
- Helps identify and protect culturally and ecologically important trees, and supports research on past climate.
Problems
- Radiocarbon dating needs costly AMS facilities and expert calibration.
- Sampling near the pith of old trees can harm them or be impossible if the trunk is hollow.
Way forward
- Apply the method to other heritage trees and build a national register of dated trees.
- Link dated trees to legal protection by forest departments and biodiversity management bodies.
No close past question yet.
No practice question for this one; the card may still help an answer. Why: Concept of radiocarbon dating is syllabus-relevant, but a news-linked question on this finding is unlikely.
Worth revising until Prelims 2028: most news questions come within two years of the event.