In upper Siang district of Arunachal Pradesh, at the edge of a forest, stood a tree that may already have disappeared. A botanist collected its specimens only once, from a single hillside, and in 2019 described it as Castanopsis pathakii, a member of the oak family. No researcher has returned to look for it since. No conservation plan has been initiated, and even six years later, the species remains absent from global biodiversity databases. Meanwhile, the forest faces pressure from road construction, hydro electric projects and agricultural expansion.
Based on the evidence—single known location, uncertainty over its existence and threats to its habitat—I, along with Joeri Strijk of Alliance for Conservation Tree Genomics (ACTG), Malaysia, proposed a provisional “critically endangered” status for Castanopsis pathakii early this year. It was part of a global assessment of Castanopsis (chinquapins) and Lithocarpus (stone oaks) by ACTG, Botanic Gardens Conservation International and IUCN (International Union for Conservation of Nature) Species Survival Commission Global Tree Specialist Group. “Critically endangered” is the highest threat category that IUCN provides before a species is listed as “extinct in the wild” or “extinct”. Yet C pathakii has not been formally assessed for IUCN Red List. Nor is it protected under India's Wildlife (Protection) Act, 1972.
Castanopsis pathakii is not an isolated case. Across the Fagaceae, the botanical family that includes oaks, chinqua-pins and stone oaks, gaps in scientific knowledge and conservation policy risk leaving threatened species without ade-quate protection. In India, members of this family grow in forests stretching from the eastern Himalayas to the Indo-Burma region. At least 34 species of Castanopsis and Lithocarpus occur across Arunachal Pradesh, Assam, Meghalaya, Nagaland, Manipur, Mizo-ram, Tripura and Sikkim. Of the 29 species assessed on the IUCN Red List, 11, or 38 per cent, are classified as “data de-ficient”. This does not mean they are safe. The category signals that there is insufficient information to assess a species’ risk of extinction and flags the need for further research. In practice, it triggers no automatic conservation action. Consider four Lithocarpus species —L cottonii, L kamengii, L milroyi and L ollus—that are endemic to India. None has a verified, geo-referenced occurrence record in the Global Biodiversity Information Facility (GBIF), an international database. Their existence is documented by botanical collections dating to the 19th century. But without precise locations, finding and protecting them is difficult. Besides, since “data deficient” is not a threatened category under the IUCN Red List, the designation does not trigger legal protection.
Various research confirm that over half of all “data deficient” species globally are likely threate ned with extinction. For species endemic to a single country, known only from type specimens collected over a century ago, the probability is substantially higher. This is not a failure of implementation, but of policy design.
The forests of the northeast are among the world's most ecologically irreplaceable. Trees of the genera Castanopsis and Lithocarpus are important structural components of these forests. Their canopies provide food and habitat for wild-life, including hoolock gibbons, lion-tailed macaques, Asian elephants and Himalayan black bears. They also help sustain forest ecosystems that regulate watersheds feeding the Brahmaputra and its tributaries. Yet they remain poorly documented.
The Botanical Survey of India (BSI) has published no national Red List assessment for tree species belonging to either genus. They are absent from the Wild Life (Protection) Act (WLPA), 1972. Nor is there a dedicated recovery plan—an ex-situ conservation programme or coordinated nursery production to support their use in forest restoration. International warnings have also failed to elicit conservation response. Consider Castanopsisarmata. IUCN's global assessment notes that its Indian sites “are believed to likely no longer hold individuals”. The warning has prompted neither a survey nor a reassessment of the species' status.
GAP BETWEEN PROMISE AND PROTECTION
In 2022, India submitted its seventh national report to the Convention on Biological Diversity. It has also committed to the Kunming-Montreal Global Biodiversity Framework, whose target 4, calls for urgent management action to halt human-induced extinction of known threatened species. Under the National Red List Assessment Initiative for 2025-30, launched at the IUCN World Conservation Congress, India aims to assess about 7,000 plant species by 2030.
These are welcome commitme nts. But implementing them requi res reliable data. A species cannot be protected if its location is unknown. Nor can its extinction risk be assessed when records needed to establish its distribution are missing from, or inaccessible through, the databases on which assess-ments depend. For instance, BSI’s Central National Herbarium in Howrah houses one of Asia's largest botanical collec-tions. Yet its holdings are not fully digitised and georeferenced records are not syste matically accessible to conservation assessors. Type specimens of Litho carpus species, endemic to India, are missing from GBIF, limiting acce ss to records that could help bota nists identify historical collection sites and verify surviving populations. Bridging this gap requires sustained investment in digitisa tion, better data-sharing between institutions and political will to make scientific records accessible.
Over half of all 'data deficient' species globally are likely threatened with extinction. For species endemic to a single country, known only from type specimens collected a century ago, the probability is much higher
To begin with, BSI must prioritise digitisation and georeferencing of Fagaceae collections from the northeast as part of the National Red List Assessment Initiative. Coordinates for type localities of all four endemic Lithocarpus species should be published through GBIF.
WLPA should also have a precautionary provision to protect species that are endemic to India, classified as “data deficient” and lack georeferenced occurrence records. Targeted botanical surveys should be funded and organised in Upper Siang, the only known location of Castanopsis pathakii, with a clear deadline for reporting the findings. If the species is found, it should be classified as “critically endangered” and given legal protec tion. If it is not found, India will have to consider whether it has already lost a tree without ever knowing it existed.
(Anurag Dhyani is senior scientist at Jawaharlal Nehru Tropical Botanic Garden and Research Institute, Kerala, and Co-Chair, IUCN Species Survival Commission Global Tree Specialist Group)
This article was first published in the November 1-15, 2026 print edition of Down To Earth.