Asia has more threatened oak tree species than anywhere in the world. First-of-its-kind report led by The Morton Arboretum will help prioritize oak conservation efforts.

LISLE, Ill., Aug. 3, 2026 /PRNewswire/ -- Many threatened or understudied oak tree species are at risk of extinction in Southeast and East Asia, where more than half of their native range is subject to sharply increasing human pressure. Should these species of oak disappear from the wild, most of them do not have a single backup in a managed botanical collection anywhere in the world.

Those are among the findings in the first Conservation Gap Analysis of Select Native Asian Oaks, conducted by scientists at The Morton Arboretum alongside collaborators in the region. Oaks are a crucial species that anchor entire ecosystems—supplying food and shelter for humans and wildlife alike—and by addressing vast disparities in data about these at-risk trees, this report informs the most practical next steps for conserving them.

"Southeast Asia is a biodiversity hotspot for oaks," said lead author Kate Good, the Arboretum's global tree conservation research manager. "There are more threatened species of oak in Asia than anywhere in the world, and yet many of these species are not adequately represented in protected areas or in botanic gardens."

Immediate next steps toward implementing on-the-ground restoration projects include local partners, with the support of the Arboretum, attending a propagation and planting training, collecting and planting oak trees in Vietnam, and conducting further surveys and collecting in Laos.

According to the Conservation Gap Analysis of Select Native Asian Oaks, the most commonly reported threat to existing oak habitat in the region is agriculture, including wood and pulp plantations, cited for two-thirds of the species. Others include development, climate change and extremely small populations (few trees left in the wild).

The report analyzed 54 species on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species assessed as either threatened or Data Deficient within the study area of Vietnam, Laos, Thailand, Cambodia, Myanmar, Brunei, Malaysia, Singapore, Indonesia, Philippines, Timor-Leste, Korea, Japan and Taiwan. The IUCN Red List is the globally recognized and standardized system for assessing the extinction risk of the world's plant, animal and fungal species.

Of those 54, 40—or 74%—are not currently held in botanical collections. For perspective, the Arboretum's conservation gap analysis of U.S. oaks identified only one species of 91 studied not in collections (1.1%), and of Mesoamerican oaks, 22 of 59 (37%).

"There is an urgent need to increase the number of threatened Southeast and East Asian oaks in managed botanical collections within their native country," Good said. "While protection of species in their native habitat is ideal, botanical collections play an important complementary role in conservation, particularly as a genetic repository for research and future reintroductions."

The analysis identifies species for which action is urgent and highlights the importance of protected areas in safeguarding these critically endangered trees. For example, critically rare Quercus trungkhanhensis has just two known individuals left in a protected area, while Q. dilacerata has only one known record, and it is outside of a protected area. Similarly, Q. dankiaensis was last recorded in a protected area in 1934, suggesting it could now be extinct in the wild.

"With so many species at risk of extinction, this report will help prioritize oak species for conservation in Southeast and East Asia," said report co-author Silvia Alvarez-Clare, Ph.D., director of the Arboretum's Global Tree Conservation Program. "By identifying the species that have very little protected area coverage, are not held in any managed botanical collections and experience high human pressure, we can focus efforts on the species and regions in which our work will have the greatest impact."

About The Morton Arboretum
The Morton Arboretum is a globally recognized leader in tree research and education. Its 1,700 acre site cares for 106,714 specimens representing 4,067 different kinds of plants. The Arboretum's Center for Tree Science, Global Tree Conservation Program, Chicago Region Trees Initiative, and Center for Species Survival: Trees are contributing scientific knowledge and technical experience to secure the future of trees locally, nationally, and worldwide. Information about the Arboretum's scientific work and how it contributes to a greener, healthier world where people and trees thrive together can be found at mortonarb.org.

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SOURCE Morton Arboretum