The world's tallest flowering plant faces a shrinking future

Nature · Published 18 October 2026 Swipe more like this →

In short: The Australian mountain ash is a botanical titan, reaching heights that rival the world's largest redwoods. Yet, as global temperatures rise, these carbon-dense giants are struggling to maintain their foothold. Scientists are now quantifying how a warming climate threatens to dismantle one of Earth's most significant carbon sinks.

Eucalyptus regnans, commonly known as the Australian mountain ash or swamp gum, holds the title of the tallest flowering plant species on Earth. Native to southeastern Australia, specifically Victoria and Tasmania, these trees can reach heights exceeding 114 meters (375 feet). While they are often compared to the giant sequoia in terms of scale, the mountain ash is distinguished by its unique growth in tall wet forests and its ability to store more carbon than any other known forest.

The tree's physical architecture is specialized for its environment. It features a straight trunk with smooth grey bark and a stocking of rough, fibrous bark at the base. Its leaves are dotted with tiny oil glands, which give the foliage an aromatic scent of eucalyptus and balsam when crushed. These oil glands are also the source of eucalyptus oil, a substance widely utilized for medicinal purposes. However, unlike some other eucalypts, this species lacks a lignotuber, making it particularly vulnerable to bushfires, from which it must regenerate solely from seed.

Recent research using data from silvicultural experiments conducted between 1947 and 2000 reveals a troubling trend. Rising temperatures and increased vapor pressure deficits are reducing the 'carrying capacity' of these forests. Specifically, a projected 3°C temperature increase by 2080 could lead to a 24% reduction in tree density and carbon stock. This loss would be equivalent to the disappearance of 240,000 hectares of mature forest, potentially undermining global efforts for carbon sequestration and forest restoration.

General information, not professional advice. Spotted an error? Flag the card or see corrections and complaints.

Intellect Plus is a visual educational discovery platform for exploring fascinating facts and ideas. Brain Food, Not Brain Rot. What is Intellect Plus?

Related

• Eucalyptus flowers have no petals, just a lid that pops off
• How Australia’s giant eucalyptus trees mastered the art of burning
• The hidden survival mechanisms that allow Australian flora to thrive after bushfires
• The rare living fossil discovered in a remote Australian canyon
• The ancient Australian grasstree can live for centuries and thrives on bushfire destruction
• The genetic blueprint for a tree's sex is hidden in its telomeres
• The genetic clock that allows cannabis to bloom on its own
• Why palm trees don't grow like the trees you know
• Decoding the complex architecture of flowering plants
• The biological blueprint: how seeds function as life bombs
• A twining vine's spin has nothing to do with the sun or the hemisphere
• Why did flowering plants independently evolve the ability to produce caffeine multiple times?

More in Botany · More in Nature · Latest · A–Z · All topics