Scientists are urging world leaders to act in order to protect the planet's threatened trees — and prevent further ecological and economic damage from their extinction.
Botanic Gardens Conservation International (BGCI), along with the Global Tree Specialist Group of the International Union for Conservation of Nature's Species Survival Commission (IUCN SSC), detailed this "warning to humanity" in a paper published last Wednesday in the New Phytologist Foundation journal Plants, People, Planet.
They say billions of people could lose their incomes, jobs and livelihoods if more isn't done to prevent tree species from going extinct.
The paper includes a call to action, which the groups say more than 30 organizations around the world have signed.
"Last year, we published the State of the World's Trees report, which showed that a third of species are at risk of extinction," Malin Rivers, lead author and head of conservation prioritization at BGCI, said in a news release.
"In this new paper, we show the wide ranging impact these tree extinctions may have on other species, on the ecosystems and for humanity. A strong and urgent response is required, both to prevent further tree species extinctions and restore the damaged ecosystems they form a part of."
BGCI, which represents botanic gardens in more than 100 countries, released its State of the World's Trees report in September 2021, which among other things said 30 per cent of the approximately 58,000 tree species worldwide are at threat of extinction.
Although this will vary depending on the region, the authors say the main threats to trees are habitat loss from the spread of agriculture, logging, livestock farming and urban development. Other threats include fire regimes, energy production and mining, and invasive species, with climate change also expected to intensify in the future and make these problems worse.
The organization says half of all known animal and plant species on Earth rely on trees for their habitat, with forests providing half of the world's carbon storage and three-quarters of its accessible freshwater.
The paper's authors warn that the "large-scale extinction of tree species will lead to major biodiversity losses in other species groups and substantially alter the cycling of carbon, water and nutrients in the world's ecosystems."
More than 100 tree species are already extinct in the wild, they say, with billions of trees destroyed each year.
On the economic side, the authors say forests contribute approximately US$1.3 trillion globally, much of it from timber but also in the form of fruit, nuts and medicine.
The paper says losing even one tree species can "substantially" alter an ecosystem, creating a domino effect or "extinction cascades."
The IUCN publishes a "red list" of threatened species, which the groups say includes more tree species than mammals, birds, reptiles and amphibians combined.
In their paper, the authors propose seven actions to prevent the widespread extinction of the planet's tree species.
These include conserving and restoring natural tree populations, addressing direct threats such as illegal logging, and mandating tree conservation in local and international policy and legislation.
"Our message for humanity is to remember how trees enrich and support our lives, as they have throughout human history. Yet we need to acknowledge that these values are at risk if we fail to consider the impacts of our actions, and to change our collective behaviour in relation to trees," Adrian Newton, co-chair of the IUCN SSC Global Tree Specialist Group, said in the news release.
"Although there is still much to learn about the biology, ecology and wonder of trees, we know how to conserve them. We also know that now is the time to act."
