Botanic Gardens Conservation International (BGCI) has published a State of the World’s Trees report. The report, compiling work led by the Global Tree Assessment (GTA), is the culmination of five years of research to identify major gaps in tree conservation efforts. It is one of the first assessments of the world’s threatened trees. Source: Timberbiz
Examining the globe’s 60,000 tree species, it reveals that 30% (17,500) of tree species are currently at risk of extinction. That means there are twice the number of threatened tree species globally than threatened mammals, birds, amphibians and reptiles combined.
According to the report more than 440 tree species are right on the brink of extinction meaning they have fewer than 50 individuals remaining in the wild. These species are found all over the world, from the Mulanje cedar in Malawi, with only a few remaining individuals on Mulanje Mountain, to the Menai whitebeam found only in North Wales, which has only 30 trees remaining.
Identifying which trees are at risk and ensuring these are protected is the most effective way to prevent extinction and restore endangered species. The report reveals that at least 64% of all tree species can be found in at least one protected area, and about 30% can be found in botanic gardens, seed banks, or other ex situ collections, but further action is needed.
The State of the World’s Trees report brings together research from over 60 institutional partners, including botanic gardens, forestry institutions and universities worldwide, as well as more than 500 experts who have contributed to tree assessments in the last five years.
The report reveals that 1 in 5 tree species are directly used by humans, for food, fuel, timber, medicines, horticulture, and more.
The greatest threats facing trees include habitat loss from agriculture and grazing, followed by over-exploitation from logging and harvesting. The report finds that 1 in 3 trees currently harvested for timber are threatened with extinction.
Climate change and extreme weather are emerging threats to tree species globally. As the temperature and weather of the world changes, many trees risk losing areas of suitable habitat. This affects species in both temperate and tropical habitats, with Cloud Forest tree species of Central America being at particular risk.
At least 180 tree species are directly threatened by sea level rise and severe weather events. This threat is most severe to island species, including magnolias in the Caribbean.
An increased occurrence of fire is a major threat to trees in Madagascar and has also been identified as a risk to US species of oak and Nothofagus trees in Australia and South America. Globally, land use change to agriculture alongside increasing global temperatures compounds the risk of fire to many tree species.
The type of threat and percentage tree species impacted:
- Agriculture (trees cleared for crop production) 29%
- Logging for timber 27%
- Livestock farming (trees cleared for farming/grazing)14%
- Urbanisation (cleared for residential/commercial development) 13%
- Fire 13%
The State of the World’s Trees report provides an in-depth analysis of which countries require further action to protect threatened trees.
In Europe, 58% of native European trees are threatened with extinction in the wild. Whitebeams and Rowan (Sorbus genus) are the most threatened species of trees in Europe.
Brazil, which has some of the most biodiverse forests in the world, has the highest number of tree species (8,847) and also the most threatened tree species (1,788).
However, the report finds that it is island tree species that are more proportionally at risk. This is particularly concerning, because many islands have species of trees that can be found nowhere else.
For the first time, the report identifies which threats are having the greatest impact on specific tree species. The main threat to tree species across the world is deforestation for agriculture.
To view the report visit: https://www.bgci.org/our-work/projects-and-case-studies/global-tree-assessment/
