Global Tree Assessment
Conservation Assessments for all the World’s Tree Species
The Global Tree Assessment is an initiative assessing the conservation status assessments for all the world’s tree species available on the IUCN Red List. It is led by BGCI and the IUCN Species Survival Commission Global Tree Specialist Group. The Global Tree Assessment is a collaborative global initiative linking taxonomic, geographical, ecological and conservation information in support of biodiversity conservation policy and action.
The Global Tree Assessment is the largest global assessment project to date, resulting in IUCN Red List assessments of nearly 50,000 tree species carried out by more than 1,000 tree experts. In fact, over a quarter of all assessments on the updated IUCN Red List are now tree assessments. IUCN Red List assessments are important to be able to direct resources to take conservation action on species that urgently need it.
The project is still ongoing and we will continue to assess the conservation status of newly described tree species and update assessments where new information has come to light.
Over 20 tree red list publications have now been authored with different taxonomic or geographic focus. The work of the Global Tree Assessment has also featured in special editions of the journals Plants, People, Planet and BGJournal.
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Introduction
The Global Tree Assessment is an initiative to have conservation assessments for all the world’s tree species available on the IUCN Red List of Threatened Species. It began in 2015 in recognition of the need to make more conservation information available for tree species, to make more and better informed decisions regarding their conservation. The production of conservation assessments for trees enables prioritisation of practical conservation action, research and funding to species at greatest risk of extinction in the wild.
The Global Tree Assessment is the largest conservation assessment to ever be undertaken. It is coordinated by BGCI and the IUCN Species Survival Commission Global Tree Specialist Group (IUCN-SSC GTSG) and acts as a continuation and expansion of the red list activities undertaken by the two groups over the last 20 years.
Since 2015, there has been a four-fold increase in the number of assessments for tree species published on the IUCN Red List. Several new red list publications for complete tree groups, and regional tree floras have been produced. Other conservation tools have also been developed through the Global Tree Assessment such as GlobalTreeSearch, ThreatSearch and the GlobalTree Portal.
State of the World’s Trees
In September 2021, BGCI released The State of the World’s Trees report. This was the interim report for the Global Tree Assessment, reporting on the first five years of the programme. The report finds 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.
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. Additionally, it reveals that 1 in 5 tree species are directly used by humans, for food, fuel, timber, medicines, horticulture, and more.
The report is both a catalyst for action and also a call for hope as it found > 3 in 5 tree species are found in at least one protected area worldwide and at least 1 in 5 trees are conserved ex situ in botanic gardens or seed banks.
Who is Involved
We work with other 60 botanical organisations and 25 IUCN Species Survival Commission groups, as well as hundreds of tree experts to produce conservation assessments of trees.
We have established partnerships with government agencies and NGOs across all tree diversity hotspots, to produce conservation assessments for endemic trees in these highly diverse regions. We are supporting taxonomic experts producing assessments for large tree families such as Lauraceae, Lamiaceae and Annonaceae. We are also working with other IUCN Red List specialist groups and plant authorities to increase their output of tree assessments.
There are many ways to contribute to the Global Tree Assessment.
- Are you working on a tree species and have data which could contribute to a conservation assessment?
- Are you concerned about the conservation status of a species?
- Are you able to review tree assessments for a specific region or a country?
- Do you or your institution hold distribution data for tree species?
- Have you produced red list assessments for tree which are not featured in ThreatSearch?
The Global Tree Assessment team are able to provide troubleshooting support for tree conservation assessments. Contact us below.
GTA Contact Form
Red List Publications
Taxonomic and regional Red List publications produced by BGCI and the Global Trees Campaign. Available here:
State of the World’s Trees
One in three tree species face extinction reveals the landmark report, documenting the conservation status of the world’s nearly 60,000 tree species.
GlobalTree Portal
A new major tool combinging information from GlobalTreeSearch, ThreatSearch, GardenSearch and Plant Search databases to perform analysis at the species, country and global level.
Red List E-Learning Modules
These are a set of four e-learning modules on red list assessments of trees. These modules offer an introduction to tree red listing for anyone interested in getting involved with red listing of tree species.
These modules are also available in French, Spanish and Chinese.
GlobalTreeSearch
The world’s most comprehensive list of tree species name and their country level distribution.
ThreatSearch
The most comprehensive database of conservation assessments of plants.
Publications
Rivers, M., Newton, A.C., Oldfield, S. and Global Tree Assessment Contributors, 2023. Scientists’ warning to humanity on tree extinctions. Plants, People, Planet, 5(4), pp.466-482.
Global Tree Assessment (2023) Plants People Planet. Vo.l. 5 No.4.
Botanic Gardens Conservation International (BGCI – 2021), The Global Tree Assessment and botanic gardens: linking assessment to conservation action, BGJournal, 19.1 (Special edition)
Beech, E., Rivers, M., Oldfield, S. and Smith, P.P. (2017) GlobalTreeSearch: The first complete global database of tree species and country distributions. Journal of Sustainable Forestry 36(25) pp.454-489
Newton, A., Oldfield, S., Rivers, M., Mark, J., Schatz, G., Garavito, N.T., Cantarello, E., Golicher, D., Cayuela, L. and Miles, L. (2015) Towards a Global Tree Assessment Oryx 49(3) pp.410-415
Rivers, M. (2017) The Global Tree Assessment – red listing the world’s trees. BGjournal. 14(1) pp.16-19.
Fensham, R.J., Laffineur, B., Collingwood, T.D., Beech, E., Bell, S., Hopper, S.D., Phillips, G., Rivers, M.C., Walsh, N. and White, M., 2020. Rarity or decline: key concepts for the Red List of Australian eucalypts. Biological Conservation, 243, p.108455.
External Links
National Red List
Search for national and regional assessments of trees.
IUCN SSC Global Tree Specialist Group
Tree specialists helping us work towards GTA.
Each quarter a newsletter is shared with the membership providing updates on the Global Tree Assessment, other news and calls to action for the group.
Guidance Brief: How to Red List a Tree Species
An overview of the process of red listing a tree species and the data that is needed. For specialists and non-specialists and for a red listing project of any size. Also available in Spanish.
