Six tree species face imminent extinction crisis
In a bid to preserve biodiversity and create more resilient ecosystems amid changing climate conditions, gardeners are adopting a science-based, climate-adaptive approach. This new strategy involves several key elements, as we explore below.
Over 100 species classified as threatened on the International Union for Conservation of Nature (IUCN) Red List are cared for within various collections, including the renowned Westonbirt Arboretum. One such threatened tree is the Star Magnolia (Magnolia stellata), native to Japan, which is Endangered due to urbanisation and illegal collecting.
To help threatened tree species survive climate change, gardeners are selectively cultivating plants that are more resilient to current and projected climate conditions, such as drought and temperature extremes. For instance, British gardeners at historic sites like Sheffield Park are incorporating monkey puzzle trees and rare succulents to create landscapes better suited to hotter, drier summers.
Botanical gardens and conservation experts are collaborating on climate-smart plant selection, propagation, and deployment initiatives, with a focus on high-priority biodiversity regions globally. This collaboration aims to restore ecosystems and bolster resilience to climate change, as seen in plantation efforts in India where species like Neem and Acacia are favored for dry conditions, while others like Indian Rosewood adapt to wetter environments.
Supporting threatened native pollinators and creating microhabitats with shaded areas and water sources help maintain ecological balance and improve survival rates for dependent species. The evolving approach also includes experimental gardening strategies that create differentiated garden zones—wet sections for winter and drought-tolerant zones for summer—to optimize water use and plant survival.
Gardeners are not only focusing on introducing drought-resistant and climate-matched tree species but also collaborating with botanical institutions for research and restoration projects. Westonbirt Arboretum, for example, is part of a project working to back-up all wild origin paperbark maple material currently held in UK tree collections.
The importance of growing threatened species in collections like Westonbirt Arboretum for conservation and research purposes is highlighted by Dan Crowley, co-author of Forestry England's The Little Book of Disappearing Trees. This book, available for purchase on a visit to Westonbirt Arboretum, profiles 50 threatened species that grow at the Arboretum, detailing each species' plight, conservation efforts, and work in partnership with other botanic gardens.
Unfortunately, many tree species are under threat. One in three of the world's tree species are threatened in the wild, with more than 17,500 of the world's 60,000 tree species at risk of extinction. Some examples include the Giant Redwood (Sequoiadendron giganteum), Endangered due to human exploitation and past forest fire management, and the Atlas Cedar (Cedrus atlantica), Endangered due to pests, diseases, timber exploitation, and overgrazing in parts of its range.
The Horse Chestnut (Aesculus hippocastum) is Vulnerable due to the leaf miner moth (Cameraria ohridella), which creates 'mines' in the leaves of horse chestnut, impairing growth and fruit production. Wild populations of horse chestnut have declined hugely as a result.
The Maidenhair tree (Ginkgo biloba) is under threat from habitat loss and timber exploitation, and is classified as Endangered. The Paperbark maple (Acer griseum) is Endangered, with only 12 fragmented populations known to exist and a lack of regeneration.
The collection at Westonbirt, The National Arboretum is of national and international significance, providing a vital resource for conservation and research efforts. For those interested in learning more about the world's threatened trees, information can be found on the Forestry England website.
- Gardens, in an effort to combat climate change, are adopting a science-based approach that nurtures threatened plants like the Star Magnolia, such as those found in the Westonbirt Arboretum.
- To adapt to the changing climate, gardeners are selectively growing more resilient plants, like monkey puzzle trees and succulents, in gardens like Sheffield Park.
- Botanical gardens and conservation experts are collaborating to select, propagate, and deploy climate-smart plants, with a focus on high-priority biodiversity regions.
- By supporting threatened native pollinators and creating microhabitats, gardeners can help maintain ecological balance and improve survival rates for dependent species.
- To preserve threatened tree species for conservation and research purposes, gardens like Westonbirt Arboretum are collaborating with botanical institutions for projects, as highlighted in Forestry England's The Little Book of Disappearing Trees.
