20 September 2024
Forgotten magnolia forests of Hispaniola
Renewed efforts to safeguard native trees in the Dominican Republic, as part of the Weston Global Tree Seed Bank: Unlocked programme
In the mountains of the Caribbean island of Hispaniola is a cool, luscious, mist-damp world – an ecosystem known as Tropical Montane Cloud Forest. These cloud forests are home to most of the Caribbean's endemic species – species that are found nowhere else in the world.
Despite their incredible natural value, the forests face a number of threats. The two countries that make up Hispaniola - Haiti and the Dominican Republic - are heavily impacted by deforestation, with Haiti having lost almost all its native forest cover, and the Dominican Republic around 60%.
Conserving the cloud forests
Working towards securing the forest’s future, scientists here at RBG Kew have collaborated with local researchers and botanists at the Dominican Republic’s Jardín Botánico Nacional (JBN) since 2007, supporting both the conservation and sustainable use of Caribbean native flora. It is among the latest projects in the Weston Global Tree Seed Bank: Unlocked Programme.
The latest stage of the project, launched in early 2024, is aimed at conserving and restoring a type of threatened cloud forest called “magnolia forest”, home to three species of endemic magnolia tree.
The project aims to conserve magnolia trees through seed-based solutions – collecting, storing and growing seeds to replant and rebuild the cloud forests from the ground up.
In April 2024, Kew’s team travelled to the Dominican Republic to formally launch the new phase of the project. Through visits to the different nature reserves and plant nurseries managed by the Fundación Moscoso Puello (FMP) and Fundación Progressio (FP), the team gained insights into the rebuilding of the magnolia forest.
Collecting magnolia seeds
Seeds need to be collected from wild magnolia trees during field trips into the magnolia forest. Trips must be timed with when the trees naturally spread their seeds, normally towards the the end of the year for Hispaniola’s magnolias, though the exact timing is now harder to predict as climate change is shifting the dates of flowering seed dispersal.
To prepare for this year’s dispersal season, Kew staff and their partners are organising seed collection and conservation training for local rangers in November 2024.
Storing seeds – the JBN seed bank
Thanks to the installation of a new cold room in December 2023, the seed bank at JBN is rapidly filling with seeds from many threatened species in the magnolia forest, where they’ll be stored until they can be used.
These newly stored seeds are mostly from species that grow alongside magnolia in the forest, but not yet magnolia itself.
Storing seeds of most species long-term requires getting rid of most of their stored moisture. In the drying room at the Millennium Seed Bank, humidities as low as 15% prepare new additions for storage.
Magnolia seeds, however, are ‘recalcitrant’ – meaning they cannot survive the drying out process. Therefore, we can't be certain that they can play a role in the future of Hispaniola’s forests if treated this way. There are solutions to this, such as directly propagating the seeds for restoration, and another of the project’s aims is to investigate new ways to successfully store and germinate the seeds of the target species.
Magnolia propagation & reforestation
The team visited the tree nursery at Natural Reserve Ébano Verde, managed by FP, where around 5,000 seedlings are propagated each year. These seeds are mostly magnolias, but include some other key tree species that grow alongside them.
Magnolias are very slow-growing trees, and it can take up to two years for a seedling to grow big and strong enough to be planted in reforestation sites. They must also be planted in a tight window of opportunity at the beginning of the rainy season, around October.
These limitations have not stopped the team at the nursery, who have successfully created a reforestation site in the reserve. It consists of a thriving, half-hectare hilly parcel of land that was planted with young magnolias in 2018 as part of an Integrated Conservation Action Plan for three native and threatened magnolia species (M. domingensis, M. hamorii and M. pallescens), supported by Botanic Gardens Conservation International, the Mohamed bin Zayed Species Conservation Fund and Fondation Franklinia.
Other native trees
This method of seed-based conservation is not limited to just magnolia, it can be applied to a wide variety of keystone and endangered species native to the cloud forests and beyond.
The Kew team also visited the tree nursery at the Valle Nuevo National Park, where the “Manacla” (Prestoea acuminata), a palm tree species that is very important in humid montane forests, and the “Sabino” (Juniperus gracilior), an endangered juniper endemic to Hispaniola, are being propagated for reforestation.
The future of the forests
Finally, the Kew team trekked through the National Park Valle Nuevo, where some scattered magnolia populations still exist in the wild. They took GPS coordinates of multiple very old trees, so they could be recorded and returned to on future seed-collection trips.
With ongoing research into better ways to store seeds, and multiple successful planting and forest regrowth schemes taking place in the Dominican Republic, there is hope that one day more magnolia cloud forests will be home to old trees like these ones.
Because of the collaborative efforts of Kew scientists and partners from the botanic garden community there is a more certain future for the forests of Hispaniola and their enchanting mountain survivors: the magnolias.
