Saving the critically endangered Mutavhatsindi tree
A committed group of conservationists and horticulturalists have successfully propagated a critically endangered tree that is prized for its medicinal properties and is getting perilously close to being extinct in the wild.
The breakthrough was achieved by a team from SANBI, conservation horticulturist and tree expert Mpendulo Gabayi from the Kirstenbosch National Botanical Garden, horticulturalist Mpho Mathalauga from KwaZulu-Natal National Botanical Garden, and Ntsakisi Masia (seed collector - Millennium Seed Bank Partnership) from Thohoyandou National Botanical Garden, who have successfully propagated the critically endangered Mutavhatsindi (Yellow Peeling Plain) tree.
The saplings of propagated trees will be used to establish ex situ collections and provide an opportunity for more propagation research trials at Cape Town's Kirstenbosch National Botanical Garden, as well as Thohoyandou National Botanical Garden. The overall success of this project contributes to the Global Strategy for Plant Conservation.
In 2020 Gabayi highlighted the threats to the Mutavhatsindi tree's existence in South Africa, as none had been successfully propagated before. The trees only exist in a small 110-hectare subpopulation in Mutavhantsindi Nature Reserve in Limpopo where they are favoured for their medicinal benefits and are therefore heavily harvested. Missouri Botanical Garden and the University of Venda, together with the SANBI team collaborated to save this highly endangered tree species.
This project was supported by ArbNet, Botanic Gardens Conservation International, the Millenium Seed Bank Partnership and Propagation BioScience Research (PBR) International. These institutions teamed up to create a long- term project that will eventually result in saving and preserving the South African gene pool through ex situ and in situ conservation.
The Mutavhatsindi, scientifically known as Brackenridgea Zanguebarica, is a species of tree that has been under extreme threat due to the harmful harvesting of mature tree parts, which inevitably resulted in the poor regeneration of the new generations of trees.
"Mutavhatsindi is highly sought after for its medicinal bark and roots, and traditional healers use the yellow dye to treat wounds, worms, aching hands, swollen ankles, and amenorrhea. Due to its severe rarity and limited occurrence, the tree is currently categorized as Critically Endangered on the Red List of South African Plants," explains Gabayi, who says that the Mutavhatsindi tree was propagated successfully after experimenting with many different propagation methods without success.
The breakthrough was achieved through the manipulation of Plant Growth Regulators using the air layering method and Dyna Ball (PBR international). The propagules had shown a good set of healthy roots emerging but had a low rooting percentage of 15%. Through a successful procedure of air layering, new trees can be grown from branches that are still attached to the parent plant. More propagation methods and procedures are still under trial to build onto the current successful experiment.
"For future generations to appreciate the existence of the Mutavhasindi tree, it is of utmost importance that the need for its conservation is incorporated into education, communication, and public awareness programmes," said Gabayi.
"By exchanging information on environmental legislation and methods of propagation and cultivation, people will better understand the value of biodiversity and the steps they can take to conserve and use it sustainably.
"This coincides with SANBI's overall mandate to explore, reveal, celebrate and champion biodiversity for the benefit and enjoyment of all South Africans," concludes Gabayi.
South Africa celebrated Arbor Week during the first week of September, and Vergelegen wine estate in Somerset West – a provincial heritage site renowned for its historic trees – marked the occasion in appropriate arboreal style.
A distinguished guest planted an oak tree sapling with a fascinating history, and garden staff revived the tradition of gathering seeds from an ancient yellowwood and distributing these to visitors.
Royal connections It is a Vergelegen custom to invite visiting dignitaries to plant a commemorative oak, and the estate has a fine collection planted by members of Britain’s royal family and other visitors. The oak tree planting on this occasion was undertaken by Mary Carlisle, renowned for her work with under-privileged communities in KwaZulu-Natal, on a visit to the estate on 2 September.
This oak sapling has a fascinating lineage, says Vergelegen Gardens Manager Richard Arm. It originates from an acorn from a famous tree at Vergelegen known as the Royal Oak. That Royal Oak, in turn, grew from an acorn planted decades ago when Vergelegen was owned by Sir Lionel and Lady Florence Phillips, from 1917-1940.
“Lord and Lady Phillips were friends of the Duchess of Marlborough, who had given Sir Lionel this acorn. It came from one of the last of King Alfred's mediaeval oaks at Blenheim Palace in Oxfordshire, England. This acorn survived the sea trip from England to the Cape in the 1920s and duly grew into the giant oak known as the Royal Oak.”
Since then, acorns from the Royal Oak have been taken back to England for planting in Blenheim Palace and Windsor Great Park.
“We planted the sapling close to the existing Royal Oak so that in a couple of hundred years, oaks can still be enjoyed as part of the heritage of the Cape,” says Arm.
Seed distribution Vergelegen is also home to a vast yellowwood (Podocarpaceae, a protected national tree) estimated to be 150-400 years old.
This venerable old specimen is the source of hundreds of seeds which the horticultural team traditionally gather every year. They skipped this custom in 2020 due to the Covid-19 lockdown, but revived it this year.
“The seed handout at the gate was extremely well received by all our guests,” says Arm, who adds that the seed collection and germination are made easier by resident fruit bats.
The bats not only drop the seeds in certain areas of the garden, so that the team know where to find them, but they also nibble at the skin and fleshy part of the fruit to expose the seed, which helps germination.
Tree viewing Vergelegen visitors can walk the Yellowwood Trail to the site of this magnificent old yellowwood. Other outstanding trees include five enormous camphor trees (Cinnamomum camphora) outside the homestead, which were declared national monuments in 1942. These are the oldest introduced cultivated trees in southern Africa, and were also the favourite trees of President Nelson Mandela on his visits to Vergelegen.
The collection also includes a hollow old English oak, believed to be the oldest living oak in Africa, and an oak arboretum. The arboretum is home to about 15 varieties of oak and helps to increase awareness of the history of oaks in the Cape, and the conservation and propagation of these trees.
Members of the public are welcome to visit he estate which is open Monday-Sunday 09h00-17h00.
Indigenous trees of Southern Africa (Part 3) – Cape Ash
By Gareth Coombs Cape Ash (Ekebergia capensis) is a large semi-deciduous tree that naturally occurs along the entire coast from Cape Town and surrounds, eastward to Mozambique, and into areas along the north and South East of Zimbabwe. It has a disjunct distribution, and is also found in Northern Botswana. Owing to its lush canopy and attractive branching pattern it makes an excellent garden and street tree. Large trees can reach up to 30 metres in height but are usually smaller, ranging from 7-15 metres. Mature trees can have different branching patterns but the branching is usually upright and spreading widening from the base to the top of the canopy. The growth form can be different depending on its environment. It can also spread laterally and form a rounded, lush green canopy that makes and excellent shade tree for gardens and public spaces.
No discussion on the Cape Ash or Cape plum is complete without that of distinguishing between the appearance of the two. Due to the similarities of Cape Ash and Wild Plum, there has always been some debate on how to readily distinguish these. The easiest distinguishing feature are the fruits which will allow you to instantly distinguish the round, berry shaped fruits of the Cape Ash from the much larger oblong, bright red coloured plums of the Wild plum. When these are not fruiting, the difference can be told apart by the leaves that are distinctively more sickle shaped in the Cape plum and straighter in the Cape Ash.
Collecting fruits and seeds
This species produces distinctive large berries, each usually containing 1- 4, kidney shaped seeds. The fruit color varies from a lightly streaked red and cream colour to a darker uniform crimson red. Green fruits are borne for 2-3 months on the tree before ripening when they are often distinctively seen on the tree and can form a dense litter on the ground where they drop. This is however seldom a nuisance to traffic or pedestrians. Fruiting trees are commonly found throughout cities, towns or gardens and the fruits can either be picked directly from the tree or picked up from the ground. Once fruits have been collected they can be stored for several days with the pulp still present, however, the pulp invariably begins to decay and attracts small fruit flies. It is therefore advisable to first remove the pulp from the seeds and store seeds after the fruit pulp has been cleaned off. Seeds can be washed with a diluted solution of household bleach (sodium hypochlorite) which inhibits fungal decay during storage. Despite the soft fleshed fruits, the seeds can be stored for at least one season, and will survive longer than this in optimal conditions.
Planting seeds and propagation
Seeds should be planted from late august to March and germinate well in mixture of 1-2:1 compost: field soil. Seeds can be sown in bags or seed trays at a depth of 3 cm. Once planted the soil must be kept moist, in a shaded area. Personal Nursery data indicates median germination period of around 47 days. Newly germinated seedlings bare two cotyledons that remain close to the soil and as the newly developing stem grows from these. This is different Cape plum where the cotyledons are kept closer to the leaf petals as the seedling stem develops. As the seedlings develop, the cotyledons shrink and become wrinkled as seedling ages. Seeds can be stored dry for some time, but there is some reduction in their viability. When the growth tip is removed, new meristems sprout from the base of the cotyledons, same in some other species.
Germinated seedling can be pricked out from planting trays very carefully and transplanted at any time from 3-5 days after germinating, however very young seedlings can be prone to damping off fungi and allowing seedlings to reach larger sizes before transplanting is advisable.
Seedling care and planting out
Seedlings can be grown for several months within the original planting container and do not compete aggressively. Once seedlings reach about 25cm they are ready for transplanting. Larger seedlings will usually transplant better and are less susceptible to fungal infection. Seedlings are not very drought tolerant and need to be watered regularly, as water stress is often followed by the development of wilting diseases in this (and other) tree species. Plants should be kept in shaded or at least partial shade for the first year until they are large enough to harden off and plant in full sun. This is a relatively fast growing species and can reach over 1m in 3 years when grown from seed. Growth rate of seedlings is variable and up to appr. 30 cm per year for the first two years, but this could be faster under optimal irrigation and fertilizing schedules.
Natural history notes Cape ash is a valuable fruit tree that provides both habitat and a food source for birds and mammals. including baboon, vervet monkey, bushbuck, nyala, red winged starlings, Knysna turaco, black collared barbets and crowned hornbills.
Selected references and further reading Dlamini, M.D. 2004. Ekebergia capensis Sparmm. SANBI. Available online at: http://pza.sanbi.org/ekebergia-capensis Coates Palgrave, M. 2002. Keith Coates Palgrave Trees of southern Africa, 3rd Ed. Struik, Cape Town.