Information provided by: South African National Parks (SANParks) – Table Mountain National Park
Following the clearing of the pines and the March 2015 fire, silver trees have reappeared at Tokai after an absence of over 100 years. Early maps of the Tokai Arboretum show silver tree forests on the slopes above Tokai Manor. However, with the establishment of pine plantations, these were replaced with pine stands and the silver trees vanished.
Silver trees are well commemorated in place names in Cape Town – Witteboom and Silverhurst are named after the stands that used to occur there. The first record of the tree was in 1620 when Augustin de Beaulieu described the plants near Kirstenbosch. Krauss claimed that they occurred “in all their glory as far as Muizenberg”. In 1687, Hendrik Claudius called it “Pinus Africana Witteboom”, and it has also been called the silver pine tree. The name ‘silverboom’ dates to 1705 and they have been likened to ‘knights in shining mail’ standing on the hills.
The Friends of Tokai Park (FOTK) and Table Mountain Honorary Rangers (TMNP HRs), in conjunction with the Threatened Species Unit at the Kirstenbosch Botanical Gardens, planted some seeds from Vlakkenberg to the Tokai slopes in May 2015. “There must still be seed banks in the soil,” said Anthony Hitchcock, curator of the nursery at Kirstenbosch. “A few survived for almost 80 years in the soil at Kirstenbosch while the area was under gum plantation. These provided seed, allowing the populations to be restored by planting. We hope to be able to do the same at Tokai.”
The plants were discovered by Friends of Tokai Park during an alien tree hack above the Tokai Arboretum. Unfortunately, the aliens here are incredibly dense. This is surprising as the areas handed over to SANParks after the pine clearing were supposedly clear of alien trees. Fortunately, SANParks have prioritised clearing of these areas and have their own teams in the area, augmenting the work being done by Working for Water teams in the area and volunteers. Friends of Tokai have also been organising hacks in the area since spring last year.
Silver trees grow at about 300-500mm per year, so in five years’ time there should be three-metre high trees present and they should be visible from the southern suburbs. However, after 100 years of pine trees, their seed banks will be heavily depleted and it will probably take another 100 years to recover healthy populations without assistance.
Part of the problem is that seed dispersal is only a few metres from the trees, said Tony Rebelo, chair of Friends of Tokai Park. “Although the fruit have parachutes to blow them about in the south-eastern winds, the seeds are very heavy and seldom disperse more than a few metres from the trees. We suspect that they are hoarded by the spiny mouse in little caches. So it will be hundreds of years before the trees recolonise the slopes. The FOTK and TMNP Hrs hope to accelerate the spread with some judicious seed dispersal. But we have to bear in mind the genetic structure of the local populations and limit contamination from gene banks of the northern peninsula. We have planted over 1,000 seeds at Tokai, but that was after the fire and few plants have come up. Presumably the fruit are safe underground though and will come up after the next fire.”
The slopes of Tokai are still closed following the fires of 2015. SANParks hope to open the area soon, but that depends on the rate of removal of the burned plantations, and contractors, with their trucks and machines, are still busy in the area, rendering it unsafe for the public.