Bored to death in Cape Town
The shot-hole borer is ravaging the city’s trees from within, while bark-strippers attack from without
BL PREMIUM - UNLOCKED BY RMB
27 APRIL 2023 - 05:00
By: ANNAMIA VAN DEN HEEVER
Cape Town’s leafy suburbs are in danger of losing up to 40% of their canopies to the same insect predator that has infected trees across the land, the tiny shot-hole borer beetle. There’s also a threat from people who strip the Cape Peninsula’s trees of their bark for medicinal purposes.
The beetle was first spotted in Newlands, Cape Town, in January and is spreading rapidly, often in firewood or pallets. “It could potentially be one of South Africa’s largest ecological tragedies,” according to TreeKeepers, an association dedicated to conserving Cape Town’s urban forest, which gives the 40% tree-loss estimate.
Though international and local researchers are working on solutions, there is no known way of eradicating the pests, other than felling susceptible reproductive host species and disposing of the wood responsibly.
The City of Cape Town has begun a social media campaign to inform residents. About 260 infested trees have been identified in the southern suburbs, according to mayoral committee member Patricia van der Ross. The number is increasing daily. Infected trees can contain more than 100,000 beetles.
The city has asked residents to report infestations to its invasive species unit, which provides assistance. Sightings are also encouraged on the social media platform iNaturalist.
“I don’t think that it’s any exaggeration to say that this is the most calamitous thing that has happened to the urban treescape in South Africa’s history. It’s like the rinderpest of trees,” arborist Francois Krige tells the FM.
“Civil society needs to get behind this. People often realise the severity of what they are facing when it’s too late.
“There is so much we can do right now: stopping the movement of firewood from region to region; not moving plant material in and out of zones of infestation; and supporting planting programmes, so that we will not be remembered as the generation that cut everything down.”
Krige and others suspect the beetle arrived in Newlands when an out-of-town rugby fan brought in wood for a braai near the sports stadium.
He believes the most important management tool available is the pre-emptive felling of box elder trees, the beetle’s preferred host. “The beetle jumps from one box elder to another,” he says. “So the initial stage of infestation is primarily a disease of box elders.” Other common hosts include oak, plane, poplar and coral trees. These are all suburban favourites.
Krige’s work includes tree management in Kirstenbosch Botanical Gardens and he is the chair of Friends of the Arderne Gardens. The Arderne Gardens in Claremont, which have one of the most diverse and valuable collections of exotic trees in Africa, are home to what Krige considers “the most iconic tree in Cape Town”, a towering Moreton Bay fig that has been a backdrop for wedding photographs for many decades.
This “wedding tree” may be at risk. The beetles have been found within 100m of the Arderne Gardens and Moreton Bay figs have been infested in Australia, where the tree comes from. An experimental protection programme, if fully implemented, could cost about R350,000 a year. “The responsibility weighs heavily on me,” says Krige.
The other calamity, illegal bark stripping, has caused serious damage in Newlands forest. Krige estimates it would take 100 years of zero tree felling, coupled with a well-funded alien clearing programme, to bring the forest to a safe and healthy state.
The Table Mountain National Park has an “integrated strategy” to combat the stripping of bark, which traditional healers use for a variety of ailments. The strategy includes intelligence gathering, law enforcement and “proactive solutions” such as painting mature and seed-producing trees with grey, water-based PVA paint, to make the bark less attractive for consumption.
“[The park] will [also] continuously implement law enforcement patrols, facilitate educational awareness campaigns through workshops with traditional healers, and set up a nursery to grow forest species for replanting trees,” according to park manager Megan Taplin.
Indigenous trees that are commonly stripped of their bark include the Cape beech, Cape chestnut, wild peach, assegai and stinkwood. “This has a huge impact on forest diversity as trees die a slow death due to the interruption of the nutritional transport system,” Taplin says.
SANParks says rangers arrested three bark strippers “in the act” last week soon after midnight in Newlands forest.
Bark- and root-harvesting have increased throughout the city’s southern and northern suburbs, CBD and conservation areas, says deputy mayor Eddie Andrews. The city has also resorted to painting trees.
He says bark stripping seems to increase before religious holiday periods such as Easter and Christmas.
The city is considering a new tree bylaw to address this issue more effectively. “As this is an extensive exercise, it may take some time to introduce,” according to Andrews.
https://www.businesslive.co.za/fm/fm-fox/2023-04-27-bored-to-death-in-cape-town/
Comentarios
Would it be feasible to establish one or more areas to specifically grow trees for the traditional healers? Rather than punitive action, perhaps conservation education might be more effective because I doubt we'll control the practise with laws.
Both the city of Cape Town and SANParks have grown trees for traditional healers. Special nurseries have been established, providing free trees.
The dont work because trees take too long to grow, and planted trees are not as efficacious as wild trees.
Also where (other than in the city and city parks) would one plant them. The natural veld is already full of plants.
@tonyrebelo the Warburgia salutris project is a great example of how a tree distribution project can work, al-biet not in the Mediterranean climate of the Cape.
Perhaps a solution could be to plant for bark harvesting and control access to the resource. It is not unheard of for a city to invest in resources outside it geographic region, (as the pocket of Cape Town near Wellington demonstrates). A hundred year lease of suitable land in the Overberg may be a solution.
But if it were economical, then it would have been done already. And one would have to lower the price of bark to the point where it wont be viable to steal it from the nature reserves.
That is a tall order.
Agregar un comentario