As the City of Cape Town begins the process of removing beetle-infested trees from publicly owned land, it invites residents to participate in a voluntary tree replacement initiative.
Alderman Eddie Andrews, the City’s deputy mayor and a member of the mayoral committee for spatial planning and environment, planted the first new tree along the Liesbeek River in Mowbray this morning. It is an assegai tree, or Curtisia dentana, a native species.
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“This morning, I planted an assegai tree along the Liesbeek River in Mowbray, where we are busy removing trees that are infested with the Polyphagous Shot Hole Borer (PSHB). This is a symbolic act to demonstrate that, as devastated as we are about the beetle pest and the impact it is having on our urban forest, there is much we can do to limit the damage—planting an indigenous tree suitable to our climate and the specific site is one example,” said Alderman Andrews.
He continued, “The assegai tree is a local indigenous tree, occurring in the kloof forests on the peninsula, and therefore well adapted and suitable to Cape Town’s climate. Also, as far as we know, the Curtisia dentana is not a reproductive host tree, meaning that, to date, the PSHB has not been sighted in these trees, which makes it a good replacement choice.”
The assegai is a small to medium-sized, very neat evergreen tree that can reach a height of 12 metres. It grows quickly and thrives when protected from strong winds. Birds enjoy the attractive yellow fruits that it produces.
The City is developing a comprehensive list of recommended trees – indigenous and mostly indigenous trees that are not known to be prone to PSHB infestations – that residents can plant to replace the trees that will have to be removed due to the beetle pest.
At the moment, the following trees are recommended:
- Assegai tree (Curtisia dentana)
- White milkwood (Sideroxylon inerme): a well-known, large tree that does well in coastal sands.
- Camphor bush (Tarchonanthus camphoratus): a very tough, small, multi-branched tree that does well on the Cape Flats.
- Water pear (Syzigium quineense): A medium to large classic park-type tree
“We will make the list of recommended trees available on the city’s website and will add to it in the coming weeks. Residents can use it as a guide to participating in a voluntary tree planting effort. In the meantime, we are finalizing our official tree replacement program to replace those infested trees we have to remove from city-owned land,” said Alderman Andrews.
The City started removing infested trees along the Liesbeek River corridor, near the N2 highway and Liesbeek Park Way, with chainsaws and wood-chipping machines on Wednesday, March 8, 2023. The beetle-infested biomass is being transported to an appropriate site for incineration.
Alderman Andrews explained that infested trees must be chipped because this is the only scientifically proven method of preventing the pest from spreading to other areas of Cape Town.
This is a huge loss for all Capetonians who live in a city surrounded by natural beauty, from Table Mountain to the coastline and the thousands of trees that line our streets and parks.
As heartbreaking as it is, the only way to limit the loss of our urban forest is by planting trees to replace those that will need to be removed in the coming months.
“We also hosted a very successful PSHB training session in Muizenberg yesterday for small businesses dealing with plant material. Over 40 people attended. A similar training session will be hosted at the Helderberg Nature Reserve next week,” said Alderman Andrews.
Latest update about the beetle pest:
- By 9 March 2023, the city had found 191 infected trees, 104 of which were on land owned by the city and 87 of which were on private land in the southern suburbs.
- The most infested and affected trees in the southern suburbs are Box Elder, London Plane, English Oak, and Grey Poplar.
- Areas affected are Newlands, Kenilworth, Mowbray, Rondebosch, Observatory, and Wynberg.
- At the moment, getting rid of box elders from city-owned land along major transportation routes is the top priority.
Dos and don’ts:
- Do not move any plant or tree parts from places where PSHB has been found, such as Somerset West, Newlands, Kenilworth, Mowbray, Rondebosch, Observatory, and Wynberg.
- When handling plant material, inspect the tree for PSHB symptoms.
- Clean gardening tools and other tools before and after use, and clean and sanitize vehicles that move green waste.
- Transport green waste in closed and sealed bags or cover the back with a tarp.
- Avoid routes passing through areas with PSHB-infested trees.
- Buy firewood where you are going to use it.
- Don’t fall for fake remedies. There is no known cure as of yet.
What to look out for and symptoms of infested trees:
- Branch dieback: cracks on the branch; discoloured leaves; dry and leafless branches; branch break-off revealing webs of galleries filled with black fungus.
- Gumming: blobs of goo coming out of the bark; oozing of liquid and gum from the beetle holes.
- Entry and exit holes: very small holes on the bark of the tree, the size of a sesame seed (2mm); shotgun-like scars developing around the holes.
- Staining: brown or dark stains on the bark of the tree.
Important: Infested trees must be chipped on site and may not be removed from the property, as the removal of the chipped wood will spread the pest to other areas.
How to report PSHB beetle sightings
- Online, at: www.capetown.gov.za/InvasiveSpecies
- Call the City of Cape Town’s Invasive Species Unit at 021 444 2357.
- Send an email to: [email protected]
What to do with infested trees:
- Chip the tree, place the infested material in refuse bags, seal it, and put these in direct sunlight for at least six weeks.
- Dump the chips in your compost heap, as the heat buildup will kill the beetle.
- Burn infected wood at appropriate incineration facilities.
- Seek assistance from trained and equipped service providers with sound knowledge of PSHB.
- Do not move plant material or firewood outside of areas where PSHB has been confirmed to be present.
- Do not transport any form of green waste in open vehicles; cover it with sail covers even if no PSHB has been identified as such green waste.
- Clean tools and equipment are used to trim, cut, and prune plants.
The City said that it would do its best to respond to a sighting report within 10 business days. However, the response time will depend on the number of sightings reported.
Invasive PSHB beetle pest spreading steadily in the Cape, what to do
Picture: City of Cape Town