From Tuesday 4 April the City of Cape Town has removed 40 trees infested with the invasive Polyphagous Shot Hole Borer (PSHB) beetle along the Liesbeek River corridor, near the N2 highway and Liesbeek Park Way – and more fellings are likely to follow as the pest continues to spread.
First discovered on a private property off Kildare Road, Newlands on Tuesday 24 January, evidence of the borer beetle’s spread is already evident in Wynberg, Rondebosch, Mowbray, Claremont, Kenilworth and Observatory.
With pesticides and fungicides at present only showing a limited effect, the management protocol drawn up by the City’s Invasive Species Unit calls for the swift identification and removal of highly infested trees to reduce the beetle population.
Like the City, homeowners too have had to make the difficult decision to remove much-loved, well-established trees from their private gardens as they support the effort to slow the spread of PSHB.
Katherine Christie, councillor for Ward 58, is among them.
Christie shares she was faced with the difficult decision late last month when she discovered that a 20-year-old London Plane tree on her Rondebosch property was infested with PSHB.
“I was in mourning over this gracious and tall tree which offered shade and coolness and, of course, oxygen to our road. However, I felt I had to lead by example as a ward councillor.”
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She says the City of Cape Town officials who came to her property to confirm that it was a PSHB infected tree, said whether the tree was removed immediately or not, it would eventually die.
“And it is a safety hazard, because one of the branches could easily fall on one of us or a passerby so for safety sake, they advised us to take down the tree before it falls down and hurts someone.”
Still, she says, she was torn.
“My mother said something helpful. She said, consider it a mercy killing, and my husband said it was like putting down your dog when your dog has got cancer.”
At present, the chipped remains of the London Plane is being solarised on-site. Solarisation is when the infested material is covered in plastic and left to bake in the sun for up to six months.
Christie describes it as coffin-like containers.
Chipping kills 98% of the beetle; to kill the remaining 2%, the infested wood needs to be solarised.
A young yellowwood tree, bought from Jenni Rowe’s Hearts company in Harfield Village, now grows next to where the cut-down tree once stood.
Christie says they planted the tree about three weeks ago before the City’s list of recommended trees to replace those infested by borer beetle came out.
“I then saw that it’s not on the list of recommended trees. However as an indigenous tree it has a harder trunk and the contractor told me he has seen yellow woods in Somerset West survive attempted invasions by the PSHB beetle. He said they manage to get through the outer layer of bark of our yellow woods but then leave as they are unable to penetrate any further.”
Christie says she never saw herself as a tree hugger.
“But now I am, an ardent tree hugger.”
- Report PSHB beetle sightings online, at www.capetown.gov.za/InvasiveSpecies, call the City of Cape Town’s Invasive Species Unit on 021 444 2357, Monday to Friday, from 07:30 to 16:00, or email to: invasive.species@capetown.gov.za
