Gardens fungus threat

15 March 2016 - 02:44 By Bobby Jordan

Scientists are puzzled by a "mystery" fungus that is attacking a cluster of iconic camphor trees at Kirstenbosch Botanical Gardens - first planted at the request of Cecil John Rhodes in the 19th century.Kirstenbosch confirmed yesterday they were still clueless as to what might be threatening their famous trees, a key attraction at the gardens.Several of the giant camphors that completely encircle Camphor Avenue - a popular thoroughfare - have lost branches and leaves, prompting concern from staff.Kirstenbosch horticulturalist Adam Harrower said: "It's a bit of a tricky situation because we don't know what it is, or how dangerous it is, or how to treat it. We have sent off samples to a lab in Pretoria. They are busy analysing them and culturing them."We are looking into possible treatments, even though we don't have an exact diagnosis."It is believed the fungus attacks the trees' vascular system.It's not the first time the Kirstenbosch camphors have come under attack. Several years ago another fungus severely infected many of the trees, forcing them to be cut back. They have since resprouted.Kirstenbosch was once a large farm owned by mining magnate Rhodes, who commissioned a long line of camphor trees. He bequeathed the land to the state, which has been custodian since his death in 1902.Some tree experts believe climate change is having a negative impact on a number of indigenous tree species.Recent scientific studies have highlighted the impact of climate change on indigenous fauna and flora, such as fynbos and fynbos birds.However, Harrower said he doubted climate change was to blame for the latest Kirstenbosch infestation, since the trees had deep roots and were less likely to be affected by low rainfall or extreme heat."The fact that it was hot might lead to some effect, but it doesn't account for some branches dying," he said.A far greater threat to local camphor trees was bark-stripping, presumably for traditional medicines. He said several trees just outside Kirstenbosch had been targeted.Kirstenbosch recently installed an alarm system to stop thieves stealing plants out of the garden, following the loss of 13 critically endangered Albany cycads from their cycad garden.

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