Cape Town - Kirstenbosch Botanical Garden needs to burn.
As dramatic as that sounds, that was the finding of a Stellenbosch University applied ecology professor, who said while it may seem a blessing that the world-famous garden escaped the fires that ravaged the Peninsula earlier this year, the fynbos there has not burned for more than 30 years – and is in need of a fire.
Professor Brian van Wilgen, from Stellenbosch’s Centre of Excellence for Invasion Biology, said natural fires in the greater Table Mountain area had been successfully suppressed for decades.
This meant they didn’t spread naturally to Kirstenbosch Garden, as they would have done in the past.
Fynbos, however, needs fire to propagate and survive.
And Van Wilgen, an associate editor of the South African Journal of Science and Fire Ecology, warned that if fire was kept out for much longer, the fynbos in the garden would begin to be overtaken by forest.
“Kirstenbosch will end up with more forest and less fynbos; thus, overall, the diversity of the area will decline, which would be a pity.”
He suggested that controlled burns in the natural fynbos areas would be “very beneficial”, stressing that he was not proposing burning the formal part, with its manicured lawns and pathways where families picnic.
Rather, he was referring to areas on the lower slopes on Table Mountain, away from the formal gardens. The formal gardens account for most the popular tourist attraction.
“Some of these areas are natural forest, which won’t burn, but some are fynbos that will burn if they are ignited under the right conditions,” said Van Wilgen.
He cautioned however: “Because they have not burnt for so long, a lot of fuel has built up, and that will make any fire difficult to control.”
But convincing the public of the need for controlled burns would “require a lot of PR”.
“The citizens of Cape Town and other visitors may not understand why such burns would be necessary,” he said.
Kirstenbosch Garden’s curator Philip le Roux described controlled burns as “high-risk activities” that were often necessary, but seldom received the public support they deserved.
Le Roux said that while a large area of fynbos on the estate’s southern side had burnt twice in the past 15 years, other areas would indeed benefit from fire.
Fynbos adjacent to this area was being considered for prescribed burning with logistical support from SANParks.
“There are other parts of Kirstenbosch, in the vicinity of Skeleton and Window Streams, that are slowly transforming from fynbos to indigenous forest through the exclusion of fire,” he said.
“These forests may be botanically less diverse than fynbos but are nonetheless valuable, particularly in the Western Cape, which has so little natural forest.”
Le Roux argued that these areas should not be burnt at all.
“Kirstenbosch and Table Mountain is surrounded by a city whose citizens love these forests for their recreational and aesthetic value, and this should be acknowledged,” he said.
Fynbos and fire
Fynbos is a vegetation type unique to the area between Cape Town and Port Elizabeth, where it thrives in the sandy soils.
According to Professor Brian van Wilgen, it needs fire to survive. The heat triggers the release of seeds, while smoke stimulates germination.
Van Wilgen said that without fire, many fynbos plants will die, eventually disappearing from the vegetation.