Any history of native people doing regular small-scale burns in the area? That usually seems to be a factor in places like Oz, California, even Palestine, where discontinuation of native management practices lead to the build-up of combustible material so instead of small, not-too-hot fires every couple of years you get nothing for 50 years then a massive conflagration. A brief search turned up this 2013 paper which talks about the ecological importance of fire for preserving the 'fynbos' ecology: https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.1890/120137
'Prescribed burning has been regarded as an important management practice in fynbos ecosystems for over 40 years (van Wilgen 2009). While indigenous African peo-ples have both tolerated and used fire for millennia, European colonists were, for almost three centuries, strongly opposed to its use in ecosystem management. It was only in the mid-20th century that Wicht (1945) sug-gested that the phenomenon of fire deserved closer scrutiny, to assess both its role and potential use in fynbos management. Prescribed burning was eventually intro-duced into fynbos protected areas in the 1970s, at which time its major goals were to ensure a sustained flow of water from adjacent mountain areas and for nature con-servation (Bands 1977). Subordinate goals included the control of invasive alien plants and fuel reduction to pro-tect plantations of alien pines (Bands 1977).'
And the wikipedia page for controlled burn has an image of Helderburg nature reserve, bordering Capetown, being deliberately burned for the same reasons of 'maintaining the ecological health of indigenous fynbos as well as reducing the intensity of future burns.' - https://en.wikipedia.org/wiki/Controlled_burn
Though I doubt that the arsonist had these things in mind somehow!