Highly flammable alien plants like stone pines and date palms contributed to the rapid spread of Cape Town’s 2021 Table Mountain fire, new UCT research finds. Image: Mail & Guardian
(The Post New)- Flammable foreign plants worsened the devastating Table Mountain fire in 2021, new University of Cape Town research reveals.
Following the April 2021 Table Mountain fire, new research has found that certain exotic plants in Cape Town’s urban areas may raise wildfire risks due to highly flammable leaf traits.
Researchers from the University of Cape Town’s biological sciences department will share their findings in the upcoming September issue of the South African Journal of Botany.
Muthama Muasya, the study’s senior author and an internationally renowned expert in plant taxonomy and evolutionary biology, explained, “While laboratory tests alone cannot fully predict how plants behave in real-world fires, they offer valuable insight into key characteristics that influence ignition, burn duration, and intensity.”
He emphasized that understanding this information is vital for managing natural hazards, especially in regions like the Western Cape that are prone to wildfires.
The team studied 42 different plant species, including 22 native and 20 non-natives, assessing their leaf traits alongside important fire-related properties like how easily they ignite, how long they burn, and how intensely they combust.
Their findings revealed that alien plants typically caught fire more quickly and burned more intensely, while native plants usually burned for a longer duration but with less intensity.
The study noted, “Leaf functional traits such as thickness, specific leaf area (the area of a leaf relative to its weight), and leaf surface area were significantly correlated with flammability measures. Exotic plants were particularly flammable due to traits like large leaf surface area, higher specific leaf area, and thin leaves.”
Additional findings revealed that plants fully burned in the 2021 fire were linked to high combustibility and moderate ignitability, whereas partially burned plants generally had thicker leaves. Those that remained unburned were associated with longer ignition periods.
The researchers said their results underline how certain alien ornamental plants contribute to higher fire hazards in city environments.
The April 2021 fire, which damaged parts of the University of Cape Town including its historic Jagger Library, was linked to the large presence of easily flammable exotic plants, with Pinus pinea (stone pine) and Phoenix canariensis (Canary Island date palm) identified as two key species at the fire’s center.
Lead author Dunja MacAlister urged city planners to consider fire safety in urban greening by avoiding flammable species near homes and schools and favoring low-flammability native plants.
Substituting these species with native plants suited to the local climate can help boost biodiversity, support ecosystem health, and lower the risk of wildfires over time.
She noted that each year, Cape Town and its surrounding regions face increasingly hotter summers, often accompanied by reports of severe wildfires during the season.
She stressed the need for forward-thinking approaches in planning and policy, rather than waiting to respond after fires occur.
Managing vegetation must become a key part of wildfire prevention, even though it can be difficult given that the fynbos ecosystem a fire-prone native shrubland typical to the Western Cape is naturally prone to burning.
As the Western Cape braces for hotter summers and longer fire seasons, MacAlister warns that ‘we can’t afford to be reactive anymore. Plant choice is not just about beauty it’s about safety.’ Her team hopes city officials will act on these findings, reshaping Cape Town’s green spaces to be as fire resilient as they are vibrant.
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