If, heaven forbid, you were hiking with me in the Cape mountains and we saw a fire sweeping towards us, my instruction might surprise you: “Run for the trees!”

People from the northern hemisphere and Australia would look at me like I were a lunatic: we all know pine and eucalyptus forests burn like a bonfire, and anyway – where are the trees? We’re supposed to be in shrubby, bushy fynbos.

But there they are: wedged into shady clefts and steep-sided ravines across the mountains – pockets of rich dark-green forest, clearly visible against the olive-grey of the surrounding fynbos. What are they doing there? Why don’t they burn?

The interior of the Afro-montane Forest is charmingly dappled & cool in temperature.

It may equally surprise you to learn that, millions years ago, much of the Western Cape was covered in the stuff: Afro-montane Forest to give it its proper name. Huge, half-fossilised trees – some over 80 feet long – have been dug up from Cape Town to Stellenbosch.

Their origin is unclear – perhaps they are the remnants of a great forest belt that covered most of Africa. After all, stand in the forests on Table Mountain and you’re looking at half of the tree species that you’d find in a Rwandan forest full of mountain gorillas. Or maybe the forest trees were dispersed by migrating birds and were never much more extensive than they are now.

Evidence of squeaky-clean air, Old Man’s Beard lichen (Usnea) covers many forest trees & was once used to treat fever & heal wounds.

Either way, with the drying-up of the Cape’s climate and the subsequent arrival of fire around four million years ago, the forests retreated. Trees are tough but unable to take a roasting every 10 or 20 years. Fynbos plants – proteas, heathers and so on – moved in to fill the gap, adapting to the new fire regime and by the time the Europeans arrived, the forests had already been reduced to patchwork.

The magnificent, primal Orange Kloof forest, tucked away out of sight in the interior of Table Mountain with Cape Town less than a mile away.

It’s a curious type of forest: view it from a distance and it looks like tropical rainforest, complete with giant ferns and hanging lianas. Step inside and it’s as cool and damp as a Welsh woodland. Dark too: these slow-growing forest trees keep their leaves for years, creating a permanent sun-blocking canopy and thus a largely uncluttered forest floor. And unlike its neighbouring fynbos, the Afro-montane Forests are not known for their floral diversity; there are only 33 species of natural tree on the Cape Peninsula compared with the 113 different kinds of heather that you’ll find in the local fynbos.

The Rooi Els (Cunonia capensis) grows along the edge of forest streams & on wet mountain seeps; its extravagant white flowers smell sweet & attract clouds of insects.

You’ll know some of the trees: Real Yellowwoods (Podocarpus latifolius) – great furniture – and Wild Olives (Olea europaea africana) for example, while the names of others reveal their traditional use or character: Assegai (Curtisia dentata) – once used to make the shafts of spears (assegais); Ironwood (Olea capensis) – hard to cut; and Stinkwood (Ocotea bullata) – unpleasant to cut. One of the most famous forest trees is actually a protea, the enormous Wild Almond (Brabejum stellatifolium) whose swollen sprawling branches were crafted by Dutch settlers into South Africa’s first security fence, still visible at Kirstenbosch Botanical Gardens.

The forests are oddly quiet too: not much to hear other than a vague hum of insects and a handful of forest birds although Afro-montane Forest is certainly home to more animals (mostly invertebrates) than fynbos which is infamous for its lack of animal life. Bird calls are the most obvious sign of life: it’s impossible to walk in the Cape’s mountain forests without hearing the strident whistle of the thrush-like Sombre Greenbul (Andropadus importunus) and it’d be unusual not to pick up the rattling call of a local flycatcher, the Cape Batis (Batis capensis), like someone shaking a box of matches at you.

Damp areas in the forest are also home to the Red Disa (Disa uniflora), one of the Cape orchids & a sure sign that we are in mid-summer.

Which is all very well but these mountains have been ravaged by fire for millions of years – why don’t they burn? Their location is part of it: these forests are invariably found in sheltered valleys with permanent water and loamy damp soil. The leaves of the forest trees are not especially flammable (compared to the dry, oil-laden shrubs of fynbos) and the forest flanks are often protected by dripping mossy walls.

But not always: these Afro-montane Forests will nearly always have some kind of interface with fire-prone fynbos, and that’s where the most fascinating aspect of the forests is found. Virgilia divaricate is known as a Keurboom – the ‘choice tree’- and it’s a fast-growing member of the pea family with a flower that smells like a fruit salad. Along with other broad-leaved shrubs, Keurboom forms a fire-resistant barrier between fynbos and forest, soaking up the flames that rampage through fynbos but preventing them from reaching the forest core.

In the background a wedge of green – the core forest – survives after a fierce mountain fire thanks to the protective belt of scorched smaller trees & shrubs. The green in the foreground is resprouting Palmiet (Prionium serratum) – a river plant.

Walk in fynbos after a fire and it’s like the place has been napalmed. Take three or four big strides through the charred buffer zone and into the forest patches and you’ll find them untouched – it’s uncanny, rather like walking off a busy street and into the cool, hushed atmosphere of a cathedral.

Want to see for yourself? The nearest Afro-montane Forest to Cape Town is at the back of Kirstenbosch Botanical Gardens but the largest patch of remaining forest is the peerless Orange Kloof, hidden away in the interior of Table Mountain and accessible by permit only. Try Leopard Kloof at the Harold Porter Botanical Gardens in Betty’s Bay or if you are on the Garden Route then you have the well-known Knysna Forests to explore – who knows, maybe you’ll see the forest’s last remaining elephant: after all, these forests are full of surprises.

You can easily hike in Afro-montane Forest – Table Mountain’s Skeleton Gorge is the most accessible but you’ll need a guide & permit for Orange Kloof – pictured here.