Fighting fire with bark

Leucospermum conocarpodendron is in full flower at the moment. I took this photo of a fine speciman above Somerset West in the fynbos overlooking the Da Capo vineyards ( on the lower slopes of the Hottentots Holland Mountains).

The area where the photo was taken was burnt in a massive fire earlier this summer and as a result most of the surrounding vegetation is low and either resprouting after the fire or only germinated from seed this winter. However in the middle of this low, early post-fire fynbos are these magnificent tree pincushions, perfectly intact and in full flower. How can this be?

Well virtually all fynbos plants are adapted in some way to survive fires. Leucospermum conocarpodendron is one of a few species that is able to survive fires by having thick, fire-protective bark.

The thick bark protects the stem and buds from fire. Over time plants that survive fire tend to develop an unbrella-shaped form as their lower branches burn off and new growth is produced from the surviving upper branches. Nevertheless, this species is not a resprouter and plants can and do sometimes get burnt and even die in fire.

A study I was involved in a few years back in the Cape of Good Hope Nature Reserve showed that long intervals between fire results in greater build up of fuel loads, leading to more intense fires and a higher liklihood of death in fire.  So thick bark only works with shorter, natural fire cycles. Hot fires resulting from excessive fuel build up because of long intervals between fires or invasion by alien plants can kill these beauties, but under natural fire regimes their thick bark provides them with the necessary defenses to survive most fynbos fires.

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