Tropical African cedars (Widdringtonia, Cupressaceae): systematics, ecology and conservation status

Abstract

Phenetic analyses of 24 morphological characters, collected in the field for 150 trees ofWiddringtoniain Malawi, Zimbabwe, Mozambique and northern South Africa, show two distinct clusters. One can be identified asW. whytei, a tall, wide-crowned forest tree endemic to Mt Mulanje in Malawi, while the other isW. nodiflora, a multi-stemmed shrub or narrow-crowned tree, which is common on Mulanje and widespread in southern Africa. These two sympatric species are distinct on phenetic, phylogenetic, ecological and biological grounds. The distinguishing characters of the two species are analysed and discussed and the differences are related to different responses to fire.Widdringtonia whyteiis a forest pioneer with limited fire survival ability, whileW. nodifloracoppices after fire and is common in fire-prone heathlands. To date it has been assumed that there is a single species ofWiddringtoniaon Mt Mulanje, and this has led to faulty management and exploitation decisions. Extensive plantations of the economically uselessW. nodiflorahave been established, in the belief that they are the economically desirable Mulanje cedar,W. whytei, which is now in danger of extinction.