is no formal "Thicket Biome" recognized in the scientific literature.
However, we felt that the vegetation which replaces forest - where
a degree of fire protection is still evident, but rainfall is too
low - did not fit within the "Forest" type as it does not have the
required height nor the many strata below the canopy. Nor is it
a "Savanna" type, in that it does not have a conspicuous grassy
Subtropical thicket is a closed shrubland to low forest dominated
by evergreen, sclerophyllous or succulent trees, shrubs and vines,
many of which have stem spines. It is often almost impenetrable,
is generally not divided into strata, and has little herbaceous
cover. Because the vegetation types within the "Thicket Biome" share
floristic components with many other phytochoria and lie within
almost all the formal biomes, Thicket types have been referred to
as "transitional thicket". Thicket types contain few endemics, most
of which are succulents of Karoo origin(e.g. plakkies Crassula
spp. and sheep fig Delosperma spp.). A complete list of characteristic
species of subtropical thicket and subdivisions into different types
can be found in Everard (1987).
In this overview, five vegetation types are recognized on the basis
of their distribution and the degree of succulence in the shrub
and tree species.