Plant Species Composition

The structure of the woody vegetation is not only reflected by the age structure of each individual species, but by the number of different species themselves (alpha diversity), and their individual characteristics.

Growth form

Different woody species have different growth forms.  These range from low shrubs like Baphia massaiensis and bushes like Bauhinia petersiana and various Combretum species, through small trees such as Terminalia sericea and Ochna pulchra to larger trees such as Burkea africana, Gouibortia coleosperma, Pterocarpus angolensis and others.   The growth forms of the different species determine the canopy cover of the woodlands, in height and in density.  These two parameters are of particular importance due to their effect on light penetration to the woodland floor and their effective arangement of the fuel load. but also on the interception and concentration of water around tree roots.
See also:
Light penetration
The arrangement of the fuel load
Water availability

Competition for water

The availability of water seems to be the factor that most limits the growth and development of the vegetation.  Plants therefore need to be able to access as much water as possible.  This is dependent on the rooting strategy of the plant, soil conditions, and the water potential of the soil and plant.
See also:
The importance of soil conditions
The rooting strategy of woodland trees

Competition for light

Although the light intensity in the savannah woodlands is much higher than in tropical rain forest, the availability of light has a significant effect on the establishment of the seedling of some species.
See also:
Light penetration

Fire tolerant species

Different plants have different ability to withstand the effects of fire.  While some plants are able to withstand fire quite well, and have adapted strategies like copicing (Ochna pulchra and Grewia flava) or survival as sufrutex (Pterocarpus angolensis), others are eventually removed from the system by fire, as may be the case for Schinziophyton rautanenii.  The ability to withstand fire may be the reason that some of the Burkea africana stands have developed (Rutherford 1981).  He also reported, however, that most B. africana plants that died the fires he studied were seedlings.  The ability of plants to withstand fires not only depends very much on the prevailing fire regime, but also on the size of the plants involved.  Rutherford (1975) found, for instance that even infrequent fires may kill Burkea africana trees up to a height of 4m, while larger trees are not as seriously affected.
See also:
Fire regimes

Fuel Load Characteristics

Stem diameters of woody plants very significantly influence the behavior / condition of the fuel load.  Many small shrubs or bushes, with thin stems like Grewia flava or Bauhinia petersiana will represent a higher fire danger than thicker stemmed plants.

Appart from the size of fuel and its arrangement, von Breitenbach (1968) mentions differences in flamability between different woody plants.
See also:
The characteristics and development of a fuel load