By J

By
J.I. House & D.O. Hall
Division of Life Sciences, King's College London

Table 2. Broad plant functional types found in African savannas (from Scholes et.al., 1997)

	Phenology	Water	Herbivory	Nutrients	Plant Functional Type common name
Woody Plants Long-lived (> 5 years) High fraction of secondary growth	Drought deciduous	(Mostly fine-leaved)	Thorny (hydrolysable tannins)	Fast growth and nutrient uptake. May be N-fixing	Thorn shrub/tree
	Drought deciduous	(Mostly broad-leaved)	Indigestible (condensed tannins)	Inherently slow growth and uptake capacity	Broad-leaved shrub/tree
	Evergreen	Sclerophyllous	Indigestible (fibre and tanins)	Inherently slow growth and uptake capacity	Evergreen shrub/tree
		Succulent	Often palatable, sometimes tannins, resins or alkaloids		Succulent shrub/tree.
		Phreatophytic	Tall, or unpalatable		Phreatophyte
	Wet season deciduous	Water storage organ	Toxic	Inherently slow growth	Geoxylic suffrutex
Graminoids Short-lived (< 2 years per tiller). Monocots, buds basal. Mainly vegetative reproduction		Xerophytes	High fibre	Root sheaths common on sandy soil	Wire grasses
		Mesophytes	Low digestibility	Seasonally low N	Tuft grasses
			Lawn-forming	Continuously adequate N	Creeping grasses
Forbs As above, but dicots with terminal buds mainly sexually reproducing	Ephemeral/ annual	Avoid drought as seeds	Toxic (alkaloids, etc.)		Ephemeral forbs
	Perennial	Drought deciduous	Often palatable but hairy	N-fixing	N-fixing forbs
	Perennial	Drought deciduous	Often palatable but hairy	Non-N-fixing	Perennial non-N-fixers
Geophytes	Anti-seasonal	Water storage bulb	Toxic		Geophytes

Notes:
From Scholes et al, 1997
The difference between "trees" and "shrubs" is based on height not on species. Therefore one species can have both tree and shrub
forms. Trees are sufficiently tall not to have above-ground buds damaged by fire, and to escape mammalian herbivory.

ACKNOWLEDGEMENTS

Many thanks to Bob Scholes (CSIR, South Africa), Xavier Le Roux (INRA, Clermont-Ferrand, France), Jonathan Scurlock (ORNL, USA) and Joe Scanlan (Department of Natural Resources, Queensland, Australia) for providing information and making corrections to the manuscript. Dale Kaiser & Sonja Jones (ORNL, USA) for calculating tropical % of the Olson et al (1983) "grasslands" category.

Sadly, David Hall passed away in August 1999 before this chapter was published. His knowledge and love of savannas was only surpassed by his eagerness to learn and teach.

REFERENCES

Table 1: Previous estimates of area, biomass and NPP of savannas and grasslands

Table 3: Biomass reported for tropical grasslands and savannas

	Table 4: Primary production reported for tropical grasslands and savannas
	Table 5: Biophysical properties, fluxes and efficiencies
	Figure 2: The relationship between total NPP and aboveground NPP

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