Artificial or cutting methods
This is the mechanical defoliation of a plant with the hand or by means of a power-driven implement. In a case like this the intensity, frequency and season of defoliation can be almost fully controlled by man.
Natural methods
Grazing
Cattle grazing a veld
Grazing is the most common method of defoliation and also the most complicated method. With grazing the intensity and frequency can only be controlled to some extent, but the season of grazing can be controlled more accurately. Grazing also introduces secondary factors such as treading, selective grazing, etc.
Burning
Removal of vegetation through veld burning
Burning is one of the most drastic ways of defoliation because it usually goes along with the development of very high temperatures which can easily cause the death of a plant. It is very difficult to control the intensity of defoliation by burning, but the frequency and season can be controlled more accurately.
Frost, hail, droughts and insects
Defoliation by these factors is almost uncontrollable by man and little is known about the influence of defoliation by these factors.
Swarm of locust. Image: REUTERS