150 
NaNX’Y T. Bl’RBTDfiK. 
Observations showed that along the coastal zone, from Port Hedland 
to the northern end of the 80-Mile Beach, burning left the tussocks with a 
viable butt Avhose regrowth Avas aA^ailable to the grazing animal Avithin a 
feAV months. HoAvever, through the inland country along the Be Grey, 
ShaAV and Coongan Rivers up to Marble Bar the tussocks are completely 
destroyed and it is at least a year before regroAA'th is available to the sheep. 
Under such conditions the risk of soil erosion is great. Fortunately the 
Triodia tussocks are fairly AA’idely spaced (Fig. 4) and it is difficult to keep a 
running fire going. Thus only small patches from tAvo or three tussocks 
up to about an acre are burnt in each place. The spacing of the ground 
cover has probably played an important role in protecting the vegetation 
from the consequences of biotic activities during the seventy years of pas- 
toral occupation. 
The general custom is to burn during the mustering period in April 
and June when the men, riding the paddocks, drop lighted matches at ran- 
dom. Sporadic burning is carried out at any time during the year. 
It is evident that, if the tussocks are completely destroyed in May or 
June, the ground Avill lie bare until the following January or March Avhen 
the summer rains bring about seedling germination. It aA'US hoped that a 
study of the progTess of regeneration might shoAv w^hether any undesirable 
changes are likely to occur as a result of the burning process. That the 
vegetation may be altered Avill be shoAvn in the discussion on succession. 
The alteration is a result of a combination of factors of AAhich fire is one. 
Figure 1. 
