PLANT MORPHOGENESIS FOR SCIENTIFIC MANAGEMENT OF RANGE RESOURCES 



133 



Figure 4. — Low woodland of mulga (Acacia aneura). 



have to be cut with chain saws or pushed over 

 with bulldozers. 



In central Australia and some parts of West- 

 ern Australia, mulga stands have a cover of 500 

 or so trees per hectare, and a reduction in den- 

 sity is desirable (26, 35) It has been shown in 

 trials in Western Australia that clearing thick 

 mulga promotes Danthonia and Neurachne 

 (both perennial grasses) and forbs. Production 

 is increased by 50 percent, and carrying capacity, 

 lamb marking percentages, and wool production 

 per head are all raised (35). 



In central and southern Queensland, mulga has 

 increased under grazing and impenetrable stands, 

 with as many as 8,000 trees per hectare and vir- 

 tually no ground cover, have been produced (5). 

 In this area, mulga is clearly a weed and manage- 

 ment for reducing it is required. Beale (personal 

 communication) has found in a trial of various 

 tree densities that ground yield was similar for 

 160 and 40 trees per hectare. The higher density 

 has the advantage of additional drought forage 

 reserves. He also found that mulga germination 

 was highest at 160 trees per hectare, but probably 



could be controlled by heavy stocking at the time 

 seedlings are present. 



In some areas of mulga. unpalatable shrubs, 

 especially Eremophila spp., have increased. In 

 the Goldfields District of Western Australia, un- 

 palatable forms of mulga itself have replaced 

 original stands cut for timber and firewood for 

 mining operations. 



In the higher rainfall parts of the rangelands 

 in northern New South Wales, the original open, 

 low woodland on an undulating topography has 

 been converted to dense unproductive scrub 

 through the increase in unpalatable shrubs and 

 low trees (/, 20). It has been suggested that burn- 

 ing or heavy stocking by goats might be solu- 

 tions to the woody weed infestation, but it is 

 likely that mechanical or chemical treatment will 

 be necessary. It is doubtful if this can be done 

 economically at present, although much of the 

 area is suited to water spreading, the use of 

 which would raise productivity. 



Spinifex 



The vast areas of spinifex sand plains (fig. 5) 

 and dunefields are mostly unoccupied because they 



