The landcover changes that occurred in the Nyngan area in New South Wales during the period December 1972 to December 1990. The Difference FCC image shows that there was clearing and cultivation both on the heavy soils of the Bogan River floodplain (RHS) and the lighter red earths (LHS). The largest area of clearing is in the west (LHS) where poplar box (E. populnea) woodland, mostly used for extensive grazing, has been cleared for wheat growing.

The landcover changes in just one such marginal area in New South Wales are illustrated in the Nyngan scene. This whole scene is particularly interesting because it is virtually two halves: the soils on right half of the scene are clays associated with the old floodplains of the Bogan River while those on the left are red earths. The clays give a bluish cast while the red earths a red-yellow cast. The nature of the soil as well as access to water for irrigation affect paddock size. All the regular marks of human activity overlie an extraordinary pattern of landforms associated with the Bogan River.

The Difference FCC image shows the extent of new clearing and cultivation in this area. The largest new fields are in the west where poplar box (E. populnea) woodland, principally used for extensive grazing, has been cleared for wheat growing. The change in landcover is dramatic and irreversible.

The reader not personally familiar with this area may nonetheless be feeling some disquiet. Haven't we been through all this 'in good times' expansion of agriculture before? Isn't it usually followed by collapse when average conditions, both climatically and economically, return? Are the changes we see in this scene any different?

I am familiar with the Nyngan area. My replies to these three questions are: Yes, Yes and No. I hope I am wrong. However, in this case I don't think so.