In September 2015 the mid-north of South Australia is a sea of green and gold, with the intense green of lush grain crops interspersed with the brilliant yellow of canola and bordered by native golden wattles and senna bushes. Streams are running and the countryside is full of healthy signs of spring.
On my eighth survey of red gum health in the region, this is the most water I have seen in the landscape, the best crops and the healthiest state of mature river red gums. However, there are still no signs of significant regeneration by red gums, with no new stands found since 2008.
The villains preventing regeneration of the red gums appear to be the soft spring weeds, knee-high across the landscape in all the spaces along the banks of rivers and streams where seedlings might grow. Red gum seeds need to fall from the parent tree and land on bare moist soil, where they will germinate within 24 hours and begin to grow, before ants can gather the seeds into their nests for food.
In addition, the river valleys of the mid-north are choked by phragmites reedbeds, currently in their dry winter state, but just starting new dense green growth for summer. Locals report that the reeds have expanded across the whole width of river channels since the 1960s, as the river flows have reduced in volume and duration, allowing the reeds to cover more potential habitat for regeneration of red gums.
The red gums are producing plenty of seed, but there is no space for seedlings to establish. Active intervention will be needed, to clear spaces for seed to fall on moist soil, to keep the competing weeds down, and to prevent stock from grazing young seedlings. Without action, there will be no new generations of red gums in the mid-north landscapes, to replace the current aging red gum communities.