Photograph courtesy of Launceston Field Naturalist Club

Wildflower "walks and talks" in woodland communities generally focus on all those pretty herbaceous understorey favourites which display their delicate bright coloured blooms amongst the less spectacular framework of native grass, shrubs and trees; and one of the most commonly overlooked is Acacia mearnsii (Black Wattle). Although seasonally variable it is generally covered in full blooms of sweetly scented flowers by mid to late November. So why talk about these boring, soft, green, fern-leaf wattles? Because this common tree deserves some of the respect so deeply engendered in the traditions of the local aboriginal tribes and early colonists. Let's pull them apart starting from the roots up and see what's interesting about them.

Roots:
        As a pioneer or scab plant their roots are first to rapidly bind the erosion prone soil following wild fires and, like peas, fix the atmospheric nitrogen in the soil. Woodland species can rapidly utilise these increased nitrogen levels provided by the nodules of rhizobia bacteria present in their expansive root systems.

        Mycorrhizal (meaning fungus roots) fungi attach to their roots and produce "yummy" truffles for bettongs, bandicoots, potoroos etc. The digging or "bio turbations" produced in search of these fungi create micro sites on the soil surface for difficult-to-germinate species. A good feed of truffles will mean Mycorrhizal spores are spread far and wide in the marsupials' droppings. This dispersal process perpetuates the symbiotic relationship between wattle roots and the Mycorrhizal fungi.

Bark:
        The cracks and crevices in the wattle's bark are home for many insects and other invertebrates including the rare Tasmanian Hair Streak Butterfly which lays her eggs in the cracks; these hatch to produce caterpillar larvae attended by ants ( Indomyrmex sp.) that feed off the sweet exudates of the larvae. When ready to pupate these "dairy farmer" like ants herd the larvae down the wattle and across the grassy understorey to Eucalyptus viminalis (White Gum) where they pupate in protective bark crevices.

        Early this century the tannin industry thrived on tannic acid extracted from the Black Wattle bark (up to 45 per cent) and the subsequent logging of the wattle caused rapid deforestation of the woodlands in the early 1900's. The highly valued tannins were used for tanning, plywood and particleboard adhesives as well as antiseptics. Today Australia imports its tannin products from South Africa which now has massive plantations of black wattle for this industry.

        Aborigines used to soak the bark in a wooden waddie next to an open fire to extract their own antiseptics for treating cuts and aching joints. They also used to split the bark into lengths of coarse string to produce baskets and bind the flintheads onto their spear shafts.

Wood:
        Black cockatoos love the grubs (wood moths etc.) in the wood and voraciously strip the bark for access to these borers. Bark gleaner birds such as Thornbills thrive on insects present under the bark.

        "Wattle and daub" huts were constructed using the flexible limbs to structure a framework for supporting mud walls. This cottage style structure was common in Australia's early colonial history. Also, aborigines constructed their "lean to’s" or "half dome" huts from these flexible limbs, covering them with bark sheaths or coarse foliage.

        Black Wattle provides comparable qualities to Acacia melanoxylon (Blackwood) as a craft wood for fine furniture manufacturing.     With no "whiteners" for sheets the colonists often relied on the white ashes of burnt black wattle to help rid their soiled linens of dark stains. These ashes also provided the basis for soap making, producing a "lye" (or alkali) when mixed with water. This lye and the fat from game meat formed a chemically reactive mix producing soap which was perfumed by herbal extracts or lavender oil.

        Wattle grub frass was a valuable fuel for fire lighting, and ensured the ease of rekindling glowing embers often carried by the aborigines.

Sap:
        The sap was prized as a food by aborigines. Dissolved in water with a dash of sweet wattle flower nectar and a few formic ants for a lemony flavour, it was a quenching drink - a treat during their long joumeys across the woodland landscape.

        Mixed with ash when melted, it plugged holes in their water carrying vessels and watercraft.         The sap was so important that they melted and mixed it with burnt mussel shells or ashes and carried it about in balls when on walkabout.

Foliage and Flowers:
        When the black wattle was in full flower, the men of the aboriginal bands sharpened their flint headed spears. They understood that the flowering was nature's indication that the roots were in the best condition for eating following a lush grazing period on the succulent, springtime grasslands and grassy woodlands.

        During winter insects, birds and marsupials are hosted by the black wattle with the aid of the nectar in its leaf axials. In turn these creatures provide an important predatory role to deal with tree die-back caused by scarab beetles and pasture pests.

        Black wattles, along with gums, native box, and native hop form the framework vegetation on so-called "Hill-topping" sites. They are often isolated remnant pockets of native vegetation amongst a lower sea of exotic pasture. These sites are critical habitat for male butterflies to attract females for mating, which then lay their eggs under the wattle's bark elsewhere but still within close proximity. It's the only acceptable mating area for these butterflies.

        Black wattle flowers provide very nitrogen rich pollen with no nectar. They attract pollen-feeding birds such as Wattle Birds, Yellow Throated Honey Eaters and New Holland Honey Eaters. The protein rich nectar in the leaf axials is very sustaining for nurturing the growth of juvenile nestlings and the young of invertebrates such as ants.

        The seeds are highly prized by both wandering aboriginals and jet setting modern day traveller alike. Think of those "wattle seed" biscuits passed out by the National Airlines - part of the bush tucker revolution.  Aborigines would grind the seeds into nutritious flour rich in polysaccharides and very high in protein content. Flat bread, baked in the ashes, was the delicious wattle seed flower reward for the hours of grinding and winnowing.