In the right hands, wattle trees are true champion trees, giving commercial and small-scale growers multiple product options. Unmanaged, these prolific seeders can spread far and wide across the hills and valleys, negatively impacting biodiversity and using up scarce water resources.

However, when managed correctly in a plantation or woodlot environment, they are among the most productive and useful commercial tree species. Wattle is a great crop for small-scale tree farmers operating on tribal land.

Value-adding

This is especially so when there is a wattle bark factory nearby because mature black wattle trees (Acacia mearnsii) deliver at least two highly valuable marketable products at harvest time: timber for pulp, and bark that is processed to make tannin and adhesives. These products are in high demand worldwide and provide the essential raw material for a vibrant export trade.

Wattle timber that doesn’t meet the specs required by the pulp/chip mills makes excellent firewood and can be utilised as feedstock for charcoal manufacturing, another highly marketable product.

Wattle trees are also planted strategically by some tree farmers as a “green” fire break to shelter their pine or Eucalyptus compartments from wildfires because healthy wattle trees don’t burn easily. Wildfires that enter well-kept wattle blocks tend to slow down and lose momentum.

Sustainability

Because they grow so fast and self-seed so prolifically in various climatic conditions, it is often assumed that wattle trees are easy to grow commercially … just plant and go and come back to harvest in 8 - 10 years.

But this is not necessarily the case, as the demands of the market and the economics of commercial tree farming today require a sound management approach to growing wattle based on improved planting stock, good silviculture practices and sound science.

Growers must also contend with the variables of a changing climate, extreme hail, wind, frost and snow events, and a significant increase in pests and diseases impacting the health of commercially grown wattle trees.

Chief among these is wattle rust, Ceratocystis wilt, Phytopthora spp, mirrid, bagworm, white grub and a couple of newcomers in the wood boring jewel beetle (Agrilus grandis) and the Melenterius seed weevil.

International markets

The New Hanover district in the KwaZulu-Natal Midlands is one of the prime wattle-growing regions in South Africa. It is close to NCT’s woodchip mills at Richards Bay and Durban and there are bark factories at Dalton (UCL), and Hermannsburg and Iswepe (NTE) near Mkhondo in Mpumalanga.

At a recent field day, NCT’s tree farming manager, Craig Norris, said advances in tree breeding are developing a range of black wattle clones that have taken the humble wattle tree to new heights – quite literally.

The wattle tree breeding programme is a collaborative effort between NCT, TWK, NTE, UCL and the ICFR. It means there are choices to be made when planting wattle:

• Seedlings or clones
• Rust tolerance or frost tolerance
• Black wattle or green wattle (Acacia decurrens).

The advice from Craig and Friedel Eggers of UCL is to plant clones sourced from reputable nurseries ahead of seedlings if possible. Clones are significantly more expensive than seedlings, so good silviculture is critical to protect your investment and ensure you reap the rewards of the enhanced growth and form that cloned black wattle can deliver.