LOOKING GLOBAL

Bush Encroachment: FROM CHALLENGE TO OPPORTUNITIES

What was until fairly recently considered a scourge by commercial and communal farmers in Namibia has found a use for a range of value-added products with an estimated net value of N$8 billion over 25 years – encroacher bush.

Bush encroachment can be defined as the excessive invasion and/or thickening of undesired woody species at the expense of other species, especially grasses. Swarthaak (Senegalia mellifera), also known as Black Thorn, is the most common encroacher species, but at least eight other invasive species have been identified in Namibia.

Encroacher bush has invaded more than 30 million ha of the country’s rangelands – or close to 30% of Namibia’s total land surface – in ten of the 14 regions. Although there are several factors responsible for this, overgrazing as a result of overstocking livestock has been identified as one of the main causes. Other factors include the increase in carbon dioxide levels which favours the growth of bush over grasses, the displacement of browsing game species and the introduction of domestic livestock which are grazers, as well as periodic droughts and changing rainfall patterns as a result of climate change.

The negative impacts of bush encroachment are, amongst others, the reduction of grass cover and the availability of food for grazers, reduced groundwater recharge and soil moisture content and a reduction in biodiversity. Research has shown that the carrying capacity of encroached land is 17 ha per head of cattle, but improves to 10 hectares per head of cattle four years after bush thinning.

CHARCOAL EXPORT

Namibia’s charcoal industry has been converting biomass to a value-added product for over 30 years, but with the utilisation of encroacher bush as its feedstock, the industry has boomed over the past decade. The country now ranks as the largest exporter of charcoal in the world and volumes are projected to reach 200,000 tonnes by 2020.

Extensive research in recent years has shown that there are numerous other economic opportunities and value-added products that could be derived from the bush encroachment scourge. These products range from compressed firewood, wood chips and pellets and animal feeds to thermal power generation and the generation of electricity, as well as a number of other products. The good news is that only a fraction of this almost inexhaustible biomass, estimated at between 200 and 300 million tonnes, is currently being utilised.

BUSHBLOKS FROM WOOD CHIPS

Compressed firewood, made by finely grinding and compacting wood chips, is one such product. Known under different names internationally, the Cheetah Conservation Fund (CCF), located northeast of Otjiwarongo, began producing the “Bushblok” in 2004 by harvesting encroacher bush in order to open up rangelands for cheetahs which require open savannas. The fuel log is made from chipped wood which is compacted with a press and offers an environmentally friendly alternative to wood and coal fires. It not only has a much longer burning time than wood (up to one-and-a-half hours) but produces very hot temperatures, is smokeless and leaves surprisingly little ash.

FOSSIL FUEL ALTERNATIVE

Some manufacturers have already reduced the use of fossil fuels by incorporating biomass fuels. Wood chips and pellets are increasingly being used as an alternative to fossil fuels which must be imported and have a high carbon footprint. The four industrial combustion chambers of the Ohorongo Cement Factory, north of Otavi, are fired with wood chips made from encroacher bush instead of diesel and the factory plans to eventually generate 80% of its energy requirements from this source. The biomass boiler of Namibia Breweries in Windhoek became operational in mid-2016. The boiler, the largest in the country, uses wood chips instead of heavy furnace oil and generates 80% of the breweries’ heat demand.

BOSKOS AND BIOFUEL

Necessity is the mother of invention and when Namibia was gripped by the worst drought in almost a century following the poor rainy season of 2018/2019, the production of animal feed from encroacher bush gained traction. The chipped raw material is mixed with different additives such as molasses, providing a vital source of feed during droughts.

Biofuel, renewable energy from encroacher bush, has enjoyed considerable attention in the past few years. NamPower, Namibia’s electricity utility, plans to build a 40 MW biofuel plant near Tsumeb at a cost of N$1.9 billion. The plant, which is scheduled to become operational in 2022, will require over 200,000 tonnes of biomass a year, or 5 million tonnes over its 25-year lifespan.

What was once seen as a challenge has been turned into numerous opportunities that will not only restore degraded agricultural land to productive rangeland, but will also increase the soil moisture content and groundwater recharge, as well as the biodiversity of more than a third of the country’s land surface. It also creates jobs, reduces the importation of fossil fuels and electricity as well as the carbon footprint.

Namibian freelance journalist and travel writer: Willie Olivier