the Bush Encroachment issue

When thinking of Namibia, grassland savannas immediately come to mind which this African country is renowned for. But many areas of the country no longer have these open expanses of grassland because dense bush has taken over.

Between 300,000 and 450,000 square kilometers of land in Namibia are now bush encroached. To put it into context, this is as large as the whole of Sweden or Germany.

And the effects brought about by this phenomenon of bush encroachment are detrimental, as agricultural productivity in Namibia has declined by two-thirds throughout the past decades.

What is Bush Encroachment?

Bush encroachment is defined as the invasion and/or thickening of aggressive undesired woody species resulting in an imbalance of the grass-to-bush ratio, where woody species are out-competing grasses. The term bush encroachment refers to the expansion of native plants and not the spread of alien invasive species, therefore it’s about plant density and not species. 

The main species causing Namibia’s bush encroachment problem are Acacia mellifera subsp. detinens (Black thorn), Dichrostachys cineria (Sickle bush), Terminalia sericea (Silver terminalia), Terminalia prunioides (Purple-pod terminalia), Acacia erubescens (Blue thorn), Acacia reficiens (False umbrella thorn) and Colophospermum mopane (Mopane).

There are several factors that lead and contribute to bush encroachment, and all of them have a strong link to human influence and behaviour.

The first is overgrazing, which is commonly a result of livestock overstocking and the fencing of farms, as well as the lack of animal rotation and land resting periods. Overgrazing plays an especially strong role in mesic grasslands, where bushes can expand easily when gaining a competitive advantage over grasses.

The reduction and absence of large mammals such as elephants and rhinos are another contributing factor, which is linked to the introduction of rangeland agriculture as well as unsustainable hunting practices.

Fire suppression is another cause, this is the reduction in the frequency of wildfires that would occur naturally but are suppressed in frequency and intensity by landowners and farmers due to the associated risks.

Population pressure is also a cause for bush encroachment, happening when large trees are cut as building material or fuel.

Bush encroachment is furthermore fuelled by climate change and increases in atmospheric CO2, where predictions pronounce shifts toward tree-dominated biomes.

The phenomenon of bush encroachment has led to serious negative consequences for Namibia, which includes:

• Decreased biodiversity, 
• An increase in land degradation and deterioration,
• The degradation of the functions and structures of ecological ecosystems, 
• A decrease in rangelands’ livestock carrying capacity, 
• A decrease of between 30% and 50% in Namibia’s beef production,
• The displacement of wildlife, 
• As well as impacting groundwater recharge, and importantly
• The decrease in food security and livelihoods in rural communities throughout the country.

Namibia’s tourism industry has undergone rapid growth in the past three decades, with an average increase in international arrivals of 16% per year on average. This growth is however being undermined by bush encroachment as well. Tourism in Namibia relies largely on the wildlife sector and changes in the quality of wildlife viewing, wildlife numbers and vegetation because of bush encroachment are expected to affect the demand for wildlife tourism, which is estimated to be as much as a 15% reduction in tourism demand.

But there lies an opportunity within this bush encroachment problem, and that is the huge source of biomass it offers. Calculated conservatively, around 450 000 million tonnes of encroacher bush can be sustainably harvested, and this excludes annual expansion.

There needs to be a balance between rehabilitating and maintaining savanna ecosystems while commercially using bush resources.

Omiti Biochar rigorously uses sustainable bush thinning and bush control techniques to contribute to improved water and nutrient cycling, better soils, enhanced ecosystem functionality, more resilient ecosystems, and improved biodiversity.

We practice a holistic approach to integrated bush management control that involves various preventive and restorative control measures which include:

1. Training and coaching on interventions to avoid bush encroachment.
2. Interventions that reduce bush densities.
3. Follow-up interventions that prevent re-encroachment.

Our team members undergo thorough theoretical and practical training delivered by the Namibia Biomass Industry Group in which the following segments are covered:

• The concept of Bush encroachment
• Extent and Impact of bush encroachment
• Species identification of encroacher bush
• Bush biomass quantification
• Legal aspects and principles of Bush control
• Bush control methods
• Aftercare
• Value addition
• Certification