Cutting corners when protecting trees? Not a great idea …

An elephant reaches for higher branches. Credit Ruth Smith
An elephant reaches for higher branches. Credit Ruth Smith


Elephants Alive


Read the original scientific article by Robin Cook here:

A unique solution to a unique problem?

The conservation successes of the Greater Kruger Region has meant that its resident elephant population is doing so well, that their abundance is increasingly cause for debate. If ever you find yourself in the proximity of South Africa’s Kruger National Park, there is a good chance you will come across high-spirited conversations about the impact of the Kruger’s thriving elephant population on the vegetation, and the various solutions to the so-called “elephant overpopulation problem”. These debates are a classic example of the eternal balancing act between animal populations and the ecosystems they are a part of. As with all human-managed protected areas, where fences and other human activity have impacted ancient migration pathways and dynamics, the natural relationship between animal behaviour and the environment suffers disruptions in need of “fixing”.

To top it all off, theimpact that elephants have on their environment is far from straightforward. Whilst elephants are in fact preferred grazers, they will browse on woody vegetation when grasses are in limited supply (for instance in the dry season). This browsing sometimes comes with negatively perceived impacts on vegetation and trees, such as “ringbarking”, branch breaking or toppling over the entire tree.

Tusk marks on a nearly ringbarked tree in the Kruger National Park. Credit Robin Cook


However, elephant browsing has many other - and often more subtle - effects on the ecosystem. Elephants distribute more seeds (up to 3200 per day) and do so further than any other land mammal: up to 65km(topped only by migratory birds). Their digestive system and dung also increases the germination success of those seeds once deposited. By browsing on tree branches and fruit, elephants are essentially doing what the trees themselves are intending. Plants grow fruit to multiply and encourage animals to eat and disperse the seed further away from the parent plant - avoiding competition and potential pathogens that may occur in the area. At the root (pun intended), trees do this to maximise their “offspring’s” chances of survival, and as the farthest seed dispersal species on land, elephant play a key role in this.

This niche seed dispersal role means that elephants contribute directly to genetic tree diversity across large landscapes, and are therefore critical to the integrity of African ecosystems. There are even certain tree species, for instance Lala Palms (Hyphaene palm), that are reliant on elephants for seed dispersal. Other than seed dispersal, elephant browsing provides life-giving light for smaller saplings to grow. Even further down the line, elephants help store large quantities of soil organic carbon, via soil carbon sequestration of woody biomass and transient carbon storage via their dung in the soil substrates. This carbon storing impact can even compensate the loss of tree biomass from elephant browsing.

Elephant dung amongst the leaf litter in a forested area along the Timbavati River: how many seeds are hidden? Credit @Ambersunny


The diverse impacts of elephant browsing on the surrounding ecosystem isn’t the only contentious and highly complicated aspect of elephant conservation. The impact from elephants’ use of the available landscape, as well as their population growth, differs greatly between habitats, regions and countries.While elephants are thriving in the protected areas of Southern Africa, Human-Elephant Conflict (HEC) is a huge threat to wild roaming populations elsewhere. Where there are no fences dividing protected areas and rural settlements, retribution to elephant crop raiding and ivory poaching continue to negatively impact elephant population growth.

Elephant crossing the road near a village by Lake Jipe, Kenya © Zacharya Mutinda, Save the Elephants


In Southern Africa however - and in particular the Kruger National Park, the safety granted to the resident elephant population has seen their numbers surging. While this is a testament to the successes of conservation management, it does not take a lot for the general perception of elephants’ use and value(often based on a human-centric perception of the aesthetic value of a healthy and functioning ecosystem) to sway the other way, as localised elephant impact on vegetation can appear heightened.

A large breeding heard in the Timbavati Private Nature Reserve, Kruger National Park. Credit Chad Cocking


For instance, when the fences were removed between the Associated Private Nature Reserves (APNR) and the Kruger National Park and elephants moved into an area they had been excluded from for 30 years, some areas suffered significant impact. This has resulted in a mild form of Human-Elephant Conflict, where breakage of large amounts of trees has created somewhat of a resentment amongst stakeholders like landowners, reserve management and park visitors. Importantly, large trees also provide ecological benefits to savanna ecosystems, including: providing habitat for more shade-tolerant plant species, transporting nutrients upwards from deeper soil layers, and serving important habitat functions within ecosystems.

In our human-dominated world, the survival of wildlife and maintenance of wild spaces is largely dependent on goodwill and funding from tourist income. It is therefore crucial to balance the need of elephants (and other species) for large, uninterrupted wilderness areas without fences, with mainstream aesthetic perceptions and the ecological role of large trees. Elephant impact mitigation methods to protect large trees is one of the ways to preserve that balance.Especially in small reserves with high elephant densities, or those with an abundance of water (like the APNR), direct tree protection methods can be highly effective.

A breeding herd enjoys one of the many water points in the APNR. Credit Elephants Alive


With an abundance of mitigation methods available, and the diverse habitats where they might be applied, it is of vital importance to use proven effective methods within specific areas. While mitigation strategies based on anecdotal evidence, hear-say or so-called empirical experience, can work, incomplete or wrong application can lead to unsatisfactory results. As the saying goes, “one man’s trash is another man’s treasure”. This may, in turn, lead management to adapt unnecessary (lethal) methods of elephant population management. Luckily, we’ve done the work for you, and developed a toolkit of tree protection methods based on scientific research.

A tree-lovers toolkit: which method to use when and where?

The study, conducted by Robin Cook - PhD student at Wits University and Elephants Alive, assessed the effectiveness, conditions for effective application and cost implications of four tree protection methods.From least (overall) effective, to most effective: creosote jars, pyramids or rocks, wire-netting, and beehives.

The creosote method is a prime example of how a mitigation method that works in one area, does not automatically translate to different areas or types of HEC. Creosote is a smelly residue created by the distillation of coal-tar. It has a thick and oily composition, is highly flammable and has carcinogenic properties. Whilst the repellent smell of the creosote oil has shown potential for deterring elephants from crop raiding in Zimbabwe, it was completely ineffective at protecting trees in the APNR from elephant impact during the two-year study period. Even though it was the cheapest out of the four methods, it was the only tested method to have a lower survival rate in comparison to their control trees!

Creosote jar installed on a tree. Credit Elephants Alive.
Elephant damage on tree and broken jar after installation of creosote jar. Credit Elephants Alive.


The second method has been used extensively throughout protected areas: placing pointy rocks or concrete pyramids in circular formation around the base of a tree to prevent elephants from reaching the tree trunk and branches. This study is the first of its kind to actually investigate how composition and distance determine effectiveness of this method. We found that, at the correct distance between the elephant and the tree’s main stem and if correctly arranged pyramids can prevent elephants from getting sufficiently close to push the tree over. The pyramids can be replaced by rocks but in both cases, their placement should be occasionally monitored to ensure that they have not been re-arranged by ever-so intelligent and adaptable elephants.

Pyramids being installed around a marula tree. Credit Elephants Alive.
A marula tree pushed over, with incorrectly placed pyramids at the base of the trunk. Credit Elephants Alive


The third and fourth methods of wire-netting tree trunks and hanging beehives proved to be the most effective protection methods for large trees, each having their own merits depending largely on tree size. Effective against bark-stripping, wire-netting is most effective mainly for larger trees, with a trunk diameter of 40cm or more, that elephants cannot push over. Click here to read more about applying wire-netting as a large tree protection method. While some periodical follow up is required, wire-netting is also significantly cheaper and less labour-intensive than beehives.

The Elephants Alive team wire netting a marula tree as part of the study. Credit Moritz Muschick.

And the winner is… the most expensive option…

Whilst the effectiveness of beehive fences to deter elephants from raiding crop fields has been proven on multiple occasions and in multiple countries, at the beginning of our study it remained to be seen whether they could do the same for trees. The Elephants Alive team hung two beehives in 50 trees, from extended branches on opposite sides of the main stem. After five years, 10% of the beehive trees had died, at an annual tree mortality rate of a mere 2% per year. This is 3.4 times less compared to the control trees that did not have beehives.

Ronny climbs down after securing beehives in the tree. Credit Elephants Alive


To this day, no active beehive was ever tampered with by elephants during the study! Whilst inactive beehives also showed a degree of deterrence, ensuring maintenance of beehive occupancy is important for the longterm success of this method. Again, the adaptability and intelligence of elephants means that they will eventually catch on to the fact that empty beehives equal no stings… This became apparent during the final two years of the five-year study, when 14 empty beehives were opened or pulled down by elephants.

An herd of elephants shaking their head and throwing sand after being chased by bees. Credit Robin Cook.


On the flip side, quality comes at a cost. The beehive project proved to be the most effective - yet most costly and labour-intensive - way of preventing elephant impact on large trees. The results of Elephants Alive’s honey sales show that the financial costs of setting up a beehive in a tree could be recuperated five years from project setup. It is also more labour intensive, as ensuring hive occupancy means looking after the bees, ensuring that they have sufficient access to water and pollen, and protecting the hive against any diseases or other naturally occurring threats.

As with anything in life, if you want results, cutting corners is never the way to go. Looking after an environment that humans as a species have impacted so pervasively, means investing the time, money and effort it requires to solve the issues we have created. After all, if we hadn’t fenced in our elephants or provided them with artificial resources (water), wouldn’t they have had the need and space to disperse, giving nature the opportunity to balance itself?


Written by Evelyn Poole for Elephants Alive. For re-publication, contact

Article originally published as:


Read the original scientific article by Robin Cook here:

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