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Tagging Trees: A Volunteer's Perspective

Date: 2008-01-18

By Dimitri Dimopoulos: Honorary Ranger

A systematic tree marking process in Kruger National Park (KNP) is the first step by SANParks' Scientific Services staff in Skukuza towards producing more detailed biodiversity surveys in the park. Dimitri Dimopoulos, one of SANParks volunteer Honorary Rangers, recently assisted in this process...

Adolf Manganyi tagging a tree.


Before tagging begins, about 20 to 25 trees are selected in a designated area in the park. The survey team then makes a loop in that area on foot, selecting trees for tagging based on their height and a careful assessment of each tree's condition. Once a tree is located, the survey team notes the species, the tree height, canopy width and stem diameter of the tree. The level of damage to the tree or bark by elephants, other herbivores and fire is also noted. A Global Positioning System (GPS) reading is then taken, using a highly accurate differential GPS, which makes it easier to find the tree again during subsequent surveys. The trees are then marked with small, numbered, silver tags.

The study is projected to run for the next three years when selected trees will continue to be marked throughout the park. Considering that Kruger is the size of a small country, systematically tagging trees throughout the park is a mammoth task and Scientific Services called in the help of volunteers from the Honorary Rangers to assist in the tree marking process.


"I am currently based in the Johannesburg region of Honorary Rangers (HR) and have been working under the guidance of Ashraf Sayed who is himself an Honorary Ranger. When there is a requirement for some assistance to be provided to SANParks, our branch of the HR’s is usually informed by Ashraf and, if we are available, we volunteer our time, skills and passion to helping with research and other related activities.

A volunteer force managed to get to Kruger and mark trees during December 2007, at the request of Scientific Services. A few sites were completed during the week of field work but our efforts were also hindered by rain.

The 'tag' team, lead by Adolf Manganyi from Scientific Services, set off at 5.30am each day to find our sites for tree marking. The team then worked in an anticlockwise direction towards certain trees (mainly Red Bushwillow, Russet Bushwillow, Leadwood, Knobthorn, Marula, Boerbean and Jackalberry among others) which were pre-marked with GPS co-ordinates. We shared the workload by taking turns measuring the height of trees, their vertical and horizontals lengths, measurements of stem circumferences, and amount of de-barking or other damage such as fire and then finally marking the tree with a numbered tag. All of this information is recorded on a data sheet and will be added to the biodiversity survey database.

Working in the veld is a far cry from the busy world of finance and banking, which usually occupies my time. Staying in the research homes in Skukuza made me feel like I was really a research scientist, and I was privileged to have this experience and time in the bush. We (the tree tagging team) were fortunate to see lots of very young wildlife too, given the time of year.

During the time we were busy with the tree marking I saw the following wildlife:

10 Lion (including a mating pair)

11 Hyena (including a baby)

3 leopard (including a mating pair)

14 Rhino

2 male cheetah

Lots of Warthog (with 5 little piglets)

Lots of Giraffe (with little ones)

Lots of Zebra (with little one)

Lots of Buffalo

Lots of Elephant (with quite a few babies)

Impala (lots of new-borns)

Hippo (new-borns)


Baboons (new-borns)

Monkeys (new-borns)

Crocs (young)

Lots of Kudu

A buffalo rubbing it's horns

against a tree trunk.

What was also great to see were animals like buffalo, elephant, giraffe, and rhino and how they would use trees to rub their tusks, horns, and bodies against the tree trunks. A baby elephant actually used a tree that its mother had toppled over to scratch its bum. Even buffalo, to my amazement, rub their horns quite low on the trunk making it easy to confuse their rubbing with other animal markings. After seeing how amimals rub against, strip, de-bark, tear, break, and topple trees on previous visits to the park, what we saw and learnt while tagging these trees puts this animal behavior into context, and measuring the damage even more so.

The trip was a huge learning experience for me and extremely satisfying. The opportunity to work in the field was amazing, and the Kruger staff were very friendly and supportive.

To put the weeks experience in perspective:

Outdoor Leather Hat for Fieldwork - R255.00

Portable GPS - R3500.00

The look on tourists faces as they see us walking amongst elephant - Priceless".