Tag: Baobab Science and Research

Measuring Baobab girth

It feels a bit like when you mark off the height of your children on the doorpost, but every year in May Diana Mayne, a baobab colleague, and I visit Skelmwater Baobab research plot to do annual growth measurements. This research plot was started in 1931 to measure the annual diameter growth of baobabs. This year was the 83rd measurement and most of the trees got a bit wider due to the good rains, but some years if its very dry, the trees shrink. This little tree is the smallest tree on the plot.

Miracle Tree!

A few years ago I was called by a local farmer to see some baobabs that were very ill and dying.  There was a group of four baobabs, some of them were still standing and others had already collapsed in to a heap of fibre.  This tree was still standing, but was hot and ‘sweaty’ with droplets on its bark, almost as if it had a fever and I did not think it was going to survive.  This year I visited the site again and found the tree well recovered. They really are remarkably sturdy and resiliant trees!  After decades of living with them and many many years of studying them, I still see there's so much more to learn and wish we understood these trees better…

Monitoring with baobab harvesters

Last week I did my annual baobab fruit monitoring trip where I gather research information on a spcecific population of 40 baobab trees.  This year I am looking at how much fruit each tree produces each year and how that varies from season to season and between land use types.  Usually I have a field assistant whom I hire from the village, but this time I decided to train some of the fruit harvesters how to do the monitoring.  They found it really interesting and now have a better understanding of resource management.   It's part of a long-term development plan and very important for the harvesters to know how to monitor as one day they will be doing all the monitoring themselves! 

 

Where did that baobab come from?

There are 8 different species of Baobab trees 6 of which are native to Madagascar, one in Africa and one in Australia. There’s a lot of controversy about where the Baobab tree originated  as it’s often been assumed that Madagascar is the centre of origin because it has the most different species. This implies that Adansonia digitata migrated from Madagascar to Africa. It’s been estimated that the divergence between the African Adansonia digitata and the Madagascan trees occurred about 10 million years ago dating well after the breakup of Gondwana and the separation of Madagascar from Africa which happened about 100 million years ago. However, in 2009 a group of researchers lead by Jean-Michel Pock Tsy conducted research and their findings strongly suggested that the centre of origin of baobab is actually West Africa. With the species being distributed by humans travelling across Africa. Recent studies clearly indicate that most of Madagascar’s plants descended from ancestors that have colonized the island from overseas. So Africa is in fact the most likely cradle of the Baobab tree! 

What’s in a name: Adansonia digitata

The latin name, Adansonia digitata, was given to the baobab by Carl Linneaus.  He named the baobab after the a French naturalist Michel Adanson.  Adanson was posted to Senegal in 1749 to research the natural resources of the area. He was blown away by his first sight of a baobab describing it as "a forest in itself”. This description of the tree reached Linneaus while Adanson was still in Africa, However when Adanson retuned to Europe he opposed the name, suggesting it be named baobab from the earlier description made by Alpini.  But Linneaus would not change his mind and thus the genus continues to be known as Adansonia. 

The specific name for this species is ‘digitata’ from the palmate shaped leaves which look like a hand with digits (fingers).  

Source: Watson, 2007

What’s in a name: baobab

Across Africa baobabs are known by many different names and we know that the fruit have been used for thousands of years. However, the first detailed botanical descriptions were made by Prospero Alpini, a 16th Century physician and botanist living in Venice who spent three years in Cairo. He first saw the fruit being sold in the Cairo Souks and came to know them as ‘bu hubab’, meaning “having many seeds” in Arabic.  And hence the common name ‘baobab’

Source: Watson, 2007

The real truth about water in baobab trees

baobab water storage

 

There’s a bit of a myth out there that you can tap water out of a baobab which is illustrated by this delightful cartoon.

The truth is that a freshly felled baobab trunk weighs about 850kg per cubic meter.  Once dried out, it weighs 200kg per cubic meter.  This means that baobabs are able to store 650 litres of water per cubic meter of tree.  In other words the tree consists of 76% water which is a lot!   But even though it has so much water, it is sadly not available for us to drink just like that.  Baobabs are actually very careful with how much water they use; they have ‘tight stomatal control’ (sounds like pinching my bladder).  The two most important functions of their stem water is to keep them standing upright and to help them flush new leaves at the beginning of the growing season.   They often shrink when this happens. 

Baobabs also store water in natural hollows between branches and on the outside for the trunk.  In very arid areas people often cut hollows into baobabs to create storage ‘wells’ to catch rainwater and perhaps this is where the myth began that Baobab trees can offer drinking water to passing animals and humans. 

Encounters with a family tree

When I was visiting friends in Cordoba, Argentina recently I came across this tree that looked so much like a baobab that I thought it must be some relation.  When I looked it up, I found it was indeed part of the same family as the Baobab Malvaceae. Its scientific name is Ceiba speciosa commonly known as palo borracho which means “drunken stick” in Spanish.  It is thought that baobabs (before they were baobabs) originated in South America and hence their relations are found here.

The palo borracho occurs in Argentina, Bolivia, Paraguay, Uruguay and Brazil.

Its trunk is bottle shaped, much like the baobab, but with swelling at the bottom of the trunk which makes it look like it may fall over, hence the name.  It never gets as big nor as old as a baobab and is studded with thick thorns along its trunk which store water.  Like the baobab there is chlorophyll just under the bark of the trunk which may allow it to photosynthesize when it does not have leaves.

The fruit and leaves also look like that of baobabs, but the fruit does not have the wonderful nutritious content our trees have.  The palo borracho fruit are filled with masses of fluff that looks like cotton. Meeting it unexpectedly while out exploring was almost as exciting as meeting a far distant member of my own family tree!  

Brief Beauty

In contrast to the solid bulkiness of the tree, the Baobab’s flowers are delicate and fragile looking. The pendulous white flowers, centred with a soft brush of bright yellow pollen, bloom for just 24 hours before falling gracefully to the ground.  The waxy white flowers appear in spring or early summer. The buds start to open in the late afternoon, the flowers opening completely at sunset to be pollinated at night by fruit bats and several species of bushbaby. By the next afternoon they have wilted and fallen, their work completed. 

How fat are baobab trees?

This week I did my annual trip to Skelmwater.  This is a baobab research plot situated near Musina long the N1.  Skelmwater was established in 1930 by the late Professor de Villiers of Stellenbosch University.  The aim was to measure the rate of growth of baobabs in their natural environment.   Despite the small number of baobabs in the plot, the long term observation has provided invaluable data in growth, health, reproduction and the effects of climate.  Dr Diana Mayne and I have been doing the measurements at the plot since 2002. Can you believe that this little tree (see photo with my field assistant Alexio Gundani) has been measured for 83 years, carbon dating results show that this tree is 130 years old! I hope to do the 100th year measurement in 17 year’s time when I am 57 years old, I should still be feeling young!

Featured in Forest Ecology and Management Journal

I'm really pleased to announce that my article on my scientific research findings regarding the sustainability of the Baobab Tree population has been recently published in the science journal Forest Ecology and Management. 


This journal has a very rigorous selection process and acceptance is based on relevance, whether your article can demonstrate a genuine contribution to scientific knowledge, originality and most importantly has to have a high impact factor in order to be considered for publication. Articles also have to be peer-reviewed by other scientists in your field before it can be accepted.  It took me 3 years to collect the data and around 6 months to write the article (which happens to be the last chapter of my thesis) so having it appear in a journal of this calibre gives my work great credibility and I'm delighted! Click here to link to it: http://buff.ly/12GcyMI

Baobab Fruitfulness

How old were your parents when you were born?  Not as old as the Baobab tree has to be before it's capable of bearing fruit. It can take a Baobab tree up to 200 years before it produces its first green-brown velvety pod-shaped fruit.  January is when Baobabs start to fruit and fruit production is highly variable between trees. Some trees never produce fruit even though they flower every year. Some trees produce only a few fruit a year and others produce huge quantities. I have been monitoring baobab tree fruit production in Venda for 7 years. The record was 1200 fruit on one tree, but this was highly unusual. Mostly they average about 65 fruit per tree per year. EcoProducts only ever harvests fallen fruit to avoid harming the parent tree.

AT WHAT AGE DO BAOBAB TREES START TO PRODUCE FRUIT?

Flower and fruit production usually only takes place once a tree is a certain size. Baobab tree growth is dependent on access to water. Where trees grow in high rainfall areas (+1000mls …per year) baobabs can reach maturity much more quickly than in arid areas. We have worked out that in Venda where rainfall is 350ml per year it can take a ‘young’ baobab 200 years before it produces its first baobab fruit ! Here is a picture of a youthful 180 year old tree. It gives you a real sense of how easily we take the resources of nature for granted without appreciating the energy and time nature puts into the creation of what we harvest.

 

HOW ANCIENT ARE BAOBAB TREES REALLY?

I often get asked how old baobabs become. There is a lot of myth with most people believing that they live for up to 5000 years. I have been working with Dr Adrian Patrut, who has made it his mission to find the oldest baobab in the world. He has been at this for about 10 years, sampling trees all over Africa and publishing his results in Scientific Journals. So far the oldest tree dated was the multi-stemmed Glencoe Tree near Hoedspruit that was dated to 1800 years old.(see pic).  In Venda people often say that they live forever. I like to believe they do.

Interesting baobab tree roots

On my field trip a few weeks back we went into northern Venda which was very badly struck by the recent floods. Many roads were washed away and people's houses damaged. I came across this uprooted baobab. It was in a sandy area so when the floods washed around its roots it just toppled over! Notice the masses of adventitious tree roots extending horizontally out from the main tuber. Baobabs have a shallow and very wide spreading root system so that they can immediately take up the first rains of the season. Unfortunately, this one got taken out instead!

Dr Sarah Venter

How do I measure the height of a baobab?


Have just returned from a truly inspiring research trip on Quilalea Island where I studied and reported on 56 Baobab trees. One of the many measurements I do is to measure the height of a baobab. It's a question I'm often asked: how does a short person like me manage this?  Well, I don't climb the tree with an extremely long tape measure as has been suggested!

I use a clever little device called a clinometer. I stand exactly 15m away from the tree and look up through the clinometer to the top of the tree, the clinometers calculates the height of the tree by using 1) the distance from me to the tree (15m) and 2) the angle from me to the top of the tree – its basic trigonometree!