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Hagen, E - Baobob tree

Page history last edited by PBworks 11 years, 10 months ago

 

Adasonia digitada

 

Ethan Hagen

 

 

                I chose Adasonia digitada because this plant is a dominating form in the African landscape and it sparked my interest because of its enormous size and odd branching patterns.  The common names for Adasonia digitada are the common baobab tree, monkey-bread tree, dead-rat tree, and cream-of-tartar tree (Bosch, C.H. & Sié, K. & Asafa, B.A., 2004). However this term is used to describe the whole genus and is therefore a general term. Adasonia digitada is the most common species in the Adasonia family and is located in Africa. The countries in Africa where it is not found are mostly along the Mediterranean such as Egypt, Libya, Tunisia, Morrocco, Algeria, and Western Sahara, in the south such as South Africa, Lesotho, and Swaziland and in central Africa such as Rwanda, Burundi, Djibouti, and Uganda. The odd distribution is due to human introduction and spread of Adasonia digitada to Central Africa and the islands.  This plant is found only in hot-frost free areas and is indigenous to very dry areas with well-drained soils. It is naturally located in the Afrocentric region in tropical & subtropical grasslands, savannas, & shrublands and desert and xeric shrublands (Palmer, E. & Pitman, N. 1972) but can and is cultivated throughout the world including the U.S. anywhere that meets those conditions. 

 

 

Figure 1: Range of Adasonia digitada.

( Bosch, C.H. & Sié, K. & Asafa, B.A., 2004.)

 

 The common baobab has four stages of growth.  The sapling phase lasts 10-15 years. The second phase, known as the conical phase, will last until the tree is 60-70 years old.  Adasonia digitada will grow the most during this time and achieve its maximum height.  The third phase is the bottle phase where the canopy expands horizontally and the trunk girth increases.  This lasts until the tree is 200-300 years old.  The old age phase sets in after this as the tree begins to hollow and decay.  Baobabs will live to be 500-800 years old but there are many that live much longer some estimated to be as much as 5000 years old (Bosch, C.H. & Sié, K. & Asafa, B.A., 2004).

Adasonia digitada flowers at any time during the year except during the extreme dry season and usually leaves will appear shortly after.  The flowers smell like carrion and are pollinated mainly by bats though bushbabies, wind, and insects also play a part (Bosch, C.H. & Sié, K. & Asafa, B.A., 2004).  The 12cm egg shaped fruits contain many kidney-bean sized seeds that are spread mainly by elephants and baboons naturally, however most of this species spread is due to human cultivation.

           Adasonia digitada is a fairly common tree that is cultivated for many uses.  It is not considered either rare or invasive.  Almost any part of Adasonia digitada can be used as a source of food.  The leaves are either boiled or dried and eaten as a cooked vegetable or in soups as flavoring.  The flowers are eaten raw and roots are sometimes boiled and eaten.  The large baobab fruit is sweet and is consumed by using it in making gruel and refreshing drinks and ice-cream. The seeds are eaten raw, dried in soups, made into oil or fermented and drank.  A unique trait of Adasonia digitada pertains to its enormous trunk size. The trunk has been hollowed and used for houses, prisons, pubs, storage barns, and water tanks.  The purpose of the large trunk is to store water for the tree and they are sometimes tapped for this resource. 

 

 

Figure 2: Adasonia digitada fruit (Hanky, Andrew 2004)

The bark is also used for a variety of purposes including rope, string, cords for musical instruments, snares, fishing-nets, loin cloths, sacking, baskets, mats, roofing and waterproof hats (Venter, F. & Venter, J. 1985).  Adasonia digitada also is used profusely in medical compounds aimed at a number of ailments such as malaria, asthma, fatigue, kidney and bladder diseases, diarrhea, inflammations, and hangovers.  The baobab tree is a striking presence in any landscape and especially in the grasslands of Africa.  Its useful properties ensure its prominence in African society which will guarantee its survival in the foreseeable future.

Figure 3: Adult Adasonia digitada (Hanky, Andrew 2004)

 

 

            Adasonia digitada lives in very arid climates that have stony and sandy soil substrates.  There are periodic rainy and dry seasons and its life cycle is closely correlated to this. However, it will not live on soils that have deep sandy horizons because of anchorage requirements.  It is able to survive in these environments because it is deciduous and can store vast amounts of water in its trunk (Hanky, Andrew 2004). 

            While Adasonia digitada is not currently threatened, it faces the same basic problems that nearly every other species on the planet faces; humans.  Humans have cultivated this species for thousands of years but overuse of this resource could potentially spell destruction for this species. Deforestation, overpopulation and overgrazing all are potential threats that if not properly mediated could have negative impacts of the population.  While Adasonia digitada is subject to attacks by most insects that prey on cotton and cocoa plants, these attacks are only rarely fatal.  Adult trees main threat is the grazing done by the elephants who strip the bark.  Recently, a trend has been noted in the increase of a fatal fungal disease known as sooty mould.  This is a secondary infection that appears on stressed trees and occurs during the dry season and results in the death of the tree.  This increase is thought to have occurred because of an increase in the drought season.

            The greatest long-term threat to the species as a whole is the desertification of Africa.  The alarmingly rapid spread of the Sahara Desert spells disaster not only for this species but its entire habitat.  Located only in areas that are actually xeric, or very nearly xeric due to lack of precipitation, makes this a very serious threat. Adasonia digitada lives in those areas that have a greater threat than anywhere else in the world of becoming desert wastelands.  Adasonia digitada is becoming extirpated slowly as the desert rapidly expands.

 

 

Bibliography

 

 

Bosch, C.H. & Sié, K. & Asafa, B.A., 2004. Adansonia digitata L. [Internet] Record

from Protabase. Grubben, G.J.H. & Denton, O.A. (Editors). PROTA (Plant

Resources of Tropical Africa / Ressources végétales de l’Afrique tropicale), Wageningen, Netherlands. <http://database.prota.org/search.htm>. Accessed 18 February 2008.

 

 Hanky, Andrew 2004. Adasonia digitada. The South African National Biodiversity

            Institute. [cited February 18, 2008].  Available from:

            <http://www.plantzafrica.com/plantab/adansondigit.htm>

 

Palmer, E. & Pitman, N. 1972. Trees of southern Africa, vol. 2. Balkema, Cape Town.

 

 

Venter, F. & Venter, J. 1985. Making the most of indigenous trees. Briza Publications,

Pretoria.

 

 

 

 

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