Marvelous Mahogany
Khaya senegalensis
The African mahogany tree can grow to over 35 metres, it has one tap root that will extend deep into the ground if not watered too much and a multitude of shallow roots extending to the drip line. It is native to Africa and Madagascar and would appear to have been introduced to the Top End of Australia in the 1930’s possibly from Asia as the French introduced them to Vietnam. They are also found in Singapore and Malaysia.
Australia has maybe the largest diversity of Khaya senegalensis genetics due to its dwindling natural occurrence caused by over-logging in Africa
It is fast growing, needs little water and provides beautiful high shade that allows air flow as well as protection from the hot sun. It is highly prized for furniture making and construction. It’s abundance of leaves fall steadily through the year and if gathered and kept moist make amazing compost in a very short period of time.
The seeds contain oil which is used in West Africa for cooking. The tree is an important medicinal plant in Africa, the bitter bark considered a fever remedy, an anti-inflammatory and is also used as an anti-aging cream.
The young leaves, though not very tasty contain digestible protein and can be used as fodder for cattle and camels. They are useful trees in cattle stations, providing shade and a food source when nothing else is available. They easily survive without constant water and are in fact best left as dry as possible so that their tap root penetrates as deep as possible into the ground.
These trees have acquired a bad reputation as being dangerous because of their shallow root systems and dense canopies which make them prone to falling over in storms. This is an attitude born of ignorance about how to care for the tree so that it provides the maximum benefit with a minimum of risk.
The safety and well being of the tree depends on how it is cared for!
1.) It should not be watered constantly. Once established they can be left to the mercy of the rainy season. This encourages the growth of a deep tap root and thus greater stability for the tree.
2.) It should be pruned carefully. At the beginning of the dry season the heavy leaf growth should be thinned out. It should not be just lopped at the top leaving a bare stump, doing this put the trees nervous system on high alert and it starts sprouting as many leaves as possible in dense clumps. These clumps in turn act like sails in high winds and consequently limbs fall or the tree topples over bringing the roots with it.
Local Councils need to lead the way in pruning management, employing only qualified arborists to manage the trees so that we have much needed shade at minimum watering cost.
The photos below show well-pruned trees that whilst still providing high shade are thinned enough for air to circulate. This not only protects from the intense heat of the sun but also reduces the humidity in the air.
Below are before and after shots of the same tree with its canopy drastically reduced but retaining high shade and space for the winds to move through with ease.
This work was done by Brad Bain and Jordan Garret from Roebuck Tree Services. Both are qualified arborists and are passionate and truly knowledgeable about trees and how they live and function. They know how to treat a tree with respect for its particular qualities and growing habits. Their love of trees and understanding of the functions of different trees in our ecosystem is shown in how they go about their work.
In conclusion, don’t be frightened of mahogany trees, they are wonderful shade trees for this hot and humid climate and just like people and everything in nature if they are well treated they will give us not only shade but many other benefits.
