Khaya senegalensis, also known as Senegal mahogany, is a tree that grows to be about 30 meters high with a 3 meter girth (Gaoue, Ticktin, 2007: 425). Its bark is very rough, scaly and dark grey. The species also has a dense crown of leaves, which is high up on the tree. Its flowers are white and sweet-scented, and its fruit changes from a grey to a black as it ripens (Gaoue, Ticktin, 2007: 425).
Khaya senegalensis is native to central African countries (Nikles 2008: 34). The three main regions of this part of Africa are known as the Guineo-Congolean, Sudano-Guinean, and Sudanian regions (Gaoue & Ticktin, 2007: 425). The species can thrive from sea level up to 1800 meters in elevation. It is known to also thrive in a variety of different soils including dry deserts, forests, and higher-rainfall savannah woodlands. It is also very resistant to flooding and is sometimes considered for planting on swampy soils. It is tolerant to rainfall of up to 1750mm, however it can survive in dry areas (Nikles, Bevege, Dickinson, Griffifths, Riley, & Lee, 2008: 34). The Sudano-Guinean woodland region is comparably wetter, with a rainfall of 1100-1300mm, than the dry Sudanian region in the savannah that has a rainfall of 800-1100mm (Gaoue & Ticktin, 2008: 35). The more environmentally stressful region of Sudan yields fewer fruit and seeds from its trees when compared to the less stressful region of Sudano-Guinean (Gaoue & Ticktin, 2008: 37).
This species is listed as vulnerable because of harvesting for timber, fuel, dyes, tannins, fodder, and medicinal uses (World Conservation Monitoring Centre, 1998; Gaoue & Ticktin, 2008: 34-35).). Khaya senegalensis bark is used to treat malaria, intestinal diseases, and anemia (Gaoue & Ticktin, 2008: 34-35). The bark also feeds many African native’s cattle, and the whole tree can be cut down for lumber (Gaoue & Ticktin, 2008: 34). The bark is also believed to cure some livestock diseases (Gaoue & Ticktin, 2007: 425). Livestock is a main source of income for West African Fulani (Gaoue & Ticktin, 2008, 2009: 34, 425). Fulani also gain income by selling milk from their livestock, and to increase milk production they feed their livestock Khaya senegalensis leaves (Gaoue & Ticktin, 2009: 258). Khaya senegalensis is illegally harvested by commercial companies for lumber (Gaoue & Ticktin, 2007: 425).
A study was conducted in the Republic of Benin in West Africa to quantify harvest patterns (Gaoue & Ticktin, 2007: 425). Density of Khaya senegalensis also changes depending on region and harvest intensity (Gaoue & Ticktin, 2007: 431). In both the region of Sudanian and Sudano-Guinean, all of the trees in the largest size-classes were harvested (Gaoue & Ticktin, 2007: 428). Of the high harvest populations in both the Sudanian and Sudano-Guinean regions the percentage of trees pruned was 58%, the percentage of debarked trees was 18%, and the percentage of trees pruned and debarked was 13% (Gaoue & Ticktin, 2007: 428). Of the low harvest populations of the Sudanian and Sudano-Guinean regions the percentage of trees pruned was 5%, the percentage of trees debarked was 10%, and the percentage of trees pruned and debarked was 13% (Gaoue & Ticktin, 2007: 428). Local harvesters prefer to debark larger trees, with most trees being harvested for 50% or more of their trunk bark (Gaoue & Ticktin, 2007: 430). Partially debarked trunks recovered and regrew half of the wound, unlike a tree that has been debarked across its entire circumference; which are known as ringbarked trees (Gaoue & Ticktin, 2007: 428). The removal of bark exposes the internal structures of the species which could lead to fungal attacks, parasitic attacks, and severe dryness (Gaoue & Ticktin, 2008: 35).
High harvest rates across the Guineo-Congolean, Sudano-Guinean, and Sudanian regions of West Africa affect the reproduction rates of this species and can decrease fruit and seed production (Gaoue & Ticktin, 2008: 34). Percentage of fruiting trees varied from each region and its harvest intensity (Gaoue & Ticktin, 2007: 45). In the Sudanian region, high harvest locations had about 25% fruiting trees and low harvest locations had about 32% (Gaoue & Ticktin, 2008: 45). In the Sudanian-Guinean region, high harvest locations had about 5% fruiting trees, and low harvest locations had about 32% (Gaoue & Ticktin, 2008: 45).
Now that Fulani harvesters are noticing a decrease in population, these people are choosing to harvest smaller trees (Gaoue & Ticktin, 2007, 2008: 39, 430). This choice in smaller trees prevents the high risk involved with climbing and harvesting bark (Gaoue & Ticktin; 2009: 258). Pruning requires skill and experience because of the difficulty involved to climb Khaya senegalensis (Gaoue & Ticktin, 2007: 432).
Fulani have kept the tradition of leaving the top branches of the tree unpruned, which they call “sopoodu”, in order for the tree to continue to reproduce and grow (Gaoue & Ticktin, 2007b: 433). About 75-99% of the Khaya senegalensis population has “sopoodu” in Benin (Gaoue & Ticktin, 2007: 433). Fulani believe that pruning and harvesting increases quality and quantity of leaves produced (Gaoue & Ticktin, 2009: 260). Although the Fulani believe that protecting this tree is important, they do not believe that the level of harvesting will decrease because of the many helpful uses it provides to the people of Benin (Gaoue & Ticktin, 2009: 260). This species, with a vulnerable status, could be saved by passing down the tradition of leaving “sopoodu” on the tree after harvesting and planting new trees around native’s homes (RedList, 2014, Gaoue & Ticktin, 2007: 433). Fulani also state that populations are decreasing because of international logging pressure for use of furniture, trim, plywood, decorative pieces, and boatbuilding (TheWoodDatabase 2015; Gaoue & Ticktin, 2007: 39).
Some areas protect the species by only allowing restricted access to the area and use of its resources. For example, conservation of Khaya senegalensis is becoming a priority in Kainji Lake National Park, Nigeria (Amusa, 2010: 182).
