73 Rev. Mar. Sci. Agron. Vét. (2018) 6 (1):73-77 Assessment of gum yield of Sterculia setigera Del. in relation to diameter and trees condition W. ATAKPAMA 1 , H. PEREKI 1 , K. BATAWILA 1 , K. AKPAGANA 1 (Reçu le 06/06/2017; Accepté le 25/01/2018) Abstract Sterculia setigera Del. is well-known in Sub-Saharan Africa as a multipurpose tree species, especially due to the economic value of its gum. The present study carried out in the Kantindi experimental station was a contribution to the valorization of S. setigera in Togo. It sought to appraise the gum yield capacity of S. setigera according to stem girth and target trees’ condition. Trees tapping were carried out on forty non-burnt trees and twelve burnt trees with a girth equal or greater than 90 cm. Trees were tapped from 1 to 5 April 2014 and gum harvest occurred three weeks later, on 30 th April 2014. The mean value of gum exudate from trees early burnt is higher than those obtained from non-burnt trees, respectively 103.2 ± 68.5 g and 64.4 ± 35.3 g. Gum yield increased with diameter increase. Even thought the mean gum yield seems greater on burnt trees than non-burnt trees; the statistical tests showed no signifcant diference (p = 0.095). In contrast, there is a signifcant diference according to tree diameter (p = 0.047). Further studies will evaluate both quantitatively and qualitatively methods of gum tapping, nursery plants production, and regeneration techniques. Keywords: Sterculia setigera, gum, yield, tree diameter, ecosystem services, Togo 1 Laboratoire de Botanique et Écologie Végétale, Université de Lomé. Togo Résumé Sterculia setigera Del. est bien connue en Afrique subsaharienne comme espèce à multiples usages et en particulier pour l’importance économique de sa gomme. La présente étude, réalisée dans la station expérimentale de Kantindi, est une contribution à la valorisation de S. setigera au Togo. Elle a évalué la capacité de production de gomme de S. setigera en fonction du diamètre et de l’état du pied. La saignée des arbres a été réalisée du 1 er au 5 avril 2014 sur 40 pieds seins non brûlés et 12 pieds brûlés de circonférence g≥90 cm. La récolte de la gomme est intervenue trois semaines plus tard, le 30 avril. La valeur moyenne de gomme exsudée sur les pieds précédemment brûlés est supérieure à celle des arbres sains, respectivement 103,2 ± 68,5 g et 64,4 ± 35,3 g. La quantité de gomme exsudée augmente suivant la circonférence. Même si la productivité moyenne en gomme est plus grande sur les pieds brûles que les pieds non brûles, les tests statistiques montrent qu’il n’existe pas de diférence signifcative (p = 0,095). Par contre, une diférence signifcative s’observe en fonction de la circonférence du pied (p = 0,047). Des études complémentaires examineront les méthodes quantitative et qualitative de production de gomme, les techniques de production des pépinières et de régénération. Mots-clés: Sterculia setigera, gomme, production, circonférence, Togo INTRODUCTION It is known that poverty is one of the important causes of plant resources degradation. However, the preservation of the natural capital is one of the components of the long- lasting development, with the economic growth, social fairness, territories’ steadiness and life quality (Louina, 2006). Consequently, forest genetic resources management is a priority. This challenge could be achieved by providing to indigenous, often poorest population, a sustainable in- come through the promotion of non-timber forest products (NTFPs). There is a wide range of NWFPs with a great economic importance such as gum provided by several tree species. One of these gum species found in West Africa is Sterculia setigera Del. S. setigera is a multipurpose and valuable savannah tree belonging in the Sterculiaceae family (Cronquist, 1968) or in the Malvaceae family (APG III, 2009), growing under wide ranges of soils and ecological ecosystems. However, it enfolds gravelly soils and rocky hills (Sacandé et Sanon, 2007). It is mainly known in sub-Saharan Africa for its medicinal uses and gum economic value (Henric, 2001; Tor-Anyiin et al., 2011; Atakpama et al., 2012; Hamidu, 2012; Atakpama et al., 2015; Ndiaye et al., 2012). It is also used for cosmetic, fodder and cultural purposes (Idu et al., 2008; Mbow et al., 2013a; Mbow et al., 2013b). S. setigera is recognized as a high economic value species and it gum is exploited since several decades in Senegal (Henric, 2001). Sterculia gum commonly known as ‟gum karaya” (Jonhson et al., 2005) is an important raw material used in cosmetic, pharmaceutical and food-processing industries due to its phytochemical and physical properties (Elkhalifa et Has- san, 2010). The production of Sterculia gum is localized mainly in India (S. urens) and Senegal (S. setigera) and re- mains consequently, a meaningful asset for exports (Gomis, 2004). Senegal is the major producer of ‟gum karaya” in Africa and the second world’s largest producer (1500 tons per year) after India (3500 tons per year) (Jonhson et al., 2005; Niang et al., 2010). Considering incomes generated by the yield of gum, a reasonable exploitation of S. setigera gum can occupy populations, particularly peasants during the free time (Sène et Ndione, 2004), generate supplement income, and create employments. Évaluation de la productivité en gomme de Sterculia setigera Del. en fonction du diamètre et de l’état de l’arbre