Spatial Distribution of Pterocarpus erinaceus Poir. Natural Stands in the Sudanian and Sudano-Guinean Zones of West Africa: Gradient Distribution and Productivity Variation across the Five Ecological Zones of Togo - Segla, Kossi Novinyo; Adjonou, Kossi; Rabiou, Habou; Radji, Abdou Raoufou; Kokutse, Adzo Dzifa; Bationo; Ali, Mahamane; Ouinsavi; Kokou, Kouami (Advances in Agriculture and Fisheries Research Vol. 1, 2020)