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

Aims: This study aims to analyze the structure of some populations and the natural regeneration
potentials of Pterocarpus erinaceus Poir. According to the environmental conditions, taking into
account the 5 ecological zones of Togo. Especially, it aims to: (i) Describe the geographical
distribution of the species in Togo, (ii) Analyze the influence of environmental variables (climates, soils
and type of vegetation) on the structural characteristics of natural stands and (iii) Determine the
natural regeneration potentialities of the species.
Place and Duration of Study: Fieldworks were done from 10 October to 15 December 2013
throughout Togo.
Methodology: Forestry inventory was carried out on 200 plots of 1000 m2 randomly set up in P.
erinaceus natural stands in the 5 ecological zones of Togo. In each plot, total height, the
merchantable height and diameter at breast height (DBH) ≥ 10 cm were measured. The regeneration
was studied in sub-parcels of 25 m2 set up in the previous parcels of 1000 m2. In these sub-parcels,
the natural seedlings, coppices, sucker which the DBH is less or equal to 10 cm were counted. The
geographic coordinates of each tree are registered with the GPS.
Results: The results show that P. erinaceus had a wide distribution and tolerance range in Togo.
Trees populations' average density is between 57±23 N/Ha and 76.5±42 N/Ha. The average
diameter, the average total height, the basal area are significantly different for the stands of the 5
ecological zones (P= 0, 00). Diameter distribution indicates a reversed-J in ecological zones 2, 4 and
5 i.e. dominated by small diameters structure of P. erinaceus (Poir.) and unimodal distribution in
zones 1 and 3. The study shows that a seedling which is the main strategy of regeneration is not
significantly different between the stands studied. Results also show a good natural regeneration
capacity of P. erinaceus by a coppice.
Conclusion: This study enables to describe the main characteristics of the natural stands of P.
erinaceus in Togo and constitute therefore a useful source of information for the management of
natural stands notably that of P. erinaceus.