Evaluation of Catchment Afforestation Potentials of Seedlings of Three Native Tree Species under Different Soil Moisture Conditions

In many parts of the world, key water catchments and watershed ecosystems have been degraded by successive waves of anthropogenic activities, thus requiring rehabilitation. One of the drawbacks of rehabilitation of degraded catchments is the lack of information about species suitable to local conditions. This study was designed to evaluate the catchment afforestation/reforestation potentials of three native tree seedlings under different moisture levels. In a complete randomised design (3 species x 4 treatments x 12 replicates) in a shade house, 144 pots with fairly uniform actively growing seedlings of Markhmia tomentosa, Funtumia Africana and Prunus Africana were treated to 4 soil moisture levels, corresponding to12.5, 25, 50 and 100% field capacity determined gravimetrically. Growth parameters (collar diameter, height and number of leaves) were measured fortnightly, while leaf area, biomass components and their derivatives were measured destructively after six months of growth. The seedlings’ rate of transpiration and evapotranspiration (gH2O/s/m2) were determined gravimetrically and water-use efficiency derived (g/L). The general effects of the soil moisture capacity on the growth performances were significantly different at P < 0.001. Markhmia tomentosa showed maximum leaf number (42) and leaf area (10712.8 cm2, 25% treatment), collar diameter (17.8 cm) and root shoot ratio (2.8, 50% treatment). Funtumia africana at 50% soil moisture capacity showed maximum height (88.6 cm) and total biomass (60.3g). Prunus africana had the least growth performances. Markhmia had the maximum rate of transpiration (12.69 gH2O/s/m2), evapotranspiration (14.20 gH2O/s/m2). Funtumia gave the best water-use efficiency (176.5 ml/g). Their least values were observed in P. Africana.  Funtumia africana had the best water use efficiency while Markhmia tomentosa had the best root development. These two species would be suitable for the afforestation/reforestation of water catchment areas in Cameroon at low altitude while P. africana, naturally adapted to high altitudes require further investigations.