Carbon stock in topsoil, standing floor litter and above ground biomass in Tectona grandis plantation 10-years after establishment in Ile-Ife, Southwestern Nigeria

This paper provides information on carbon stock at the habitat level in the above ground biomass (ABG), standing floor litter and soils in a 10 year-old Tectona grandis plantation following restoration of a degraded secondary forest at Obafemi Awolowo University, Ile-Ife Nigeria. Four sample plots 25 m x 25 m, two in Tectona grandis plantation and two in a nearby degraded secondary forest were studied. Soil samples were randomly collected at 0-20 cm and bulk density determined. Standing floor litter was randomly collected at five points every three months for one year, sorted into different litter components. Soil and standing floor litters carbon concentration and C stock were determined. Above ground biomass (ABG) and carbon stock were significantly (p=0.003 and p=0.0001) higher in the plantation, the order is ABG > soil > standing floor leaf litter > standing floor wood litter. Soil C stock varies from 10.47 t ha-1 in the plantation to 10.58 t ha-1 C in the forest. Above ground biomass, standing leaf and wood litter were estimated as 18.26-5.81, 0.49-0.36, 0.06-0.08 t ha-1 C, respectively (plantation to secondary forest). Reforestation after 10 years has increased C stocks by 45% in ABG in the plantations.Keywords: Carbon stock, degraded forest, plantation, reforestation, standing litter

Effect of air pollution on the foliar morphology of some species in the family Euphorbiaceae in southwestern Nigeria

Morphological studies of the leaves of ten species in the family Euphorbiaceae collected from three different locations with different pollution levels in Southwestern Nigeria were carried out in order to establish the effect of air pollution on these species. The study was carried out in both dry and wet seasons. Climatic data and pollutants concentration levels of the study sites were determined. Leaf area of all the species was measured using an established nondestructive method while petiole length was determined using metric ruler. The result showed that most species showed significant reductions (p<0.05) in the leaf area and petiole length across the three locations and this reduction is from rural to sub-urban to urban areas. Among all the species that showed reductions in leaf area, Alchornea cordifolia showed the highest response while Euphorbia hyssopifolia, E. hirta and Croton lobatus do not show clear reductions. Similar significant reductions were recorded for petiole length with the highest impact recorded in Manihot esculenta while species like E. hyssopifolia, E. hirta, C. lobatus and Flueggea virosa were not significantly reduced. This study showed that plants generally respond to air pollution with reduction in foliar morphology and the response is species specific.Keywords: Pollution, leaf morphology, Euphorbiaceae, leaf area, petiole lengt