FUELWOOD EXTRACTION AND CONSUMPTION IN THE FOREST AND SAVANNA ECOSYSTEMS, OYO STATE, NIGERIA

Abstract

Fuelwood, also known as firewood is unprocessed woody biomass and a major energy source in Nigeria. Research on fuelwood extraction has largely focused on its consequences for deforestation and climate change, while studies on fuelwood consumption have focused on household use and its effect on human health. However, studies on fuelwood extraction effects on vegetation and soils in different ecological zones are limited. This study was designed to investigate the effects of fuelwood extraction (forest and savanna) on vegetation characteristics, associated soil properties, and fuelwood consumption differentials between households (HH) and food vendors (FV) in Oyo State.

Soil-vegetation, and Driver Pressures State Impact and Response (DPSIR)theories provided the framework, while a mixed-method design was adopted. A fuelwood Exploited Forest (EF) ecosystem site in Igbo-Oloyin (Ibadan) and fuelwood Exploited Savanna (ES) site in Iseyin were purposively selected based on the outcome of an Ibadan fuelwood merchants’ survey. Control sites for exploited forest (CF) and control sites for exploited savanna (CS) were appropriately located. Using a 400 meter transect, 12 (20m x 20m) sample plots were laid out in each of the EF, ES, CF and CS. Measurements of Tree Height (TH), Diameter-at-Breast Height (DBH) and tree species count were conducted in the plots. Five topsoil samples were taken from each plot and bulked to form a composite. Using standard procedures, soil physical (sand, silt and clay, bulk density), and chemical ((Organic carbon (SOM), total nitrogen (N), available phosphorus(P), exchangeable calcium (Ca), potassium (K), sodium (Na), cation exchange capacity (CEC), extractable iron (Fe)) properties were analysed. Questionnaire was administered to 200 purposively selected household-heads and 200 randomly selected food vendors drawn from the list of Canteen Workers Association in Ibadan - a major fuelwood consumption centre. Descriptive statistics, student t-test, Mann-Whitney techniques were used to analyse the data at p≤0.05.

Household-heads and food vendors were aged 40.8±0.8 and 45.0±10.5 years respectively. Tree height in ES and EF were 4.8±0.3m and 10.04±0.5m; DBH were 25.3±0.4cm and 53.0±3.0cm respectively. There were significant differences in TH for EF (t(11)=19.40) and ES (t(11)=4.36) as well as for DBH in EF (t(11)=1.03) and ES (t(11)=64.03). Higher homogeneity of species were observed in EF (CV=30%) compared to ES (CV=49%). There were significant differences in soil chemical properties for EF ((SOM (t(11)=6.4), Ca (t(11)=17.95), K (t(11)=22.5), Na (t(11)=10.5), N (t(11)=182.4), CEC (t(11)=3.4)). Also, there were significant differences in soil physical and chemical properties for ES (3), Fe (t(11)=7.78)) respectively. Soil chemical properties in EF and ES varied while physical properties in EF except clay and bulk density were unchanged. There was a higher frequency of FV users (56.5%) compared to HH (5.0%). Weekly fuelwood consumption for household (13.77±10.0) was significantly lower than FV (84.1kg±103).

Fuelwood extraction alters tree structure and complexity in savannas than in forests. Chemical changes in exploited soils were more pronounced irrespective of the ecosystem type. Interventions aimed at reducing fuelwood extraction and consumption are recommended.

Keywords: Fuelwood extraction, forest and savanna vegetation, Food vendors and household fuelwood consumption Word count: 483