Browsing by Author "Onilude, Q. A."

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Evaluation of height-diameter models for community Parkia biglobosa Jacq B. plantation in wasangare, Oyo State.
(Northeast Forestry University and the Ecological Society of China in collaboration with Springer Verlag., 2023) Onilude, Q. A.; |Ige, P.O.; Alo, A.A.
Forest growth and yield models are fundamental tools for sustainable forest management planning and future inventory assessments. In order to quantify the growing stock of Parkia biglobosa in Wasangare, Oyo state, reliable height-diameter (H-D) models are required. Therefore, the aim of this study was to evaluate 2-parameter H-D models for the prediction of heights of Parkia biglobosa tree which are consistent with current forest management practices in the country. Measured 1,196 pairs of height and diameter data were subjected to six (6) 2-parameter H-D models viz Naslund, Meyer, Curtis, Modified Log Logistic, Michaelis-Menten and Wykoff. Model fitting and validation was done in ratio 75:25. With the use of R software tools, the fitting and validation was done. Root mean square error (RMSE), mean absolute bias (MAB), Akaike information (AIC) and Bayesian information criterion (BIC) were used to assess the models. The result showed that all the models were significant but based on the goodness-of-fit statistics, Meyer H-D model had the least rank value, followed by the Modified log logistics H-D (M. LogL) model. The Meyer H-D model had RMSE, MAB, AIC and BIC of 2.996, 2.389, 4520.263 and 4524.660 respectively while M. LogL HD model had 2.999, 2.421, 4522.082 and 4536.480 respectively. Therefore, it was concluded that Meyer H-D model and M. LogL model written as and, respectively were selected as the best candidate models for H-D relationships of Parkia biglobosa plantation especially in the savanna zone of Oyo state.
Stand growth, Biomass and Carbon sequestration potentials of Parkia biglobosa (jacq.) Bench plantation in South-Western Nigeria
(Joint Coordination Centre of the World Bank assisted National Agricultural Research Programme (NARP), 2024) Akintunde-Alo, D. A.; Onilude, Q. A.; Ige, P. O.; Adeoti, O. O.
This study assessed tree growth variables, above (AGB), below ground biomass (BGB) and total carbon content (TC) sequestered by Parkia biglobosa (Jacq.) Bench. Plantation in Wasangare, Oyo State using nondestructive ground base survey. Tree growth data (Diameter at breast height, Dbh and Tree height, Th) were collected using lacer ace hypsometer and diameter girth tape from 20 temporary sampling plots of size 25 m X 25 m established through systematic transect lines. Diameter size classes (DSC) for the plantation was examined, carbon stock for each DSC was also determine while basal area (m2 ha-1), volume (m3 ha-1), Biomass (Mg ha-1) and Carbon (Mg ha-1) were also estimated. Results showed mean Dbh of 18.7 + 0.25 cm with 8.14 + 0.10 m, 0.033 + 0.00 m2 ha- 1 and 0.320 + 0.01 m3 ha-1 for tree height, basal area and volume respectively. AGB and BGB were 10.877 + 0.39 Mgha-1 and 2.175 + 0.08 Mgha-1 respectively while TC was 6.527 + 0.24 Mgha-1. The percentage carbon stock proportion for each DSC revealed class size 25-29-9 cm (19.02%) as the highest while the least proportion was observed in less than 5 cm class with 0.04% of carbon. The DSC showed majority of the tree Dbh in lower Dbh classes with fewer trees in higher classes forming almost a normal bell shape. The study provides information that can help the management in planning silvicultural activities and selective removal from the stand (harvesting schedule). Tree Dbh, height, basal area, volume and biomass are the determinant characteristics for forest carbon assessment. In conclusion, the plantation actively sequesters carbon showing potentials for indigenous trees in climate change mitigation.