Development of Diameter Distribution Models for The Management of Omo Biosphere Reserve, Ogun State, Nigeria

• A. O. Oladoye

  Department of Forestry and Wildlife Management, Federal University of Agriculture, Abeokuta, Nigeria

  Author

• S. O. Akindele

  Department of Forestry and Wood technology, Federal University of Technology, Akure, Nigeria

  Author

• V.A.J. Adekunle

  Department of Forestry and Wood technology, Federal University of Technology, Akure, Nigeria

  Author

Stem diameter distributions are highly needed in the majority of forest management decisions such as forest exploitation and predicting forest growth. This study developed some models for describing the diameter of Omo biosphere reserve in lowland rainforest ecosystem, Nigeria. Systematic sampling design was used to lay three straight line transects. Four temporary plots of 0.25ha were laid in alternating position along each transect at 100 m interval to make up a total of 12 plots for the study and the diameter at breast height (Dbh) was measured for all trees with Dbh ≥ 10cm in every plot. A total of fifty-seven species were encountered and exploratory analysis of the data collected showed that the observation was right–skewed consequently resulting in the choice of six probability diameter distribution functions using Maximum likelihood estimator. The selected distribution models are Weibull, Lognormal Distribution (LN), Gamma, Logit-logistic (LL) and Burr distribution. The Kurtosis and Skewness are 1.34, 6.43 and 2.28 respectively with a mean Dbh of 36.40cm. Burr had the lowest values of Kolmogorov Smirnov (Dn) (0.046), Anderson Darling (AD) (1.102) and Cramer-von Mises (CvM) (0.178). This is followed by log logistic with 0.05, 2.769 are 0.258 for Dn, AD and CvM respectively. High and positive skewness and kurtosis values are a reflection of abundance of trees in the lower Dbh class. These are sufficient enough to replace the trees in the upper dbh class through regeneration. Hence, the Burr and Log-logistics distributions were adjudged to be the most flexible to describe the diameter structure of the Omo Biosphere Reserve.

1. A. O. Oladoye, Department of Forestry and Wildlife Management, Federal University of Agriculture, Abeokuta, Nigeria

   Department of Forestry and Wildlife Management, Federal University of Agriculture, Abeokuta, Nigeria

2. S. O. Akindele, Department of Forestry and Wood technology, Federal University of Technology, Akure, Nigeria

   Department of Forestry and Wood technology, Federal University of Technology, Akure, Nigeria

3. V.A.J. Adekunle, Department of Forestry and Wood technology, Federal University of Technology, Akure, Nigeria

   Department of Forestry and Wood technology, Federal University of Technology, Akure, Nigeria

• PDF