MODELS FOR GROWTH CHARACTERISTICS AND THEIR APPLICATIONS IN YIELD STUDIES FOR Pinus caribaea Morelet 1851 IN SOUTHWESTERN NIGERIA

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Development of empirical models provides ample prospects of exploring established mathematical theories and relationships among tree growth variables for sustainable forest management options. However, there is inadequate information on modelling growth characteristics and productivity potentials of Pinus caribaea, a pulpwood species which is now being proposed for timber production in Nigeria. Hence, models for growth characteristics and their applications in yield studies for Pinus caribaea in southwestern Nigeria were investigated. Sixty Temporary Sample Plots (TSPs) of size 20m x 20m each and of different Age (A) series based on stocking density were sampled from Omo Forest Reserve (n=16 TSPs -15 and 21 years), Oluwa Forest Reserve (n=36 TSPs-18, 20, 35, 36 and 37 years) and Shasha Forest Reserve (n=8TSPs-27years) in Ogun, Ondo and Osun States respectively using stratified random sampling method. Growth variables: Diameter at Breast Height (DBH), Stem Quality (SQ) and Total Height (THT) were measured in each plot and Basal Area (BA), Stem Volume (SV), Tree Slenderness Coefficient (TSC), Crown Ratio (CR), Crown Projection Area (CPA) and Site Index (SI) estimated. A total of 1,592 trees were enumerated and each tree per plot classified into four canopy layers as dominant, co-dominant, intermediate and suppressed. Data obtained were used for modelling and categorized into individual tree level, size class level and whole stand level with Maximum Likelihood Estimation (MLE) technique adopted in 3-parameter Weibull Probability Distribution Functions (WPDF). Data were analysed using descriptive statistics, ANOVA, correlation and regression analyses at α0.05.

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