Search results

Search:
in the keywords: basal area

Sort By:

Limit search:

Individual tree basal area equation for a young Tectona Grandis (Teak) plantation in Choba, Port Harcourt, Rivers State, Nigeria

100%

Oyebade B. A., Anaba J. C.

World News of Natural Sciences

2018

vol. 16

130-140

An individual Tree Basal Area Equation was developed for a Young Tectona grandis plantation of the Department of Forestry and Wildlife Management, Faculty of Agriculture, University of Port Harcourt (UNIPORT) Choba, Rivers State; using diameter at breast height (dbh), diameter at the base (db), crown diameter (CD), and crown projection area (CPA) as predictor variables. The individual basal area estimates were obtained from data collected from 437 trees in the five-year-old plantation of dimensional area of 2737.5m2.The individual trees were measured for dbh, CD, and db using traditional measuring techniques, while individual Basal Area (BA) and CPA were estimated from the data sets. The data collected were further subjected to descriptive, correlation and regression analyses with different empirical models, using STATISTICA statistical package. The results of the descriptive analyses produced a mean values of DBH of 7.89±0.0097 cm, BA with the mean value of 0.0052±0.0001 m2, DB with 32.64±0.397 cm, CD of 3.1004±0.041 m and CPA with a mean value of 8.1268±0.215 m2. The results of regression analyses and modelling with empirical non-linear basal area equations fitted with Quadratic models, Exponential models, Linear Fit models and Polynomial models on STATISTICA produced best fits estimates in accordance with residual analyses and fit indices such as Mean Prediction Residual (MPR), Standard Error of Estimate (SEE), Residual Coefficient Variation (RCV) and Prediction Sum of Squares (PRESS). The Quadratic equation (BA = bo + biCPA + DB2; R2 - 0.8959; SEE - 0.0004) after the evaluation procedures gave the most robust fit indices for the individual basal area, and was thus adjudged the best individual basal area equation for Tectona grandis plantations in the study area. This study has shown that the selected model can be effectively used for predicting individual tree basal area of Tectona grandis both within the study area and in any other Tectona grandis plantations and, hence, for management and for making timber harvest decisions.

Tree basal area models and density for selected plantation species in swamp forest zone of Rivers State, Nigeria

63%

Oyebade B. A., Eguakun F. S., Duru B. N.

World News of Natural Sciences

2020

vol. 30

issue 2

271-286

Individual-tree models of basal area growth and density were developed for seven plantation species in swamp forest zone of Rivers State, Nigeria. Tree growth data were collected from pure permanent sample plots of seven plantation species within the study area with measurements of diameter at breast height (cm), diameter at the base (cm), total height of tree (m), and also the number of tree per plot was taken and obtained from plantation records. The Quantitative data collected from these selected plantation species were subjected to descriptive analysis, correlation and regression analyses. Linearized models for description of relationship between BA and other growth attributes were developed. The results of the major growth variables by species in the study area showed that Treculia africana has the highest dbh mean value 30.804 ±2.031 (cm) with density 0.0022 and basal area per hectare 1.79×10–4 (m2). Similarly, the results also showed that Nauclea dedirrichii has the lowest dbh mean value 08.484 ±0.339 (cm) with basal area 3.92×10–5 (m2) and density 0.0063 per hectare. The results of correlation analyses showed general associations between basal area and the growth attributes by species with coefficients of correlation ranging from –0.023 to 0.999. The results similarly revealed distinct variations by species in density, basal area and tree number in the study area. The results of relationship between basal area and other growth variables showed significant model fit (best fit) with diameter attributes with model order: LNBA = b0 + b1lnDb + b2Dbh2 in Enthandrophragma angolense (R2 - 0.964, RSME – 0.837). The results of the study revealed that there were significant variations in the growth attributes by species in the study area; with significant associations between the basal area and major growth variables evaluated in the study, while the selected best adjudged fit model in the study area could be reasonably used for predicting basal area which is critical in cubical volume estimation and sustainable management of the study area.

Refine search results

2 World News of Natural Sciences

1 2020

1 2018

2 Oyebade B. A.

1 Anaba J. C.

1 Duru B. N.

1 Eguakun F. S.

Search results

Individual tree basal area equation for a young Tectona Grandis (Teak) plantation in Choba, Port Harcourt, Rivers State, Nigeria

Tree basal area models and density for selected plantation species in swamp forest zone of Rivers State, Nigeria