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Tytuł:
Individual tree basal area equation for a young Tectona Grandis (Teak) plantation in Choba, Port Harcourt, Rivers State, Nigeria
Autorzy:
Oyebade, B. A.
Anaba, J. C.
Powiązania:
https://bibliotekanauki.pl/articles/1113008.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
basal area
equation and management decision
individual tree
Opis:
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.
Źródło:
World News of Natural Sciences; 2018, 16; 130-140
2543-5426
Pojawia się w:
World News of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pollution assessment models of surface soils in Port Harcourt city, Rivers State, Nigeria
Autorzy:
Verla, Evelyn Ngozi
Verla, Andrew Wirnkor
Enyoh, Christian Ebere
Powiązania:
https://bibliotekanauki.pl/articles/1113910.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Anthropogenic
Contamination
Pollution indices
Residential area
Opis:
Environmental pollution has resulted in several health and physiological problems in both plants and animals. This has witnessed growing number of models for assessment purposes. Some of these provide useful information, and reduce large data for easier understanding by policy-makers. In the current study of pollution, we used data from four locations: Oil Market, Trans Amadi, Borrokiri and GRA in Port Harcourt and a control taken from Federal Land Resource Umuahia (FLRU). A total of 25 composite soil samples were analyzed for physicochemical parameters and heavy metals, by means of a 969 Unicam AAS model series. The data obtained were then subjected to index models. Results showed iron (Fe) to be most abundant metal, ranging from 10.44 to 19.54 mg/kg, then Ni (8.03 to 13.6mg/kg), Cd (3.96 to 5.41 mg/kg), Pb (1.36 to 7.64 mg/kg), Zn (0.09 to 7.24 mg/kg), Cu (0.16 to 0.32) and As (0.07 to 0.11 mg/kg). All metal concentrations were below permissible limits set by NESRA. Contamination factor (Cf) and Igeo revealed moderate to heavy contamination by Cd and Zn. Anthropogenicity revealed that increasing metals in the environment are largely from anthropogenic inputs. The Pollution Index revealed that soils were unpolluted (PLI < 1) with the heavy metals. Furthermore, the Sodium absorption ratio showed that the soils are less sodic and could be good soils for plant growth. All four sites showed a linear relationship between anthropogenicity and geoaccumulation indexes, and so both indexes furnish basically the same information However, pollution from these metals in the study area should be under routine check for possible pollution in the near future, as some metals showed elevated concentrations above background values.
Źródło:
World News of Natural Sciences; 2017, 12; 1-20
2543-5426
Pojawia się w:
World News of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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