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Tree Species and Size Diversity of Akure Strict Nature Reserve, Nigeria

Received: 31 May 2023    Accepted: 21 June 2023    Published: 11 July 2023
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Abstract

Size and species structures control the natural mechanisms maintaining high structural diversity. Use of size inequality and species diversity measures singly for conservation decisions brings about inconsistent results. Therefore, most conservation efforts fail due to lack of understanding of mechanisms promoting coexistence of tree species. However, relationship between size inequality and species diversity indicates the natural mechanism promoting coexistence of high species diversity. Therefore, this study investigated the relationship between tree size inequality and species diversity in Akure Strict Nature Reserve. Eighteen and twelve plots (30m × 30m) were laid on parallel transects of 3.60km long and 50m width in Old-growth and Riparian forests, respectively. Trees with diameter-at-breast-height (dbh) ≥ 10cm were counted and identified to species level. Tree diameter at base, middle and top and total height were measured using girth tape and Relaskop. Tree species diversity (Shannon-Weiner; Simpson; Margalef indices) and dbh inequality measures (Gini coefficient, Gini; Coefficient of Variation, CV; Skewness Coefficient, Skewness) were computed and compared. Stem biomass were computed and converted to carbon stock. Data were analysed using descriptive, and correlation analysis at α0.05. Fifty-five (56) tree species representing 17 families were found in the forest. Species diversity indices were higher in Riparian while size inequalities in Old-growth forests. GC correlate with Shannon-Weiner (r=0.54; n=18, p≤0.018) and Margalef (r=0.473; n=18, p≤0.04) in Old-growth while GC correlate with CV (r=0.716; n=12, p≤0.09) in Riparian forests. The size inequality measures were strongly related with each other in Riparian while species and size inequality measures were strongly related with each other in Old-growth forests. The carbon stocks of Old-growth and Riparian forests were 117.21Mg/ha and 43.47Mg/ha, respectively. Triplochiton scleroxylon and Bridelia micrantha contained highest carbon stock in Old-growth and Riparian forests, respectively. Asymmetric mode of interaction in the absence of competition shows competition for below-ground resource, especially presence of moisture and nutrient gradient. Size inequality among different and within the same species determined coexistence tree communities in Old-growth and Riparian forests of Akure Strict Nature Reserve, respectively.

Published in American Journal of Agriculture and Forestry (Volume 11, Issue 4)
DOI 10.11648/j.ajaf.20231104.12
Page(s) 128-135
Creative Commons

This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.

Copyright

Copyright © The Author(s), 2024. Published by Science Publishing Group

Keywords

Tree Species Diversity, Stem Size Hierarchy, Tree Size Inequality, Stem Carbon Stock

References
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[8] Malhi, y., Baker, T. A., Phillips, O. O., Almeida, S., Alvarez, E., Chave, J. et al. 2004. The above-ground coarse woody productivity of 104 Naotropical forest plots. Global Change Biology 10: 563-591.
[9] Metsaranta, J. and Lieffers, V. J. 2008. Inequality of size and size increment in Pinus banksiana in relation to stand dynamics and annual growth rate. Annals o Botany 101: 561-571. doi.10.1093/aob/mcm320.
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    Oladele Fisayo Falade, Dami Adewale Aruwajoye. (2023). Tree Species and Size Diversity of Akure Strict Nature Reserve, Nigeria. American Journal of Agriculture and Forestry, 11(4), 128-135. https://doi.org/10.11648/j.ajaf.20231104.12

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    Oladele Fisayo Falade; Dami Adewale Aruwajoye. Tree Species and Size Diversity of Akure Strict Nature Reserve, Nigeria. Am. J. Agric. For. 2023, 11(4), 128-135. doi: 10.11648/j.ajaf.20231104.12

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    AMA Style

    Oladele Fisayo Falade, Dami Adewale Aruwajoye. Tree Species and Size Diversity of Akure Strict Nature Reserve, Nigeria. Am J Agric For. 2023;11(4):128-135. doi: 10.11648/j.ajaf.20231104.12

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  • @article{10.11648/j.ajaf.20231104.12,
      author = {Oladele Fisayo Falade and Dami Adewale Aruwajoye},
      title = {Tree Species and Size Diversity of Akure Strict Nature Reserve, Nigeria},
      journal = {American Journal of Agriculture and Forestry},
      volume = {11},
      number = {4},
      pages = {128-135},
      doi = {10.11648/j.ajaf.20231104.12},
      url = {https://doi.org/10.11648/j.ajaf.20231104.12},
      eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ajaf.20231104.12},
      abstract = {Size and species structures control the natural mechanisms maintaining high structural diversity. Use of size inequality and species diversity measures singly for conservation decisions brings about inconsistent results. Therefore, most conservation efforts fail due to lack of understanding of mechanisms promoting coexistence of tree species. However, relationship between size inequality and species diversity indicates the natural mechanism promoting coexistence of high species diversity. Therefore, this study investigated the relationship between tree size inequality and species diversity in Akure Strict Nature Reserve. Eighteen and twelve plots (30m × 30m) were laid on parallel transects of 3.60km long and 50m width in Old-growth and Riparian forests, respectively. Trees with diameter-at-breast-height (dbh) ≥ 10cm were counted and identified to species level. Tree diameter at base, middle and top and total height were measured using girth tape and Relaskop. Tree species diversity (Shannon-Weiner; Simpson; Margalef indices) and dbh inequality measures (Gini coefficient, Gini; Coefficient of Variation, CV; Skewness Coefficient, Skewness) were computed and compared. Stem biomass were computed and converted to carbon stock. Data were analysed using descriptive, and correlation analysis at α0.05. Fifty-five (56) tree species representing 17 families were found in the forest. Species diversity indices were higher in Riparian while size inequalities in Old-growth forests. GC correlate with Shannon-Weiner (r=0.54; n=18, p≤0.018) and Margalef (r=0.473; n=18, p≤0.04) in Old-growth while GC correlate with CV (r=0.716; n=12, p≤0.09) in Riparian forests. The size inequality measures were strongly related with each other in Riparian while species and size inequality measures were strongly related with each other in Old-growth forests. The carbon stocks of Old-growth and Riparian forests were 117.21Mg/ha and 43.47Mg/ha, respectively. Triplochiton scleroxylon and Bridelia micrantha contained highest carbon stock in Old-growth and Riparian forests, respectively. Asymmetric mode of interaction in the absence of competition shows competition for below-ground resource, especially presence of moisture and nutrient gradient. Size inequality among different and within the same species determined coexistence tree communities in Old-growth and Riparian forests of Akure Strict Nature Reserve, respectively.},
     year = {2023}
    }
    

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  • TY  - JOUR
    T1  - Tree Species and Size Diversity of Akure Strict Nature Reserve, Nigeria
    AU  - Oladele Fisayo Falade
    AU  - Dami Adewale Aruwajoye
    Y1  - 2023/07/11
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    DO  - 10.11648/j.ajaf.20231104.12
    T2  - American Journal of Agriculture and Forestry
    JF  - American Journal of Agriculture and Forestry
    JO  - American Journal of Agriculture and Forestry
    SP  - 128
    EP  - 135
    PB  - Science Publishing Group
    SN  - 2330-8591
    UR  - https://doi.org/10.11648/j.ajaf.20231104.12
    AB  - Size and species structures control the natural mechanisms maintaining high structural diversity. Use of size inequality and species diversity measures singly for conservation decisions brings about inconsistent results. Therefore, most conservation efforts fail due to lack of understanding of mechanisms promoting coexistence of tree species. However, relationship between size inequality and species diversity indicates the natural mechanism promoting coexistence of high species diversity. Therefore, this study investigated the relationship between tree size inequality and species diversity in Akure Strict Nature Reserve. Eighteen and twelve plots (30m × 30m) were laid on parallel transects of 3.60km long and 50m width in Old-growth and Riparian forests, respectively. Trees with diameter-at-breast-height (dbh) ≥ 10cm were counted and identified to species level. Tree diameter at base, middle and top and total height were measured using girth tape and Relaskop. Tree species diversity (Shannon-Weiner; Simpson; Margalef indices) and dbh inequality measures (Gini coefficient, Gini; Coefficient of Variation, CV; Skewness Coefficient, Skewness) were computed and compared. Stem biomass were computed and converted to carbon stock. Data were analysed using descriptive, and correlation analysis at α0.05. Fifty-five (56) tree species representing 17 families were found in the forest. Species diversity indices were higher in Riparian while size inequalities in Old-growth forests. GC correlate with Shannon-Weiner (r=0.54; n=18, p≤0.018) and Margalef (r=0.473; n=18, p≤0.04) in Old-growth while GC correlate with CV (r=0.716; n=12, p≤0.09) in Riparian forests. The size inequality measures were strongly related with each other in Riparian while species and size inequality measures were strongly related with each other in Old-growth forests. The carbon stocks of Old-growth and Riparian forests were 117.21Mg/ha and 43.47Mg/ha, respectively. Triplochiton scleroxylon and Bridelia micrantha contained highest carbon stock in Old-growth and Riparian forests, respectively. Asymmetric mode of interaction in the absence of competition shows competition for below-ground resource, especially presence of moisture and nutrient gradient. Size inequality among different and within the same species determined coexistence tree communities in Old-growth and Riparian forests of Akure Strict Nature Reserve, respectively.
    VL  - 11
    IS  - 4
    ER  - 

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Author Information
  • Department of Forest Production and Products, University of Ibadan, Ibadan, Nigeria

  • Department of Forest Production and Products, University of Ibadan, Ibadan, Nigeria

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