The tree composition of Onigambari Forest Reserve in Oyo State was
evaluated by laying out a plot size of 50 x 50/m2 resulting to four
plots per hectare. 104 and 93 stems per hectare were recorded. A total
of 197 tree stands were encountered in the two compartments studied
with family Sterculiaceae with species Cola gigantean, Cola millenii  ,
Sterculia africana  , Sterculia oblonga  , Sterculia tragacantha  ,
Triplochiton scleroxylon  , Pterogota macrocarpa and Nesogordonia
papaverifera   .as the most abundant having 34 stands, followed by the
family Papilionoideae with species Baphia nitida with 20 stands as the
most abundance species. About thirty-nine percent of the tree species
encountered were wildlings having a diameter at breast height of
 64 10 cm. Less than one percent (0.50%) of the trees were of
merchantable size. This could be a thing of concern and it calls for
adequate resourceful and sustainable management techniques. Habits in
Onigambari Forest Reserve are presented in Table 1. A total of
forty-three (43) species of trees distributed into twenty (20) families
were encountered. Family Sterculiaceae and Fabaceae was the richest
with eight (8) species each followed by family Euphobiaceae with (5)
tree species. Based on their habit, these species were classified into
100% trees. Furthermore, it is of the importance that the forest
reserves be protected from illegal/indiscriminate logging among other
anthropogenic activities in order to allow it regenerate

AGBOJE, I

FADIMU, BO

FADOYIN, AS

GANIYU, OA

HAASTRUP, NO

LAWAL, MO

MANGODO, C

ORIPELAYE, OS

SANGOTOYINBO, OA

Bioline International

 *Corresponding Author Email: haastrup.no@frin.gov.ng; Tel: 08065567335 PRINT ISSN 1119-8362 Electronic ISSN 1119-8362    J. Appl. Sci. Environ. Manage.  Vol. 24 (10) 1815-1819 October 2020 Full-text Available Online at https://www.ajol.info/index.php/jasem http://ww.bioline.org.br/ja Composition of Tree Species in Onigambari Forest Reserve, Oyo State, Nigeria  *1HAASTRUP, NO; 2AGBOJE, I; 1LAWAL, MO; 1FADIMU, BO; 2SANGOTOYINBO, OA; 2MANGODO, C; 3ORIPELAYE, OS; 1GANIYU, OA; 2FADOYIN, AS  1Forestry Research Institute of Nigeria, Ibadan. Oyo state, Nigeria 2Federal College of Forest Resources and Management, Sakpoba. Edo State, Nigeria 3Moist Forest Reserve Station, Benin. Edo State *Corresponding Author Email: haastrup.no@frin.gov.ng; Tel: 08065567335  ABSTRACT: The tree composition of Onigambari Forest Reserve in Oyo State was evaluated by laying out a plot size of 50 x 50 m2 resulting to four plots per hectare. 104 and 93 stems per hectare were recorded. A total of 197 tree stands were encountered in the two compartments studied with family Sterculiaceae with species Cola gigantean, Cola millenii, Sterculia africana, Sterculia oblonga, Sterculia tragacantha, Triplochiton scleroxylon, Pterogota macrocarpa and Nesogordonia papaverifera.as the most abundant having 34 stands, followed by the family Papilionoideae  with species Baphia nitida with 20 stands as the most abundance species. About thirty-nine percent of the tree species encountered were wildlings having a diameter at breast height of ≤ 10 cm. Less than one percent (0.50%) of the trees were of merchantable size. This could be a thing of concern and it calls for adequate resourceful and sustainable management techniques. Habits in Onigambari Forest Reserve are presented in Table 1.  A total of forty-three (43) species of trees distributed into twenty (20) families were encountered. Family Sterculiaceae and Fabaceae was the richest with eight (8) species each followed by family Euphobiaceae with (5) tree species. Based on their habit, these species were classified into 100% trees. Furthermore, it is of the importance that the forest reserves be protected from illegal/indiscriminate logging among other anthropogenic activities in order to allow it regenerate.  DOI: https://dx.doi.org/10.4314/jasem.v24i10.16  Copyright: Copyright © 2020 Haastrup et al. This is an open access article distributed under the Creative Commons Attribution License (CCL), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.  Dates: Received: 15 August 2020; Revised: 22 September 2020; Accepted: 19 October 2020  Keywords: Abundance, merchantable, sustainable, resourceful  Forest reserves are portions of state lands where commercial harvesting of wood products is excluded in order to capture elements of biodiversity that can be missing from sustainably harvested sites. Forest reserve can also be described as an area of forest set aside and preserved by the government as a wilderness, national park, or the like. The forest reserves are established with a vision to protect the forests from human exploitation. The main purposes they serve are: (i) Protect the natural habitat of wildlife. (iii) Supporting reforestation by planting new trees and lots of other things in order to sustain the existence of floristic and faunas species. There are 445 gazetted forest reserves located in different parts of Nigeria. But recently this year 2020, the Finima nature park, when finally gazetted, will be Nigeria's 12th Ramsar site. Established by the Nigerian Liquefied Natural Gas Company in 2001, the park covers about 1,000 hectares. It's a mixture of tropical rain forest, mangrove swamps and freshwater ponds and is home to birds, crocodiles, snakes, alligators and the salt water hippopotamus. Only about 137 of these reserves are located in the forest region harboring the bulk of the natural forest wealth of the country (UNEP, 1992). Of the 560 species of trees present in these reserves in Nigeria, only 60 species are currently important commercially. (Nwoboshi, 1982).  Adeyoju (2001) argued that global standard against deforestation was the establishment of reserves with a ratio of forest to land of 30%.  World Bank (2005) carried out forestry survey in Nigeria; and observed that Nigeria’s remaining forest comprising reserves (788,053 ha) and off-reserve tree (1,854,360 ha), have been degraded. In the 1960s, forest cover was estimated at close to 10 million hectares. By 1978, it diminished to 4 million hectares (ha). Kumar et al. (2006) noted that many forests are under great human pressure and require urgent intervention to maintain the overall biodiversity, productivity and sustainability. The intricacy and rich diversity of life found in forests provides important services to human beings. Moreover, humans are destroying forest biodiversity at an alarming rate. Singh et al., 2002 described biodiversity as the aggregate of genes, species and ecosystem in a particular location. It is useful for human survival and economic well-being and for the Composition of Tree Species in Onigambari Forest…..                                                                                   1816 HAASTRUP, NO; AGBOJE, I; LAWAL, MO; FADIMU, BO; SANGOTOYINBO, OA; MANGODO, C; ORIPELAYE, OS; GANIYU, OA; FADOYIN, AS ecosystem productivity and balance. Walker (1992) and Purvis et al., 2000 indicated that the concept of biodiversity is considered to be the integration of biological difference across all scales, from genetic level, through species and ecosystems, to the landscape that they present, or are part of, and the ecological processes that works with them. The purpose of this work therefore is to evaluate the effects of such uncontrolled exploitation on the tree population of Onigambari Forest Reserve. The purpose of this work therefore is to evaluate the effects of such uncontrolled exploitation on the tree population of Onigambari Forest Reserve situated in Oyo State of Nigeria.  MATERIALS AND METHODS  Study Location: Onigambari Forest Reserve lies on latitude 7o 81 N and 7o 31 N longitude 3o 491 E and 3o 221 E (Fig 3.1). The plot lies within 17 km South-east of Ibadan on the Idi-Ayunre-Ijebu-Ode road, Oyo State. It was laid about 2 km away from the nearest road well obscured by some forest fallows in the neighborhood. The Onigambari Forest Reserve was declared from Ibadan Forest Reserve by a resolution of the Ibadan city council passed in September 1899 (Ajibode, 2002). Two sections were consolidated to form a Forest Reserve in 1953 making a total area of 125.62 km2 (Ajibode, 2002). Hence tree like Teak (Tectona spp), Mahogany (Khaya ivorences), and other Agricultural crops like cocoa (Theobroma cacao), cassava (Manihot spp) with exotic trees and crops were cultivated. The  inhabitants  of  the  area  are  predominantly  farmers  with  relatively  low  number  of  hunters (Ajibode et al., 2002).  Some of the forestry practice includes; Planting of trees for both timber and fuel wood production; Collection  and  sales  of  non-wood  products  such  as  leaves  and  bark  for  herbs, rattan (cane), One of the main feature of this forest is that most of the plants, climbers and epiphytes are woody and of the sizes of trees. There is an outstanding diversity of flora and fauna.  Survey method: Systematic line transect was employed for the laying of plots in the unlogged and logged forest sites. Two transects with a distance of 500 m between them was laid at the centre of each site. A sample plot of equal size (50 m × 50 m) was laid in alternate direction resulting into four plots and a total of 8 sample plots for the study sites. Using this method ensured that the forest is relatively covered.  The botanical name of every living tree that was encountered in each sample plot was recorded for the study site and their girths at breast height were measured. Where a tree’s botanical name was not known immediately, such a tree was identified by its commercial or local name. Such commercial or local names were translated to correct botanical names using Gbile (1984) and Keay (1989). Trees that could not be identified were tagged ‘unknown’. Specimens of such unknown trees were collected and preserved in a wooden press and taken to Forestry Herbarium, Ibadan (FHI) of the Forestry Research Institute of Nigeria for their identification. From the raw data obtained from the floristic enumeration and survey, the following vegetation attributes were extracted.   Fig 1: Map of Onigambari Forest Reserve  Analysis of field data: The following parameters were studied (a) Relative diversity which is the number of species in each family represented. (b) Diameter at breast Height using the formula     ℎ  Where л   is a constant of 3.142  RESULTS AND DISCUSSION A catalogue of the trees species, their families, and habits in Onigambari Forest Reserve are presented in Table 1.  A total of forty-three (43) species of trees distributed into twenty (20) families were encountered. Family Sterculiaceae and Fabaceae was the richest with eight (8) species each followed by family Euphobiaceae with (5) tree species. Based on their habit, these species were classified into 100% trees. Table 2 presents the result of the various diameter class sizes and Figure 2.presents the 197stands encountered in the study. 78 were in the diameter class of ≤ 10 cm which amount to about 39.59% of the total trees encountered.  Composition of Tree Species in Onigambari Forest…..                                                                                   1817 HAASTRUP, NO; AGBOJE, I; LAWAL, MO; FADIMU, BO; SANGOTOYINBO, OA; MANGODO, C; ORIPELAYE, OS; GANIYU, OA; FADOYIN, AS Table1: Tree species, Habits and families represented at Onigambari Forest Reserve FAMILIES SPECIES Habit Apocynaceae Funtumia elastic Tree  Astonia booneii Tree  Aningeria robusta Tree Boraginaceae Cordia millenii Tree Capparaceae Boscia angustifolia Tree Combretaceae Terminalia superba Tree Caesalpinioideae Erythrophylleum ivorensis Tree Clusiaceae Allanblackia floribunda Oliv.  Garcinia kola Heckel  Pentadesma butyracea Sabine Tree Tree Tree Euphobiaceae Bridelia micrantha Tree  Ricinodendron heudelotii Tree  Diospyros alboflavescens  Diospyros dendo  Diospyros mesipiliformis Tree Tree Tree Fabaceae Gossweilorodendron balsaminiferum (Verm.) Harms Guibourtia sp. Benn.  Hymenostegia afzelii (Oliv.) Harms  Lonchocarpus griffonianus (Baill.) Dunn.  Pachyelasma tessmannii (Harms) Harms  Pentaclethra macrophylla Benth.  Piptadeniastrum africanum (Hook F.)  Brenan Pterocarpus osun Craib Tree Tree Tree Tree  Tree  Tree Tree Tree Leguminoseae Daniellia ogea Tree Maliaceae Trichilia monadelpha Tree Mimosoideae Albizia zygia Tree  Piptadeniastrum africanum Tree Moraceae Treculia Africana Tree Myristicaceae Pycnanthus angolensis Tree Olacaceae Strombosia pustulata Tree Papilionoideae Baphia nitida Tree Phyllanthaceae Bridelia micrantha Tree Rutaceae Fagara macropylia Tree  Fagara zanto Tree Sapotaceae Chrysophyllum albidum Tree Sterculiaceae Cola gigantean Tree  Cola millenii Tree  Sterculia Africana Tree  Sterculia oblonga Tree  Sterculia tragacantha Tree  Triplochiton scleroxylon Tree  Nesogordonia papaverifera Tree Ulmaceae Celtis zenkeri Tree     This was followed by the diameter class of 10-20 cm with 50 stands which is 25.38% of tree population in the reserve. The diameter class of 91-100 cmand 100> had the least stand of 1 with about 0.51% each.  Relative diversity: The families Fabaceae and Sterculiaceae has the highest diversity of eight species each according to this study carried out in Onigambari Forest Reserve, Oyo State in South-West Nigeria. Similar quantity was recorded in the report of Haastrup et al (2018) when they carried out a study on the effect of logging on diversity of forest trees.  Euphobiaceae comes next after Fabaceae and Sterculiaceae with five spp; Apocynaceae and Clusiaceae with three spp. each. Mimosoideae and Rutaceae had two.  Fig 2: Diameter Class Distribution of trees in Onigambari Forest Reserve   Fig 3: Percentage Distribution of stem diameter classes≤ 10 cm in Onigambari Forest Reserve, Oyo State  Table 2: Percentage distribution of the various diameter class sizes  Diameter class (cm) Number of trees Percentage Proportion ≤ 10 78  39.59 11-20   50 25.38 21-30   25 12.69 31-40   14 7.11 41-50   12 6.09 51-60   9 4.57 61-70   3 1.52 71-80   2 1.02 81-90 2 1.02 91-100 1 0.51 >100 1 0.51 Total 197 100  These serves as the most occurring/dominant families represented in the study area. Moksia et al. (2012) and Sawadogo et al. (2007) reported that families Combretaceae and Sterculiaceae were the most dominant families in Kalfou forest Reserve in Cameroon and Togo forest in Burkina Faso 78502514 1293 2 2 1 101020304050607080900102030405060708090<1011-2021-3031-4041-5051-6061-7071-8081-9091-…>100NumberoftreesDiameter class of trees (cm)Composition of Tree Species in Onigambari Forest…..                                                                                   1818 HAASTRUP, NO; AGBOJE, I; LAWAL, MO; FADIMU, BO; SANGOTOYINBO, OA; MANGODO, C; ORIPELAYE, OS; GANIYU, OA; FADOYIN, AS respectively which are also in Savannah region. Dispersal of seeds might be a contributing factor to the dominace or occurrence of some species in family than the others. This of course is as a result of a conducive environment where the seeds are been dispersed far away from the mother tree. And a situation where there is competition for survival, only the strongest will adapt and survive.   The dominance of Fabaceae and Meliaceae in Olokemeji Forest Reserve reported by Ogunleye et al. (2004) was because of easy wind dispersal which consolidates their spread in the study location. On the contrary, twelve families within the study site of the Forest Reserve had poor species diversity. Each of the family had only one species. This could be accredited to anthropogenic activities like illegal logging. Salami et al (2006) reported that the current concern in the environment stems from evidence that natural processes are being disrupted by uncontrollable /unproductive means of forest extraction.  Diameter at breast height (dbh): The result of the dbh (m/ha) for the forest showed that the highest dbh (m/ha) respectively belonging to the family Fabaceae and Sterculiaceae. About fourty percent of the trees encountered were in the diameter class of ≤ 10 cm. This is in accordance with the findings of Adekunle et al. (2004) in the moist forest of South Western Nigeria. Also, Oduwaiye et al. (2002) reported that all plots studied by them had the largest number of trees in the smallest diameter class of below 10 cm at the Okomu permanent sample plots.   It was also reported that the smallest number of trees in the diameter class of 25-30 cm. Only one stand was found in the diameter class of 91-100 cm and >100cm in the study at Onigambari Forest Reserve. There has been constant felling of both timber and fuel trees in Onigambari Forest Reserve and it calls for grave concern and for the trend in order for sustainability of the forest trees.  Conclusion: Composition of Tree Species in Onigambari Forest Reserve, Oyo State, Nigeria was established in this study. The composition in Onigambari Forest Reserve was sparsely populated with tree species. The species distribution pattern of the study area indicates that the forest is characterized by a uniform distribution of individual tree species. The low stem density obtainable in logged area is an evidence of the degree of devastation the forest has been subjected to due to human interference. This calls for an urgent solution so as devastating loss of these tree species particularly those already threatened into extinction.  REFERENCE Adekunle, VAJ; Akindele, SO; Fuwape, JA (2004). Structure and yield models of tropical lowland rainforest ecosystem of southwest Nigeria. Food. Agric. Environ. 2 (2) 395-399.  Adeyoju, SK (2001). Forestry for National Development: a critique of the Nigeria situation in Popoola L; Abu JE; Oni PI (editors) Forestry and National Development. Proceedings of the 27th Annual Conference of the F.A.N. Abuja Nigeria pp 54-68.  Ajibode, MO (2002).Wood species composition and regeneration potential of Onigambari Forest Reserve, Oyo state. A project submitted to the Department Forestry and Wildlife Management FUNNAB Pp.18.  Gbile, ZO. (1984): Vernacular Names of Nigerian Plants-Yoruba. – Forestry Research Institute of Nigeria, Ibadan, Nigeria.   Haastrup, NO; Oke, SO. (2018): Effect of Logging on Diversity and Abundance of Tree Species in Onigambari Forest Reserve, Oyo State, Nigeria. Inter. J. Appl. Res. Tech. 7, 10, 45 – 51.  James, W. (1992): Human resource strategy New York: McGraw Hill, pp. 378 pages, ISBN 007 0678464  Keay, RWJ.(1989): Trees of Nigeria. – A revised version of “Nigeria Trees” (Keay, et al., 1964) Clarendron Press, Oxford. pp.476.  Kumar A; Marcot, BG; Saxena A (2006). Tree species diversity and distribution patterns in tropical forests of Garo Hills. Cur. Sci. 91: 1370-1381   Nwoboshi, LC (1982): Tropical Silviculture. Ibadan University Press. Ibadan; p333  Oduwaiye, EA; Oyeleye, B; Oguntala, AB (2002): Species Diversity and Potentiality for Regeneration in Okomu Permanent Sample Plot. – In: Forestry and Challenges of Sustainable Livelihood, Abu, J.E., Oni, P.I., Popoola, L. (eds) Proceeding of the 28thAnnual Conference of the Forestry Association of Nigeria, Akure, Nigeria. 4th-8th Nov.2002, pp. 264-271.  Ogunleye, AJ; Adeola, AO; Ojo, LO; Aduradola, AM (2004). Impact of Farming activities on Vegetation of Olokemeji Forest Reserve, Nigeria, Global Nest: the Inter.  J. 6(2): 130-139. Composition of Tree Species in Onigambari Forest…..                                                                                   1819 HAASTRUP, NO; AGBOJE, I; LAWAL, MO; FADIMU, BO; SANGOTOYINBO, OA; MANGODO, C; ORIPELAYE, OS; GANIYU, OA; FADOYIN, AS Purvis, A; Agapow, PM; Gittleman, JL; Mace, GM. (2000). Nonrandom extinction risk and the loss of evolutionary history. Sci. 288. 328–330.   Salami, AT; EE Balogun (2006), Monitoring Deforestation and Implications for  Biodiversity in Nigeria Using Data from NigeriaSat-1 and other Satellites, A Project Report Submitted to National Space Research and Development Agency (NASRDA), Federal Ministry of Science and Technology, Abuja.  Ayobami, T.S. Sawadogo P; Tigabu, M; Sawadogo, L; Oden PC (2007). Woody species composition, structure and diversity of vegetation patches of a Sudanian Savanna in Burkina Faso, Bois et Forets des Tropiques 294(4):5-20.                                        Singh, JS; Khurana, E (2002). Proc. Indian Natl. Sci. Acad., B68 in press.  UNEP- United Nations Environment Programme (1992) Biological Diversity in Nigeria- A country study. 53p.  World Bank (2005): Elements of Strategy for Forest Reform: World Agro Forestry Center, Phase 1Report No. 27323. 

Composition of Tree Species in Onigambari Forest Reserve, Oyo State,
Nigeria

Composition of Tree Species in Onigambari Forest Reserve, Oyo State, Nigeria

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