scholarly journals Growth characteristics of tree species in natural stands of Gambari forest reserve, Southwestern Nigeria

2020 ◽  
Vol 7 (1) ◽  
pp. 101-109
Author(s):  
Q. A. Onilude ◽  
◽  
R. Adewoye ◽  
O. A. Akinyemi ◽  
S. O. Osundun ◽  
...  
2012 ◽  
Vol 47 (3) ◽  
pp. 333-338
Author(s):  
AF Ojo ◽  
O Kadeba ◽  
J Kayode

The study investigated the rate of litter decomposition in three prominent litter releasing indigenous tree species in the natural rainforest and an exotic species Teak, Tectona grandis Lim., in the adjacent plantation in Akure forest reserve, southwestern Nigeria. Results showed that teak had the highest litter decomposition rate and Mansonia altissima the least. There was no relationship between the rates of decomposition among all species examined. The implication is that teak litter had the highest probability of releasing litter nutrients into the soil nutrient pool than any of the selected indigenous tree species while Mansonia altissima had the least. However all species had high decomposition rates. This implies that soil fertility will be maintained if any of the tree species were to be used for monoculture plantations. DOI: http://dx.doi.org/10.3329/bjsir.v47i3.13069 Bangladesh J. Sci. Ind. Res. 47(3), 333-338 2012


1990 ◽  
Vol 4 (4) ◽  
pp. 405-416 ◽  
Author(s):  
MIGUEL PINEDO-VASQUEZ ◽  
DANIEL ZARIN ◽  
PETER JIPP ◽  
JOMBER CHOTA-INUMA

2021 ◽  
Vol 25 (8) ◽  
pp. 1449-1452
Author(s):  
P.A. Ukoha ◽  
S.J. Okonkwo ◽  
A.R. Adewoye

This study uses satellite acquired vegetation index data to monitor changes in Akure forest reserve. Enhanced Vegetation Index (EVI) time series datasets were extracted from Landsat images; extraction was performed on the Google Earth Engine (GEE) platform. The datasets were analyzed using Bayesian Change Point (BCP) to monitor the abrupt changes in vegetation dynamics associated with deforestation. The BCP shows the magnitude of changes over the years, from the posterior data obtained. BCP focuses on changes in the long‐range using Markov Chain Monte Carlo (MCMC) methods, this returns posterior probability at > 0.5% of a change point occurring at each time index in the time series. Three decades of Landsat data were classified using the random forest algorithm to assess the rate of deforestation within the study area. The results shows forest in 2000 (97.7%), 2010 (89.4%), 2020 (84.7%) and non-forest increase 2000 (2.0%), 2010 (10.6%), 2020 (15.3%). Kappa coefficient was also used to determine the accuracy of the classification.


2019 ◽  
Vol 12 (1-2) ◽  
pp. 1-11
Author(s):  
Isaac Adelakun Gbiri ◽  
Nathaniel Olugbade Adeoye

Abstract Forest Reserves in Southwestern Nigeria have been threatened by urbanization and anthropogenic activities and the rate of deforestation is not known. This study examined the vegetation characteristics of Akure Forest Reserve using optical remote sensing data. It also assessed the changing pattern in the forest reserve between 1986 and 2017. Global Navigation Satellite System (GNSS) receiver was used to capture the location of the prominent settlements that surrounded the Forest Reserve in order to evaluate their effects on the forest. Landsat TM 1986, Landsat ETM+ 2002 and Landsat OLI_TIRS 2017 with 30m resolution were classified to assess the spatio-temporal changing pattern of the forest reserve. The results showed different composition of vegetation, which include undisturbed forest, secondary regrowth and farmlands. The study further revealed that in 1986, 2002 and 2017, undisturbed forest constituted 63.3%, 32.4% and 32.1% of the entire land area respectively, while secondary regrowth occupied 8.3% in 1986, 9.5% in 2002 and 15.6% in 2017. The farmlands had erratic growth between 1986 and 2017. It was 16.9% in 1986, 22.1% in 2002 and 17.5% in 2017. The bare ground exhibited inconsistency in the coverage. In 1986 the areal extent was 11.5%, when it increased to 36% in 2002 and decreased to 31.9% in 2017. In conclusion, the study revealed the extent of forest depletion at Akure Forest Reserve and it is therefore important that the residents, the government and the researchers show major concern about some of the critical factors to human beings that are responsible for forest depletion.


2010 ◽  
Vol 3 (1) ◽  
pp. 7-13 ◽  
Author(s):  
Jacob Godfrey Agea ◽  
Clement Akais Okia ◽  
Refaat Atalla Ahmed Abohassan ◽  
James Munga Kimondo ◽  
Susan B. Tumwebaze ◽  
...  

Pasoh ◽  
2003 ◽  
pp. 241-250
Author(s):  
Yoosuke Matsumoto ◽  
Yutaka Maruyama ◽  
Akira Uemura ◽  
Hidetoshi Shigenaga ◽  
Shiro Okuda ◽  
...  

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Moses Kwesi Yalley ◽  
Daniel Adusu ◽  
Abdul-Rahman Bunyamin ◽  
Isaac Okyere ◽  
Austin Asare

Broussonetia papyrifera invasion poses a serious threat to indigenous tree species in Ghana. Many conservation scientists therefore emphasize the need to control, manage, and possibly eradicate the species. However, attempts at control and management require adequate knowledge of its ecology and impact on invaded ecosystems. Employing a complete randomized design with twenty-four (24) 20 m × 20 m plots, 12 each on invaded and uninvaded sites, this study assesses the indigenous species regeneration potential under Broussonetia papyrifera-invaded sites in the Pra-Anum forest reserve. The study provides evidence of the negative impact of Broussonetia on the regenerative capacity of the reserve, as 335 seedlings per 4800 m2 distributed over 43 species were recorded on the uninvaded site compared to 156 seedlings per 4800 m2 distributed over 31 species on the invaded site. The study, however, observed some level of resilience of species belonging to the Ulmaceae and Lecythidaceae families, as they appeared fairly represented on the invaded site. Floristic diversity was also observed to be negatively impacted by Broussonetia invasion as mean Shannon and Simpson index values of 2.39 ± 0.71 and 0.89 ± 0.08 and 1.39 ± 0.24 and 0.64 ± 0.08 were recorded on the uninvaded and invaded sites, respectively. Furthermore, the Broussonetia invasion compromised the productivity of the forest ecosystem as 4.9 ± 1.61 mean economic tree species per 400 m2 plot were recorded on the invaded site compared to 13.8 ± 1.28 per 400 m2 plot on the uninvaded site. The study, therefore, concludes that Broussonetia invasion poses a serious threat to the integrity and productivity of the Pra-Anum forest reserve. Consequently, the study recommends the control of the spread of the species to protect the integrity of the Pra-Anum forest reserve. Also, restoration efforts in invaded areas of the reserve could consider the use of native species belonging to the Ulmaceae and Lecythidaceae families as they appear to be resilient to Broussonetia invasion.


1990 ◽  
Vol 6 (4) ◽  
pp. 387-408 ◽  
Author(s):  
Steven H. Rogstad

ABSTRACTOne component of the high organismal diversity of tropical lowland rain forests is the existence of series of closely related, sympatric species. For example, the six distinct tree species of the monophyletic Polyalthia hypoleuca complex regularly grow sympatrically in various combinations throughout the rain forests of Malesia. Theoretical and empirical evidence has been presented indicating that the members of such series either (1) are well differentiated with respect to at least one major niche component; or (2) may lack differentiated niches. In this study, certain sympatric members of the complex are shown to have clearly diverged in autecological characteristics that affect their distribution including: (1) P. glauca, P. hypoleuca, and P. sumatrana differ in growth characteristics, height at maturity, seedling germination requirements, and are found on soils with differing degrees of hydration; (2) P. discolor grows to a different height and on different substrate types than does P. multinervis; and (3) P. glauca and P. hypoleuca seedlings differ in transpiration characteristics and response to flooding and drought.


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