DEPARTMENT OF FOREST RESOURCES MANAGEMENT
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Item Soil carbon distribution in three land uses of Gambari Forest Reserve Area, Oyo State(University of Ibadan, Faculty of Agriculture and Forestry, 2019) Falade, O. F.; Adeagbo, A. A.Soil adsorptive property is considered for mitigation of climate change in the terrestrial ecosystem. However, there are inconsistent findings on the contribution of aggregate sizes to carbon sequestration in soil depths. Inappropriate land-use practices cause increasing greenhouse gases in the atmosphere. Detail estimation of carbon associated with soil aggregates in different land-uses is required to identify land-use practice that promotes carbon accumulation. Therefore, the objective of the study was to investigate distribution of organic carbon associated with the soil aggregate sizes in selected land-uses. Three (30 m x 30 m) sample plots were established randomly in each of Natural Forest (NF), Plantation Forest (PF) and Cultivated Land (CL). Soil core samples were collected at 0-15, 15-30 and 30-45 cm depths using steel soil corers). Soil core samples were oven-dried at 105°C and bulk densities were computed. Oven-dried soil sample of 100 g was separated into five aggregates (>2, 2-1, 1-0.5, 0.5-0.05 and <0.05 mm) using the dry sieve procedure. Each aggregate (10 g) was heated in Muffle furnace at 500oC for 4 hours for soil carbon estimation. Aggregate sizes >2mm dominated NF and PL while 0.05 mm dominated CL. There was no significant difference in the distribution of aggregate sizes of NF and CL, except PL. The three land-use practices have the same proportion of aggregate 1-0.5mm at topsoil. Macro- and micro-aggregates influence soil carbon content in natural forest and plantation forest, respectively. Depth and land-use change caused re-distribution of carbon on soil aggregate sizes.Item Forest structure and tree stem carbon stock of Gambari Natural Forest Reserve, Oyo state, Nigeria(Faculty of Agriculture, University of Uyo, 2019-06) Falade, O. F.; Aderemi, S. A.Tree stems are major above-ground carbon pools in the tropical forest structure. Forest structure creates micro-climatic conditions for various ecosystem services. Natural and man-made disturbances cause changes in forest structure. However, the effect of forest structure dynamics on stem carbon sequestration is yet to be clarified in Gambari Natural Forest Reserve, Oyo State, Nigeria. Understanding influence forest structure dynamics on stem carbon could improve prediction of carbon sequestration potential of Gambari Natural Forest Reserve. Therefore, the aim of this study was to quantify forest structure and stem carbon stocks in Gambari Natural Forest Reserve. Ten sample (30m×30m2) plots were randomly demarcated in Gambari Natural Forest using stratified random sampling method comprising 5 sample plots in each identified canopy structures; closed and open. Tree stems ≥10cm diameter-at-breast-height (dbh) were identified, enumerated and species diversity indices computed. Total height (TH) and diameter were also measured for volume and carbon estimation. Data collected were analyzed using descriptive statistics and ANOVA α0.05. A total of 50 tree species representing 25 families were identified in Gambari Natural Forest Reserve and closed canopy had higher diversity indices than open canopy structure. The lower and middle canopy class had the highest stems/ha in both structures. Diameter distribution of closed and open structure expressed extended reverse J-shaped and rotated sigmoid curves, respectively. Tree stem carbon stock were 0.66Mg/ha and 0.436Mg/ha in closed and open canopy structure, respectively. Microphyla pterigota (12.11%) and Triplochiton scleroxylon (25.84%) contributed highest carbon stock in closed and open canopy structures, respectively. The study concludes that the closed canopy structure of Gambari Natural Forest Reserve offers good option for carbon sequestration strategies as its structure and tree composition influences its stem carbon stock. However, only few tree species contributed to the high stem carbon stock in the study area. Therefore, these tree species can be considered in the establishment of carbon credit for carbon sequestration in Nigeria.Item Soil aggregates and carbon distribution in tectona grandis (linn. f.) plantation, Nigeria(2017-12) Falade, O. F.Soil and tree biomass are reservoir for carbon but there is uncertainty regarding their influence on soil carbon stabilization. Carbon associated with clay size aggregate is considered a major determinant of soil carbon accumulation. However, other aggregates are becoming relevant in the estimation of soil carbon accumulation. These limit the detail carbon estimation of soil. Therefore, soil carbon accumulation of aggregate sizes was estimated at two soil depths in Tectona grandis plantation. Six (30 x 30m2) plots were randomly demarcated in the plantation and 360 topsoil and subsoil samples were used for this study. Soil core samples were collected at five points at depths of 0-15, 15-30 cm in each plot for period of six months. Soil core samples collected were oven dried at 105 0C. Soil sample (100g) from each core sample was sieved into >2.0, 2.0-1.0, 1.0-0.5, 0.5-0.050 and <0.050 mm aggregate sizes using dry sieve procedure and proportions weighed. A subsample of 10g of each fraction was combusted in Muffle furnace at 500 0C for 4 hours and carbon content estimated. Carbon content of the bulk soil was also determined. Data were analysed using descriptive statistics, regression analysis at α0.05 The 0.5-0.05 mm fraction had the highest proportion of soil at top and subsoil (39 and 28%, respectively). Aggregate size of <0.05 mm had the highest soil carbon concentration at topsoil and subsoil. Exponential and logistic equations performed better on the basis of R2, F-value and Standard Error of Estimate. Therefore, carbon content of 0.5-0.05 and 1.0-0.5 mm aggregates accurately estimate carbon content of topsoil and subsoil using the exponential equation. Carbon content of fine silt size aggregate (0.5-0.05 mm) determined carbon accumulated. Exponential model of soil carbon is determined by the aggregate size distribution of each soil layer.Item Quantification of soil aggregate carbon in tectona grandis (Linn. f) plantation at University of Ibadan, Ibadan, Nigeria(Forestry Association of Nigeria, 2016-12) Falade, O. F.Forest soils are important reservoir for carbon and contribute to global climate mitigation. Fine clay size aggregate is considered a major determinant of soil carbon distribution. Other aggregate sizes are also important in carbon distribution and estimation. Therefore, soil carbon accumulation of aggregate sizes was quantified at two soil depths in Tectona grandis plantation. Six (30 x 30m') plots were randomly demarcated in the plantation and 360 topsoil and subsoil samples were used for this study. Soil core samples were collected at 4 comers and centre of each plot to depths of0-15,15-30 cm in each plot for period of five months. Soil core samples were oven dried at 105 °C. Soil bulk density and moisture content were estimated from the core samples. Soil sample (100g) from each core sample was sieved into >2,2-1,1-0.5,0.5-0.050 and <0.050 mm aggregate size fractions using dry sieve procedure and proportions estimated. Sub-sample (10g) of each fraction was combusted in Muffle furnace at 500 °C for at least 4 hours and carbon content estimated. Carbon concentration of the bulk soil was also determined. Data were analysed using descriptive statistics and ANOVA at a0 05 Bulk density ranged from 1.08 to 1.33 and 1.39 to 1.54 g/cm3 for subsoil and topsoil, respectively. Soil moisture content ranged from 17.23 to 23.36 and 14.08 to 22.15 cm for topsoil and subsoil, respectively. The 0.5-0.05 mm fraction had the highest values at top and subsoils (39 and 28% of the soil by weight, respectively) followed by 1 -0.5mm size fraction (27% of the soil by weight) at the topsoil and >2mm fraction (27% of the soil by weight) at the subsoil. Topsoil and subsoil had approximately the same proportion of 2-1mm and <50µm fractions. Fine silt (<0.05mm) fraction had the highest soil carbon concentration followed by sand size fraction (>2.0mm) and silt-size fraction (2-lmm) in topsoil and (0.5-0.05mm) in subsoil. The soil carbon associated with <0.05mm was greater than the >2mm fractions. The coefficient of Variation of carbon content were higher among the aggregates of subsoil than topsoil. The mean values of carbon content of bulk soil in topsoil were high than subsoil. Carbon concentration of fine silt size aggregate (0.5-0.05 mm) accurately estimate carbon content of topsoil and subsoil. Moisture content of the bulk soil influence carbon concentration of aggregate size of 1 mm and 0.05.Item Woody species diversity and regeneration patterns in Osun-Osogbo sacred grove, Nigeria(Ecological Society of Nigeria, 2017-12) Falade, O. F.; Bada, S. O.Osun-Osogbo Sacred Grove in Nigeria is one of the major biodiversity hotspots in sub-Saharan Africa with high plant diversity that has suffered considerable human-induced disturbance in the recent times. Therefore, this study aimed to quantify the canopy species diversity and regeneration pattern in the Sacred Grove. Three (0.09ha) plots were sampled in each identified forest type (old-growth, secondary-regrowth, and riparian forests) for the inventory of tree / sapling stems, and nested quadrats (5 x 5m2) for seedlings. All stems enumerated were identified to species level. Data on diameter-at-breast height (dbh) and number of individuals per species were collected by plot. The patterns of tree (dbh ≥ 10 cm) distribution and regenerating (dbh ≤ 10 cm) population were examined using Detrended Correspondence Analysis (DCA) while the regeneration status of the grove was assessed by comparing the Importance Value Indices (IVI) of the current stocking and regenerating populations of the tree species. A total of 75 vascular species representing 66 genera and 30 families were identified. Fabaceae (13 spp), Apocynaceae (8 spp.), Euphorbaceae (7 spp.) and Rubiaceae (7 spp.) contributed 47.5% of the flora. The first two component axes of DCA (79.59%) delineated three community assemblages along disturbance gradient in the tree population. In addition, the first two component axes of DCA (107.70%) identified four communities along composition and disturbance gradients in the regenerating population. Analysis of IVI indicated that Dialium guineense (4.11), Funtumia elastic (6.08) and Cola millenii (5.06) were dominant and the most widely distributed tree species in the Grove. Osun Sacred Grove is rich in vascular species diversity with diameter distribution showing poor growth and inadequate self- replacement of emergent tree species. Gap creation and appropriate cultural practices should be undertaken to improve the regeneration of the emergent species.Item Nutrient-use efficiency of tectona grandis (Linn. f.) seedlings on basement complex and ferric luvisol soils of Ibadan, Nigeria(Agricultural Research Council of Nigeria, 2011) Falade, O. F.; Oyeleye, B.The study investigated the use-efficiency of selected soil nutrient elements - Nitrogen (N), Phosphorus (P) and Potassium (K) in the synthesis of dry matter by Tectona grandis (Linn.f.) seedlings. T. grandis seedlings were grown on basement complex and ferric luvisol soils for 77 days after transplanting (DAT). Sixty polythene pots were filled with each soil type. Sixty soil seedling samples formed an experimental unit that was replicated three times making a total of 360 seedlings. Eight seedlings were selected at intervals of 7 days for the first 28 DAT and four seedlings for the remaining 42 DAT in each experimental unit. Composite samples of soil media and seedlings were taken at intervals of 7 days and chemically analyzed. The dried shoot and leaves were combusted at 500oC, for carbon content determination. Range of daily light intensity during the experiment was 3.5 to 6.2 Klux while daily mean temperature was 24.7 to 27.5oC. Total carbon and biomass results showed that photosynthetic efficiency and photosynthetic carbon production of seedlings grown on basement complex were not significantly different from those of ferric luvisol. It is concluded that an increase in biomass could not be a major indicator of an increase in biomass carbon production. Therefore, photosynthetic efficiency alone may not be an adequate indicator of efficient photosynthetic carbon fixation. The root/shoot ratio was higher than 1.0 in both soils, indicating higher biomass allocations to the roots of the seedling. The study provides basis for the estimation of the phosphorus and nitrogen-supplying power of ferric luvisol and basement complex soils,Item Carbon fraction distribution of soil depths of Omo Biosphere Reserve, Nigeria(Forestry Association of Nigeria, 2019-10) Ubaekwe, R. E.; Falade, O. F.; Ariwaodo, J. O.Soil is regarded as largest carbon reservoir in terrestrial ecosystem but availability of Information on soil aggregates cum carbon fraction distribution along depths in relation to specified location is lacking. Soil carbon accumulation of aggregate sizes was estimated at five soil depths in natural forest reserve, Omo Biosphere Reserve, Nigeria. Guided by the heterogeneity of the reserve, it was stratified into close and open canopy structures. Fourteen and six (30m x 30m) sample plots were demarcated in close and open canopy, respectively. Profile pit was dug at the center of sample plots (30m x 30m) and soil samples were collected at 0 - 20, 20 - 40, 40 - 60, 60-80, 80 - 100cm depths and air dried. Air- dried soil samples (100g) were separated into five aggregate sizes (>2.0, 2-1, 1-0.5, 0.5-0.052mm, <0.052mm) using wet sieving method, and percentage carbon content of each aggregate fractions were determined using Loss on Ignition Method. Data collected were analyzed using descriptive statistics and ANOVA at α 0.05. Carbon distribution varied among the soil aggregates and across the depths. The degree of carbon protection and carbon stability are higher in <0.052mm aggregate size than in other aggregates. Macro-aggregate and micro-aggregate are responsible for carbon accumulation in surface and sub-surface soils, respectively. Therefore, macro-aggregate and micro-aggregate are responsible for carbon Sequestration in soil of Omo Biosphere Reserve.Item Determinant of carbon stabilization in tropical soils: a review of carbon sequestration potential of soil aggregate fractions(Forestry Association of Nigeria, 2018-03) Falade, O. F.Soils contribute to global climate mitigation through Sequestration of carbon. Soils that remain undisturbed for long period of time could be the best choice for carbon Sequestration. Quality of organic matter, land management practices and land use types had been considered the major factors influencing accumulation and stabilization of carbon associated with soil aggregate fractions. This understanding had limited the efforts at tracking carbon accumulation and stabilization of various aggregate fractions. However, other factors are becoming relevant in the evaluation carbon stabilization potential of various soil aggregate fraction in different soil texture and types. Therefore these factors require detail description. Organic and inorganic carbon compounds contribute to the soil carbon stabilization and subsequently, enhance carbon Sequestration. Understanding of the critical factors that control stabilization of carbon in soil aggregate fractions is limited. This limits the efforts on how to optimize carbon Sequestration potential among soil aggregate fractions and soil types and consequently, one of the reasons for unabated evolve of greenhouse gases from soils to the atmosphere. Therefore, brief description of factors that influence and optimize the Sequestration of carbon in tropical soils were reviewed. Hence, quantity and quality of organic matter, availability of basic cations; proportion of fine particle fraction in the soil; land management practices Option; organic and inorganic carbon concentration and soil moisture content were identified as the major factors influencing the soil carbon stabilization in tropical soils. The processes involve in carbon stabilization of tropical soils could be classified into Chemical and physical protecting mechanisms. Organic compounds derive from plant origin enhance soil particle aggregation while cations facilitate organo-mineral formation among soil fine particles. Surface area specificity is essential facilitator of organo- mineral formation among soil fine particles.Item Role of traditional institutions in conservation of plant diversity(Forestry Association of Nigeria, 2010-10) Falade, O. F.; Bada, S. O.Plant diversity is the vast variety of plant life and its ecological complexities existing in any region. Circumstances gave rise to diverse experiences among indigenous societies about plant wealth around them. Plants are integral for the survival of the traditional culture. Each community has a unique set of social institutions. Conservation efforts can be more efficient if it is based on deep knowledge of social institutions. Plant diversity Conservation thrive if synchronizes with improvement in human welfare. It is imperative that plant diversity Conservation and its sustainability should focus traditional institutions because of its voluntary compliance features and cost effectiveness. This review focuses on critical factors in traditional Institution that can affect Conservation of plant diversity. These factors include local attitude, land use change, indigenous knowledge, religious belief, and cultural traditions.Item Assessment of florsstic composition of forest undergrowth of international institute of iropscal agriculture (iita) forest reserve Ibadan, -Nigeria.(2014) Oladoye A.0; Aduradola; Olubode O.S.; Basiru A.O; Ezenwwenyi J.U.Assessment of understorey species of a tropical rainforest ecosystem in South-western Nigeria, exemplified by International Institute of Tropical Agriculture (IITA) forest reserve, Ibadan. A total of twenty-four permanent sample plots of 0.0625 ha were used for the assessment of understorey composition, density and frequency. Relative frequency, Relative Density and Importance Value Index (TVT), similarity, diversity and Detrended Correspondence Analaysis (DCA) statistics were used to analyse the data. The result showed a total of 3,833 individual from 128 species and 44 families (28 shrub, 57 trees, 33herbs, 2 grasses and 8 climbers ) were identified. Papilonaceae had the height number of species (11) followed by Moraceae (10), Albizia zygia had the height frequency of occurency (24), density of 169.33/ha. However Culcasia scandens had the height density of 299.33/ha. Highest Importance value index of 13.82 was recorded for Culcasia scandens, followed by Chromolaena odorata (11.80). The.least (IVI) 0.18 was recorded for Blepharis maderaspatensis, Carica papaya, Cissus pinata. Similarity between paired plots varied from 0.16 to 0.75, Simpson diversity (0.9529) and dominance of 0.0471, number of species present in each of the plotranged from 0-39. Plot 84 had the heighest species (39), high Eigen value (73.7%), length of. ordination space (-2 to 6) and the location of all the plots in the first quadrant indicated that the environment was stable indicative of minimal variation in floristic composition between plots and high heterogeneity of the site and species respectively. These findings showed that the IITA forest is diverse in species composition and the diversity of the understory may act as a catalyst for successful natural forest succession. Hence may be creating a more favourable environment for the establishment of native forest flora and habitat for fauna. Ultimately may be leading to conserving biological diversity. The study eventually concluded that a proper protection from human interferences and scientific management of undergrowth of the study area may lead to biodiversity rich site in the country.