DSpace Collection: scholarly

GROWTH PREDICTION IN SOME PLANTATIONS OF EXOTIC TREE SPECIES IN THE NORTHERN GUINEA AND DERIVED SAVANNA ZONES OF NIGERIA

Sat, 01 Jun 1985 00:00:00 GMT

Title: GROWTH PREDICTION IN SOME PLANTATIONS OF EXOTIC TREE SPECIES IN THE NORTHERN GUINEA AND DERIVED SAVANNA ZONES OF NIGERIA Authors: ADEGBEHIN, J. O. Abstract: Growth studies which include diameter distribution using the Weibull function, development of stand volume models, and construction of provisional top height-age and total volume production-age curves for the average site class were carried out in plantations of Eucalyptus cloeziana, E. tereticornis and Pinus caribaea. The study locations were Kabama (Zaria) and Afaka (both typical of Northern Guinea savanna zone of Nigeria), Nimbia (Derived savanna zone) and Miango, Vom and Ta-Hoss (on the Jos Plateau). E. cloeziana represented only at Afaka had 4 experimental sample plots with age range of 4.2 - 15.5 years. E. tereticornis represented at Kabama and Afaka had 6 sample plots with ages from 3.7 - 15.5 while P. caribaea represented in all the study locations except Zaria had 43 plots with ages between 4.7 - 29 years. In fitting the Weibull distribution to the individual diameter plot data, WWINGO, the most suitable Weibull (program) subroutine for determining the Weibrill parameters in the stands, was capable of describing the diameter distribution in the plots as from the minimum age of 4 years for E. cloeziana and 6 years each for E. tereticornis and P. caribaea. On testing the Weibull parameter predictive models constructed (based on stand attributes and site factors) in new stands, while those of E. cloeziana and E. tereticornis gave good predictions as from the respective minimum age limits stated above, those of P. caribaea did not give reliable predictions until the age of 10 years. With reference to the stand volume model developed for each species, that of E. cloeziana gave the best prediction with the root mean square error (RMSE) of 2.25 m3/ha, followed by that of E. tereticornis with RMSE of 4.7 m3/ha and that of P. caribaea with RMSE of 10.1 m3/ha. The models predicted well within the range of field data when tested in new stands. Out of the three functions used in fitting the provisional top height-age (site index) curve for the average site class for each species, the Gompertz model, in most cases, gave better fittings than the Logistic while the polynomial function was the poorest. Based on the best-fit model for each species and some other criteria, a provisional average site class was defined as top height of 27.4 m at a reference age of 13 years for E. cloeziana, 24.8 m at the age of 15 years for E. tereticornis and 23.4 m at age 20 for P. caribaea. The Gompertz model was also more reliable than the Logistic in fitting the provisional average total volume production-age curve for each of the species. A maximum total volume production of about 240 m3/ha at age 13.4 years, 286 m3/ha at age 19.4 years and 726 m3/ha at age 30 could be obtained for E. cloeziana, E. tereticornis and P. caribaea, respectively, on an average site. The applications of the Weibull parameter predictive models in forest management, and the expected optimum rotation ages for the species in view of the growth figures obtained from the other growth models were discussed. Description: A THESIS SUBMITTED TO THE DEPARTMENT OF FOREST RESOURCES MANAGEMENT, FACULTY OF AGRICULTURE AND FORESTRY, IN PARTIAL FULFILMENT FOR THE REQUIREMENTS FOR THE AWARD OF THE DEGREE OF DOCTOR OF PHILOSOPHY AT THE UNIVERSITY OF IBADAN

SIMULATION MODEL FOR PREDICTION OF STAND GROWTH AND YIELD OF Tectona grandis Linn F. IN AKINYELE LOCAL GOVERNMENT AREA, OYO STATE, NIGERIA

Fri, 01 Aug 2014 00:00:00 GMT

Title: SIMULATION MODEL FOR PREDICTION OF STAND GROWTH AND YIELD OF Tectona grandis Linn F. IN AKINYELE LOCAL GOVERNMENT AREA, OYO STATE, NIGERIA Authors: UREIGHO, Nelly Ufuoma Abstract: Effective management planning tools for forest require growth and yield functions that can produce detailed predictions of stand development. Models such as Gamma Distribution Function (GDF), Weibull, Beta, and similar functions have been used to predict growth and yield of forest stands. However, information on the use of GDF in forest management has not been fully documented. The development of a program using Java programming language for GDF to predict growth and yield of Tectona grandis was studied in Akinyele Local Government Area, Oyo State, Nigeria. Stratified random sampling was used to select four different age classes of teak plantation namely; 11, 13, 22 and 59 years. Based on the size of each plantation, 7 and 8 temporary sample plots of 0.04 ha were selected from 11, 13, 22 and 59 year-old plantations respectively. Complete enumerations of trees (n = 433.) was done. Growth data sets collected include Diameter at Breast Height (DBH), total and merchantable heights. Basal Area (BA) and Volume were computed from measured variables. Data obtained were processed into tree level, stand level and size class. Parameters α and β for GDF were estimated from growth data. Based on the algorithm of GDF, α, β and n parameters, for the Java Program (JP) was written. Values obtained were fitted into the JP for growth and yield prediction. Linear and non- linear models were used to compare their predictive ability to the JP developed. At individual tree level using JP, the Observed and Predicted (O&P) values for height and BA ranged from 16.80-43.80 m, and 16.10-39.30 m; 2.49-4.51m2, and 2.45-4.31m2. Volume ranged from 2.09-10.54m3 and 2.04-12.03m3. Error rate varied from 0.00-9.00, -23.09-4.99 and -14.09-5.27 for height, BA and volume respectively. At stand level the O&P values for height, BA and volume from JP ranged from 17.10-28.30 and 17.90- 32.10 m; 2.55-3.69 m2 and 2.58-3.69m2; 2.25-3.69m3 and 2.28-3.69 m3 with error rate of -2.77-13.4; -0.10-5.65 and -0.10 -0.40 respectively. Size class level shape and scale parameter of GDF for diameter distribution ranged from 0.96-25.20 and 0.07-2.28 respectively. These values have better predictive power than non-linear and linear models which at individual tree level, O&P values for height and BA models of best fit ranged from 16.80-43.80m and 15.86-39.00 m; 2.49-4.51m2 and 2.50-4.98m2 . For volume, it ranged from 2.09-10.54m3 and 2.02-12.05m3 with error rate of -14.32-6.37. At stand level, O&P ranged from 17.10-28.30m and 17.95-32.18m for height; 2.55-3.69 and 2.59-3.72 m2 for BA and 2.25-3.69 and 2.29-3.65m3 for volume with error rate from -2.88-13.71; -4.58 -0.81 and -1.77-1.08 respectively. The R2 values for height, BA and volume models of best fit were 0.9490, 0.8981 and 0.9800 with the equations given as H= [1.31.08 + (H1.08 dom -1.31.08)1-e-0.06dbh/1-e-0.06*1.08 dom]1/1.08, 1n(B) = ln(0.32)+ 0.42(1/A)+ 0.77(lnH)+1.82(lnN)+1.89(H/A) and V= 1.62+22.38*DBH. The predictive ability of gamma distribution function for height, basal area and volume for teak plantation from the developed Java program consistently performed better than other models and could therefore be used for prediction of growth and yield in forest stands. Keywords: Gamma distribution function, Teak plantation, Growth and yield models, Forest management Word count: 498 Description: A Thesis in the Department of Forest Resources Management Submitted to the Faculty of Agriculture and Forestry in partial fulfilment of the requirements for the Degree of DOCTOR OF PHILOSOPHY of the UNIVERSITY OF IBADAN

MODELS FOR GROWTH CHARACTERISTICS AND THEIR APPLICATIONS IN YIELD STUDIES FOR Pinus caribaea Morelet 1851 IN SOUTHWESTERN NIGERIA

Tue, 01 Jul 2014 00:00:00 GMT

Title: MODELS FOR GROWTH CHARACTERISTICS AND THEIR APPLICATIONS IN YIELD STUDIES FOR Pinus caribaea Morelet 1851 IN SOUTHWESTERN NIGERIA Authors: OYEBADE, Bukola Amoo Abstract: Development of empirical models provides ample prospects of exploring established mathematical theories and relationships among tree growth variables for sustainable forest management options. However, there is inadequate information on modelling growth characteristics and productivity potentials of Pinus caribaea, a pulpwood species which is now being proposed for timber production in Nigeria. Hence, models for growth characteristics and their applications in yield studies for Pinus caribaea in southwestern Nigeria were investigated. Sixty Temporary Sample Plots (TSPs) of size 20m x 20m each and of different Age (A) series based on stocking density were sampled from Omo Forest Reserve (n=16 TSPs -15 and 21 years), Oluwa Forest Reserve (n=36 TSPs-18, 20, 35, 36 and 37 years) and Shasha Forest Reserve (n=8TSPs-27years) in Ogun, Ondo and Osun States respectively using stratified random sampling method. Growth variables: Diameter at Breast Height (DBH), Stem Quality (SQ) and Total Height (THT) were measured in each plot and Basal Area (BA), Stem Volume (SV), Tree Slenderness Coefficient (TSC), Crown Ratio (CR), Crown Projection Area (CPA) and Site Index (SI) estimated. A total of 1,592 trees were enumerated and each tree per plot classified into four canopy layers as dominant, co-dominant, intermediate and suppressed. Data obtained were used for modelling and categorized into individual tree level, size class level and whole stand level with Maximum Likelihood Estimation (MLE) technique adopted in 3-parameter Weibull Probability Distribution Functions (WPDF). Data were analysed using descriptive statistics, ANOVA, correlation and regression analyses at α0.05. Growth variables exhibited significant variations among the canopy layers with the dominant canopy layer having the highest mean THT of 14.9±0.2m and intermediate canopy layer lowest with 7.8±0.1m. Stem volume (1.4±0.04m3) and BA (0.1±0.002m2) were also highest in the dominant canopy layer. Slenderness coefficient however was highest (80.6±1.1) within the suppressed canopy layer while crown ratio was highest (0.27±0.001) in intermediate canopy layer. There were positive relationships between the growth variables across the stands with coefficients of correlation (r) ranging from 0.01-0.98 for individual tree level and 0.41-0.91 for whole stand level. Similar results of UNIVERSITY OF IBADAN LIBRARY iii correlation between Weibull parameters and other growth variables at the size class level were significant with r ranging between -0.72 and 0.92 with location parameter „a‟ of the WPDF having the highest positive association of r = 0.92 with DBH. The growth-yield models were of the forms lnCR =-3.5507+0.6263lnTHT+0.1558CPA+10.2339A 1, R2 =0.98 for dominant layer, lnCR = -3.1922+0.6363CPA+7.6876A-1, R2 = 0.994 for intermediate layer, lnTHT= 0.4547+0.0032lnSQ+0.6757CPA+0.1052A-1, R2=0.989 for suppressed layer and lnTHT=0.5872+0.5348CPA+0.0567A-1 with R2= 0.996 for co-dominant layer respectively. The overall best model among individual, size and whole stand categories was found within the whole stand level with R2=0.999 and of exponential form: lnSV=-0.7759+0.0001SI+0.0005A-1 +0.9532lnBA. The best adjudged growth-yield model among the canopy layers was found within the co-dominant layer. The selected whole stand growth-yield model was suitable for both current and future prediction of major growth characteristics and productivity potentials of Pinus caribaea in southwestern Nigeria. Keywords: Pinus caribaea, Growth variables, Yield models, Tree canopy layers Word count: 489 Description: A thesis in the Department of Forest Resources Management, Submitted to the Faculty of Agriculture and Forestry in partial fulfilment of the requirement for the award of the Degree of DOCTOR OF PHILOSOPHY (FOREST BIOMETRICS) of the UNIVERSITY OF IBADAN, NIGERIA.

CONFLICTS BETWEEN FORESTRY AND AGRICULTURAL LAND – USES IN OGUN STATE

Tue, 01 May 2012 00:00:00 GMT

Title: CONFLICTS BETWEEN FORESTRY AND AGRICULTURAL LAND – USES IN OGUN STATE Authors: OTESILE, Adegboyega Ayodeji, Abstract: Clash of interests between custodians of government Forest Reserves (FRs) in Ogun State and farmers operating within them, often results in conflicts causing disruption of socio-economic activities and sometimes loss of lives. Information on the causes and effects of these clashes would better inform policy makers and forestry professionals on workable and sustainable land-use practice. Therefore, factors responsible for such conflicts and their effects were investigated. Seven hundred and fifty farmers were randomly selected based on probability proportionate to size from 72 enclaves. This represents 30% of the total number of enclaves in the nine FRs in the State. In addition, 30% of staff of Ministries of Forestry and Agriculture (72 and 32 respectively) were randomly selected for questionnaire administration. Furthermore, 30% (32) of the timber contractors operating within the FRs were randomly selected for interview using an interview schedule. Data were collected on existence, causes and effects of conflicts, land hunger, accessibility to forestland and farming systems practised. Secondary data on the thrust of subsisting forestry and agricultural policies were obtained from the State Agricultural Policy, Federal land-use Act of 1978 and reports from the State Ministry of Forestry. Data were analyzed using descriptive statistics and logit model at p<0.05. Among the farmers, descriptive statistics revealed that 74.3% had unauthorized access to FRs, 68.1% were resident within FRs while 55.4% utilized lands approved by government for farming. Furthermore, 68.7% of the farmers identified taungya system and shifting cultivation as the prevalent farming systems practised. An average of two forest land encroachment cases were reported at each of Arakanga and Edun stream FRs yearly in the last 10 years while an average of 24 forest land encroachment cases was reported yearly in the last 10 years in Omo FR. Also, results of logit regression analysis revealed that the location of FRs where farmers operate (odds ratio = 2.39), rights of farmers to use forestland for farming (odds ratio = 2.19) and farm size (odds ratio = 1.52) are factors that are likely to cause conflicts over the use of forest lands in Ogun state. Furthermore, descriptive analysis of timber contractors‟ response revealed that, 72.6% identified destruction of cash crops during timber exploitation as cause of conflicts between them and farmers. State Ministries of Forestry and Agriculture officials identified loss of forests (27% and 25.2%), species (25.5% and 24%) and lives (22.5% and 22%), as effects of conflicts in the FRs. The thrust of the extant agricultural land-use policy made no provision to UNIVERSITY OF IBADAN LIBRARY iv penalize forestland encroachers. Conflicts in the use of forest land ensued between farmers and timber contractors on one hand and farmers and forest custodians on the other. The existence of land hunger in the forest reserves host communities, unauthorized access to forest land and absence of provision for penalty in the extant agricultural land use policy for forest encroachers encouraged activities engendering conflicts over the use of forest land. Keywords: Land-use conflicts, Forest policy, Forest reserves, Land hunger Word count: 481 Description: A Thesis in the Department of Forest Resources Management Submitted to the Faculty of Agriculture and Forestry in partial fulfillment of the requirements for the Degree of DOCTOR OF PHILOSOPHY of the UNIVERSITY OF IBADAN IBADAN