Springer Dordrecht, The Netherlands, Pp. 351 – 367.

 Others

 Silviculture In Secondary Forests. In: Silviculture In The Tropics (Günter, S. Weber, M., Stimm, B. And Mosandl, R., Eds).

 Akindele, S.O. And Onyekwelu, J.C.

 2011

Secondary forests are forests regenerating through natural processes after significant reduction in the original vegetation at a point in time or over an extended period, and displaying a major difference in forest structure and/or canopy species composition with respect to nearby primary forests on similar sites. Despite their large extent, existing and potential benefits, secondary forests are mostly overlooked. The increasing area of secondary forests necessitates their professional management. If properly managed, secondary forests can provide important social and environmental benefits, contribute to poverty alleviation and reduce the pressure on the few remaining areas of primary forest. However, only suitable silvicultural treatments can restore and increase the commercial value of secondary forests. This chapter discusses the degradation processes leading to secondary forest formation, their structures, growth and yield and regeneration processes. Three insightful and demonstrative case studies were also presented to illustrate key points. 

 Journal Of Biodiversity And Ecological Sciences, 1(1): 77 – 94

 Journal

 Urban Forest Development In West Africa: Benefits And Challenges.

 Fuwape, J.A. And Onyekwelu, J.C.

 2011

This study assessed development of urban forestry, evaluated the effect of population growth on urban forests landscape and designed innovative strategies that will ensure sustainability and improvement of urban living environment. Urban forestry development was investigated through secondary data, directed enquiries to relevant stakeholders, on-the-spot assessment and observations of urban and peri-urban forest facilities in selected West African cities. The result revealed that numerous environmental and material benefits are derived from urban forests in West Africa. The types of tree species planted for landscape enhancement, environmental protection and other benefits varied with ecological zones and cultural values. In Sahel savannah, the preponderance of Adansonia digitata, and Acacia species were observed while in Guinea and Sudan savannah, Azadirachta species, Eucalyptus species, Acacia species and Gmelina arborea dominated. Terminalia species, Gmelina arborea, Tectona grandis, Delonix regia, species of palm, etc were common in tropical rainforest zone. Rapid urban population growth, limited land area, and poor implementation of government policies are some factors affecting urban forests development in West Africa. To ensure sustainable development, forest management technique that accommodates human, social, political, cultural and economic factors should be adopted. Political goodwill should be secured while appropriate social awareness should be promoted to guarantee that forest initiatives are upheld. 

 Applied Tropical Agriculture, 16 (1 & 2): 120 - 127.

 Journal

 Taper Equations For Gmelina Arborea In Omo Forest Reserve, Southwestern Nigeria.

 Alo, A. A., Onyekwelu, J.C. And Akindele, S.O.

 2011

Taper equations were generated for Gmelina arborea in Omo forest reserve, Nigeria. Four different age series (11, 16, 21, and 26-year-old) of Gmelina arborea plantations in the forest reserve were investigated. Three temporary sample plots of 20 m x 20 m were randomly selected from each age series. Taper functions were developed for the species using regression analysis. The functions generated were assessed using F-ratio, Root Mean Square of Error (RMSE), adjusted R-square (R2adj). The taper functions generated in this study were found to be satisfactory based on the various criteria used for their assessment 

 Nigerian Journal Of Forestry, 40 (1&2): 60 – 68.

 Journal

 Effect Of Land-use Systems And Seasonal Variation On Microbial Biomass And Population In Tropical Rainforest Soils.

 Onyekwelu, J.C., Mosandl, R. And Stimm, B.

 2010

Ecosystem degradation could result in land-use change and alterations in soil physical, chemical and/or biological properties. Soil microbial population plays important role in ecosystem functioning, as they decompose organic matter and determine the release of nutrients in the soil. The effects of land-use systems, seasonal variations and soil depths on microbial biomass and population in Oluwa forest reserve, Nigeria were investigated. Soil samples were obtained from two soil depths (0–15 and 15–30 cm) from primary forest, degraded forest, plantation forest and agricultural land during the rainy and dry seasons as well as their transitions. Plate count method was used for microbial population determination while fumigation–extraction method was used for microbial biomass carbon (MB-C) and nitrogen (MB-N). One-way analysis of variance (three-factor factorial) was used to test for significant difference and interaction among the factors. In all the ecosystems and soil depths, MB-C and MB-N ranged from 50.63–125.45µg g-1 and from 7.51–18.62 µg g-1, respectively during rainy season and from 26.76–97.13 and 3.79–14.41 µg g-1 during dry season. Land-use system, soil depth and seasonal variation significantb4ly affected microbial population, MB-C and MB-N. The trend was: primary forest > Gmelina plantation ? degraded forest > agricultural land for land-use system; peak of rainy season > onset of rainy season ? onset of dry season > peak of dry season for seasonal variation and 0–15 cm > 15–30 cm for soil depth, thus revealing that increased ecosystem degradation led to increased soil microbial indices degradation. The results also revealed the influence of investigated variables on microbial indices and by implication on source or sink of nutrients, nutrient conservation and cycling and soil primary productivity. The higher microbial indices of the forested ecosystems explain why farmers encroached into the forest in search for fertile land and tend to suggest more imminent encroachment. Implications of the results for land-use systems were discussed. 

 Applied Tropical Agriculture, 16 (1 & 2): 60 – 68.

 Journal

 Non-Timber Forest Products For Rural Livelihood Security: Evidence From Akure Markets, Nigeria.

 Chigbu, K., Chigbu, U.E And Onyekwelu, J.C.

 2010

The forestry perspective of rural livelihood security in Nigeria is, from a policy angle, downplayed in comparison to other agriculture-based activities. This makes the importance of Non-Timber Forest Products (NTFPs) to be underestimated in the economic development of the country. The rationale for this study is to bring to fore the importance of NTFPs in the livelihood security of the rural people. Four rural markets around Akure metropolis were used as case study. Questionnaires and expert opinions were used to obtain information about NTFPs from forty (40) respondents. A total of 35 major NTFPs were identified in the four markets. Majority (90%) of NTFPs market participants were women. Though the markets are periodic (weekly) markets, average monthly income from NTFPs sale ranged from N10,000 to N15,000, with the possibility of earning as much as N20,000 per month. This is an indication of the potentialities that may exist in NTFPs trade if practised within daily markets or in a better organised setting. Though financial returns from NTFPs may appear generally low, rural people still gain important livelihood options from them. In addition to the financial returns, the unquantifiable satisfaction rural people gain from carrying out their NTFPs activities provides them with additional livelihood security. The paper advocates the necessity for entrepreneurial steps for boosting the economic contribution of NTFPs to rural livelihood security. Also, the paper proposes three main NTFPs-based objectives for rural livelihood security and five measures necessary for achieving the identified objectives. 

 Annales Des Sciences Agronomiques, 14(1): 37 – 61.

 Journal

 Biodiversity Conservation Under Monoculture And Mixed Species Forest Plantations Of Different Ages In Rainforest Ecosystems Of Nigeria.

 Onyekwelu, J.C., Oyun, M.B., Adekunle, V.A.J., Akindele, S.O. And Olagoke, A.O.

 2010

Biodiversity conservation has become an issue of increasing relevance in plantation management. It is believed that on the average, plantations are less favourable to biodiversity conservation, particularly in exotic species monoculture, which may not always apply to understorey biodiversity. Understorey (plant, insect and mesofauna) and bird biodiversity conservation was assessed for exotic, indigenous and mixed species plantations in rainforest ecological zone of Nigeria. Two plantation sites with age series of each plantation group were selected from the ecological zone. Young and old stands of the dominent exotic, indigenous and mixed plantations were selected from each site. Eight temporay sample plots of 20 m x 20 m were randomly laid within each plantation and a 2 m x 2 m quadrant laid at the centre of each plot. All understorey plants within the quadrants were identified and recorded. For insect species, four pitfall traps (8 cm x 10 cm) were placed at least 5 m apart within each plot. Insects that fell into the trap were captured and preserved with 1.5L of 0.2% formalin. Flying insects were captured with sweep net and light net. Bird count was conducted in the mornings and evenings, using line transect and indirect methods. All birds seen or heard were identified and recorded. The dominant exotic and indigenous plantation species are G. arborea and N. diderrichii, respectively. Mixed species plantations had only two species (an exotic and indigenous species). Understorey plant richness varied from 13–22; 10–26 and 17–26 in exotic, indigenous and mixed species plantations, respectively. Species richness did not follow any clear trend with plantation age for exotic species but old indigenous species plantations had more species richness than young ones while the reverse was the case in mixed stands. Insect species richness followed the order: exotic species > indigenous species > mixed species plantations and did not reveal any clear trend with age. There were significant differences in all the biodiversity indices of the various plantations. A total of 38 bird species were identified. Bird species richness followed the order: old G. arborea > old growth N. diderrichii > young G. arborea plantations. The biodiversity indices of the plantations compared favourably with that of natural forest sites in the study area, thus indicating that forest plantations establishment in the study area has not led to understorey biodiversity loss but rather to their conservation. 

 Forest And Forest Products Journal, 3: 12 – 19.

 Journal

 Seed Germination And Early Growth Of Moringa Oleifera Seedlings.

 Onyekwelu, J. C. And Olabiwonnu, A.A.

 2010

Currently, much attention is being focused to identifying suitable tree species that can provide large biomass that can be used for bioenergy. Short rotation tree species have been recognized as one of the main bioenergy resources. Seed germination and early growth potentials of Moringa oleifera seedlings were investigated under five potting media. Germination was monitored for 35 days while early growth characteristics were monitored for 16 weeks. Germination commenced on the 6th day after sowing and was completed between 11th and 12th day, indicating a uniform and quick germination of the seeds. Germination percentage varied between 58 and 76%. The effect of potting media on germination was significant, with seeds sown in river sand giving a significantly lower germination than those sown in other media. At the end of the 16th week of growth, average number of leaves produced varied between 793 and 1657 (maximum: 4000). This high number of leaves, which implies large photosynthetic area for Moringa seedlings were probably responsible for rapid total height and diameter growth of the seedlings. Mean total height ranged from 72 and 100.9 cm (maximum: 145 cm) while mean collar diameter varied from 0.67 to 0.89 cm (maximum: 1.49 cm) during the four months growth period. The effects of potting media on total height, collar diameter and number of leaves were not statistically significant indicating the ability of Moringa seedlings to grow in a wide range of site conditions. 

 Applied Tropical Agriculture, 15: 21 – 28.

 Journal

 Adaptive Forest Management For Sustainability Of Nigerian Forests.

 Onyekwelu, J.C.

 2010

This paper reviews the development of forest management in Nigeria and advocates the adoption of adaptive forest management to achieve sustainable forest management. Adaptive Forest Management (AFM) is a dynamic approach to forest management in which the effects of treatments and decisions are continually monitored and used, along with research results, to modify management on a continuing basis, to ensure that objectives are met. AFM is compatible with and complementary to traditional forest management methods and has been noted to be an effective component of SFM. It stresses monitoring, evaluation, adaptation, and reporting and has been successful applied in the management of various forest ecosystems. Effective application of AFM in Nigeria will require, definition of management goals and objectives, involvement of relevant stakeholders, documentation of the extent and conditions of the forest, monitoring and evaluation. It is recommended that AFM should commence on a small-scale in Nigeria as forest managers and forest policy makers became more familiar with its techniques and convinced of its value. Forest managers must start simply, by initially applying AFM in few locations in form of pilot projects, which can later be applied at both stand and landscape levels. 

 UFRO World Series Vol. 25, Pp 299 – 313.

 Others

 Secondary Forests In West Africa: A Challenge And Opportunity For Management. In: Forests And Society – Responding To Global Drivers Of Change

 Jobst-Michael Schroeder, J.M., Oke, D.O, Onyekwelu, J.C. And Yirdaw, E.,

 2010

Secondary forests cover about 90% of West Africa’s forests. These forests are often degraded and are under strong and diverse pressures. Concepts on how to deal with this type of land resource are mostly missing. It is thus necessary to develop options for a wise and sustainable utilisation of secondary forests. Prerequisites for the development of rehabilitation concepts are knowledge and understanding of the ecological processes within the ecosystem, especially succession. Based on this knowledge, silvicultural management options can be designed, or complementary land-use systems may be identified and applied. Silvicultural systems offer a variety of opportunities, such as enrichment planting, refining, and liberation to gradually re-convert degraded forests into valuable timber resources. Agroforestry offers various possibilities for close-tonature management and economic improvement of impoverished resources. New approaches, like outgrower schemes, can play a catalyst role for a broader implementation of agroforestry. Simultaneously, this land-use system contributes to food security, thus stabilising the livelihoods of rural populations. Furthermore, non-wood forest products bear a substantial potential for the valorisation of secondary forests that, ideally, will result in sustainable utilisation of the resource. 

 Journal Of Tropical Forest Science, 20 (3): 193 – 204

 Journal

 Tree Species Diversity And Soil Status Of Primary And Degraded Tropical Rainforest Ecosystems In South-Western Nigeria.

 Onyekwelu, J.C., Mosandl, R. And Stimm, B.

 2008

Tree species diversity and soil status of primary and degraded tropical rainforest ecosystems in south-western Nigeria. We investigated the tree species diversity and soil properties of primary (Queen’s) and degraded (Elephant and Oluwa) rainforests in south-western Nigeria. Results revealed that differences in soil properties of the sites could not be attributed to the effect of forest degradation since there was no discernable pattern between properties of primary and degraded forest soils. A total of 31 families (26, 24 and 22 in Queen’s, Oluwa and Elephant forests respectively) were encountered. Species diversity index, species richness and species evenness were in the order Queen’s > Oluwa > Elephant forests and decreased as the level of forest degradation increases, thus indicating that these indices depended on site conditions. Queen’s forest had the highest species diversity (51), followed by Oluwa (45) and Elephant forests (31). About 30% of tree species in the three sites were among the endangered tree species in Nigeria, a situation that calls for urgent conservation measures. The similarity of diversity index of the once highly degraded Oluwa forest with that of the primary forest indicates that rainforests have the ability to return to their original ‘species rich’ situation even after significant degradation, provided that the physical factors of the forest are intact, seed dispersal is present, the site does not become invaded by aggressive weed species and all forms of degradation activities ceases or are controlled.