Tree Species Richness, Diversity, and Vegetation Index for Federal Capital Territory, Abuja, Nigeria

This study was conducted to investigate the tree species richness and diversity of urban and periurban areas of the Federal Capital Territory (FCT), Abuja, Nigeria, and produce Normalized Difference Vegetation Index (NDVI) for the territory. Data were collected from urban (Abuja city) and periurban (Lugbe) areas of the FCT using both semistructured questionnaire and inventory of tree species within green areas. In the study location, all trees with diameter at breast height (dbh) ≥ 10 cm were identified; their dbh was measured and frequency was taken. The NDVI was calculated in ArcGIS 10.3 environment using standard formula. A cumulative total of twenty-nine (29) families were encountered within the FCT, with 27 occurring in Abuja city (urban centre) and 12 in Lugbe (periurban centre) of the FCT. The results of Shannon-Wiener diversity index (H′) for the two centres are 3.56 and 2.24 while Shannon’s maximum diversity index (Hmax) is 6.54 (Abuja city) and 5.36 (Lugbe) for the urban (Abuja city) and periurban (Lugbe) areas of the Federal Capital Territory (FCT). The result of tree species evenness (Shannon’s equitability (EH) index) in urban and periurban centres was 0.54 and 0.42, respectively. The study provided baseline information on urban and periurban forests in the FCT of Nigeria, which can be used for the development of tree species database of the territory

Assessing climate risk to support urban forests in a changing climate

We thank Leslie Brandt and Gregory McPherson (USDA Forest Service, USA), Jakub Kronenberg (University of Lodz, Poland), Shawn Landry (University of South Florida, USA) and Per Anker Pedersen (Faculty of Landscape and Society, Norwegian University of Life Sciences) for their thoughts and contributions. MER, PR, SP and MGT thank Leigh Staas (Macquarie University) and funding from the Hort Frontiers Green Cities Fund, part of the Hort Frontiers strategic partnership initiative developed by Hort Innovation, with coinvestment from Macquarie University, Western Sydney University and the NSW Department of Planning, Industry and Environment and contributions from the Australian Government. DNB acknowledges support from the Research Council of Norway to the ENABLE project through the BiodivERsA COFUND 2015-2016 call for research proposals. BW acknowledges support from FORMAS (dia.nr 2016-20098). Finally, we thank the anonymous reviewers for their critical observations and thoughtful contributions that improved this work. The opinions and findings expressed in this paper are those of the authors and should not be construed to represent any official USDA or US Government determination or policy.Societal Impact Statement Globally, cities are planning for resilience through urban greening initiatives as governments understand the importance of urban forests in improving quality of life and mitigating climate change. However, the persistence of urban forests and the ecosystem benefits they provide are threatened by climate change, and systematic assessments of causes of tree dieback and mortality in urban environments are rare. Long-term monitoring studies and adaptive management are needed to identify and prevent climate change-driven failures and mortality. Research and monitoring when coupled with systematic forecasting will enable governments to incorporate climate change resilience into urban forestry planning. Future scenarios in which urban forests are resilient or in decline will depend on the management and planning actions we make today.The management of urban forests is a key element of resilience planning in cities across the globe. Urban forests provide ecosystem services as well as other nature-based solutions to 4.2 billion people living in cities. However, to continue to do so effectively, urban forests need to be able to thrive in an increasingly changing climate. Trees in cities are vulnerable to extreme heat and drought events, which are predicted to increase in frequency and severity under climate change. Knowledge of species' vulnerability to climate change, therefore, is crucial to ensure provision of desired ecosystem benefits, improve species selection, maintain tree growth and reduce tree mortality, dieback and stress in urban forests. Yet, systematic assessments of causes of tree dieback and mortality in urban environments are rare. We reviewed the state of knowledge of tree mortality in urban forests globally, finding very few frameworks that enable detection of climate change impacts on urban forests and no long-term studies assessing climate change as a direct driver of urban tree dieback and mortality. The effects of climate change on urban forests remain poorly understood and quantified, constraining the ability of governments to incorporate climate change resilience into urban forestry planning.Hort Frontiers Green Cities Fund, Hort Frontiers strategic partnership initiativeResearch Council of NorwaySwedish Research Council Formas 2016-2009

Assessment of Urban Forest Tree Species Population and Diversity in Ibadan, Nigeria

Abstract This research focuses on the urban tree species population and diversity within Ibadan metropolis as a means of creating biodiversity database for the urban centre in South west, Nigeria. This was determined by assessing urban forest tree abundance, species diversity and growth yield. All trees with diameter at breast height (dbh) ≥ 10 cm were identified, dbh measured and their frequencies taken in all the area enumerated within Ibadan. There are 155 tree stems belonging to 26 families and 54 tree species within Ibadan built-up areas and 101 tree stems belonging to 16 families and 19 tree species in peri-urban centre of Ibadan. The two most abundant species and families were Delonix regia of Fabaceae family and Terminalia ivorensis of Combretaceae family (18 and 17 stems) respectively while Fabaceae family has (7 species). The value of the Shannon's max diversity index (H max ) of (3.99 and 2.94), Shannon-Wiener diversity index (3.35 and 2.48) and species evenness 0.84 were the same for peri-urban centre, while the growth variable were basal area and volume of (22.8m 2 and 18.5m 2 ) and (284.8m 3 and 275.3m 3 ) respectively. This study provide information on the level of tree species biodiversity due to infrastructure development that has reduced forest cover within the built-up areas of Ibadan which can expose the city to lot of environmental hazard

Regional Examples of Forest Related Challenges and Opportunities 18 Secondary Forests in West Africa: a Challenge and Opportunity for Management

Abstract: 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