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Liang C, Serge A, Zhang X, Wang H, Wang W. Assessment of street forest characteristics in four African cities using google street view measurement: Potentials and implications. ENVIRONMENTAL RESEARCH 2023; 221:115261. [PMID: 36657594 DOI: 10.1016/j.envres.2023.115261] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 12/30/2022] [Accepted: 01/09/2023] [Indexed: 06/17/2023]
Abstract
Accurate information on urban forests of tree sizes, health state, community structures, and spatial distribution is still limited in African cities. Using a Google Street View (GSV)-based tree-size measuring method developed by our team, this paper aims to evaluate street trees of four African metropolitan cities using GSV data. The study compiled a large dataset with 46,016 street trees in 3454 sites in Kampala, Nairobi, Bloemfontein, and Johannesburg. The data including tree size (diameter at breast height, DBH; tree height, TH; underbranch height, UBH; canopy size), tree floristic composition (apical dominance types, broadleaf-conifer-palm leaf, flowering or not), tree health (leaf color, diebacks, dead tree, and bracket-supporting percent), streetside development (lane number, roadside shops, parking vehicle, and pedestrian density), and geolocation (latitude, longitude). These data can be spatially visualized with the help of ArcGIS, and the large dataset favors reliable maps from the street-view level. Data statistics showed that four cities were dominated by broad-leaved, apical dominance, and flowering trees, with a low level of unhealthy leaves and a tiny percentage of dead. The arbor-shrubs-herb structure vegetation dominated all four cities. Kampala had the most slender trees (DBH = 23 cm, TH = 8.4 m), while Nairobi and Johannesburg had the thickest trees (DBH = 38 cm, TH = 8.5-8.6 m). Bare land rates were lowest at 23% in Bloemfontein and highest at 33% in Nairobi. Principal analysis and Pearson correlations showed that these tree variations were closely associated with street development and local land use configuration. By comparing the urban tree data in other regions of the world, we found that the trees in African cities are generally giant but have a lower density (the trees within a 100-m street segment). Our findings emphasized that GSV data is feasible enough for urban forest monitoring in Africa, and the database is helpful for urban landscape planning and management.
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Affiliation(s)
- Chentao Liang
- Key Laboratory of Forest Plant Ecology (MOE), Heilongjiang Provincial Key Laboratory of Ecological Utilization of Forestry-based Active Substances, College of Chemistry, Chemical Engineering and Resource Utilization, Northeast Forestry University, Harbin, 150040, China
| | - Angali Serge
- Key Laboratory of Forest Plant Ecology (MOE), Heilongjiang Provincial Key Laboratory of Ecological Utilization of Forestry-based Active Substances, College of Chemistry, Chemical Engineering and Resource Utilization, Northeast Forestry University, Harbin, 150040, China
| | - Xu Zhang
- Key Laboratory of Forest Plant Ecology (MOE), Heilongjiang Provincial Key Laboratory of Ecological Utilization of Forestry-based Active Substances, College of Chemistry, Chemical Engineering and Resource Utilization, Northeast Forestry University, Harbin, 150040, China
| | - Huimei Wang
- State Key Laboratory of Subtropical Silviculture, College of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, 311300, Zhejiang, China.
| | - Wenjie Wang
- Key Laboratory of Forest Plant Ecology (MOE), Heilongjiang Provincial Key Laboratory of Ecological Utilization of Forestry-based Active Substances, College of Chemistry, Chemical Engineering and Resource Utilization, Northeast Forestry University, Harbin, 150040, China; Urban forests and wetlands group, Northeast Institute of Geography and Agroecology, Changchun 130102, China; State Key Laboratory of Subtropical Silviculture, College of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, 311300, Zhejiang, China.
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Pataki DE, Alberti M, Cadenasso ML, Felson AJ, McDonnell MJ, Pincetl S, Pouyat RV, Setälä H, Whitlow TH. The Benefits and Limits of Urban Tree Planting for Environmental and Human Health. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.603757] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Many of the world’s major cities have implemented tree planting programs based on assumed environmental and social benefits of urban forests. Recent studies have increasingly tested these assumptions and provide empirical evidence for the contributions of tree planting programs, as well as their feasibility and limits, for solving or mitigating urban environmental and social issues. We propose that current evidence supports local cooling, stormwater absorption, and health benefits of urban trees for local residents. However, the potential for urban trees to appreciably mitigate greenhouse gas emissions and air pollution over a wide array of sites and environmental conditions is limited. Consequently, urban trees appear to be more promising for climate and pollution adaptation strategies than mitigation strategies. In large part, this is due to space constraints limiting the extent of urban tree canopies relative to the current magnitude of emissions. The most promising environmental and health impacts of urban trees are those that can be realized with well-stewarded tree planting and localized design interventions at site to municipal scales. Tree planting at these scales has documented benefits on local climate and health, which can be maximized through targeted site design followed by monitoring, adaptive management, and studies of long-term eco-evolutionary dynamics.
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Nikinmaa L, Lindner M, Cantarello E, Jump AS, Seidl R, Winkel G, Muys B. Reviewing the Use of Resilience Concepts in Forest Sciences. CURRENT FORESTRY REPORTS 2020; 6:61-80. [PMID: 35747899 PMCID: PMC7612878 DOI: 10.1007/s40725-020-00110-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
PURPOSE OF REVIEW Resilience is a key concept to deal with an uncertain future in forestry. In recent years, it has received increasing attention from both research and practice. However, a common understanding of what resilience means in a forestry context and how to operationalise it is lacking. Here, we conducted a systematic review of the recent forest science literature on resilience in the forestry context, synthesizing how resilience is defined and assessed. RECENT FINDINGS Based on a detailed review of 255 studies, we analysed how the concepts of engineering resilience, ecological resilience and social-ecological resilience are used in forest sciences. A clear majority of the studies applied the concept of engineering resilience, quantifying resilience as the recovery time after a disturbance. The two most used indicators for engineering resilience were basal area increment and vegetation cover, whereas ecological resilience studies frequently focus on vegetation cover and tree density. In contrast, important social-ecological resilience indicators used in the literature are socioeconomic diversity and stock of natural resources. In the context of global change, we expected an increase in studies adopting the more holistic social-ecological resilience concept, but this was not the observed trend. SUMMARY Our analysis points to the nestedness of these three resilience concepts, suggesting that they are complementary rather than contradictory. It also means that the variety of resilience approaches does not need to be an obstacle for operationalisation of the concept. We provide guidance for choosing the most suitable resilience concept and indicators based on the management, disturbance and application context.
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Affiliation(s)
- L. Nikinmaa
- European Forest Institute, Platz der Vereinten Nationen 7, 53113 Bonn, Germany
- Division of Forest, Nature and Landscape, KU Leuven, Celestijnenlaan 200E, Box 2411, 3001 Leuven, Belgium
| | - M. Lindner
- European Forest Institute, Platz der Vereinten Nationen 7, 53113 Bonn, Germany
| | - E. Cantarello
- Department of Life and Environmental Sciences, Bournemouth University, Poole BH12 5BB, UK
| | - A. S. Jump
- Biological and Environmental Sciences, University of Stirling, Stirling FK9 4LA, UK
| | - R. Seidl
- Institute of Silviculture, Department of Forest- and Soil Sciences, University of Natural Resources and Life Sciences in Vienna, Peter Jordan Str. 82, 1190 Vienna, Austria
- Ecosystem Dynamics and Forest Management Group, School of Life Sciences, Technical University of Munich, Hans-Carl-von-Carlowitz-Platz 2, 85354 Freising, Germany
| | - G. Winkel
- European Forest Institute, Platz der Vereinten Nationen 7, 53113 Bonn, Germany
| | - B. Muys
- Division of Forest, Nature and Landscape, KU Leuven, Celestijnenlaan 200E, Box 2411, 3001 Leuven, Belgium
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Rötzer T, Rahman MA, Moser-Reischl A, Pauleit S, Pretzsch H. Process based simulation of tree growth and ecosystem services of urban trees under present and future climate conditions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 676:651-664. [PMID: 31051370 DOI: 10.1016/j.scitotenv.2019.04.235] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 04/15/2019] [Accepted: 04/15/2019] [Indexed: 06/09/2023]
Abstract
Global processes of urban growth lead to severe environmental impacts such as temperature increase with an intensification of the urban heat island effect, and hydrological changes with far reaching consequences for plant growth and human health and well-being. Urban trees can help to mitigate the negative effects of climate change by providing ecosystem services such as carbon storage, shading, cooling by transpiration or reduction of rainwater runoff. The extent of each ecosystem service is closely linked with the tree species as well as with a tree's age, size, structure and vitality. To evaluate the ecosystem services of urban trees, the process-based growth model CityTree was developed which is able to estimate not only tree growth but also the species-specific ecosystem services including carbon storage, transpiration and runoff, shading, and cooling by transpiration. The model was parametrized for the species small-leaved lime (Tilia cordata), robinia (Robinia pseudoacacia), plane (Platanus×acerifolia) and horse chestnut (Aesculus hippocastanum). The model validation for tree growth (stem diameter increment, coefficient of correlation=0.76) as well as for the water balance (transpiration, coefficient of correlation=0.92) seems plausible and realistic. Tree growth and ecosystem services were simulated and analyzed for Central European cities both under current climate conditions and for the future climate scenarios. The simulations revealed that urban trees can significantly improve the urban climate and mitigate climate change effects. The quantity of the improvements depends on tree species and tree size as well as on the specific site conditions. Such simulation scenarios can be a proper basis for planning options to mitigate urban climate changes in individual cities.
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Affiliation(s)
- T Rötzer
- Technical University Munich, Hans-Carl-von-Carlowitz-Platz 2, 85354 Freising, Germany.
| | - M A Rahman
- Technical University of Munich, Emil-Ramann-Straße 6, 85354 Freising, Germany
| | - A Moser-Reischl
- Technical University Munich, Hans-Carl-von-Carlowitz-Platz 2, 85354 Freising, Germany
| | - S Pauleit
- Technical University of Munich, Emil-Ramann-Straße 6, 85354 Freising, Germany
| | - H Pretzsch
- Technical University Munich, Hans-Carl-von-Carlowitz-Platz 2, 85354 Freising, Germany
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