The urban forest of Mexico City: structure and diversity across land use and boroughs

The effects of land tenure and land use on the urban forest structure and composition of Melbourne

Urban forests provide important ecosystem services, but species composition and canopy structure influence provisioning of these services and long-term stability of the urban canopy. Two landscape-scale data sets (presettlement land surveys and an urban tree census) were used to explore relationships among modern land use, presettlement vegetation, and urban forest canopy structure, size structure, and composition in the Chicago, Illinois, U.S., metropolitan region. Presettlement vegetation and modern land use combined to influence urban forest composition and structure. Modern forested areas with high native species dominance, canopy cover, and structural complexity were associated with forest (rather than prairie) vegetation in the presettlement landscape. Oaks (Quercus spp.), which dominated presettlement forests and provide high ecosystem service value because of their large stature and wildlife value, were strongly associated with presettlement forest areas and modern natural areas. The Chicago region is in a transitional state where composition and structure of larger size classes is heavily tied to pre-urban vegetation. In the future, this landscape is likely to experience a shift in dominance from oaks to smaller-statured, shorter-lived non-native and opportunistic species. This shift, along with climatic change and introduction of exotic pests, may result in an urban forest with reduced potential to provide important ecosystem services.

To achieve resilience goals, urban planners and decision-makers need accurate information on the benefits provided by urban trees and on the effects that management may have on them. This study investigates the impacts of management and disturbances on urban forest structure and function in Turku, Finland. Using a comprehensive urban tree database and the i-Tree software suite, we assessed the current structure and estimated the value of ecosystem services provided by Turku's urban forest. Additionally, we simulated changes in the urban forest over a 50-year period, considering different tree planting scenarios and the potential outbreak of the Asian longhorned beetle (ALB). Turku's urban forest comprised 38,438 public trees, dominated by Acer platanoides, Pinus sylvestris, Tilia × europaea, and Betula pendula. The estimated carbon storage was 12,336 t, valued at 1.98 million €, with an annual sequestration rate of 284 t (45,549 €/year). The trees also removed 8.97 t of pollutants annually, with an estimated value of 153,273 €. At the current rate of tree planting, the number of trees would decline over the course of 50 years resulting in a gradual decrease in the provision of ecosystem services. Although doubling the tree planting rate could slowly increase carbon storage and sequestration even under moderate ALB attack, it was insufficient to offset the damage caused by ALB if tree mortality rate reaches 50%. Compared to carbon storage and sequestration, changes in urban forest age structure had a more immediate impact on the removal of air pollution. These findings emphasize the importance of prioritizing investments in urban forests on grounds of their capacity to provide diverse ecosystem services. Incorporating these findings into decision-making processes would promote sustainable and resilient urban environments.

A method combining numeric data collection with the preparation of street tree cross-sections and plans, based on surveys of 33 urban forests around the world, is reviewed. The combination can provide design professionals with graphic information on urban forest structure not collected by more traditional methods for urban forest inventories.

Land use and socio-economic determinants of urban forest structure and diversity

Urban forest can help decrease land surface temperature (LST) and create urban cooling effect (UCI) to mitigate urban heat island (UHI). However, it is still unclear how urban forest structure and its location affect UCI, particularly under different seasons. In this study, with plot-based urban forest structure and UCI intensity extracted from Landsat-7 Enhanced Thematic Mapper Plus (ETM+) thermal data, we first conducted correlation analyses between UCI and different forest structures (crown closure, tree height, leaf area index, basal area, stem density and diameter at breast height, etc.) and spatial location (distances from buildings and from water bodies and elevation) attributes, and we then carried out quantitative regression analyses between them. Our results indicate that (1) Urban forest could create “urban cool islands”, which were higher in summer than those in autumn.(2) UCI could be significantly affected by urban forest structural attributes, especially by crown closure and LAI. All urban forest structural attributes had positive linear relationships with UCI except for LAI and basal area which had positive non-linear relationships with UCI.; (3) UCI in urban forest could also be affected by its spatial location but not by its elevation. The UCI non-linearly decreased with decreasing distance from buildings and with increasing distance from water bodies. The threshold values of DB for significantly affecting UCI variation is approximately between 100 m and 300 m in summer and autumn, respectively; and (4) the relationships between UCI and urban forest structure and its location attributes were complex and seasonal dependent. Urban forest attributes had greater effects on increasing UCI in summer than those in autumn. These findings would deepen our understanding of interactions between UCI and urban forest attributes and provide urban planners with useful information about how to design urban forest to effectively mitigate UHI effects.

Spatial estimation of urban forest structures with Landsat TM data and field measurements

Quantifying urban forest structure with open-access remote sensing data sets

Private trees contribute uniquely to urban forest diversity, structure and service-based traits

城市森林碳汇及其抵消能源碳排放效果——以广州为例

Some determinants of urban forest structure

Understanding the relationship between various socioeconomic factors and urban forest structure is essential for directing resources to ensure equitable distribution of green space. Through a case study of a desert city, i.e., Phoenix, AZ, this study provides a novel application of Multiscale Geographically Weighted Regression (MGWR) in which we explore the spatially variable relationships between a wide array of socioeconomic indicators and urban forest attributes. Through the computation of various scales of influence for different explanatory variables, MGWR enhances our analysis’s precision and stresses the association between socioeconomic status and urban forest structure at local and regional scales. Our results indicate that although there has been a pattern of green inequality where minority and low-income communities have less access to urban forests, education levels were mostly insignificant based on the MGWR results. In some instances, higher incomes are negatively correlated with tree canopy coverage. Additionally, the stem density model outperformed the canopy coverage model in terms of prediction accuracy. This research adds a new dimension to urban forestry literature and emphasizes the value of customized urban planning strategies and the environmental justice implications of urban forestry, particularly in arid environments.

Spatial heterogeneity and air pollution removal by an urban forest

The urban forest is a valuable ecosystem service provider that is garnering increasing attention in environmental research and municipal planning agendas. However, because of its location in heavily built-up and densely-settled environments, the urban forest is vulnerable. The purpose of this dissertation is to conceptualize, assess, and analyze urban forest ecosystems and their vulnerability at multiple spatial and temporal scales. An urban forest ecosystem classification framework that integrates biophysical, built, and human components is developed. Subsequent classification of ecosystems at the neighbourhood scale reveals the spatial arrangement of several social-ecological interactions. Such information is valuable to ecosystem-based decision support while also informing future vulnerability research. The investigation of ecosystem vulnerability began with the development of a theory-based conceptual framework. Urban forest vulnerability is defined as the likelihood of decline in ecosystem service supply and its associated benefits for human populations, urban infrastructure, and biodiversity. It is comprised of exposure, sensitivity, and adaptive capacity, which describe the built environment and associated stressors, urban forest structure, and the human population, respectively. This framework is applied using empirical field research in Toronto, Canada to explore the processes of vulnerability and their influence on ecological change. Results indicate that there are several significant predictors of urban forest decline and mortality, and emphasize the importance of applying diverse metrics to describe the built environment and urban forest structure at fine spatial scales. Vulnerability assessment and analysis at much broader spatial and temporal scales, using a spatially-explicit assessment approach and ecological modelling of alternative management and disturbance scenarios, is further investigated. This latter research emphasizes the importance of aligning scales of management with ecosystem function and the long-term influence of management intervention on ecological conditions. The multiple scales of investigation and methodological approaches developed in this study provide complementary opportunities to synthesize and apply existing theory in novel settings while also generating new theories pertaining to the processes of urban ecosystem change and decline. The intention of this study is to contribute to the understanding of urban forest ecosystems and their vulnerability, while also providing practical knowledge and tools for the sustainable management of this resource.

The urban forest is a valuable ecosystem service provider that is garnering increasing attention in environmental research and municipal planning agendas. However, because of its location in heavily built-up and densely-settled environments, the urban forest is vulnerable. The purpose of this dissertation is to conceptualize, assess, and analyze urban forest ecosystems and their vulnerability at multiple spatial and temporal scales. An urban forest ecosystem classification framework that integrates biophysical, built, and human components is developed. Subsequent classification of ecosystems at the neighbourhood scale reveals the spatial arrangement of several social-ecological interactions. Such information is valuable to ecosystem-based decision support while also informing future vulnerability research. The investigation of ecosystem vulnerability began with the development of a theory-based conceptual framework. Urban forest vulnerability is defined as the likelihood of decline in ecosystem service supply and its associated benefits for human populations, urban infrastructure, and biodiversity. It is comprised of exposure, sensitivity, and adaptive capacity, which describe the built environment and associated stressors, urban forest structure, and the human population, respectively. This framework is applied using empirical field research in Toronto, Canada to explore the processes of vulnerability and their influence on ecological change. Results indicate that there are several significant predictors of urban forest decline and mortality, and emphasize the importance of applying diverse metrics to describe the built environment and urban forest structure at fine spatial scales. Vulnerability assessment and analysis at much broader spatial and temporal scales, using a spatially-explicit assessment approach and ecological modelling of alternative management and disturbance scenarios, is further investigated. This latter research emphasizes the importance of aligning scales of management with ecosystem function and the long-term influence of management intervention on ecological conditions. The multiple scales of investigation and methodological approaches developed in this study provide complementary opportunities to synthesize and apply existing theory in novel settings while also generating new theories pertaining to the processes of urban ecosystem change and decline. The intention of this study is to contribute to the understanding of urban forest ecosystems and their vulnerability, while also providing practical knowledge and tools for the sustainable management of this resource.