scholarly journals Origins of the Chicago Urban Forest: Composition and Structure in Relation to Presettlement Vegetation and Modern Land Use

2012 ◽  
Vol 38 (5) ◽  
pp. 181-193
Author(s):  
Robert Fahey ◽  
Marlin Bowles ◽  
Jeanette McBride

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.

2018 ◽  
Vol 04 (04) ◽  
pp. 1850022 ◽  
Author(s):  
Benjamin A. Jones ◽  
John Fleck

Managing outdoor water use while maintaining urban tree cover is a key challenge for water managers in arid climates. Urban trees generate flows of ecosystem services in arid areas, but also require significant amounts of irrigation. In this paper, a bioeconomic-health model of trees and water use is developed to investigate management of an urban forest canopy when irrigation is costly, water has economic value, and trees provide ecosystem services. The optimal tree irrigation decision is illustrated for Albuquerque, New Mexico, an arid Southwest US city. Using a range of monetary values for water, we find that the tree irrigation decision is sensitive to the value selected. Urban deforestation is optimal when the value of water is sufficiently high, or alternatively starts low, but grows to cross a specific threshold. If, however, the value of water is sufficiently low or if the value of tree cover rises over time, then deforestation is not optimal. The threshold value of water where the switch is made between zero and partial deforestation is well within previously identified ranges on actual water values. This model can be applied generally to study the tradeoffs between urban trees and water use in arid environments.


2020 ◽  
Vol 12 (11) ◽  
pp. 1820
Author(s):  
Raoul Blackman ◽  
Fei Yuan

Urban forests provide ecosystem services; tree canopy cover is the basic quantification of ecosystem services. Ground assessment of the urban forest is limited; with continued refinement, remote sensing can become an essential tool for analyzing the urban forest. This study addresses three research questions that are essential for urban forest management using remote sensing: (1) Can object-based image analysis (OBIA) and non-image classification methods (such as random point-based evaluation) accurately determine urban canopy coverage using high-spatial-resolution aerial images? (2) Is it possible to assess the impact of natural disturbances in addition to other factors (such as urban development) on urban canopy changes in the classification map created by OBIA? (3) How can we use Light Detection and Ranging (LiDAR) data and technology to extract urban canopy metrics accurately and effectively? The urban forest canopy area and location within the City of St Peter, Minnesota (MN) boundary between 1938 and 2019 were defined using both OBIA and random-point-based methods with high-spatial-resolution aerial images. Impacts of natural disasters, such as the 1998 tornado and tree diseases, on the urban canopy cover area, were examined. Finally, LiDAR data was used to determine the height, density, crown area, diameter, and volume of the urban forest canopy. Both OBIA and random-point methods gave accurate results of canopy coverages. The OBIA is relatively more time-consuming and requires specialist knowledge, whereas the random-point-based method only shows the total coverage of the classes without locational information. Canopy change caused by tornado was discernible in the canopy OBIA-based classification maps while the change due to diseases was undetectable. To accurately exact urban canopy metrics besides tree locations, dense LiDAR point cloud data collected at the leaf-on season as well as algorithms or software developed specifically for urban forest analysis using LiDAR data are needed.


2015 ◽  
Vol 41 (1) ◽  
pp. 169-174 ◽  
Author(s):  
Akira KATO ◽  
Yuma OKITSU ◽  
Nobumitsu TSUNEMATSU ◽  
Tsuyoshi HONJYO ◽  
Tatsuaki KOBAYASHI ◽  
...  

Author(s):  
Z. Uçar ◽  
R. Eker ◽  
A. Aydin

Abstract. Urban trees and forests are essential components of the urban environment. They can provide numerous ecosystem services and goods, including but not limited to recreational opportunities and aesthetic values, removal of air pollutants, improving air and water quality, providing shade and cooling effect, reducing energy use, and storage of atmospheric CO2. However, urban trees and forests have been in danger of being lost by dense housing resulting from population growth in the cities since the 1950s, leading to increased local temperature, pollution level, and flooding risk. Thus, determining the status of urban trees and forests is necessary for comprehensive understanding and quantifying the ecosystem services and goods. Tree canopy cover is a relatively quick, easy to obtain, and cost-effective urban forestry metric broadly used to estimate ecosystem services and goods of the urban forest. This study aimed to determine urban forest canopy cover areas and monitor the changes between 1984–2015 for the Great Plain Conservation area (GPCA) that has been declared as a conservation Area (GPCA) in 2017, located on the border of Düzce City (Western Black Sea Region of Turkey). Although GPCA is a conservation area for agricultural purposes, it consists of the city center with 250,000 population and most settlement areas. A random point sampling approach, the most common sampling approach, was applied to estimate urban tree canopy cover and their changes over time from historical aerial imageries. Tree canopy cover ranged from 16.0% to 27.4% within the study period. The changes in urban canopy cover between 1984–1999 and 1999–2015 were statistically significant, while there was no statistical difference compared to the changes in tree canopy cover between 1984–2015. The result of the study suggested that an accurate estimate of urban tree canopy cover and monitoring long-term canopy cover changes are essential to determine the current situation and the trends for the future. It will help city planners and policymakers in decision-making processes for the future of urban areas.


Land ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 22
Author(s):  
Wei Shui ◽  
Kexin Wu ◽  
Yong Du ◽  
Haifeng Yang

Bay areas are endowed with unique sea and land resources, location advantages, and high environmental carrying capacities. The rapid urbanization process has intensified the demand for limited natural resources, leading to a series of problems in coastal zones such as land use conflicts and the degradation of ecosystem services. Taking Quanzhou, a bay city in a metropolitan region, as an example, this paper established an accounting model of ecosystem services supply and consumption demand based on multisource data (meteorological site data, land use data and statistical data). We estimated the supply capacity and consumption demand of provisioning services, regulating services, and cultural services in Quanzhou from 2005 to 2015. In addition, the supply and demand of ecosystem services were simulated for 2030 under different scenarios. The results showed that the supply capacity of ecosystem services in Quanzhou was greater than the demand in general, but the supply-demand difference showed a gradual decrease. The high-value areas of supply capacity were concentrated in the upstream basin in the non-bay area, while the high-value areas of consumption demand were located downstream of the river basin in the bay area. The supply-demand difference in the bay area was negative, indicating that it was in a state of supply-demand imbalance and that the ecological security was under threat. Among the three simulated scenarios in 2030, the balance between supply and demand declined compared with the results of 2015, with the most serious decline in the natural scenario. The method to quantify the evolution of spatial and temporal patterns in supply and demand of ecosystem services could provide a decision-making reference for natural resource management in Quanzhou. This is conducive to the improvement and establishment of urban ecological security research systems, especially in bay areas that are lacking research.


Data ◽  
2019 ◽  
Vol 4 (4) ◽  
pp. 145
Author(s):  
Fabien H. Wagner ◽  
Mayumi C.M. Hirye

Mapping urban trees with images at a very high spatial resolution (≤1 m) is a particularly relevant recent challenge due to the need to assess the ecosystem services they provide. However, due to the effort needed to produce these maps from tree censuses or with remote sensing data, few cities in the world have a complete tree cover map. Here, we present the tree cover data at 1-m spatial resolution of the Metropolitan Region of São Paulo, Brazil, the fourth largest urban agglomeration in the world. This dataset, based on 71 orthorectified RGB aerial photographs taken in 2010 at 1-m spatial resolution, was produced using a deep learning method for image segmentation called U-net. The model was trained with 1286 images of size 64 × 64 pixels at 1-m spatial resolution, containing one or more trees or only background, and their labelled masks. The validation was based on 322 images of the same size not used in the training and their labelled masks. The map produced by the U-net algorithm showed an excellent level of accuracy, with an overall accuracy of 96.4% and an F1-score of 0.941 (precision = 0.945 and recall = 0.937). This dataset is a valuable input for the estimation of urban forest ecosystem services, and more broadly for urban studies or urban ecological modelling of the São Paulo Metropolitan Region.


2010 ◽  
Vol 40 (5) ◽  
pp. 872-884 ◽  
Author(s):  
Torbjörn Josefsson ◽  
Björn Gunnarson ◽  
Lars Liedgren ◽  
Ingela Bergman ◽  
Lars Östlund

In studies on natural dynamics, biodiversity and reference conditions legacies of preindustrial human land use are often neglected. In this study, using archaeology and dendrochronology combined with field surveys on present forest characteristics, we assessed the naturalness of a protected forest landscape and examined the role of indigenous peoples in shaping forest structure in the past. Our results show that the studied Scots pine ( Pinus sylvestris L.) forest conforms to the generally accepted impression of pristine forests and that it has a long history of human utilization. Areas with human presence over long time periods, especially in and near settlements, show significant differences in current forest characteristics compared with the rest of the landscape: the forest is younger (mean age 140–190 years compared with >300 years), the volumes of deadwood lower (8–13 m3·ha–1 compared with >20 m3·ha–1), and the tree species composition is substantially different from the surrounding forest. We suggest that these disparities are strongly linked to past land use and that indigenous people can alter ecosystems substantially and that the legacies of their activity may last for centuries. Consequently, in ecological research and conservation strategies, forest characteristics should always be considered in the light of their historical context.


2017 ◽  
pp. 25 ◽  
Author(s):  
Bárbara Heliodora Alves d'Ancampora

ResumenLos nueve manglares existentes de la Región Metropolitana de Florianópolis se encuentran en diferentes estados de degradación ambiental por la ocupación inadecuada del entorno físico a lo largo de la historia. Dentro de este marco, esta investigación tiene como objetivo caracterizar espacialmente el paisaje cultural de los manglares de la Región Metropolitana, en cuanto a los factores naturales y humanos, contrastándolo con el paisaje percibido por la población residente nativa y la residente temporal y visitante. Este hecho está relacionado con el valor cultural atribuido a este tipo paisaje a través del grado de conocimiento de la población sobre los componentes bióticos y abióticos, los servicios ecosistémicos, los impactos ambientales generados y los cambios para el futuro. Como conclusión, se ha verificado que la percepción de la población sobre este paisaje se presenta de forma muy diferente de la realidad física y ambiental, demostrando disparidades relevantes entre ambos.Palabras clave  Manglares, uso del suelo, paisaje cultural, impacto ambientalAbstractThe nine existing mangroves of the Metropolitan Region of Florianópolis are in different states of environmental degradation. The causes are derived from the inadequate occupation of the physical environment throughout history. Regarding this fact, this research aims to spatially characterize the cultural landscape of the Metropolitan Region’s mangroves, in terms of natural and human factors, contrasting with the landscape perceived by the native resident population, the temporary resident, and the visitor. This analysis is related to the cultural value attributed to this landscape type through the degree of knowledge of the population about the biotic and abiotic components, the ecosystem services, the generated environmental impacts and the changes for the future. As a conclusion, it has been verified that the perception of the population on this landscape is presented in a very different way from the physical and environmental reality, showing relevant disparities between both. KeywordsMangroves, land use, cultural landscape, environmental impact


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