scholarly journals Different Responses of Evapotranspiration Rates of Urban Lawn and Tree to Meteorological Factors and Soil Water in Hot Summer in a Subtropical Megacity

Forests ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1463
Author(s):  
Zhendong Zou ◽  
Chunhua Yan ◽  
Leiyu Yu ◽  
Xianchenghao Jiang ◽  
Jinshan Ding ◽  
...  
Keyword(s):  
Soil Water ◽  
Urban Areas ◽  
Vapor Pressure Deficit ◽  
Meteorological Factors ◽  
Flow System ◽  
Urban Forestry ◽  
Bowen Ratio ◽  
Rapid Urbanization ◽  
Urban Tree ◽  
And Diffusion

Urban evapotranspiration (ET) is an effective way to mitigate ecological challenges resulting from rapid urbanization. However, the characteristics of urban vegetation ET, especially how they respond to meteorological factors and soil water, remains unclear, which is crucial for urban ET regulation. Therefore, this study measured the actual ET rate of an urban lawn (ETlawn) using the Bowen ratio system and an urban tree (Ttree) by a sap flow system in the hot summer of a subtropical megacity, Shenzhen. The results showed that the daily ETlawn was more restricted by energy (Rs) and diffusion conditions (vapor pressure deficit, VPD), while the daily Ttree was more restricted by VPD and relative extractable water (REW) in the urban area. The daily Ttree decreased when the REW was lower than 0.18, while the daily ETlawn started to decrease when it was lower than 0.14. When REW was lower than 0.11, the Ttree stayed at a relatively low level. The impacts of VPD was more evident on the diurnal Ttree than on the diurnal ETlawn. Wind speed had a scarce impact as it was relatively low in urban areas. This study clarifies the different responses of ETlawn and Ttree to meteorological factors and soil water based on actual ET. The results are of great significance for the knowledge of urban forestry and urban hydrology.

scholarly journals Remotely Sensed Tree Characterization in Urban Areas: A Review

2021 ◽  
Vol 13 (23) ◽  
pp. 4889
Author(s):  
Luisa Velasquez-Camacho ◽  
Adrián Cardil ◽  
Midhun Mohan ◽  
Maddi Etxegarai ◽  
Gabriel Anzaldi ◽  
...  
Keyword(s):  
Urban Areas ◽  
Urban Forestry ◽  
Remotely Sensed ◽  
Critical Discussion ◽  
Urban Trees ◽  
Future Research ◽  
Remotely Sensed Data ◽  
Individual Tree ◽  
Processing Methods ◽  
Urban Tree

Urban trees and forests provide multiple ecosystem services (ES), including temperature regulation, carbon sequestration, and biodiversity. Interest in ES has increased amongst policymakers, scientists, and citizens given the extent and growth of urbanized areas globally. However, the methods and techniques used to properly assess biodiversity and ES provided by vegetation in urban environments, at large scales, are insufficient. Individual tree identification and characterization are some of the most critical issues used to evaluate urban biodiversity and ES, given the complex spatial distribution of vegetation in urban areas and the scarcity or complete lack of systematized urban tree inventories at large scales, e.g., at the regional or national levels. This often limits our knowledge on their contributions toward shaping biodiversity and ES in urban areas worldwide. This paper provides an analysis of the state-of-the-art studies and was carried out based on a systematic review of 48 scientific papers published during the last five years (2016–2020), related to urban tree and greenery characterization, remote sensing techniques for tree identification, processing methods, and data analysis to classify and segment trees. In particular, we focused on urban tree and forest characterization using remotely sensed data and identified frontiers in scientific knowledge that may be expanded with new developments in the near future. We found advantages and limitations associated with both data sources and processing methods, from which we drew recommendations for further development of tree inventory and characterization in urban forestry science. Finally, a critical discussion on the current state of the methods, as well as on the challenges and directions for future research, is presented.

Urbanization and Changes in Cropping Patterns at Kathmandu Valley

2007 ◽  
Vol 7 ◽  
pp. 113 ◽  
Author(s):  
Raj Man Shrestha
Keyword(s):  
Urban Areas ◽  
Cropping System ◽  
Considerable Change ◽  
Rapid Expansion ◽  
Leafy Vegetables ◽  
Kathmandu Valley ◽  
Rapid Urbanization ◽  
Average Growth ◽  
Cropping Patterns ◽  
Agriculture Land

The increase of population in Kathmandu valley is bringing a considerable change in cropping system. Rapid urbanization and introduction of new agriculture technology have encouraged the valley’s farmers to change their cropping patterns from traditional (low value crops) to new crops (high value crops). According to numerous studies made in Nepal, the change is seen considerably in winter crops than in summer crops and the land under cultivation of green leafy vegetables is increasing rapidly in the urban and semi-urban areas. An average growth of population at 3 % in the valley during the period 1951-2001 has resulted in the rapid expansion of area under urban coverage (24.6 % growth per year from 1984 - 2000) has made agriculture land of Katmandu valley to decline per year by 2.04 % (836.27 ha per year). If this trend of decline in agriculture land in Kathmandu valley continues in future too, it is expected that there will be no agriculture land left over by two and half decades in the valley. The planners should take note of this fact that if fertile land of Katmandu valley is to be preserved for agriculture necessary planning is urgently needed. <i>Nepal Journal of Science and Technology</i> Vol. 7, 2006

scholarly journals Where Do I Allocate My Urban Allotment Gardens? Development of a Site Selection Tool for Three Cities in Benin

Land ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 318
Author(s):  
B. G. J. S. Sonneveld ◽  
M. D. Houessou ◽  
G. J. M. van den Boom ◽  
A. Aoudji
Keyword(s):  
Food Insecurity ◽  
Urban Agriculture ◽  
Low Income ◽  
Urban Areas ◽  
Urban Poor ◽  
Site Suitability ◽  
Rapid Urbanization ◽  
Middle Income ◽  
Support Tool ◽  
Allotment Gardens

In the context of rapid urbanization, poorer residents in cities across low- and middle-income countries increasingly experience food and nutrition deficiencies. The United Nations has highlighted urban agriculture (UA) as a viable solution to food insecurity, by empowering the urban poor to produce their own fresh foods and make some profit from surplus production. Despite its potential role in reducing poverty and food insecurity, there appears to be little political will to support urban agriculture. This is seen in unclear political mandates that are sustained by information gaps on selection criteria for UA sites. The research reported here addresses this issue in the form of a decision-making support tool that assesses the suitability of cadastral units and informal plots for allotment gardens in urban and peri-urban areas. The tool was developed and tested for three rapidly expanding cities in Benin, a low-income country in West Africa, based on an ordered logit model that relates a set of 300 expert assessments on site suitability to georeferenced information on biophysical and socio-economic characteristics. Soil, land use, groundwater depth, vicinity to market and women’s safety were significant factors in the assessment. Scaled up across all cadastral units and informal sites, the tool generated detailed baseline maps on site suitability and availability of areas. Its capacity to support policymakers in selecting appropriate sites comes to the fore by reporting changes in site suitability under scenarios of improved soil fertility and enhanced safety for women.

Transpiration Response to Vapor Pressure Deficit in Field Grown Peanut

2012 ◽  
Vol 39 (1) ◽  
pp. 53-61 ◽  
Author(s):  
Maria Balota ◽  
Steve McGrath ◽  
Thomas G. Isleib ◽  
Shyam Tallury
Keyword(s):  
Vapor Pressure ◽  
Soil Water ◽  
Water Deficit ◽  
Water Conservation ◽  
Vapor Pressure Deficit ◽  
Stomatal Closure ◽  
Genotypic Variation ◽  
Moisture Stress ◽  
Breeding Lines ◽  
Wide Range

Abstract Water deficit, i.e., rainfall amounts and distribution, is the most common abiotic stress that limits peanut production worldwide. Even though extensive research efforts have been made to improve drought tolerance in peanut, performance of genotypes largely depends upon the environment in which they grow. Based on greenhouse experiments, it has been hypothesized that stomata closure under high vapor pressure deficit (VPD) is a mechanism of soil water conservation and it has been shown that genotypic variation for the response of transpiration rate to VPD in peanut exists. The objective of this study was to determine the relationship between stomatal conductance (gs) and VPD for field grown peanut in Virginia-Carolina (VC) rainfed environments. In 2009, thirty virginia-type peanut cultivars and advanced breeding lines were evaluated for gs at several times before and after rain events, including a moisture stress episode. In 2010, eighteen genotypes were evaluated for gs under soil water deficit. In 2009, VPD ranged from 1.3 to 4.2 kPa and in 2010 from 1.78 to 3.57 kPa. Under water deficit, genotype and year showed a significant effect on gs (P  =  0.0001), but the genotype × year interaction did not. During the water deficit episodes while recorded gs values were relatively high, gs was negatively related to VPD (R2  =  0.57, n  =  180 in 2009; R2  =  0.47, n  =  108 in 2010), suggesting that stomata closure is indeed a water conservation mechanism for field grown peanut. However, a wide range of slopes among genotype were observed in both years. Genotypes with significant negative relationships of gs and VPD under water deficit in both years were Florida Fancy, Gregory, N04074FCT, NC-V11, and VA-98R. While Florida Fancy, Gregory, and NC-V11 are known to be high yielding cultivars, VA-98R and line N04074FCT are not. The benefit of stomatal closure during drought episodes in the VC environments is further discussed in this paper.

Study on Hazard Analysis Method of Earthquake Secondary Fire Disaster in Urban Area Based on GIS

2012 ◽  
Vol 204-208 ◽  
pp. 3457-3461
Author(s):  
Tian Qi Li ◽  
Fei Geng
Keyword(s):  
Urban Areas ◽  
Hazard Analysis ◽  
Probability Model ◽  
Probability Models ◽  
Housing Density ◽  
Earthquake Excitation ◽  
Fire Disaster ◽  
High Hazard ◽  
The City ◽  
And Diffusion

In order to study the probability of occurrence of secondary fire after the earthquake in urban areas, the probability model of the hazard analysis that the fire occurred and the spread is established and applied. Probability models need to consider the destruction level of buildings under earthquake excitation as well as the probability of the leakage and diffusion of combustible material in the buildings in the corresponding destruction level, combination of weather, season, housing density and other factors to determine the probability of the single building earthquake secondary fire. On this basis , the natural administrative areas in the city as a unit , considering the factors of regional hazard analysis such as population density , property distribution and density within a region , to calculate the hazard indicator and determine the high hazard areas of secondary fire in the city. The Geographic Information System was used as the platform, to division of urban earthquake secondary fire high-hazard areas.

scholarly journals Towards eco-social housing in Vietnam: challenges and opportunities

2018 ◽  
Vol 193 ◽  
pp. 01001
Author(s):  
Van Thuong Le ◽  
Tuan Tran ◽  
Truc Truong
Keyword(s):  
Low Income ◽  
Social Housing ◽  
Urban Areas ◽  
Housing Demand ◽  
Living Conditions ◽  
Local Economy ◽  
Rapid Urbanization ◽  
Long Run ◽  
Challenges And Opportunities ◽  
The Government

Since Doi Moi (Reform) policy in 1986, Vietnam has experienced rapid urbanization and economic growth. Urbanization has resulted in increasingly high housing demand in the urban areas but this has largely unmet, especially housing for low-income people. Development of social housing for low-income and under-privileged people in cities has been seen as an urgent and important task of the government to pursue stable social and economic development. Low-income people are most vulnerable to environmental impacts and in need of energy-efficient houses to reduce their cost of living. Eco-social housing is seen as a solution to protect the natural environment as well as to boost local economy, improve living conditions particularly for low income people. Through preliminary assessments of three social buildings at three distinct regions of Vietnam, this paper found that despite many challenges, eco-social housing is a solution to Vietnam's needs in providing houses with adequate living conditions to low-income people while protecting the environment and achieving sustainable eco-social development in the long run.

scholarly journals Spatial–Temporal Impacts of Urban Sprawl on Ecosystem Services: Implications for Urban Planning in The Process of Rapid Urbanization

Land ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1210
Author(s):  
Xiaoyan Li ◽  
Gulinaer Suoerdahan ◽  
Zhenyu Shi ◽  
Zihan Xing ◽  
Yongxing Ren ◽  
...  
Keyword(s):  
Ecosystem Services ◽  
Urban Planning ◽  
Carbon Storage ◽  
Crop Yield ◽  
Urban Sprawl ◽  
Habitat Suitability ◽  
Urban Areas ◽  
Water Retention ◽  
Rapid Urbanization ◽  
Study Region

Rapid urbanization drives land cover change, affecting urban ecosystems and inducing serious environmental issues. The study region of Changchun, China was divided into three urbanization categories according to different urbanization levels and the characteristics of urban sprawl and changes and relationships between typical ecosystem services (ESs) under rapid urbanization were analysed. The results showed that Changchun has undergone considerable urban expansion since 2000, which has significantly impacted all ESs in terms of spatial and temporal heterogeneity. Habitat suitability and crop yield have relatively stronger service capacity in the study area. Since the expansion of large-scale infrastructures, the mean ES values of developed urban areas are the lowest among the three zones, except for water retention and sandstorm prevention in 2015, when the balance between all services decreased. Over the past 16 years, habitat suitability in developing urban areas has decreased to a large extent due to urban sprawl. Because of the improvement in agricultural science and technology, crop yield in three regions increased, while the area of cropland reduced from 1720 km2 to 1560 km2 (9.3%). Synergies between habitat suitability and carbon storage and habitat suitability and soil retention were detected in three areas. A trade-off between habitat suitability and water retention was detected in three areas. The interactions between crop yield and carbon storage, habitat suitability, and soil retention were more complex in this study region. In addition to water retention, urbanization index has a negative correlation with ESs. According to the results, some suggestions to alleviate ES loss during the process of rapid urbanization were proposed, which may guide scientific urban planning for sustainable urban development.

scholarly journals DOENÇA DE CROHN

2017 ◽  
Vol 4 (2) ◽  
pp. 25
Author(s):  
Nicolas Garcia Papacosta ◽  
Gabriel Martins Nunes ◽  
Renato Jácomo Pacheco ◽  
Macaulay Viturino Cardoso ◽  
Virgílio Ribeiro Guedes
Keyword(s):  
Inflammatory Bowel Disease ◽  
Crohn’S Disease ◽  
Crohn's Disease ◽  
Bowel Disease ◽  
Urban Areas ◽  
Diagnostic Techniques ◽  
Rapid Urbanization ◽  
De Se ◽  
Inflammatory Bowel ◽  
Keywords Crohn's Disease

INTRODUÇÃO: A doença de Crohn é qualificada como uma doença inflamatória intestinal, de caráter crônico, recidivante, transmural e que pode afetar qualquer parte do trato digestivo, desde a boca até o ânus, mas, principalmente, o intestino delgado e o cólon. São de cunho multifatorial, com prevalência e incidência variando de acordo com a genética, meio ambiente, microbiota intestinal e até mesmo um possível agente entérico infeccioso. É uma doença que afeta pessoas de várias idades, sexos e raças, apesar de se verificar maior incidência em jovens do sexo feminino e em regiões urbanas. METODOLOGIA: Trata-se de um artigo de revisão no qual, a partir das palavras “doença de Crohn” e “doença inflamatórias intestinais”, foi realizado busca por periódicos nos bancos de dados: PubMed, Scielo, Portal Periódicos CAPES e Google acadêmico. CONCLUSÃO: A doença de Crohn apresenta uma importante taxa de morbimortalidade no mundo, principalmente em regiões em franca urbanização e industrialização. O diagnóstico é um procedimento extremamente complicado devido a sua clínica inespecífica e pelos vários aspetos em comum com outras patologias. Dessa forma, ainda se faz necessário uma melhor investigação científica na área, com intuito de se desenvolver melhores técnicas diagnosticas e condutas a serem tomadas no seguimento e cura dessa patologia.Palavras-chave: Doença de Crohn, Doença inflamatórias intestinais, Diarreia. ABSTRACT INTRODUCTION: Crohn's disease is described as an inflammatory, chronic, recurrent, transmural inflammatory disease that can affect any part of the digestive tract, from the mouth to the anus, but especially the small intestine and colon. They are multifactorial, with prevalence and incidence varying according to genetics, environment, intestinal microbiota and even a possible infectious enteric agent. It is a disease that affects people of various ages, sexes and races, although there is a greater incidence in young women and in urban areas. METHODOLOGY: This is a review article in which, from the words "Crohn's disease" and "inflammatory bowel disease", a search was made for journals in the databases: PubMed, Scielo, Portal Periódicos CAPES and Google academic. CONCLUSION: Crohn's disease presents an important morbidity and mortality rate in the world, especially in regions where there is rapid urbanization and industrialization. Diagnosis is an extremely complicated procedure due to its nonspecific clinical and various aspects in common with other pathologies. Thus, a better scientific investigation in the area is still necessary, in order to develop better diagnostic techniques and behaviors to be taken in the follow-up and cure of this pathology.                                              Keywords: Crohn's disease, Inflammatory bowel disease, Diarrhea.

scholarly journals The impact of urbanization expansion on agricultural land in Ethiopia: A review

2020 ◽  
Vol 8 (4) ◽  
pp. 73-80
Author(s):  
Assefa Ayele ◽  
Kassa Tarekegn
Keyword(s):  
Urban Areas ◽  
Agricultural Land ◽  
Urban Expansion ◽  
Rural Livelihoods ◽  
Vital Role ◽  
Rapid Urbanization ◽  
Economic Resource ◽  
House Construction ◽  
Impact Of Urbanization ◽  
The Impact

AbstractIn a country like Ethiopia where the vast majority of the populations are employed in agriculture, land is an important economic resource for the development of rural livelihoods. Agricultural land in peri-urban areas is, however, transformed into built-up regions through horizontal urban expansion that has an effect on land use value. In recent years Ethiopia has been experiencing rapid urbanization, which has led to an ever-increasing demand for land in peri-urban areas for housing and other nonagricultural activities that pervades agricultural land. There is a high demand for informal and illegal peri-urban land which has been held by peri-urban farmers, and this plays a vital role in the unauthorized and sub-standard house construction on agricultural land. This urbanization has not been extensively reviewed and documented. In this review an attempt has been made to assess the impacts of rapid urbanization on agricultural activities. Urban expansion has reduced the areas available for agriculture, which has seriously impacted upon peri-urban farmers that are often left with little or no land to cultivate and which has increased their vulnerability. Housing encroachments have been observed to be uncontrolled due to a weak government response to the trend of unplanned city expansion. This has left peri-urban farmers exposed to the negative shocks of urbanization because significant urbanization-related agricultural land loss has a positive correlation with grain production decrease. Appropriate governing bodies should control urban development in order to control the illegal and informal spread of urbanization on agricultural land that threatens food production.

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