scholarly journals The Variation of Air Purification Benefit Provided by Street Tree Assemblages in Shenyang, China

2021 ◽  
Author(s):  
Jing Yao ◽  
Miao Liu ◽  
Nina Chen ◽  
Wei Chen ◽  
Xiaobo Wang ◽  
...  
Keyword(s):  
Ecosystem Services ◽  
Urban Form ◽  
Time Lag ◽  
Road Construction ◽  
Vegetation Management ◽  
Air Purification ◽  
Street Trees ◽  
Street Tree ◽  
Significant Difference ◽  
Tree Assemblages

Abstract Street tree assemblages are a widespread natural component in cities and provide a range of ecosystem services. The spatial distribution of street tree assemblages within cities, however, is not uniform. We assessed the air purification benefits provided by street trees in Shenyang, China, to examine how urban form, urban geography and drivers of vegetation management affect this ecosystem service. The i-Tree Street Model was utilized to evaluate air purification benefits provided by street trees. We analyzed the results using two indices, with values expressed in US dollars (USD, $): the per kilometer benefit (PKB) and average tree benefit (ATB). Neither index displayed a consistent trend across the human population density gradient or along the urban-suburban continuum. The district with the highest PKB and ATB is neither the oldest nor the newest one to develop, but rather the one that began to develop around 2002. We conclude that public policy is a main driver of vegetation management, especially for street trees, because street tree abundance is closely related to road construction, which, in turn, is closely tied to economic development in a region. We also discovered no significant difference in the benefit of street tree assemblages along the urban-suburban continuum. That's probably because all areas within the different beltways contain mature street trees, the time-lag effect for growth is inconsequential. We recommend that the dynamic variations of street tree assemblages over a certain time span be taken into consideration when examining the effects of urban sprawl on ecosystem services provided by street tree assemblages.

scholarly journals The Variation of Air Purification Benefit Provided by Street Tree Assemblages in Shenyang, China

2021 ◽  
Author(s):  
Jing Yao ◽  
Wei Chen ◽  
Miao Liu ◽  
Xiaobo Wang ◽  
Nina Chen ◽  
...  
Keyword(s):  
Ecosystem Services ◽  
Urban Form ◽  
Time Lag ◽  
Vegetation Management ◽  
Air Purification ◽  
Street Trees ◽  
Street Tree ◽  
Lag Effect ◽  
Wide Range ◽  
Main Driver

Abstract Background: Street trees assemblage is a widespread natural component in the cities and provides a wide range of ecosystem services to the cities. However, the distribution of street trees assemblage within a city is inequal. In this paper, we took air purification benefit provided by street trees for example to examine how urban form, urban geography and drivers of vegetation management affect the variation of ecosystem services provided by street trees in metropolitan Shenyang, Northeastern China. The i-Tree Street (2018) was utilizing to evaluate air purification benefit provided by street trees.Results: We analyze the results using 2 indices: per kilometer benefit and average tree benefit. The results showed us that (1) both indices didn’t vary along the population gradient. (2) The per kilometer benefit had a decreasing trend along the urban-suburban gradient. (3) The districts which had the highest per kilometer benefit and average tree benefit are neither the old ones nor the newest one, but the districts start to develop from around 2002 and 2003.Conclusions: We infer that the public policy is a main driver of vegetation management, especially for street trees, because street tree is closely related to road/street development which is closely related to economic development of a region. Besides, there could be a time lag effect for ecosystem services provided by trees.

The Effects of Residential Street Tree Spacing and Crown Interactions on Crown Dimensions and Canopy Cover

2021 ◽  
Vol 47 (5) ◽  
pp. 183-195
Author(s):  
Bimal Aryal ◽  
James Steenberg ◽  
Peter Duinker
Keyword(s):  
Ecosystem Services ◽  
Urban Forest ◽  
Canopy Cover ◽  
Interaction Effects ◽  
Projection Area ◽  
Street Trees ◽  
Street Tree ◽  
Crown Shape ◽  
Crown Projection Area ◽  
Crown Dimensions

Urban trees provide people with a range of ecosystem services. Trees planted along streets have been a large focus of urban forest research and practice, and municipalities invest significant resources in their survival. However, the optimal spacing of street trees is not addressed in the scientific literature, and existing municipal street tree spacing standards are highly variable and poorly enforced. In this study, we examine variability in crown shape and size for street trees to test for possible interaction effects at closer spacings. We measured variability in crown diameters both parallel and perpendicular to street tree rows to test whether changes in crown dimensions can be explained by interaction effects with neighbouring trees, and whether crown interactions lead to a reduction in total crown projection area (i.e., canopy cover). We measured the crown dimensions and diameter at breast height of 1,338 street trees in Halifax, Canada. We used two-way analysis of variance to test whether crown shape and crown projection area were affected by crown interactions and spacing. We found that the effect of narrower spacing and interactions (i.e., crowns touching/overlapping) among trees translated to crowns extending away from the direction of interaction. We also found that these changing crown dimensions were associated with increases in canopy cover. Urban forest ecosystems are a vital resource for the increasingly urban population. There is a need for empirical research on spacing standards and practices that investigate their influence on the supply of ecosystem services, such as stormwater retention, air pollution removal, and cooling.

The spatial variation of air purification benefit provided by street tree assemblages in Shenyang, China

2021 ◽  
Author(s):  
Jing Yao ◽  
Miao Liu ◽  
Nina Chen ◽  
Wei Chen ◽  
Chunping Miao ◽  
...  
Keyword(s):  
Spatial Variation ◽  
Air Purification ◽  
Street Tree ◽  
Tree Assemblages

scholarly journals Street Tree Density and Distribution: An International Analysis of Five Capital Cities

2020 ◽  
Vol 8 ◽  
Author(s):  
Nicholas Smart ◽  
Theodore S. Eisenman ◽  
Andrew Karvonen
Keyword(s):  
Urban Form ◽  
Tree Density ◽  
Washington Dc ◽  
Urban Greening ◽  
Street Trees ◽  
Climate Zones ◽  
Climate Zone ◽  
Capital Cities ◽  
Tree Distribution ◽  
Street Tree

Municipal leaders around the world are demonstrating significant interest in urban greening to realize a range of socioecological benefits. The urban greening toolkit often includes street trees, an essential component of urban design informed by historic legacies of both human and environmental factors. To date, there has been little comparative analysis of street tree density and distribution across international and intercontinental settings, and associated research has not been situated within the broader discussion of historical legacies. This study focuses on five capital cities (Ottawa, Stockholm, Buenos Aires, Paris, and Washington, DC) situated in two climate zones and it addresses two research questions: (1) What are the density and distribution of street trees across a given city and its street hierarchy? and (2) How do these metrics compare within and between cities by climate zone? The analysis draws upon up-to-date datasets from local authorities and includes geospatial analysis of street trees across hierarchical street classes within the central zones of each city. The results show clear differences in street tree density in cities within and between climate zones as well as differences in street tree distribution in cities within the same climate zone. Substantial differences within climate zones further suggest that cultural factors—including but not limited to urban form, aesthetic norms, and governance regimes—may play a pivotal role in the distribution and density of street trees. This illustrates the importance of place-specific cultural and environmental legacies as determinants of street tree density and distribution and supports further comparative research on the topic.

Pruning intensity of street trees and associated effects on ecosystem services

2020 ◽  
Author(s):  
Su-Ting Cheng ◽  
Shuo Wei
Keyword(s):  
Ecosystem Services ◽  
Carbon Storage ◽  
Ecosystem Service ◽  
Tree Height ◽  
City Government ◽  
Street Trees ◽  
Street Tree ◽  
Taipei City ◽  
Pollution Removal ◽  
Pruning Intensity

<p>Urban street trees provide multiple ecosystem services to city residents. In the Taipei city of Taiwan, street tree pruning is periodically applied due to disastrous prevention of typhoons or storms. To understand how pruning intensity affects the value of ecosystem services, we evaluated the changes of ecosystem services provided by a total of 87,014 street trees in Taipei in terms of pollution removal, carbon storage, gross carbon sequestration, and runoff avoidance. The current status of each ecosystem service was calculated using i-Tree Eco developed by US Forest Service based on the street tree inventory conducted by Parks and Street Lights Office, Taipei City Government during 2015 to 2017. Inventory information included tree species, diameter at breast height (DBH), tree height, and their locations. To simulate pruning intensity from 10% to 100%, we adjusted the crown missing rate from the current canopy cover estimated by DBH and tree height and quantified their associated effects on the ecosystem services. Then, for comparison purposes, each ecosystem service was transformed into monetary values using US market value of water, carbon, air pollution removal, and electricity. Our analysis showed that the Taipei street trees currently hold a relatively stable age structure with lower risk of disease or pest outbreak. These trees were estimated to deliver ecosystem services of equivalent value of 5.6 million USD, to which 4.97 million USD was contributed by carbon storage. Based on the pruning intensity simulation, we suggest a 20% or lower pruning intensity considering street trees’ impairment and physiology, to maximize the ecosystem service values. We also recommend landscape managers to monitor and assess the growth and health of the street trees to promote sustainable development in the Taipei city.</p>

Soil Compaction Affects the Growth and Establishment of Street Trees in Urban Australia

2019 ◽  
Vol 45 (6) ◽  
Author(s):  
Gregory Moore ◽  
Alicia Fitzgerald ◽  
Peter May
Keyword(s):  
Chlorophyll Fluorescence ◽  
Bulk Density ◽  
Leaf Area ◽  
Species Selection ◽  
Shoot Biomass ◽  
Street Trees ◽  
Compacted Soil ◽  
Trunk Diameter ◽  
Street Tree ◽  
Significant Difference

Growing conditions for street tree roots are generally harsh with restricted space and soils compacted from streetscape infrastructure. Allocasuarina littoralis, Corymbia maculata, Cupressus sempervirens var. stricta, Eucalyptus polyanthemos, Lophostemon confertus, Olea europaea, Quercus palustris, and Waterhousea floribunda were grown in compacted and uncompacted soils for 20 months in experimental blocks. The bulk density and penetrative resistance of the soils and height, canopy spread, trunk diameter, leaf area, and chlorophyll fluorescence were measured regularly. Root and shoot biomass were determined after harvesting. Since the bulk density of compacted compared to uncompacted soil was root growth limiting, it was hypothesised that species would have reduced growth in compacted soils. However, C. maculata and E. polyanthemos grew better, C. sempervirens, Q. palustris, and W. floribunda grew well, and A. littoralis, L. confertus, and O. europaea were the worst performing in compacted soil. E. polyanthemos, L. confertus, and Q. palustris had higher canopy:root ratios in compacted soil. Q. palustris had greater mass below ground than above, which has implications for its use in confined sites. In a field study, C. maculata, E. polyanthemos, L. confertus, O. europaea, and Q. palustris growing as street trees were surveyed to determine their rates of establishment and growth under urban conditions. In addition to the soil and tree parameters mentioned above, a Visual Tree Assessment (VTA) was undertaken. E. polyanthemos had the largest trunk diameter, height and canopy spread, indicating its potential for rapid establishment in streets. It was the only species with a larger mean leaf area in compacted soil. E. polyanthemos and O. europaea were the only species classed as healthy from chlorophyll fluorescence but there was no significant difference in fluorescence between compacted and uncompacted soils. VTA showed that C. maculata and O. europaea performed best and that E. polyanthemos, L. confertus, and Q. palustris had reduced but acceptable growth in compacted soil. Soils ranged from non-saline to moderately saline and were slightly to strongly acidic. All soils were compacted to some degree and penetrative resistance was at root limiting levels. The results suggest that careful species selection and soil amelioration for species prone to the effects of compaction would facilitate street tree establishment.

Spontaneous Blinks as a Criterion of Visual Fatigue during Prolonged Work on Visual Display Terminals

2001 ◽  
Vol 92 (1) ◽  
pp. 234-250 ◽  
Author(s):  
Kenichi Kaneko ◽  
Kazuyoshi Sakamoto
Keyword(s):  
Time Lag ◽  
Vertical Direction ◽  
Visual Display ◽  
Hard Copy ◽  
Subjective Feeling ◽  
Visual Fatigue ◽  
Work Time ◽  
Mean Values ◽  
Significant Difference ◽  
The Mean

Visual fatigue caused by prolonged work viewing a Visual Display Terminals (VDT) and of work reading a hard-copy were assessed by electromyogram (EMG) waveform and electrooculogram (EOG) waveform in spontaneous blinks as objective criteria, and by questionnaire of subjective feeling, and by task performance. The duration and the amplitude of the EMG of the orbicularis ocular muscle on the right side and the EOG of the vertical direction to the eyelid were measured for 10 subjects who participated in a figure task consisting of the addition of single-digit numbers on a VDT work or a work with a hard-copy. The mean values of the duration and the amplitude of the EMG and the EOG were evaluated by the averaging of 10 waveforms of the spontaneous blinks for all subjects. The time lag from the EMG to the EOG in the process of the generation of spontaneous blinks was also analyzed. These five parameters were evaluated during the work time. The mean values for the duration of the EMG increased gradually during the work time, but the amplitude did not show significant difference between the prework and a work time. There was no significant change of the duration of the EOG, but the mean amplitude of the EOG decreased as the work time progressed, and the time lag significantly extended. The blinks frequency increased relatively when using a VDT. The rate of fluctuation for these parameters was higher during use of a VDT than use of a hard-copy. The time lag at five hours of VDT work was extended by 90% based on the value at the prework. The symptoms of general fatigue and fatigue of the eyes increased linearly during the VDT work for six hours. The results indicated a significant correlation between the objective parameters for the activity of the spontaneous blinks, i.e., duration and amplitude of EMG and EOG, and the time lag between EMG and EOG, and the subjective feeling was recognized in the time course of the task. These experimental results suggested that the parameters regarding the EMG and the EOG for the spontaneous blinks were effective indices for assessing visual fatigue during prolonged VDT work.

The Hidden Half: Linking microbial communities to habitat condition and vegetation management in UK blanket bogs

2021 ◽  
Author(s):  
William Burn ◽  
Andreas Heinemeyer ◽  
Thorunn Helgason ◽  
David Glaves ◽  
Michael Morecroft
Keyword(s):  
Water Quality ◽  
Ecosystem Services ◽  
Microbial Communities ◽  
Structural Equation ◽  
Management Strategies ◽  
Vegetation Management ◽  
Equation Model ◽  
Habitat Condition ◽  
Blanket Bog ◽  
The Uk

<p>Peatlands are globally valued for the ecosystem services they deliver, including water quality regulation and carbon sequestration. In the UK, blanket bogs are the main peatland habitat and previous work has linked blanket bog management, especially rotational burning of heather vegetation on grousemoors, to impacts on these ecosystem services. However, we still lack a mechanistic, process-level understanding of how peatland management and habitat status is linked to ecosystem service provision, which is mostly driven by soil microbial processes.</p><p>Here we examine bacterial and fungal communities across a spectrum of “intact” to degraded UK blanket bogs and under different vegetation management strategies. Sites included grousemoors under burnt and alternative mown or uncut management along with further locations including 'near intact', degraded and restored sites across a UK climatic gradient ranging from Exmoor (South UK), the Peak District (Mid) to the Flow Country (North). Moreover, an experiment was setup at the University of York with peat mesocosms taken from all sites and management/habitat conditions to allow a comparison between field and controlled conditions and assessing root-mediated processes. Using a structural equation model, we linked grousemoor management to specific fungal/bacterial functional groups, and have started to relate this to changes in water quality provision and carbon cycle aspects. This represents a significant step in the effort to use microbial communities as indicators of peatland habitat condition in UK upland blanket bogs. </p><p> </p>

Evaluating the Ecosystem Service Benefits of Native Vegetation Management at Solar Energy Facilities

2021 ◽  
Author(s):  
Leroy Walston ◽  
Heidi Hartmann
Keyword(s):  
Ecosystem Services ◽  
Solar Energy ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Vegetation Management ◽  
Energy Development ◽  
Department Of Energy ◽  
Land Uses ◽  
Solar Pv ◽  
Pollination Services

<p>Concomitant with the increase in solar photovoltaic (PV) energy development over the past decade has been the increasing emphasis on land sharing strategies that maximize the land use efficiency of solar energy developments.  Many of these strategies focus on improving the compatibility of solar energy development with other co-located land uses (e.g., agriculture) and by improving several ecosystem services that could have natural, societal, and industrial benefits. One such land opportunity is the restoration and management of native grassland vegetation beneath ground-mounted PV solar energy facilities, which has the potential to restore native habitat to conserve biodiversity and restore previously altered ecosystem services (e.g., natural pollination services). This presentation will discuss various assessment and modeling approaches to evaluate the scale and magnitude of the ecosystem services provided by different vegetation management strategies at solar PV energy development sites. This work demonstrates how multifunctional land uses in energy systems represents a win-win solution for energy and the environment by optimizing energy-food-ecology synergies. This work was conducted by Argonne National Laboratory for the U.S. Department of Energy Solar Energy Technologies Office under Contract No. DE-AC02-06CH11357.</p>

O2-. release by activated Kupffer cells upon hypoxia-reoxygenation

1991 ◽  
Vol 261 (4) ◽  
pp. G602-G607 ◽  
Author(s):  
B. Rymsa ◽  
J. F. Wang ◽  
H. de Groot
Keyword(s):  
Nadph Oxidase ◽  
Kupffer Cells ◽  
Cell Injury ◽  
Cell Damage ◽  
Primary Cultures ◽  
Time Lag ◽  
Specific Inhibitor ◽  
Significant Difference ◽  
Reoxygenation Injury ◽  
Hypoxia Reoxygenation

Primary cultures of rat liver Kupffer cells generated large amounts of superoxide anion radical (O2-.) when subjected to reoxygenation after a hypoxic period of at least 2 h. O2-. formation reached its maximum rate of approximately 25 nmol/10(6) cells within 1 h after reoxygenation. Two to four hours after reoxygenation, the number of injured cells began to increase and after 10 h approximately 60% of the cells were dead. During the period of O2-. release no significant difference in cell viability was observed between reoxygenated and hypoxically incubated cells, indicating a distinct time lag between O2-. release and onset of cell damage. Addition of diphenyliodonium, a specific inhibitor of the neutrophilic NADPH oxidase, to the Kupffer cells just before reoxygenation diminished both O2-. formation and cell injury up to 70%. Reoxygenation injury was completely prevented when superoxide dismutase and catalase were added immediately before reoxygenation. The results indicate that Kupffer cells subjected to hypoxia-reoxygenation generate a burst of reactive oxygen species and that this kind of "activation," probably by activating the NADPH oxidase, contributes to the self-destruction of the cells.

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