scholarly journals The Removal Efficiencies of Several Temperate Tree Species at Adsorbing Airborne Particulate Matter in Urban Forests and Roadsides

Forests ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 960 ◽  
Author(s):  
Myeong Ja Kwak ◽  
Jongkyu Lee ◽  
Handong Kim ◽  
Sanghee Park ◽  
Yeaji Lim ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Tree Species ◽  
Morphological Characteristics ◽  
Urban Forests ◽  
Urban Trees ◽  
Widespread Species ◽  
Area Index ◽  
Canopy Density ◽  
Leaf Surfaces ◽  
Removal Efficiencies

Although urban trees are proposed as comparatively economical and eco-efficient biofilters for treating atmospheric particulate matter (PM) by the temporary capture and retention of PM particles, the PM removal effect and its main mechanism still remain largely uncertain. Thus, an understanding of the removal efficiencies of individual leaves that adsorb and retain airborne PM, particularly in the sustainable planning of multifunctional green infrastructure, should be preceded by an assessment of the leaf microstructures of widespread species in urban forests. We determined the differences between trees in regard to their ability to adsorb PM based on the unique leaf microstructures and leaf area index (LAI) reflecting their overall ability by upscaling from leaf scale to canopy scale. The micro-morphological characteristics of adaxial and abaxial leaf surfaces directly affected the PM trapping efficiency. Specifically, leaf surfaces with grooves and trichomes showed a higher ability to retain PM as compared to leaves without epidermal hairs or with dynamic water repellency. Zelkova serrata (Thunb.) Makino was found to have significantly higher benefits with regard to adsorbing and retaining PM compared to other species. Evergreen needle-leaved species could be a more sustainable manner to retain PM in winter and spring. The interspecies variability of the PM adsorption efficiency was upscaled from leaf scale to canopy scale based on the LAI, showing that tree species with higher canopy density were more effective in removing PM. In conclusion, if urban trees are used as a means to improve air quality in limited open spaces for urban greening programs, it is important to predominantly select a tree species that can maximize the ability to capture PM by having higher canopy density and leaf grooves or trichomes.

scholarly journals Edge Growth Form of European Buckthorn Increases Isoprene Emissions From Urban Forests

2021 ◽  
Vol 3 ◽  
Author(s):  
Aarti P. Mistry ◽  
Adam W. T. Steffeck ◽  
Mark J. Potosnak
Keyword(s):  
Invasive Species ◽  
Air Quality ◽  
Species Composition ◽  
Tree Species ◽  
Urban Forests ◽  
Google Earth ◽  
Urban Trees ◽  
Emission Rates ◽  
Isoprene Emission ◽  
Environmental Controls

Urban trees provide numerous benefits, such as cooling from transpiration, carbon sequestration, and street aesthetics. But volatile organic compound emissions from trees can combine with anthropogenic nitrogen oxide emissions to form ozone, a harmful air pollutant. The most commonly-emitted of these compounds, isoprene, negatively impacts air quality and hence is detrimental to human health. In addition to environmental controls such as light and temperature, the quantity of isoprene emitted from a leaf is a genus-specific trait. Leaf isoprene emission is enzymatically controlled, and species are typically classified as emitters or non-emitters (near-zero emission rates). Therefore, the species composition of urban forests affects whole-system isoprene production. The process of plant invasion alters species composition, and invasive tree species can be either emitters or non-emitters. If an invasive, isoprene-emitting tree species displaces native, non-emitting species, then isoprene emission rates from urban forests will increase, with a concomitant deterioration of air quality. We tested a hypothesis that invasive species have higher isoprene emission rates than native species. Using existing tree species inventory data for the Chicago region, leaf-level isoprene emission rates of the six most common invasive and native tree species were measured and compared. The difference was not statistically significant, but this could be due to the variability associated with making a sufficient number of measurements to quantify species isoprene emission rates. The most common invasive species European buckthorn (Rhamnus cathartica, L.) was an emitter. Because European buckthorn often invades the disturbed edges common in urban forests, we tested a second hypothesis that edge-effect isoprene emissions would significantly increase whole-system modeled isoprene emissions. Using Google Earth satellite imagery to estimate forested area and edge length in the LaBagh Woods Forest Preserve of Cook County (Chicago, IL, USA), edge isoprene emission contributed 8.1% compared to conventionally modeled forest emissions. Our results show that the invasion of European buckthorn has increased isoprene emissions from urban forests. This implies that ecological restoration efforts to remove European buckthorn have the additional benefit of improving air quality.

scholarly journals Identifying Tree Traits for Cooling Urban Heat Islands—A Cross-City Empirical Analysis

Forests ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1064
Author(s):  
Carola Helletsgruber ◽  
Sten Gillner ◽  
Ágnes Gulyás ◽  
Robert R. Junker ◽  
Eszter Tanács ◽  
...  
Keyword(s):  
Ecosystem Services ◽  
Leaf Area ◽  
Tree Species ◽  
Urban Trees ◽  
Cooling Effect ◽  
Site Conditions ◽  
Area Index ◽  
Tree Management ◽  
Urban Heat ◽  
Tree Traits

Research Highlights: This paper presents a cross-city empirical study on micro-climatic thermal benefits of urban trees, using machine-learning analysis to identify the importance of several in situ measured tree physiognomy traits for cooling. Background and Objectives: Green infrastructure and trees in particular play a key role in mitigating the urban heat island (UHI) effect. A more detailed understanding of the cooling potential of urban trees and specific tree traits is necessary to support tree management decisions for cooling our progressively hot cities. The goal of this study was to identify the influence and importance of various tree traits and site conditions. Materials and Methods: Surface temperature, air temperature at 1.1 m and at tree crown height, as well as wet bulb globe-temperature of shaded and fully sun-exposed reference areas, were used to study the cooling effect of seven different urban tree species. For all 100 individuals, tree height, crown base, trunk circumference, crown volume, crown area, leaf area index (LAI) and leaf area density (LAD) were measured. Measurements were conducted in the cities of Dresden, Salzburg, Szeged, and Vienna as representatives for middle European cities in different climate zones. Results: Beside site conditions, tree species, height, height of crown base, as well as trunk circumference, have a great influence on the cooling effect for city dwellers. The trunk circumference is a very valuable indicator for estimating climate regulating ecosystem services and therefore a highly robust estimator for policy makers and tree management practitioners when planning and managing urban green areas for improving the availability and provision of ecosystem services.

scholarly journals A Comparison of the Shading Effectiveness of Five Different Street Tree Species in Manchester, UK

2013 ◽  
Vol 39 (4) ◽  
Author(s):  
David Armson ◽  
Mohammad Asrafur Rahman ◽  
Anthony Roland Ennos
Keyword(s):  
Tree Species ◽  
Urban Areas ◽  
Urban Landscape ◽  
Urban Trees ◽  
Area Index ◽  
Pyrus Calleryana ◽  
Human Thermal Comfort ◽  
Surface Temperatures ◽  
Street Tree ◽  
Crataegus Laevigata

One major benefit of urban trees is the shade they provide on sunny days; this reduces the heat stored in engineered surfaces and lowers the heat load on people, increasing their comfort. This study compared the shading effectiveness of five small street tree species within the urban landscape of Manchester, UK. The area of shade produced by each tree during early and midsummer 2012 was calculated from morphological measurements, such as canopy height, width, and aspect ratio. The effect of tree shade on air, mean radiant and surface temperatures was also compared and related to the leaf area index (LAI) of the canopy. It was found that tree shade reduced mean radiant temperatures by an average of 4°C, though neither tree species nor LAI had a significant effect. Tree shade reduced surface temperatures by an average of 12°C, and the tree species and LAI both had significant effects. Tree species with higher LAI, Crataegus laevigata and Pyrus calleryana, provided significantly more cooling than the other species, and surface temperature reduction was positively correlated with LAI. This study has shown that trees are useful in improving both human thermal comfort and reducing surface temperatures in urban areas, and that selection of tree species with high LAI can maximize the benefits they provide.

scholarly journals The Best Urban Trees for Daytime Cooling Leave Nights Slightly Warmer

Forests ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 945
Author(s):  
Agnieszka Wujeska-Klause ◽  
Sebastian Pfautsch
Keyword(s):  
Tree Species ◽  
Surface Air Temperature ◽  
Canopy Cover ◽  
Urban Trees ◽  
Radiative Cooling ◽  
Street Trees ◽  
Near Surface ◽  
Canopy Density ◽  
Air Temperatures ◽  
Urban Heat

Summer air temperatures will continue to rise in metropolitan regions due to climate change and urbanization, intensifying daytime and nighttime air temperatures and result in greater thermal discomfort for city dwellers. Urban heat may be reduced by trees which provide shade, decreasing air and surface temperatures underneath their canopies. We asked whether tree height and canopy density can help to identify species that provide greater microclimate benefits during day and night. We also asked if increased canopy cover of street trees provides similar microclimate benefits. We used continuous measurements of near-surface air temperatures under 36 park trees and from two urban streets to assess these questions. In the park, trees were grouped according to their height (<10 m, 10–20 m, >20 m) and canopy density (low, high), while the effect of canopy cover was tested using streets with high (31%) and low (11%) cover. Daytime near-surface air temperature declined with increasing height and canopy density providing significant cooling benefits. However, this trend was reversed at night when tall trees with dense canopies restricted longwave radiative cooling and trapped warm air beneath their crowns. High canopy cover of street trees reduced daytime air temperatures more, resulting in a lower number of days with hot (>35 °C) and extreme (>40 °C) air temperatures compared to the street that had low canopy cover. These findings suggest that tree species and streetscapes with dense canopy cover improve local thermal conditions during the day but do not seem ideal to allow for nighttime cooling, creating potential discomfort for residents during hot summer nights. Our results indicate that classifying trees using a simple metric can assist in selecting tree species that can alleviate the local negative effect of urban heat during the day, but at the same time, their effect in preventing optimal longwave radiative cooling during the night must be factored into planting strategies.

scholarly journals Variation in Tree Species Ability to Capture and Retain Airborne Fine Particulate Matter (PM2.5)

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Lixin Chen ◽  
Chenming Liu ◽  
Lu Zhang ◽  
Rui Zou ◽  
Zhiqiang Zhang
Keyword(s):  
Particulate Matter ◽  
Tree Species ◽  
Fine Particulate Matter ◽  
Fine Particulate

How anatomical and morphological characteristics affect the flexural properties of two angiosperm species at the sapling stage

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 5843-5858
Author(s):  
Seray Özden Keleş
Keyword(s):  
Tree Species ◽  
Ring Width ◽  
Morphological Characteristics ◽  
Deciduous Tree ◽  
Flexural Properties ◽  
Functional Stability ◽  
Growth Stability ◽  
Fagus Orientalis Lipsky ◽  
Angiosperm Species ◽  
Common Oak

The sapling stage is an important phase due to maintaining plant growth, stability, and survival over the life cycle of trees. However, there are limited investigations in the literature related to both growth and stability of different tree species. This study thus investigated how different tree species at the sapling stage showed different anatomical, morphological, and flexural traits despite being of similar age and growing under the same environmental conditions. The variation of sapling properties was determined in two deciduous tree species: common oak (Quercus robur L.) and Oriental beech (Fagus orientalis Lipsky). The results of anatomical and morphological measurements showed that the highest average values of ray length, ray width, pith radius, pith%, bark%, and node numbers were obtained in oak saplings, whereas average ring width, number of rays, and wood% were found to be higher in beech saplings. Oak also exhibited better functional stability in its saplings. The flexural properties were almost 60% greater in oak stems than beech stems. The variations in flexural properties were explained by the morphological and anatomical traits since stability was positively correlated with pith radius, pith%, and bark% and negatively correlated with the number of rays and wood%.

Structure and Regeneration of Sal (Shorea robusta Gaertn. f.) Forests in Shiwalik Region of Kumaun Himalaya, India

2017 ◽  
Vol 40 (1) ◽  
pp. 1-8
Author(s):  
Bhawna Adhikari ◽  
◽  
Bhawana Kapkoti ◽  
Neelu Lodhiyal ◽  
L.S. Lodhiyal ◽  
...  
Keyword(s):  
Tree Species ◽  
Basal Area ◽  
Tree Canopy ◽  
Canopy Density ◽  
Kumaun Himalaya ◽  
Shorea Robusta ◽  
Canopy Trees ◽  
Dense Forest ◽  
Open Forest ◽  
Sal Forest

Present study was carried out to assess the structure and regeneration of Sal forests in Shiwalik region of Kumaun Himalaya. Vegetation analysis and tree canopy density was determined by using quadrat and densitometer, respectively. Density of seedlings, saplings and trees was 490-14067, 37-1233, and 273-863 ind.ha-1 respectively. The basal area was 0.12-5.44 m2 ha-1 reported for saplings and 25.4-77.6 m2 ha-1 for trees. Regeneration of Sal was found good in Sal mixed dense forest followed by Sal open forest and Sal dense forest, respectively. Regeneration of Sal was assisted by the presence of associated tree species as well as the sufficient sunlight availability on ground due to adequate opening of canopy trees in Sal forest. Thus it is concluded that the density of tree canopy, sunlight availability and also associated tree species impacted the regeneration of Sal in the region.

scholarly journals GROWTH OF DIFFERENT FRUIT TREE SPECIES IN SILVOPASTORAL SYSTEMS DURING THE ESTABLISHMENT PHASE

2017 ◽  
Vol 30 (4) ◽  
pp. 1040-1049 ◽  
Author(s):  
CAROLINA DELLA GIUSTINA ◽  
ROBERTA APARECIDA CARNEVALLI ◽  
MARCELO RIBEIRO ROMANO ◽  
DIEGO BARBOSA ALVES ANTONIO ◽  
CAMILA ECKSTEIN
Keyword(s):  
Tree Species ◽  
Block Design ◽  
Control Plant ◽  
Fruit Trees ◽  
Fruit Tree ◽  
Silvopastoral Systems ◽  
Area Index ◽  
Mato Grosso ◽  
Plant Accumulation ◽  
Establishment Phase

ABSTRACT The benefits of integrating agricultural components into silvopastoral systems are widely known, but the limited knowledge about ecological processes in the establishment phase impedes the use of this technology. The objective of this study was to evaluate interactions between fruit tree species and the sward layer under canopies of trees in the establishment phase of silvopastoral systems in Mato Grosso, Brazil. The experiment was implemented in October 2013, with an evaluation period from January to July 2015. The systems were composed of eight fruit trees intercropped with Tifton 85 grass. A completely randomized block design was adopted, with two replications per area per treatment. We evaluated the agronomic performance of the fruit trees, the categories of the light environment, and the plant accumulation under the canopies. The acerola fruit trees of the variety Roxinha had higher Leaf area index (LAI) and Light interception (LI) values, showing a denser canopy with small porosity and the lowest light quality available to the plants beneath the canopy (lower red/far-red ratio), thereby decreasing plant accumulation under trees. The guava fruit trees showed higher growth rates than the other fruit trees, but lower LAI and LI values and a higher red/far-red ratio, allowing higher plant growth under the canopy. Cajá trees showed a similar behavior; however, this species is deciduous, which limits its potential use in integrated systems. Banana and coconut trees were highly dependent on irrigation during the dry season. The remaining species showed an adequate growth and potential to control plant species growth under their canopies.

scholarly journals MORPHOLOGICAL AND PRODUCTIVE CHARACTERIZATION OF FORAGE CACTUS VARIETIES

2015 ◽  
Vol 28 (3) ◽  
pp. 230-238 ◽  
Author(s):  
PHILIPE LIMA DE AMORIM ◽  
JANAINA AZEVEDO MARTUSCELLO ◽  
JOSÉ TEODORICO DE ARAÚJO FILHO ◽  
DANIEL DE NORONHA FIGUEIREDO VIEIRA DA CUNHA ◽  
LIANA JANK
Keyword(s):  
Block Design ◽  
Morphological Characteristics ◽  
Correlation Coefficients ◽  
Dry Mass ◽  
Negative Effects ◽  
Breeding Programs ◽  
Area Index ◽  
Promising Alternative ◽  
Randomized Block Design ◽  
Use Efficiency

ABSTRACT: Cultivars of the genus Nopalea are known in Brazil for being tolerant to cochineal carmine attacks, thus making the cultivation of this genus a promising alternative for mitigating the negative effects of this insect on the production of biomass. With the objectives of characterizing morphologically spineless forage cactus varieties and identify morphological characteristics that may be the focus in spineless forage cactus breeding programs, an experiment was conducted in a completely randomized block design with 11 treatments and four replications. The variety Alagoas showed the highest values of weight, area and volume of cladodes. The varieties Negro Michoacan F7 and V7, Tamazunchale V12 showed the highest values of the cladode area index, the total volume of cladodes and total fresh mass production. The varieties Negro Michoacan V7 and F7 presented the highest water use efficiency and dry mass yield. Cladode volume showed the highest correlation coefficients with the fresh weight of cladodes. Aiming the release of varieties for biomass production, varieties Negro Michoacan F7, V7 and Tamazunchale V12 may substitute the Miúda variety. The number and cladode area index may be used as criteria for selection of superior varieties in breeding programs.

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