Median Strip Research Articles

Secondary wind dispersal enhances long-distance dispersal of an invasive species in urban road corridors

Roads contribute to habitat fragmentation and function as dispersal barriers for many organisms. At the same time many nonnative plant species are associated with road systems, a relationship that has been explained by the availability of disturbed habitats along roadsides and traffic-mediated dispersal of species. By studying secondary wind dispersal (SWD) over paved ground in an urban road corridor, we add the perspective of corridor-specific, but traffic-independent dispersal processes to the complex dispersal systems along roads. We analyzed (1) the seed shadow of an invasive tree Ailanthus altissima along a sidewalk subsequent to a strong wind and (2) the movements of painted samaras of this species released at ground level at the same site to identify the functioning of SWD. For the first experiment, we searched for samaras in the vicinity of an isolated tree three days after a strong wind. For the second experiment, we tracked the movement of the released samaras repeatedly over a period of 9–11 days, approximated probability-distance functions to the frequency distribution of samaras along the transect for different times after release, and related nearby measured wind data to changes in dispersal kernels. Single samaras from an isolated tree formed a seed shadow that extended for a distance of 456m and fragments of fruit clusters traveled up to 130m. Forty-twopercent of the sampled samaras were moved >100 m. The second experiment revealed that painted samaras released on the ground were moved up to 150m over the pavement. Dispersal distances increased with time after seed release. A significant increase in the scale parameter b of the dispersal kernel with higher wind sums above 3.7 m/s illustrates a threshold for movement of samaras over the ground. Habitat shifts to safe sites for germination occurred during SWD, and different types of pavement influenced these processes. Smooth-surfaced pavement enhanced SWD, while cobbles with irregular surfaces slowed down or terminated SWD. During the observation period, 17% of released samaras accumulated in patches with a planted tree. Some were recaptured within the median strip and thus must have been lifted and moved over four lanes of heavy traffic. Our results suggest that impervious surfaces within road corridors can function as powerful avenues of wind-mediated long-distance dispersal and may counteract fragmentation of urban habitats. This also offers a functional explanation for the invasion success of Ailanthus at isolated urban sites.

고해상도 위성영상을 이용한 도시유역의 소강우 유출해석

Abstract : In this research, enhanced land-cover classification methods using high-resolution satellite image (HRSI) and GIS in terms of practicality and accuracy was proposed. It aims for understanding non-point pollutant origin/loading, assessment the efficiency of rainfall storage/infiltration facilities and sounds water-environment management. The result of applying enhanced land-cover classification methods to the urban region verifies that roof and road area are including various vegetations such as roof garden, flower bed in the median strip and street tree. This accounts for 3% of total study area, and more importantly it was counted as impervious area by GIS alone or conventional indoor work. The feasibility of the method was assessed by applying to rainfall-runoff analysis for three weak rainfall in the range of 7.1-10.5 mm events in 2000, Chiba, Japan. A good agreement between simulated and observed runoff hydrograph was obtained. In comparison, the hydrograph simulated with land-use parameters by the detailed land-use information of 10m grid had an error between 31%~71%, while enhanced method showed 4% to 29%, and showed the improvement particularly for reproducing observed peak and recession flow rate of hydrograph in weak rainfall condition.

도시도로 녹지의 도로 표면온도 져감 효과에 관한 연구

One of the major factors which increase urban temperature is roads. This paper is aimed to investigate the effect of urban roadside vegetation on the road surface temperature. For this, surface temperature was measured at 18 spots using the thermal imaging camera in terms of road components including use of roadside land use, roadway, sidewalk, roadside vegetation and vegetation median barrier. The size of the roadside vegetation and related urban road characteristics were also measured. In terms of the effect of roadside vegetation on a decrease in road surface temperature, the roadside land use as a green area or open space was the highest, followed by the size of vegetation median barrier and the size of roadside vegetation. Besides road surroundings, an increase in the green zone such as roadside vegetation and median strip vegetation has a significant impact on lowering road surface temperature. Therefore, a good solution for reducing urban heat island effects would be to increase the area of roadside vegetation and green areas along roads.

CARPINUS BETULUS CV FASTIGIATA—THEIR GROWTH AND DEVELOPMENT IN SUBURBAN DUBLIN

The growth rate of Carpinus betulus cv Fastigiata planted in the early and mid 1980s the inner suburbs of Dublin (Ireland) was examined. The trees were growing in the following conditions, in a grassed level area in a public park, planting pits surrounded by tarmacadam in an adjacent street, in a grassed median strip between a footpath and road and in a planting pit bordered by concrete and a concrete kerb. Records of tree height, girth and crown spread of 241 trees were taken. The mean height of trees planted in 1985 in Herbert Park, urban park was 12.92m, while the mean value of street trees in the same scheme outside the Park was 12.46m. The corresponding results for girth were 0.92m and 0.88m and for crown spread were 6.47 and 5.87. The mean height of trees planted in the early 1980s on Ailesbury Road was 14.53m while on Appian Way it was 13.55m, with the respective girth values being 1.04m and 1.02m and the mean crown spread 8.18m and 5.63m. The replanting rate varied from 5.5% to 21% which is considerably less than a general estimate of 25%-50% for the United Kingdom and 30% in Helsinki (Finland). In no location have the trees attained a height of 18m which is given as the average height of this cultivar in urban areas, however in one location the crown spread is greater than the 8 metres given for the cultivar.

An inventory of trees in Dublin city centre

While urban areas are often considered to be comprised chiefly of artificial surfaces, they can contain a substantial portion of green space and a great diversity of natural habitats. These spaces include public parks, private gardens and street trees, all of which can provide valuable environmental services, such as improved air quality. Trees play a particular role in cities as they are often placed along roadsides and in the median strip of busy streets. As such they regulate access to sunshine, restrict airflow, provide shelter, scavenge air pollutants and manage noise at the street level. A tree planting policy can be an important part of a broader environmental strategy aimed at improving the quality of life in urban areas but this requires up-to-date knowledge of the current tree stock, which does not exist for Dublin. This article presents an inventory of trees in Dublin's city centre, defined as the area between the Grand and Royal canals. The results show that there are over 10,000 trees in the study area representing a density of 684 trees km-2 or one tree to approximately every 50 residents of the city centre. The tree canopy extent when in full foliage was nearly 1 km2 in extent or 6% of the study area. A more detailed analysis of those trees planted along streets shows little species variation but clear distinction in the sizes of trees, which is indicative of the age of planting. These data are used to estimate the carbon stored in Dublin's trees.

THE SYSTEMIC, HOLISTIC, INTERDISCIPLINARY AND PARTICIPATORY (SHIP) APPROACH SUPPORTS THE CONSERVATION PROGRAM OF MEDICINAL PLANTS IN BALI

Development process brings the positive as well as negative impacts. Among others, the negative impacts include the extinction of some medicinal plants. The research issue is what strategy can be used for preserving the medicinal plants while little attention is given to them. A research action was thus started for preserving and conserving these plants. Methods used were participatory observation, field surveys, and demonstration-plots. The action consisted of: an awareness program, a preparation phase and the establishment of a park of medicinal plants. In doing that, the Systemic, Holistic, Interdisciplinary and Participatory (SHIP) approach was applied. Up to now, the results found are: 1) the awareness program was conducted several times; 2) two pieces of lands were provided from the provincial government of Bali and from the local community; 3) the field surveys identified about 200 kinds of medicinal plants in the house yards, government offices, hotels and median strips of roads; 4) in the traditional medicine texts (lontar), more then 500 kinds of medicinal plants were found to be cited; 5) the medicinal plants were classified into wooden trees, shrubs, grasses, watery plants, epiphytes and parasitic plants. It is concluded that preserving and conserving the medicinal plants in Bali is urgent and that there is a willingness to do that with the active support of the stakeholders. It is encouraging that good examples have already been established in Ubud, Tampaksiring and Karangasem. Therefore, it is recommended to establish a medicinal plants park in Bali since it will have multiplier effects.

Bayesian approach with the power prior for road safety analysis

Drawing inference from current data could be more reliable if similar data based on previous studies are used. We propose a full Bayesian approach with the power prior to utilize these data. The power prior is constructed by raising the likelihood function of the historical data to the power where . The power prior is a useful informative prior in Bayesian inference. We use the power prior to estimate regression coefficients and to calculate the accident reduction factors of some covariates including median strips and guardrails. We also compare our method with the empirical Bayes method. We demonstrate our results with several sets of real data. The data were collected for two rural national roads of Korea in the year 2002. The computations are executed with the Metropolis–Hastings algorithm which is a popular technique in the Markov chain and Monte Carlo methods.

An Analysis on Traffic Accidents on Undivided Expressway in Cold and Snow Area

Some fatal accidents occur on 2-lane expressways in cold and snowy areas in Japan and having no rigid median strip causes more damage to passenger in cars. It is very important to find effective countermeasures that reduce the number of these tragic traffic accidents. However, general characteristics and factors of traffic accidents on undivided expressways have not been clarified sufficiently yet. The authors apply a discriminant analysis to traffic accidents data for 5 years in order to find some crucial factors for traffic accidents especially in snow cold region. Two categories, fatal or serious and slight injury, are used as a dependent variable. Conversely, weather, road circumstance, and cruising speed are used as independent variables. Some useful countermeasures are also proposed to reduce the miserable traffic accidents on undivided expressways.

Evaluating Root Crown Excavation as a Treatment for Deeply-Planted Landscape Trees

An experiment was conducted over a four-year period to evaluate root crown excavation (RCE) as a treatment for deeply-planted landscape trees. Tree growth, leaf chlorophyll, stress, and pest activity were monitored to determine plant response to RCE. Four of the sites, including shingle oak (Quercus imbricaria Michx.) street median strip trees, blue spruce (Picea pungens Engelm.) park trees, and honeylocust (Gleditsia triacanthos L. var. inermis (L.) Zab.) parking lot island and street trees failed to show any influence of RCE on tree growth and leaf chlorophyll. Two sites with maple (Acer spp.) park and street trees where RCE included removal of potential girdling roots resulted in a detrimental effect on twig extension and leaf chlorophyll. Measurements of chlorophyll on ash (Fraxinus spp.) park trees, and tree height and twig extension on lacebark elm (Ulmus parvifolia Jacq.) street trees, demonstrated a positive influence of RCE. The RCE treatment did not influence stress or pest activity at any of the experimental sites. Since tree disorders frequently require many years to develop it is speculated that a longer observation period may be necessary to see a greater impact of RCE on plant growth and health.

Gliding performance and its relevance to gap crossing by the squirrel glider (Petaurus norfolcensis)

Gliding mammals occur worldwide and many are subject to increasing levels of habitat fragmentation. Knowledge of their ability to cross tree-gaps by gliding is quite poor. We describe aspects of the gliding performance of the squirrel glider (Petaurus norfolcensis) based on recorded parameters of 85 glides of 73 individuals. Animals launched from a horizontal position ~1.7 m below the top of a tree and 2.3 m out from the main trunk. All but one glide was to the trunk of a tree, landing 5.7 m above the ground. Animals glided a mean of 21.5 ± 0.9 m (range 9–47 m) in a horizontal plane, with no significant difference between the sexes. Horizontal glide distance appears to reflect tree spacing where individuals were released. The mean glide angle was 28.5 ± 0.8°, with no significant difference between the sexes. We predict that trees beside roads that create a tree-gap of 20 m (two-lane road) or 43 m (four-lane road) will need to be a least 13 m and 25 m tall, respectively, to enable animals to safely glide across a road. Where trees are absent, 12-m-high wooden poles could be installed, requiring some in the median strip of four-lane roads.

The Last Page

Signs and portents abounded that Good Friday in New Orleans as our group of New York City high school students, parents, and teachers rolled in to spend the spring break doing "relief" work. Lawns and green median strips sprouted campaign posters for the upcoming primary. Houses displayed signs for the twenty-two would-be mayors and numerous City Council wannabes. At times, they overwhelmed the lush magnolias, honeysuckle, and azaleas flowering even as the city struggled for new life. That anyone would want to be mayor of a soon-to-be-bankrupt city should have been a sign of hope. But it was the other signs during this Passover week that reminded us why we were there. Each house searched by rescue crews carried an X with a circle around it. In the triangles were notations: the date of the search, the initials of the crew, and the number of casualties, if any. Most of the time there was a zero, but sometimes a number stood as a memorial.

Triple-bottom-line assessment of water sensitive design options in a greenfield residential area

This paper presents the results of a study from Brisbane, Australia, where the relative merit of seven stormwater management design options that could be applied in typical, greenfield, medium density residential areas were assessed using a triple-bottom-line assessment framework. This framework involved assessing the financial, ecological and social dimensions of each option in consultation with stakeholders. The assessment process included the use of multicriteria analysis, a multidisciplinary expert panel, a local social survey of residents who lived adjacent to alternative design options, two workshops involving typical citizens of Brisbane, consultation with traditional stakeholder groups, pollutant export modelling, and water reuse modelling. The scope of issues investigated during the process was very broad. In addition, the information obtained from the community survey and public workshops is likely to be indicative of commonly held views of residents in cities similar to Brisbane. The multicriteria analysis stage of the assessment highlighted both large and small constructed wetlands as having the greatest overall net value compared to other options in the Brisbane region. However, the expert panel’s preferred design option at the end of the process was bioretention systems located within the median strip of roads. Reasons for this discrepancy are explored.

New Directions: The growing urban heat and pollution ?island? effect?impact on chemistry and climate*1

The effect of green space in improving the air quality and thermal comfort of urban canyons has been investigated in many pieces of research. However, most were limited regarding the date, the experiment's duration, or the phenomenon under investigation. This study investigates different greenery patterns(type and position) in urban canyons and their effects on air pollution and thermal comfort to find optimal overall patterns.The effect of patterns in seasons, different urban canyons ratios, and greenery's aesthetical, cultural, and social aspects was considered. Numerical simulations and wind flow modeling were performed in the ENVI-met software. The results show that coniferous trees on sidewalks have the weakest, and Deciduous trees in the median strip alone can have the most favorable effect on improving air quality and thermal comfort in different seasons. Moving deciduous trees from the sidewalks to the median strip has reduced air pollution by 67% in summer and 54% in winter at the pedestrian level.

The effect of military training activity on eastern lupine and the Karner blue butterfly at Fort McCoy, Wisconsin, USA.

The US Department of Defense (DOD) manages over 10.1 million ha of land, much of which is used for training military personnel. However, vast sections receive little or no use, and military lands have become refuges for many species. At Fort McCoy, Wisconsin, USA, populations of the endangered Karner blue butterfly (Lycaeides melissa samuelis) are found in oak and pine barren communities where wild lupine (Lupinus perennis), a perennial forb required by Karner blue butterfly larvae, still occurs. Oak and pine barren communities are disturbance-dependent, and the barrens ecosystems in the Midwest have declined in extent by 98% because of fire suppression, succession, and habitat fragmentation. We studied the effects of disturbance by military manuever training on the density of lupine and Karner blue butterfly at Fort McCoy. We also wanted to determine whether military training activity could enhance Karner blue butterfly habitat. At locations where tracked vehicles had driven through lupine patches, the abundance of lupine and nectar-producing plants was greater in the median strip between vehicle ruts than in vehicle ruts or 5 m outside the vehicle ruts. The proportion of lupine stems with Karner blue butterfly larvae feeding sign (the ratio of stems fed upon to stems examined) was greater in areas where military vehicles had traveled than where they had not. The proportion of lupine stems with feeding sign and lupine stem density was also positively related to the occurrence of prior bivouacs and fires caused by military munitions. Shrub and forest canopy abundance were lower in areas traveled by tracked vehicles. At the scale of the lupine patch, lupine abundance and the proportion of lupine stems with feeding sign were positively correlated with military training activities, suggesting that maintenance of lupine habitat can be achieved in concert with military training.

Mutagenic activity in roadside soils.

Mutagenicity of soils sampled at median strips, roadsides and a park neighboring arterial roads in Kurume City was determined by Ames test. Organic extracts of soils were mutagenic in strains TA98, TA100, YG1041 and YG1042 with and without S9mix. No sample showed mutagenic responses in strains YG3003 or YG7108. Extracts from soils of median strips and beside intersections showed higher mutagenicity and concentrations of PAHs and heavy metals than others, and mutagenic activity of soils correlated significantly with concentrations of PAHs and heavy metals. However, PAHs accounted for less than 12% of total mutagenicity in strains TA98 and TA100 of soil extracts. These extracts showed much higher mutagenicity in YG strains than in TA strains. The results indicate that these soils may be polluted with nitroarenes and aromatic amines.

Crossover Crashes at Median Strips Equipped with Barriers on a French Motorway Network

Examination of the accidents in which vehicles cross median barriers on part of the French interurban motorway network shows that the phenomenon is rare. In 7 percent of accidents in which trucks collide with median barriers, the vehicles pass through the barrier versus 0.5 percent for light vehicles. The severity of the accidents in which vehicles go through the barrier is significantly higher than for other types (19 percent fatal versus 1.3 percent). New Jersey–type concrete barriers are crossed in 0.3 percent of accidents involving collisions with median barriers versus 1.3 percent with guardrails, but the number of casualties in crashes involving concrete devices is 1.7 times higher. This increase in severity is not observed if the focus is on serious injuries and fatalities. Some ideas on reducing the number of median barrier crossings significantly without increasing average median barrier collision accident severity are given with regard to narrow median strips.

Effects of Road Distance and Protective Measures on Deicing NaCI Deposition and Soil Solution Chemistry in Planted Median Strips

The deposition pattern of deicing salt and the resulting concentrations in the soil water were determined in planted median strips of two major approach roads with speed restrictions of 70 kmh (43.5 mph) in Copenhagen, Denmark. The objectives were to evaluate the effect of distance from the roadside and to test different straw mat protective measures. Deposition and soil water concentrations of sodium chloride (NaCI) decreased significantly within 2 m (6.6 ft) from the roadside compared to areas farther away. Straw mats mounted like a skirt around the tree stem did not constitute a proper protection against salt spray or splash and high salt concentrations in the soil water. In contrast, protection with straw mats on all sides of the trees resulted in a small but measurable effect. The highest concentrations of NaCI in the soil water were seen during the winter. However, there was a strong tendency of elevated concentrations persisting throughout the subsequent summer, which suggests that serious salt stress exists on the trees during the growing season. We concluded that planting at a distance of more than 2 m from the roadside is more effective than using straw mats in reducing the undesirable effects of salt spray deposition on trees as well as the salt concentration in the soil water.

I Am Not Proud To Be Black

I Am Not Proud To Be Black Tyrone Williams (bio) 1. Hope ends and thinking breaks out, uncertain violence which is not despair— or, if despair, sublime despair, disfigured hope. The table, already broken, gets cleared. Double consciousness gets swept aside by polyentendres, duck-rabbits, wavicles. Neither waving nor drowning, we tread water like a page turning in a book. We trace the arc of Icarus. The sky only seems to fall—and then, only sideways like a page turning in a book. And in the larger arc of Daedalus, hope settles in another country, ending thought. We neither wave nor drown, we turn 2. the page. We begin outside the book but the book is everywhere we turn, a finishing fable: cowboys “in the boat of Ra” who “marvel at this curious thing”: hearsay circulates as he-said/she-said to the put-down dubbed as he-said/he-said. New commandments overdub the old ones. Skin grows back over old bones: disfigured hope. The table, already broken, dysfunctional, is finally institutionalized as a work of art—or the black sheep sold down the Jordan or the Nile, another country cobbled out of continents, extant and not: February, Juneteenth, Kwanzaa . . . [End Page 8] 3. “I wipe the spit from my face and read on.” We want more than this attenuation, singularity, launch windows so narrow, so fleeting, so hard to reach in time. We need more than just a book called How but the book is everywhere we turn: Blue and his shopping cart of blueprints, Trueblood in stitches—a howler—or a howl. The face-cum-spit is not mollified by inverted commas, an index of distance shaped like a promise and a threat, a covenant, a contract, on our lives. The principle flies like a flag—or spit, returned with interest— or we throw our hands in the air like we just 4. don’t care, nobodies or nations, the false dilemma. We are neither, however concentrated as teemings, trends or tendencies, bunched up at—impaled upon—opposing horns like shrunken heads or tails. The excluded middle as “dispossession makes possession joy.” Reconstruction, acreage and mule, happy days and endings: zero-sums: the median strip: Begin Here to thumb rides or jack cars. The two-way traffic— shaped like a promise and a threat, a covenant— waits for lights, not legs. It never strikes deals, only pedestrians foolish enough to venture forth. And yet, what choice but adventure? 5. The lilies of the field? The birds? The median strip: Begin Here to thumb rides? I know, I know—the trap of the Missing Ingredient, the Assumption of the Bloodied Bars. But prides and flocks are never caged in zoos, obedient in their calm, their rage. The slides and strides of Skid and Strivers’ Row enframe expedient debts and assets, the obsequious calm of bromides. We must almost come to terms and blows, [End Page 9] simulate in-flight, run in places. To dart between the cars when traffic slows invests an unsecured paper-chase. Yet we cannot simply stand and wait for deliverance. The shapeshifter debate 6 concerns both strategies and goals. And both depend on who we might, if we hold, be as then, or such, or if. Suppose we have, in fact, disappeared, or almost so, absorbed unevenly—or woven haphazardly—into the fold, which won’t, of course. For whom these variegated vectors, these conflicting and overlapping methods? And if this we is densities and clans, storied skin, do we embody, en masse, debts and assets, the obsequious calm of bromides? Say nightmare? Yes, but say it backwards, say it in a whisper over and over, mute-nigh, narcotic nonsense, never 7 to wake us. Falling deeper and deeper into sleep, we could drift apart, into unique dreams alike, dreams whose parents look like us. What is not apparent is the dream of nightmare, what we know “before the voices wake us” and we know light as day, the everyday, a dealer: five-card stud or the five fingers, it’s all just bad hands, bad luck, these conflicting and overlapping methods, meterologies and weather reports, “and” itself the means, obstacle and end, “and...

Influence of different levels of traffic pollution on haemoglobin content in the earthworm Lumbricus terrestris

Our aim was to determine haemoglobin content in earthworm populations from sites with different amounts of soil pollution. The study was done on Lumbricus terrestris specimens from four sites: the median strip of a busy street in Cracow; a city park; forest about 30 km from Cracow (100 m from a low-traffic local road); and a forest on calcareous soil about 30 km from Cracow (distant from traffic). There were statistically significant differences in haemoglobin content between study sites. The lowest amount of haemoglobin was found in earthworms from the median strip (2.19 g 100 ml −1), the highest in those from the ‘cleanest’ forest on calcareous soil (3.18 g 100 ml −1). The highest lead concentration was found in specimens from the median strip (12.3 μg g −1) and only trace amounts were found in those from the forest on calcareous soil. There was a negative correlation between haemoglobin and lead concentrations in earthworms. Species composition, density and biomass of earthworm populations at the four sampling sites as well as the body mass of adult individuals of L. terrestris were estimated. No correlation was found between any of these variables and the extent of exposure to traffic pollution.

Stemflow chemistry of urban street trees

pH and ion concentrations (Na +, K +, Mg 2+, Ca 2+, NO − 3) in the stemflow of the evergreen broad-leaved tree, Ilex rotunda, planted in the median strip of a highway and nitrogen oxides concentration in the air in an urban site were compared with a suburban site in Fukuoka city, Japan. The annual average of the nitrogen oxides concentration in the air was higher and NO − 3 concentration in the stemflow at the urban site was higher or similar compared with the suburban site. However, the annual average of pH in the stemflow at the urban site was higher than at the suburban. The annual average cation concentrations in the stemflow at the urban site were higher than at the suburban except Na +. In particular, K + and Ca 2+ were higher throughout the measurement period. Therefore, higher pH in the urban stemflow was probably due to neutralization by higher concentrations of K +, Mg 2+ and Ca 2+.