Urban trees serve important environmental, social and economic functions, but similar to other natural endowments they are
not customarily depicted in monetary terms. The needs to augment protection, funding and community support for urban greening
call for proper valuation. Heritage trees (HTs), the cream of urban-tree stock, deserve special attention. Existing assessment
methods do not give justice to outstanding trees in compact cities deficient in high-caliber greenery, and to their social-cultural-historical
importance. They artificially separate evaluation from valuation, which should be a natural progression from the former. Review
of tree valuation methods suggested the formula approach to be more suitable than contingent valuation and hedonic pricing,
and provided hints on their strengths and weaknesses. This study develops an alternative formulaic expert method (FEM) that
integrates evaluation and valuation, maximizes objectivity, broadly encompasses the key tree, tree-environment and tree-human
traits, and accords realistic monetary value to HTs. Six primary criteria (dimension, species, tree, condition, location,
and outstanding consideration) branched into 45 secondary criteria, each allocated numerical marks. Each primary criterion
was standardized to carry equal weight, and a tree's maximum aggregate score is capped at 100. A Monetary Assignment Factor
(MAF) to consign dollar value to each score unit was derived from three-year average per m2 sale price of medium-sized residential flats. The applicability of FEM was tested on selected HTs in compact Hong Kong. The
aggregate score of a tree multiplied by MAF yielded monetary value, which was on average 66 times higher than the result from
the commonly-adopted Council of Tree and Landscape Appraisers method. The computed tree values could be publicized together
with multiple tree benefits to raise understanding and awareness and rally support to protect HTs. The property-linked FEM
could be flexibly applied to other cities, especially to assess HTs in compact developing cities. 相似文献
A portion of Arizona’s San Pedro River is managed as a National Riparian Conservation Area but is potentially affected by ground-water withdrawals beyond the conservation area borders. We applied an assessment model to the Conservation Area as a basis for monitoring long-term changes in riparian ecosystem condition resulting from changes in river water availability, and collected multi-year data on a subset of the most sensitive bioindicators. The assessment model is based on nine vegetation bioindicators that are sensitive to changes in surface water or ground water. Site index scores allow for placement into one of three condition classes, each reflecting particular ranges for site hydrology and vegetation structure. We collected the bioindicator data at 26 sites distributed among 14 reaches that had similar stream flow hydrology (spatial flow intermittency) and geomorphology (channel sinuosity, flood-plain width). Overall, 39% of the riparian corridor fell within condition class 3 (the wettest condition), 55% in condition class 2, and 6% in the driest condition class. Condition class 3 reaches have high cover of herbaceous wetland plants (e.g., Juncus and Schoenoplectus spp.) along the perennial stream channel and dense, multi-aged Populus-Salix woodlands in the flood plain, sustained by shallow ground water in the stream alluvium. In condition class 2, intermittent stream flows result in low cover of streamside wetland herbs, but Populus-Salix remain abundant in the flood plain. Perennial wetland plants are absent from condition class 1, reflecting highly intermittent stream flows; the flood plain is vegetated by Tamarixa small tree that tolerates the deep and fluctuating ground water levels that typify this reach type. Abundance of herbaceous wetland plants and growth rate of Salix gooddingii varied between years with different stream flow rates, indicating utility of these measures for tracking short-term responses to hydrologic change. Repeat measurement of all bioindicators will indicate long-term trends in hydro-vegetational condition. 相似文献
Rapid industrialization and urbanization in Turkey, especially over the last twenty five years, has provided better living standards to its residents, but it also caused a decrease in environmental quality. In late 1970's, air quality monitoring activities were started in some major cities by individual researchers in Turkey. It was just around the 1990's that a countrywide program on continuous air pollution monitoring in major province centers and selected large towns was launched. The impact of air pollution on people depend on various factors, such as existence and magnitude of coal powered energy generation plants, type of urban heating and their efficiency, and the numbers and specifications of vehicles. In this study, current Turkish urban air quality over the turn of the Millennium (1992–2001) is studied in the light of the country's worst cities in terms of outdoor air quality, the number of upper respiratory diseases, sinusitis, bronchitis, and pneumonia cases in these provinces reported by the state medical treatment facilities in 2001. The population that is under outdoor urban air pollution hazard was computed. A comparative analysis between the provinces that use natural gas and others that use fossil fuels was also completed in order to project monetary gains if the studied provinces will transform their indoor heating and industrial operations to be run by natural gas or other cleaner energy sources. If natural gas use in air polluted urban centers could be realized in the near future, approximately 212 to 350 million US dollars per annum could to be saved just by reducing health related problems caused by outdoor air pollution. 相似文献
在存在壁面反射的低照度火灾环境中,传统的火焰分割算法如颜色分割、运动检测等,在进行火焰分割时造成过分割现象,分割的效果不理想,影响后续的火灾正确识别。针对上述问题,提出了一种基于自动种子区域生长(Automatic Seeded Region Growing,ASRG)的火焰分割算法。首先将从火灾视频中获取的火灾图像从RGB颜色空间转换到YCbCr颜色空间,在Y通道中采用较大自适应阈值背景减法将火灾图像二值化,分别将可疑火焰像素点的横坐标和纵坐标按大小进行排序,取排序后的中间值作为种子点,再由原RGB火灾图像转换而成的灰度图像中,以该种子点进行区域生长,最后将区域生长后的火焰分割图像与采用较小自适应阈值背景减法得到的火焰分割图像进行交集处理,得到最终的火焰分割图像。实验表明ASRG算法在存在壁面反射的低照度火灾环境中,火焰分割效果好,有效解决了该环境下的火焰过分割问题,同时在其他火灾环境中也有较好的火焰分割效果。 相似文献
Objective: The purpose of this study was to identify and better understand the features of fatal injuries in cyclists aged 75 years and over involved in collisions with either hood- or van-type vehicles.
Methods: This study investigated the fatal injuries of cyclists aged 75 years old and over by analyzing accident data. We focused on the body regions to which the fatal injury occurred using vehicle–bicycle accident data from the Institute for Traffic Accident Research and Data Analysis (ITARDA) in Japan. Using data from 2009 to 2013, we examined the frequency of fatally injured body region by gender, age, and actual vehicle travel speed. We investigated any significant differences in distributions of fatal injuries by body region for cyclists aged 75 years and over using chi-square tests to compare with cyclists in other age groups. We also investigated the cause of fatal head injuries, such as impact with a road surface or vehicle.
Results: The results indicated that head injuries were the most common cause of fatalities among the study group. At low vehicle travel speeds for both hood- and van-type vehicles, fatalities were most likely to be the result of head impacts against the road surface.
The percentage of fatalities following hip injuries was significantly higher for cyclists aged 75 years and over than for those aged 65–74 or 13–59 in impacts with hood-type vehicles. It was also higher for women than men in the over-75 age group in impacts with these vehicles.
Conclusions: For cyclists aged 75 years and over, wearing a helmet may be helpful to prevent head injuries in vehicle-to-cyclist accidents. It may also be helpful to introduce some safety measures to prevent hip injuries, given the higher level of fatalities following hip injury among all cyclists aged 75 and over, particularly women. 相似文献