Dangerous Trees Research Articles

Measuring the Distance between Trees and Power Lines under Wind Loads to Assess the Heightened Potential Risk of Wildfire

The incidence of wildfires caused by tree contact with high-voltage power lines has become an increasingly pressing issue in the United States. To prevent such incidents, local safety councils have established minimum clearance regulations between trees and power lines. While most studies have focused on the tree encroachment around power lines during normal weather conditions, recent catastrophic fires have been caused by strong winds. To address this gap in knowledge, we investigated the critical wind speed that heightens the risk of wildfires by calculating the distance between trees and wires. To conduct this study, we used airborne LiDAR data collected from Sonoma County in northern California and analyzed the behavior of a sample tree having a height of 19.2 m under wind loads. Our analysis showed that the main factor determining tree deflection is the ratio of the tree height to the trunk diameter. We also found that, although the probability of fire ignition is typically low under normal conditions, it is likely to increase at a wind speed of approximately 40.3 m/s. In conclusion, this research demonstrates the utility of point cloud data in identifying potentially dangerous trees and reducing the risk of fires.

Результаты и оценка многолетней интродукции на особо охраняемых природных территориях южно-таежного района

The article shows the analysis results of the vitality and sustainability of the plantings having introduced species in their composition in specially protected natural areas of the south taiga zone (Vologda region). The research purpose is to summarize the available information and carry out the silvicultural assessment of long-term introduction to the plantings in these territories. The species composition is revealed and the sanitary and decorative state of tree and shrub vegetation is estimated. The research objects were the plantings growing in the following parks: Arboretum in Ustyuzhna, Old Park in the settlement of Danilovskoye, Old Park in the settlement of Mozhaiskoye, and Old Park in the village of Kurkino. It was found that the species composition of the suited specially protected natural areas is represented by 34 tree and shrub species: 4 coniferous tree species, 16 deciduous tree species, and 14 species of shrubs. The share of introduced species, in the whole, for all the objects under study is more than 60 %. During the recordings, 12 types of damage were found. According to the degree of influence they were divided into 3 groups: significantly reducing the stability in the plantings (18 % of the total number of damaged trees), reducing the decorative effect (38 %), and reducing the sanitary state of wood species (44 %). In order to improve the sanitary state of the plantings, to ensure that the plantings perform their target functions, and to reduce the economic damage caused by negative anthropogenic factors, it is necessary to take sanitary and recreational measures such as removing dangerous, drying and dead trees. Valuable plants (those of old age or having historical value) were selected; certification of valuable trees was carried out. The biological diversity of tree and shrub vegetation was estimated through determining biodiversity indices. The relationship between the forest stand composition and its resistance to negative environmental factors was revealed. The results of the research can be used by the executive authorities of the constituent entities of the Russian Federation in planning and organizing the works on arranging protection forests, including urban green zones.

The effect of forest management on the frequency of dangerous trees in the Northern forests of Iran

A study of work accidents in forests has shown that dangerous trees play an important role in forest accidents. Despite the importance of safe working environments for forestry operations, the definition of these areas in natural forests is still unclear. Dangerous trees are considered those snagged with broken branches and a canopy or ones with dead trunks and stumps that have a hazard potential to the forest workers. This study investigates the frequency of these trees in the managed and unmanaged forests in the Caspian forests of Iran. In order to do the study, 15 circular plots with a total area of 1,000 square metres in two studied parcels were selected and the trees, according to their dangerous characteristics, were evaluated. The final results indicated that 66 and 50 trees per hectare had signs of being dangerous trees in the managed and unmanaged stand, respectively. A comparison of the average number of dangerous trees in the two studied parcels using the Mann-Whitney test indicated a significant difference so that the average number of dangerous trees in the managed parcel was more than the ummanaged parcel. Trees with broken branches had the highest frequency in the managed stand, while trees with a dead trunk or stump, a broken branch and canopy in the unmanaged forest were more than the other classes. Considering the relative frequency of the dangerous trees in the two study areas, identifying them could be one of the main attempts in logging safety. The existence of hazardous trees with different risk classes in each of the forest stands requires the development of specific safety instructions to deal with the risks of each tree. <br /><br />

Urban trees management methods and their suitability for creating databases

The number of decisions permitting the removal of trees in cities is increasing every year, which suggests long-term negligence, or rather insufficient funds for proper management of urban forests. Lack of appropriate tools causes difficulties in the decision-making process. This problem is especially important in a situation of increased pressure exerted by residents to remove trees, mainly due to the safety reasons. An essential element in maintaining the proper tree management in a city is to improve management systems by applying comprehensive methods and tools. For this reason, many methods are used to support the inventory and identification of dangerous trees. The presented research is a response to the need for unification of management systems based on the most effective and proven methods of defining the resource, health and static condition, value, assessment of tree life expectancy or tree damage. Such a multilateral approach can improve the safety and management of urban forests. The results of the presented analyses led to the formulation of objective guidelines for the urban tree management standards.

Апофітні та адвентивні деревні види на девастованих землях гранітних кар’єрів Криворіжжя

Апофітні та адвентивні деревні види на девастованих землях гранітних кар’єрів Криворіжжя

Job Factors Associated with Occupational Injuries and Deaths in the United States Forestry Industry.

Work in the forestry industry is recognised internationally as high risk for occupational injuries and deaths. Forestry logging operations generally involve felling trees, skidding (moving trees and logs from the stump to the point of delivery), and transporting trees to mills. Loggers need to recognize the hazards associated with identifying dangerous (dead) trees, felling, delimbing, bucking, debarking, chipping, skidding, yarding, loading, unloading, and transporting logs. The purpose of this study was to determine the specific work conditions and job factors that workers identified as greatest risk for injury or death in logging operations in the intermountain region of Montana and Idaho. The study investigators recruited professional loggers through logging companies and professional logging associations in the states of Idaho and Montana. The professional loggers were asked to participate in focus group meetings regarding their perception of the association between logging tasks and logging injuries / deaths. One focus group session of 16 participants for 90 minutes was conducted and moderated by the investigators. The focus group moderator posed a series of questions designed to promote group discussion regarding logging practices and injuries. Injury data from workers' compensation reports was also shared with the participants and served as a basis for the focus group questions. Felling trees was often associated with injuries sustained from falling branches. Conventional chainsaw logging and skyline skidding were perceived as high-risk processes. Loggers indicated that being struck by the carriage attached to the skyline was a significant risk. Other risks identified included being hit by the butt of swinging trees when that became snagged or caught on tree stumps as they were being skidded up the slope. Workers identified working on steep slopes as well as working in below freezing temperatures as a major risk for injury. Physical fatigue while performing strenuous work for 8-10 hours was also identified as a risk for injury. The results of this study identified work conditions (extreme cold temperatures, steep incline of mountain slope), as well as job factors (felling trees, skyline skidding, driving logging trucks) that professional loggers perceived as contributing to increased risk for occupational related injury and death. The conditions and factors identified will be used to target interventions that reduce the risk of logging injuries in the future. Due to the remote nature of the logging work in this region, emergency first-aid training among the crewmembers was thought to be a critical part of logging safety. A culture promoting safety was also stressed for professional loggers.

2011 Urban Geography Plenary Lecture—Colored Rabbits, Dangerous Trees, and Public Sitting: Sidewalks, Police, and the City

Urban geographers would argue that cities are distinct spaces that need to be treated on their own terms. Yet I fear that we have not given the specificity of urban law its due. My aim is to give one crucial, yet easily overlooked urban legal practice, that of "police," more careful attention. By "police" I mean "the regulation of the internal life of a community to promote general welfare and the condition of good order" (Neocleous, 2000, p. 1). I focus on the sidewalk as a particular police space. I also wish to demonstrate the distinctiveness of police, particularly when compared with rights-based understandings of public space. Yet the two frequently collide, as we can see with reference to a constitutional challenge to a sit/lie ordinance in Seattle. Police won, as it usually does. But to accuse police of an assault upon rights is, in several senses, beside the point, for police operates in a different register. Police thus must be understood on its own terms and not reduced to other governmental logics.

Coloured Rabbits, Dangerous Trees, and Public Sitting: Sidewalks, Police, and the City

Urban geographers would argue that cities are distinct spaces that need to be treated on their own terms. Yet I fear that we have not given the specificity of urban law its due. My aim is to give one crucial, yet easily overlooked urban legal practice – that of ‘police’ – more careful attention. By ‘police’ I mean ‘the regulation of the internal life of a community to promote general welfare and the condition of good order’ (Neocleous, 2000, p. 1). I focus on the sidewalk as a particular police space. I also wish to demonstrate the distinctiveness of police, particularly when compared with rights-based understandings of public space, which worry at the purification of public space. Yet the two frequently collide, as we can see with reference to a constitutional challenge to a sit/lie ordinance in Seattle. Police won, as it usually does. But to accuse police of an assault upon rights is, in several senses, beside the point, for police operates in a different register. Police thus must be understood on its own terms, and not reduced to other governmental logics.

The Utilization of Satellite Images to Identify Trees Endangering Transmission Lines

This paper introduces an innovative concept for the use of multispectral stereo pair of satellite images to identify dangerous trees and plants along overhead transmission rights of way. Multispectral satellite images of the right of way are scanned automatically and the color (wavelength) of each pixel is analyzed. This scanning identifies healthy vegetation which may contain trees that endanger the line. Using multispectral stereo images, the height of each pixel is determined and the distance from the conductor is calculated. When this distance is less than the danger zone surrounding the conductors, the identified object or tree is assumed to endanger the line. Case studies using satellite images in the vicinity of Scottsdale, AZ and San Diego, CA demonstrate the feasibility of the proposed method. Details are given for prototype software development for satellite image scanning to determine tree interference with overhead transmission lines.

Attitudes of Municipal Officials Toward Street Tree Programs in Pennsylvania, U.S.

Survey responses from 528 officials in 356 municipalities defined the developmental status of municipal street tree programs and the attitudes of three types of officials: elected chief officials, public works administrators, and municipal solicitors. In sustained programs, which had an ordinance, tree commission, inventory, and management plan, officials had more positive attitudes about trees than in developing programs, which had at least one of these elements, or in communities without a tree program. However, even in the latter, approximately half of the officials believed that benefits of street trees outweigh costs and any disadvantages, and 62% favored starting a tree program. No tree programs exist in 46% of the cities, 82% of the boroughs, and 97% of the townships, so there are many opportunities and also important barriers. Incomplete understanding of the benefits of trees and tree care practices leads to low public support, insufficient funding, and inadequate personnel and equipment. Most officials favor spending some money on trees but regard tree programs as less important than other civic responsibilities. Officials may be persuaded to start or improve tree programs by explaining benefits more fully and how public safety can be improved by proper pruning, inventories that locate dangerous trees, and management plans that arrange to remove them. Furthermore, funding may be alleviated by using volunteers, grants, and available technical advice.

Diagnosis of dangerous trees along the national road in Furano, Hokkaido

Diagnosis of dangerous trees along the national road in Furano, Hokkaido

Can Small, Rural Communities Practice Urban Forestry?

Abstract The practice of urban forestry traditionally has been confined to large cities and their suburbs. However, trees and forests within municipalities–regardless of community size or location within a rural, urban, or suburban setting–all have the potential to provide residents with the environmental benefits and other amenities associated with urban forestry. In most cases, the management afforded metropolitan trees is far superior to that in nonmetropolitan communities. As a result, small towns are often populated by unsightly, unhealthy, and potentially dangerous trees. The biological, economic, and social forces underlying the poor condition of these forests are presented and potential remedies discussed.

Historical Archaeology in Kenya 1948–56

In 1948 the ruined Arab town, sixty-five miles north of Mombasa, known as Gedi was declared a National Park, and an archaeologist was appointed as Warden of the Royal Gedi National Park and the Coastal Historical Sites of Kenya. In the ensuing eight years dangerous trees were cut down, crumbling walls were consolidated, and the fallen rubble round the principal buildings was removed. Gedi is now presented to the world as a place of interest and public resort. Excavations were carried out to discover when it was built, and by whom, and the way of life of its inhabitants. Excavations were also undertaken at a number of other sites to recover the history of the coast of Kenya (pl. XII). From these excavations it has been proved that from the thirteenth century there were extensive Arab or Arab-African settlements all down the coast of Kenya. The extent to which the East African coastal culture of the later middle ages can be regarded as truly ‘Arab’ is still undecided. I am beginning to think that there is a tendency to overstress, or to assume, a state of ‘arabism’ in provincial towns, such as Gedi and Ungwana, which never existed. These towns from their foundation would have comprised a mixed population which had come from the older settlements in Somalia. This mixed population would have contributed Hamitic, Bantu, Persian, Indian, and perhaps Indonesian elements to the predominantly Arab culture of East Africa.