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Trunk flare diameter predictions as an infrastructure planning tool to reduce tree and sidewalk conflicts

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... Population centres are changing from rural to urbanised areas, with increasing development to create supportive infrastructure (North et al., 2015). Urbanisation is set to intensify with an estimated increase in global population of 44% by 2100 (United Nations, 2010). ...
... Impervious surfaces can also increase the soil temperature, particularly in the upper layers, which can reduce root growth and kill tree roots, particularly if temperatures exceed 40°C (Kozlowski, 1984;Ingram et al., 1989). Tree health and condition decrease as the distance between the tree trunk and the pavement decreases (North et al., 2015). When trees are less than 3 m from the pavement, the probability of conflict between the pavement and tree is increased (Sydnor et al., 2000). ...
... A paradigm shift in the management of urban infrastructure is required to enable trees and urban areas to exist in harmony (North et al., 2015). The management challenge for street trees in urban areas is to provide an environment that functions like a natural environment, even though its appearance will be different (Watson et al., 2014). ...
Conference Paper
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Population centres are changing from rural to urbanised areas, with increasing development to create supportive infrastructure (North et al., 2015). Urbanisation is set to intensify with an estimated increase in global population of 44% by 2100 (United Nations, 2010). As populations continue to grow and urbanisation increases to support these communities, permeable land surfaces are being lost to urban development. The increase in impervious surfaces through the construction of roofs, pavements and roads creates an increase in urban runoff and increases the potential for downstream flooding and pollution. Urban areas also place increasing pressures on urban green spaces including street trees.
... In addition, appropriate tree selection for a given site can reduce infrastructure damage and the potential costs of maintaining trees . Medium and large-stature trees (e.g., those greater than 10 m and 20 m high) are preferentially planted as they provide greater benefits (Livesley et al., 2016), however, they are more likely to come into conflict with other elements of urban infrastructure (North et al., 2015;Watson et al., 2014b). Past research has shown that sidewalk and curb damage is more frequent alongside large trees and smaller planting space widths (Watson et al., 2014b). ...
... However, few urban tree-generated models have been developed that relate diameter at breast height to trunk flare/root flare. A study by North et al. (2015) provided models for quantitatively predicting urban tree trunk flare diameter (TFD) based on DBH and species in urban environments. The North et al. (2015) study built upon work by Costello and Jones (2003), which investigated the relationship between "diameter above flare of buttress" (DAFB) and diameter at ground-level (DGL). ...
... A study by North et al. (2015) provided models for quantitatively predicting urban tree trunk flare diameter (TFD) based on DBH and species in urban environments. The North et al. (2015) study built upon work by Costello and Jones (2003), which investigated the relationship between "diameter above flare of buttress" (DAFB) and diameter at ground-level (DGL). Creating predictive models for large growing trees based on DBH is useful since this parameter is often included in public tree inventories and is relatively quick and easy to measure if the data does not exist already. ...
Article
Tree roots often come in conflict with elements of the built environment, particularly when planted in limited soil locations. For street trees located between roadways and sidewalks, minimum planting width requirements can be calculated to prevent large supporting roots from lifting or growing over paved surfaces. In this study, we used diameter at breast height (DBH) to predict trunk flare diameter for common shade tree species from four different communities in the United States (Milwaukee, Minneapolis, Saint Paul, and Tampa). These predictive models were then used to calculate minimum width requirements to reduce infrastructure damage given the maximum expected DBH measurements for each species based on existing urban forest inventory data in the communities studied. For all ten taxa tested, DBH was a significant predictor of trunk flare diameter (minimum R2 = 0.81), indicating that this commonly used urban forestry measurement can be used to design minimum growing space based on selected species to potentially prevent root and infrastructure conflicts. The methods employed in this paper can be easily replicated by other researchers in order to create guidelines for species and environments not captured in our data set. Alternatively, broader functions for estimating trunk flare based on DBH are provided for species based on natural habitat type (i.e., upland, wetland, variable).
... It helps to overcome the harmful ideas about trees and avoid problems due to tree growth on inadequate sites in cities. In the planning process regarding different types of urban green infrastructures that compose the urban forest, the management of the space available to trees on sidewalks and the interaction with urban infrastructures is one of the main challenges faced by public managers [8,12,13]. ...
... Problems regarding sidewalk breakage and conflicts with accessibility have been reported by some studies on urban trees [2,12,13,16] and in most cases, it is due to the natural trunk flare growth in an inadequate space to the tree on the sidewalk. In some places, pavement removal around the trunk flare can be a solution, but the best thing is to promote a qualified planning process, giving trees appropriate space for their growth over the years after planting [8,13]. ...
... In general, the fitted models presented a high performance based on the evaluated parameters, showing consistency with the results obtained in similar studies [12,13,17]. For different groups of tree species and different places, with simple linear regression models using DBH as an independent variable, Hilbert et al. [13] obtained values of R 2 and R 2 adj. ...
Article
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The rule of thumb “the right tree in the right place” is a common idea in different countries to avoid damages caused by trees on sidewalks. Although many new planting techniques can be used, the estimation of the trunk flare diameter (TFD) could help the planning process to give tree roots more space to grow over the years. As such, we compared the applicability of point clouds based on iPad Pro 2020 image processing and a precise terrestrial laser scanner (TLS FARO) for the modeling of the TFD using different modeling procedures. For both scanning methods, 100 open-grown and mature trees of 10 different species were scanned in an urban park in Cracow, Poland. To generate models, we used the PBH (perimeter at breast height) and TFD variables and simple linear regression procedures. We also tested machine learning algorithms. In general, the TFD value corresponded to two times the size of a given DBH (diameter at breast height) for both methods of point cloud acquisition. Linearized models showed similar statistics to machine learning techniques. The random forest algorithm showed the best fit for the TFD estimation, R2 = 0.8780 (iPad Pro), 0.8961 (TLS FARO), RMSE (m) = 0.0872 (iPad Pro), 0.0702 (TLS FARO). Point clouds generated from iPad Pro imageries (matching approach) promoted similar results as TLS FARO for the TFD estimations
... Yet older and larger trees may be damaging to other urban infrastructures (Rotherham 2010). The costs and benefits Grabosky 2011;North et al. 2015;Grabosky and Bassuk 2016;Johnson et al. 2019;Lucke and Beecham 2019). A wider range of tree species for urban greening should be examined. ...
... Flares stemming from a trunk tapering near the ground can be quantified by trunk flare diameter (TFD), which is predictable by diameter at breast height (DBH). In order to avoid pavement damage, minimal open soil surface area could be determined according to predicted TFD values (North et al. 2015;Hilbert et al. 2020). Hilbert et al. (2020) also regressed the occurrence of pavement damage on dendrometric and habitat variables. ...
... DBH was measured at a height of 1.3 m from the soil sur face. TFD was measured in a similar fashion to North et al. (2015). In order to measure the TFD of a tree, the outer tips of each flare were first marked at soil level. ...
Article
Background: Tree pits are urban green infrastructures in paved areas. But tree roots and flares, especially of larger trees, may come into conflict with pavement, resulting in tree health decline and repair costs. This study aimed to (1) establish allometric relationships between diameter at breast height (DBH) and trunk flare diameter (TFD) of common urban tree species, and (2) identify factors affecting the presence and magnitude of protruding roots and flares. Methods: The terms “protruding roots” and “protruding flares” were strictly defined as roots and flares reaching or exceeding the border between the open soil and the adjacent paving material. The study surveyed 1,100 trees of 14 species planted in tree pits in Chai Wan, Hong Kong. Results: DBH was a significant predictor of TFD but was less significant when trees with protruding roots or flares were considered separately. In most logistic models, DBH was significantly and positively related to the odds ratio of the occurrence of protruding roots and flares. Overall, a centimetre increase in DBH brought 1.049 to 1.114 times higher likelihood of protruding roots and flares. Multiple regression suggested that for every square-metre increase in the open soil area in tree pits, the maximum length of protruding roots and flares increased by 0.154 to 0.172 m. This relationship could be attributed to the underlying association between DBH and open soil area. Species-specific regression results were tabulated to allow more accurate estimation of protruding roots and flares. Conclusion: For urban planners and pavement engineers, the approach recommended in this study could be adopted to optimise urban greening and pavement design.
... Root systems play a crucial role in forest ecosystems and in global carbon cycle processes, because they store large amounts of organic carbon (FAO 2010;Yan et al. 2013). However, roots can trigger mechanical damage to infrastructure systems-such as sidewalks, roads, sewers, and cables-mainly in urban landscapes (Randrup et al. 2001;Östberg et al. 2012;Mullaney et al. 2015;Nichols et al. 2017), because tree roots can generate an average radial pressure of 8 × 105 Newtons per square meter (N=m 2 ) (MacLeod and Cram 1996). Hence, a detailed understanding of root system architecture (RSA) in its three dimensions is highly relevant for the sake of reducing conflicts between tree roots and man-made infrastructure (North et al. 2015;Nichols et al. 2017). ...
... However, roots can trigger mechanical damage to infrastructure systems-such as sidewalks, roads, sewers, and cables-mainly in urban landscapes (Randrup et al. 2001;Östberg et al. 2012;Mullaney et al. 2015;Nichols et al. 2017), because tree roots can generate an average radial pressure of 8 × 105 Newtons per square meter (N=m 2 ) (MacLeod and Cram 1996). Hence, a detailed understanding of root system architecture (RSA) in its three dimensions is highly relevant for the sake of reducing conflicts between tree roots and man-made infrastructure (North et al. 2015;Nichols et al. 2017). Traditional methods for root system investigations, such as excavating, are time-consuming, labor-intensive, and destructive (Guo et al. 2013a;Liu et al. 2018), and provide information from excavated areas only, while a major portion of the root material remains unrevealed. ...
... However, roots can trigger mechanical damage to infrastructure systems-such as sidewalks, roads, sewers, and cables-mainly in urban landscapes (Randrup et al. 2001;Östberg et al. 2012;Mullaney et al. 2015;Nichols et al. 2017), because tree roots can generate an average radial pressure of 8 × 105 Newtons per square meter (N=m 2 ) (MacLeod and Cram 1996). Hence, a detailed understanding of root system architecture (RSA) in its three dimensions is highly relevant for the sake of reducing conflicts between tree roots and man-made infrastructure (North et al. 2015;Nichols et al. 2017). Traditional methods for root system investigations, such as excavating, are time-consuming, labor-intensive, and destructive (Guo et al. 2013a;Liu et al. 2018), and provide information from excavated areas only, while a major portion of the root material remains unrevealed. ...
Article
Tree roots can cause damage to surface and subsurface infrastructure. Hence, timely detection of root system architecture (RSA) is needed to reduce conflict between trees and man-made facilities. Because excavation is expensive and often restricted, noninvasive detection of RSA by ground penetrating radar (GPR) is a promising technique. Although several studies have proven the ability of GPR for RSA detection, the problem of distinguishing roots from unwanted reflections at urban test sites with heterogeneous, silty, clayey, or stony soil has not yet been fully solved. This study assessed the performance of GPR for in situ detection of RSA from a plane tree (Platanus acerifolia) and a buckeye (Aesculus hippocastanum) in urban heterogeneous multilayered soil using shielded 250-MHz antennas. Repeated manual hyperbola selections were performed, extracting the three-dimensional (3D) coordinates, which were visualized in top view to reveal connected structures. Unwanted selections were manually filtered by internal confirmation using depth slices from 3D radargram interpolations. Root indications were retraced in the field and validated by vacuum excavation. At our test site, the suggested approach was suitable for detecting the lateral positions of roots with diameters between 1 and 4 cm at depths of 17 to 70 cm, despite unfavorable substrate. Moreover, the assumed depth ranges were correct for both trees, and the main depth characteristics were fairly precisely projected. The rapid and cost-effective protocol allows minimal interventions and opens the door for similar applications in urban and nonurban land uses.
... The replacement or repair of paved surfaces near trees can sever or injure roots, reducing tree health [11][12][13] and undermining overall stability in the face of storm events [14]. To reduce root and pavement conflicts, researchers have investigated how planting widths relate to sidewalk damage [9,15] and created allometric models to predict trunk flare diameter (TFD; i.e., the diameter of the enlarged area at the base of the tree where the trunk connects to the main structural roots) based on tree species and stem diameter [16,17]. From these efforts, minimum planting width requirements can be estimated given species and growth potential to limit root and sidewalk or curb conflicts ( Figure 1). ...
... In this extension of past research by North et al. [17] and Hilbert et al. [16], we developed allometric models linking stem diameter to TFD in small-stature urban trees. While the large stature shade trees assessed by the two research teams cited above are important contributors of ecosystem services, modern compact development patterns leave less space for the sustained growth of large trees [18]. ...
... While the large stature shade trees assessed by the two research teams cited above are important contributors of ecosystem services, modern compact development patterns leave less space for the sustained growth of large trees [18]. As building developments continue to densify, small stature trees may be the best choice for urban greening efforts [17]. This noted, even small-stature trees have their limits with regard to minimal space allotments when trying to prevent pavement conflicts. ...
Article
Full-text available
As urban development increases in density, the space to grow urban trees becomes more constrained. In heavily developed areas, small stature trees can be planted to reduce both above- and below-ground conflicts with infrastructure elements. However, even these species can interfere with pavement when placed in extremely confining conditions. In this study, we build on past work to determine the minimum planting space widths of small stature urban trees. Species, stem diameter, and the height at which stem diameter measurements occurred were all strong predictors of trunk flare (i.e., the interface region between large structural roots and the trunk) diameter (adjusted R2 of 0.843). Additionally, we modelled the relationship between planting space and the presence or absence of pavement conflicts using the predictions derived from this effort to project the potential cost savings in two United States cities. Study results provide a guideline to create sufficient space for urban trees and minimize infrastructure damage and associated cost savings.
... The replacement or repair of paved surfaces near trees can sever or injure roots -reducing tree health (Benson et al., 2019;Hauer et al, 2020;Koeser et al., 2013) and undermining overall stability in the face of storm events (Johnson et al., 2019). To reduce root and hardscape conflicts, researchers have investigated how planting widths relate to sidewalk damage (Francis et al., 1996;Randrup et al., 2003) and created allometric models to predict trunk flare (i.e., the enlarged area at the base of the tree where the trunk connects to the main structural roots) diameter based on tree species and stem diameter (Hilbert et al., 2020;North et al., 2015). ...
... In this extension of past research by North et al. (2015) and Hilbert et al (2020), we developed allometric models linking stem diameter to trunk flare diameter in small-stature urban trees. While the large stature shade trees assessed by the two research teams cited above are important contributors of ecosystem services, modern compact development patterns leave less space for the sustained growth of large trees (Daniel et al. 2016). ...
... While the large stature shade trees assessed by the two research teams cited above are important contributors of ecosystem services, modern compact development patterns leave less space for the sustained growth of large trees (Daniel et al. 2016). As cities continue to densify, small understory trees may be the best choice for urban greening efforts (North et al., 2015). This noted, even smallstature trees have their limits with regard to minimal space allotments. ...
Preprint
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Research Highlights: • Allometric equations explain minimum planting widths for small stature trees. • Trunk flare diameter is related to species, stem diameter, and measurement height • Cost savings for increased planting widths were created for sidewalk replacement. • Minimum planting width provided for planners, urban foresters, and engineers. Abstract As urban development increases in density, the space to grow urban trees becomes more constrained. In heavily developed areas, small stature trees can be planted to reduce both above-and below-ground conflicts with infrastructure elements. However, even these species have their limits when placed in extremely confining conditions. In this study, we build on past work to determine the minimum planting widths of small stature urban trees. We found that species, stem diameter, and the height at which stem diameter measurements occurred were all strong predictors of trunk flare diameter (adjusted R 2 of 0.843). Additionally, we modelled the relationship between planting space and the presence or absence of hardscape conflicts-using the predictions derived from this effort to project the potential cost savings in two United States cities. Study results provide a guideline to create sufficient space for urban trees and minimize infrastructure damage and associated cost savings.
... Mature trees with well-developed root systems (North et al., 2015) within constrained planting areas (Watson et al., 2014;Hilbert et al., 2020b) are therefore more likely to lead to surface displacement. ...
... The 2.1 m scan is sufficient to cover a root flare radius of 1.05 m, assuming the tree abuts the footpath. Using the definition provided by Danjon et al. (2005), this would allow for a complete scan of the zone of rapid taper of a 48 cm calliper tree, making ALISS versatile enough to collect data from the root flare regions of the great majority of street trees (Peper et al., 2001;North et al., 2015North et al., , 2017Magarik et al., 2020). It takes approximately five minutes to collect all the measurements of the tree and its surroundings when working alone, and so there are 1.5-2 minutes of downtime for each scan. ...
... Furthermore, the distance between the tree and the footpath / scan, either directly or in terms of D 30 , was significant in varying combinations for each of the POS, NEG or TOT displacement models (Table 1). This may suggest that the closer a tree is to the footpath, the more likely it is to cause damage, which seems logical with the recent understanding of root system morphology versus footpath damage (i.e., structural roots closest to the trunk collar cause the most damage) (North et al., 2015;Hilbert et al., 2020b), and supports what others have seen previously, using qualitative descriptors of displacement (Francis et al., 1996;Randrup et al., 2001). With limited berm width in which to plant trees (Jim, 1997), this could instead be described as available planting space, as others have pointed out (Hilbert et al., 2020a). ...
Article
It is well-accepted that urban trees provide many benefits to society, but there are costs associated with their establishment and maintenance. Some indirect costs of juxtaposing trees with urban infrastructure are linked to the way in which tree roots interact with hard surfaces such as footpaths (sidewalks), which can result in expensive repairs and in some instances, tree removal. There is a need to understand the complex interactions between tree roots and infrastructure, to inform strategic planting and balance the needs of all stakeholders. In this short communication, we introduce a simple, cost-effective method for quantifying footpath displacement using Arduino robotics and provide the schematics and coding as an open-source tool. Using an ultrasonic sensor, the robot generates a 2.1 m long, two-dimensional profile of a given surface. The accuracy of the robot is validated with objects of known size and was subsequently field tested using 15 Liquidambar styraciflua growing in a suburban street. The robot allowed us to quantify the maximum (highest vertical point) and total (the area under the curve) displacements in the footpath surface. Trunk diameter and proximity to the footpath were significant predictors of displacement at P < 0.05, supporting the findings of other researchers. A larger dataset is required for more generalisable results, but the robot produced reliable data in this proof-of-concept field test.
... A number of social-technological factors for the model were chosen to reflect the contextual vulnerabilities of the Berlin population and assets faced with the biophysically generated UEDS hazard. Causal interactions between biophysical and social-technological processes, as demonstrated in the existing reference literature (Calfapietra et al., 2013;D'Amato et al., 2002;Lawrence, 1997;North et al., 2015;Pohle, 2014;DGUV, 2006;Haftenberger et al., 2013), were used to identify the contextual factors for the assessment. For the allergy disposition, interacting with the allergy hazard, social status was chosen as a proxy. ...
... For the damage hazard originating from street trees (D'Amato et al., 2002;North et al., 2015), the assumption that the affected people and/ or assets are in the streets lined by the potentially damaging trees, led us to use sealed street surfaces as context indicator. Data on sealed street surfaces was acquired from the Berlin Senate Administrations for Urban Development and Housing website (Senatsverwaltung für Stadtentwicklung und Wohnen, 2017a). ...
... Indicator expressions on which the point values are based for each of the seven most abundant street tree genera in Berlin. Cierjacks et al., 2013;D'Amato et al., 2002;North et al., 2015;Östberg et al., 2012 ...
Article
Urban green infrastructure, including street trees, is thought to play an important role in providing urban ecosystem services (UES) such as carbon sequestration and air quality improvement. The concept of urban ecosystem disservices (UEDS) is comparably new in landscape ecology. Research into UEDS assessment is low compared to that of UES. This paper demonstrates an approach to assess the distribution of UEDS risks caused by street trees within the city of Berlin. The approach adapts concepts from urban ecosystem service and natural hazard and risk research to demonstrate the importance of including context-specific vulnerability indicators as additional information in the assessment of UEDS risks. A cluster analysis is carried out to recognize patterns in UEDS risk distribution throughout the city. The paper demonstrates, that using context indicators in addition to biophysical indicators supports the assessment of UEDS as part of the relationship between humans and the environment.
... Sidewalks replacement near trees often result in root damage or removal. North et al. (2015) measured trunk flare width on four species of temperate shade trees and found they were consistently 30 percent to 50 percent wider than the measured trunk diameter at 1.4 meters (i.e. diameter at breast height). ...
... diameter at breast height). Given these findings, the authors suggested that planting widths should be wide enough to accommodate the projected trunk flare given anticipated trunk diameter (based on inventory records/experience) and plus an additional 2.4 meter buffer to reduce conflicts with large tapering roots at and below the soil surface (North et al., 2015) Impact of species and nursery production method on planting process ...
Chapter
While urban forest regeneration does occur naturally, many of the trees found in urban areas were intentionally planted. Conventional transplanting processes can be quite stressful for a tree. Field grown trees can lose a significant portion of their roots during harvest. All trees, regardless of how they were produced, can experience drought stress, mechanical damage, and exposure to extreme temperatures as they are transported, staged, and planted. These stresses and their impact on the success or failure of urban plantings have received considerable attention among researchers in arboriculture, urban forestry, and tree physiology. Their work has helped identified best practices for tree handling and installation which can reduce negative impacts to a tree’s long-term growth and survival. This chapter details some key considerations to promote successful tree planting. It includes information on minimum planting space requirements, seasonal impacts, proper tree storage and handling, planting hole excavation and backfilling, and early care practices (e.g. staking, mulching, pruning, etc.). Trees are typically sold as balled-and-burlapped, container, or bare-root nursery stock. Variations in handling and planting practices related to these production and delivery methods are noted where appropriate. This chapter also highlights planting practices that are specific to planting woody palms.
... Poor-quality soil at difficult sites is compounded by restrictive soil volume and surface sealing by impermeable paving materials (Koeser et al. 2013;North et al. 2015;Hilbert et al. 2020;Ugolini et al. 2020). The frequent occurrence of tree roots damaging the infrastructure highlights the shortage of rootable soil volume (Day 1991;Randrup et al. 2001;Day et al. 2010a). ...
Article
Full-text available
Aims Cramped and sealed sites common in compact city areas limit tree growth due to multiple physical restrictions and physiological stresses. Fast urbanization and densification have intensified the pressure on urban trees, demanding innovative methods and solutions. The subaerial tree-growth space attracts more attention, but the more intractable subterranean rootability constraints are often overlooked. They are expressed as external (macro-scale) soil-body volume and internal (micro-scale) soil-pore volume limitations. The double jeopardy of urban soil insularity acutely restricts root growth, root spread, tree health, and stability. Methods Some novel solutions can be distilled from a comprehensive review of recent research findings to bring effective relief. Results Pedestrians and vehicles can co-use the expanded soil area in dense urban areas. Various creative soil expansion techniques can allow tree roots to break out from conventional confined tree pits or tree strips. Subsurface connections can link a planting site to an adjacent one or a nearby green patch. The soil union could be realized by subsurface soil conduits (large-diameter buried pipes) or subsurface soil corridors covered by pier-supported paving. In the spirit of landscape altruism, soil sharing by neighbor trees optimizes using the scarce rootable soil resource. Internal soil volume expansion can be accompanied by high-quality soil mix and compaction-prevention measures to resolve porosity and rootability deficit. Conclusions Urban tree managers can adopt out-of-the-box thinking in managing critical physical soil deficiencies. New research findings can more promptly inform policymakers and practitioners. Close interactions between science and practice can be proactively cultivated.
... Prior research conducted by UF/IFAS scientists and colleagues looked at the size of common street trees at two different areas of the trunk: 4.5 feet off the ground (a common forestry measurement called diameter at breast height, or DBH) and ground level (a measurement called trunk flare diameter, or TFD) ( Figure 4). It is tricky to measure the diameter of the trunk flare, so researchers created equations allowing users to predict TFD by plugging in the more common measurement, DBH North et al. 2015). This research focused on medium-and large-stature trees (Table 1), but future work will look at small-stature trees such as crapemyrtle (Lagerstroemia indica) and Japanese privet (Ligustrum japonicum). ...
Technical Report
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Describes a method for determining planting width requirements for urban trees to prevent damage to nearby infrastructure like curbs and sidewalks. Includes tables with values for species common to Florida as well as general equations that can be used for a wider range of species in North America and beyond.
... Porém, tem sido considerado um grande desafio para os administradores municipais o planejamento e a manutenção dessa vegetação, que convive diretamente sob influência antrópica. North et al. (2015) mencionaram que escolhas inadequadas para a realização do plantio fazem com que muitas árvores sejam removidas a cada ano, devido aos seus impactos negativos sobre a infraestrutura urbana antes que seus benefícios sejam plenamente realizados. Viveiros com infraestruturas adequadas, profissionais capacitados e conhecimentos técnicos sobre os tratos culturais das espécies produzidas, impactam diretamente na quantidade e qualidade das mudas. ...
Article
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A demanda por mudas florestais para arborização de ruas e paisagismo, criação de áreas verdes, regularização ambiental, recuperação de áreas degradadas (RAD) pode ser suprida pelos viveiros municipais. O objetivo desta pesquisa foi identificar os viveiros municipais do estado de Goiás e apresentar um panorama sobre sua distribuição e caracterização regional. Os dados foram obtidos por meio de consulta eletrônica, que também buscou conhecer: número de habitantes dos municípios, região de planejamento, tipologia vegetal e instituições de ensino e pesquisa com cursos associados à produção de mudas. Também foi consultado se os viveiros possuem cadastro no Registro Nacional de Produtores de Sementes e Mudas. Os resultados indicaram que 23,6% dos municípios de Goiás possuem viveiros municipais. A informação sobre ausência ou presença destes viveiros não foi encontrada somente em 14 dos 246 municípios existentes. De maneira geral, os municípios com maior número habitantes e localização central apresentam viveiros. As formações florestais variaram de acordo com a região de planejamento do estado. Nenhum dos viveiros municipais possui registro. Foram listadas 37 instituições para possíveis parcerias com viveiros. A ausência destes compromete a arborização urbana, RAD e regularização ambiental. As parcerias podem incentivar politicas públicas de produção de mudas em Goiás.
... The findings were not surprising considering Berrang et al. (1985) found trees growing in larger tree lawns had a greater tree condition. Tree growth was better in larger tree lawns in Minneapolis/Saint Paul, United States (North et al. 2014, North et al. 2017. ...
Chapter
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The effects of street, curb, and sidewalk construction on tree growth, health, and survival were studied in Milwaukee, WI, United States. Three periods were used to contrast the implementation of tree preservation during construction: (1) a limited developed program period prior to 1989, (2) an intermediate program of development and refinement Street Trees, Construction, and Longevity • 547 between 1990 and 2004, and (3) during an advanced developed program from 2005 to 2017. Trees died at a higher annual rate (~4.1% mortality) and had a lower tree condition rating (~5.7% decrease) in the initial study period measurement in 1989. The second period found construction activities had a reduced effect on tree condition (~2.4% decrease) in 2005. There was no difference in tree survival and condition during the most recent period in 2018 and the advanced developed program. The tree preservation program was useful to promote healthy and sustained street tree populations in construction zones. Trees in larger tree lawns had higher tree survival and condition in all three periods. Larger trees on average had lower tree condition. Finally, tree condition in a previous period was a positive predictor of the current tree condition.
... According to Grimm et al. (2008), urbanisation induced land change is a complex problem that underpins the interactions taking place between spatial and temporal scales as a result of links between resources, population, physical and biological systems. Urban ecologists in both developing and developed countries employed the socio-ecological system framework to establish links between trees, habitat, the community and households, the institutional factors or governance system in explaining ecosystem services of urban trees Lo and Jim, 2015;North et al. 2015;Shackleton et al. 2015;Vogt et al. 2015). The enquiries made by these diverse studies used varied methods which included public and household surveys, streets tree inventories, visual assessment of trees, field-based observations of plant types, morphometric analysis of tree bodies and linear regression techniques. ...
Chapter
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The study of urban tree distribution and conservation continues to be an important focus of enquiry for academics and policymakers alike, particularly in the context of urban sustainability in dryland areas. A number of studies, for example, have deployed spatially explicit models to investigate patterns of tree distribution of over time. However, little attention has been paid to understanding the path dependency and historical trajectories that have shaped tree-cover change in and around growing cities, or how, in turn, urbanisation has displaced or depleted urban local trees. In response to this gap, this paper draws upon a suite of interdisciplinary methods, including autoethnography, path dependency, and the landscape biographic approach, to trace and examine processes which concern local tree depletion. In doing so, the study explores how toponyms-name of places-can serve as a facilitating criterion for tracing or tracking the current and past distribution of native trees in the northern Nigerian city of Kano, and its intensively cultivated periphery. In addition to this historical analysis, the study also highlights the critical vulnerability of urban plant diversity in drylands in sub-Saharan Africa, in its wider socio-ecological dimension of urban tree dynamics in traditional and unplanned cities. The study's main conclusion is that researchers and policymakers need to pay more attention to understanding the histories of trees in urban landscapes from different socio-ecological viewpoints.
... Para De Angelis et al. (2011), é de importância fundamental a seleção correta das espécies vegetais a serem empregadas na arborização, já que seu uso indevido poderá resultar em muitos prejuízos aos equipamentos urbanos, como comprometimento das redes de água e de esgoto, redes elétricas e passeios, trazendo transtornos ao trânsito de pedestres. North, Johnson e Burk (2015) reportam que escolhas inadequadas para a realização do plantio fazem com que muitas árvores sejam removidas a cada ano devido aos seus impactos negativos sobre a infraestrutura urbana antes que seus benefícios sejam plenamente realizados. ...
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Com o desenvolvimento das cidades, é cada vez maior a preocupação quanto à manutenção da qualidade de vida nestes centros urbanos, tendo a arborização urbana importância na melhoria de aspectos sanitários, sociais e estéticos. Nesse prisma, o estudo da problemática da existência de características indesejáveis às plantas e da compatibilização do espaço com os equipamentos públicos tem significativa relevância. Este trabalho tem por objetivo geral avaliar a arborização viária da cidade de São Tomé, Paraná, o qual corresponde a um centro urbano de pequeno porte. Para isto, foi conduzido o censo de todos os exemplares de porte arbóreo, ou conduzidos para isso, com altura acima de 1,0 metro presentes ao longo das vias públicas da cidade, e posterior análise das espécies encontradas quanto ao atendimento às normas técnicas em aspectos qualitativos: procedência, a existência de frutos grandes e carnosos e princípio tóxico e a presença de espinhos ou acúleos, respectivamente, e posterior quantificação e classificação quanto aos danos das raízes e copas aos equipamentos públicos. Foram verificadas 63 espécies vegetais distintas, com 3.085 indivíduos no total, com a predominância de Licania tomentosa (Chrysobalanaceae) (n = 1120). Após análise dos parâmetros indicados, sugeriu-se a substituição de 635 exemplares de 41 espécies (20,58% da ocorrência total) por espécies vegetais adequadas às normas técnicas e à legislação. Dentre as 22 espécies apropriadas ao uso na arborização de vias públicas encontradas na urbe, destacam-se Handroanthus chrysotrichus (Mart. ex DC.) Mattos (Bignoniaceae), Handroanthus heptaphyllus Mattos (Bignoniaceae) e Tabebuia roseoalba (Ridl.) Sandwith (Bignoniaceae), considerando os benefícios proporcionados aos citadinos.
... Increased width of tree planting spaces along streets combined with species selection that considers the mature size of a tree are strategies that can help to reduce the need for sidewalk repair adjacent to trees (Wagar and Barker, 1983;Costello and Jones, 2003;North et al., 2015) and subsequent reduction in stability, growth, and survival of trees as a result of construction activities. To stabilize and potentially increase future urban canopy cover, the interaction between site design and species adaptations should be considered to reduce effects of anthropogenic disturbance and provide adequate growing space required for large, healthy, and long-lived trees. ...
... Prior research conducted by UF/IFAS scientists and colleagues looked at the size of common street trees at two different areas of the trunk: 4.5 feet off the ground (a common forestry measurement called diameter at breast height, or DBH) and ground level (a measurement called trunk flare diameter, or TFD) ( Figure 4). It is tricky to measure the diameter of the trunk flare, so researchers created equations allowing users to predict TFD by plugging in the more common measurement, DBH North et al. 2015). This research focused on medium-and large-stature trees (Table 1), but future work will look at small-stature trees such as crapemyrtle (Lagerstroemia indica) and Japanese privet (Ligustrum japonicum). ...
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Trees provide urban landscapes with shade, beauty, and habitat. They can also help lessen the effects of flooding and urban heat buildup while storing carbon dioxide, a major greenhouse gas. When planted in the wrong place, however, trees can damage urban infrastructure. To maximize the benefits provided by urban trees, we need better-informed tree selection and larger planting spaces with the capacity to support big-canopy trees. This new 8-page fact sheet is intended to help arborists, urban foresters, landscape designers, landscapers, and anyone else responsible for the planting of trees in developed areas make informed decisions regarding the planting width requirements of the trees they select. Written by Deborah R. Hilbert, Andrew K. Koeser, Brooke L. Moffis, JuWanda G. Rowell, and Drew C. McLean, and published by the UF/IFAS Environmental Horticulture Department.https://edis.ifas.ufl.edu/ep592
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The publication aims to investigate the quantitative impact of linear earthworks in urban parks, e.g. during roads’ and pavements’ modernization in the old trees’ root zones, on the increment in their external parameters (e.g. trunk circumference). Pilot studies (Warsaw, Poland) were carried out 2003–2019 in two historical parks: Ursynów and Królikarnia. The dataset of trees’ parameters is based on detailed dendrological inventories. Test groups consisted of trees exposed to damage and not exposed to damage (Ursynów) and the control group – trees growing in unchanged site conditions (Królikarnia). Among the three most abundant species of dendroflora, Norway maples (Acer platanoides L.) show the most visible difference (>1.8 cm) between the normal and the inhibited growth in trunk circumference. Two other species – black locusts (Robinia pseudoacacia L.) and small-leaved limes (Tilia cordata Mill.) – also revealed statistically significant differences in the increment of the trunk circumference (respectively: >1.3 cm and >1.4 cm). In general, the reaction of affected trees was a significant reduction of circumference increments from 2.6 to 4.0 times concerning trees not exposed to damage. The verification made with the resistograph in 2019 confirmed a statistically significant decrease in radial increments of trees remaining in the impact zone of the earthworks.
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One issue confronting the application of forest management principles to urban tree canopy management decisions is the lack of data correlating site, tree size, and tree age. Researchers tested whether terminal size (stem diameter) can be linked to site type for informed management and design decisions. Data were considered from eleven New Jersey, U.S. communities. Diameter breast height (DBH) distribution established regionalized service life expectancies of commonly planted species by site type and expected maximum DBH. The goal was to develop a method to identify trees approaching senescence within an inventory. Three common urban landscape site types were used: tree pit, planting strip, and unlimited soil. Thirty-one taxa were present in large enough populations to use in species-specific analysis. The species were classified into small, medium, and large size categories based on published growth expectations. The study authors developed DBH occurrence percentiles, and DBH within the ninety-fifth were described as a maximum size range. There was a significant difference in maximum sizes between planting site types. Regardless of the size class of the tree, the data showed reduced planting space resulted in reduced maximum size.
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This paper develops and demonstrates a statistical sampling method that can be used to estimate the species composition of an urban street tree population quickly and accurately, i.e., with an acceptable level of error. The technique is based on stratified random sampling. We first estimate the percentage of street trees in separate zone segments throughout the city, and then distribute a sample of 2,000-2,300 trees across the city. Weighted averaging is used to obtain estimates and confidence limits. We have applied this technique in four cities in New York state and obtained results that agree closely with previously existing complete or partially complete street tree surveys.
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If fall, does it make a sound? A similar riddle can be applied to trees with stem-girdling roots: If a dead, declining, or fallen tree has roots encircling and compressing the stem, were those roots responsible for the damage? It’s a controversial question. Opinions, anecdotal information, and some research argue yes, no, and sometimes. Stem girdling roots (SGRs) do affect trees, as any disorder would. SGRs, as opposed to root-girdling roots, encircle or run tangential to a tree’s stem, eventually compressing the woody and nonwoody tissues of the stem. The degree to which trees are impacted varies with severity of encirclement, site (growing) conditions, weather, age, size, and, very likely, genetics. Urban trees are subjected to a continual barrage of natural and unnatural stresses conditions that deviate from optimal. SGRs add another layer of stress, sometimes significantly. Trees commonly fail for structural and physiological reasons. Physiologically, trees might slowly decline and die as a result of SGRs. Or, a tree might suddenly fail during a windstorm when stresses accumulate to the point of acute strain on the tree’s structural system from stem compression and decay due to SGRs. This translates to economic and environmental losses: labor and materials to maintain trees; labor to remove and replace trees; cost of new trees; damage to personal and public property; and loss of carbon sequestration, shade, wildlife habitat, noise attenuation, and other benefits of trees. The degree to which SGRs affect urban forest health and condition is not known due to insufficient research and, very likely, to inaccurate diagnoses of tree disorders and losses. The purpose of this publication is to present an objective perspective of SGRs. Most importantly, this publication reviews the symptomology, potential causes, treatments, and prevention of decline associated with SGRs. It is intended for field and diagnostic applications by arborists, landscape managers, growers, and urban forest health specialists. Research on SGRs is limited, but more practitioners are becoming aware of the problem, and new information on the formation and effects of SGRs has been recently collected. The lack of information might be partly due to the fact that roots are not always clearly visible because they are buried under soil or mulch. Another reason for the lack of research on this subject might be incorrect or incomplete diagnoses of tree problems. Few practitioners investigate below ground during tree disease/disorder diagnostic efforts. Perhaps the most important sections of this publication are those on the symptomology and prevention of SGRs. Although the extent is relatively uncertain, SGRs do cause damage and premature loss of trees or tree health. As with any other natural or unnatural stress, recognizing the problem and preventing future damage to urban trees are the practitioner’s responsibilities and goals.
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A modeling study using hourly meteorological and pollution concentration data from across the coterminous United States demonstrates that urban trees remove large amounts of air pollution that consequently improve urban air quality. Pollution removal (O3, PM10, NO2, SO2, CO) varied among cities with total annual air pollution removal by US urban trees estimated at 711,000 metric tons ($3.8 billion value). Pollution removal is only one of various ways that urban trees affect air quality. Integrated studies of tree effects on air pollution reveal that management of urban tree canopy cover could be a viable strategy to improve air quality and help meet clean air standards.
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The population of the United States of America is currently experiencing increased illness from dispersed and synergistic causes. Many of the acute insults of the past have receded due to centralized health care and regulatory action. However, chronic ailments including asthma and allergies, animal-transmitted diseases, obesity, diabetes, heart disease, and depression are on the rise. These diverse illnesses join with forest fragmentation, stream degradation, wetlands destruction, and the concomitant loss of native species to suggest detrimental contributions from the built environment.
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Urban tree cover benefits communities. These benefits' economic values, however, are poorly recognized and often ignored by landowners and planners. We use hedonic property price modeling to estimate urban tree cover's value in Dakota and Ramsey Counties, MN, USA, predicting housing value as a function of structural, neighborhood, and environmental variables, including tree cover, using a spatial simultaneous autoregressive (SAR) error model. We measure tree cover as percent tree cover on parcels, and within 100, 250, 500, 750, and 1000Â m. Results show that tree cover within 100 and 250Â m is positive and statistically significant. A 10% increase in tree cover within 100Â m increases average home sale price by $1371 (0.48%) and within 250Â m increases sale price by $836 (0.29%). In a model including both linear and squared tree cover terms, tree cover within 100 and 250Â m increases sale price to 40-60% tree cover. Beyond this point increased tree cover contributes to lower price. Tree cover beyond 250Â m did not contribute significantly to sale price. These results suggest significant positive effects for neighborhood tree cover, for instance, for the shading and aesthetic quality of tree-lined streets, indicating that tree cover provides positive neighborhood externalities.
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Investigations into girdling root formation in young landscape trees revealed that Norway and sugar maples had an average of four girdling roots per tree and that red maple had nearly twice as many. While these roots persisted to become a serious problem in older Norway maples, they did not in red and sugar maples. Removing the roots was ineffective since new girdling roots were regenerated from the same location. Of the 60 mature Norway maple examined girdling and potentially girdling roots were completely absent on only two trees. Genetic diversity may allow a rootstock to be selected and propagated so as to reduce or eliminate the character of girdling roots.
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This paper presents a sidewalk pavement width design method for making more pedestrian friendly and walk-inspiring sidewalk pavements in the urban area. Instead of using the current sidewalk pavement width design standard that usually leads to having minimum values, this research investigated pedestrians’ preferences on the levels of service, surveyed actual foot path trajectories in the sidewalk pavements, and observed pedestrian movement characteristics in the streets. Further, these investigation results were summarized to propose a new urban sidewalk pavement width determination procedure. The proposed procedure was applied in a case study site in Seoul, and its application resulted in a much higher pedestrian level of service. It is anticipated that the proposed method should be of service in both planning and retrofitting urban streets to make more pedestrian sensitive street designs.
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Since 2007, for the first time in human history, more than half of the world's population has been living in cities. The urbanization process is a key phenomenon of economic development, and leads to a significant concentration of human resources, economic activities, and resource consumption in cities. Although covering only about 2% of the earth's surface, cities are responsible for about 75% of the world's consumption of resources. This trend will intensify over the next decades as a consequence of high urbanization rates in Africa and, even more importantly, in Asia. In order to estimate the impact of urbanization on energy demand, we have to identify the different processes and mechanisms of urbanization that substantially affect urban structures as well as human behavior. Taking a closer look at city-related production, mobility and transport, infrastructure and urban density, as well as private households, we find that various mechanisms of urbanization within the different sectors of the economy lead to a substantial increase in urban energy demand and to a change in the fuel mix. The relevance of these mechanisms differs considerably between developed and developing countries as well as within the group of developing countries. Over the next decades, cities and especially newly emerging megacities in developing countries will play a key role concerning the development and distribution of global energy demand. Hence, urban energy planning and urbanization management will be pivotal for creating the right framework conditions for a sustainable energy future.
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Research in the area of sustainable urban infrastructure reflects the need to design and manage engineering systems in light of both environmental and socioeconomic considerations. A principal challenge for the engineer is the development of practical tools for measuring and enhancing the sustainability of urban infrastructure over its life cycle. The present study develops such a framework for the sustainability assessment of urban infrastructure systems. The framework focuses on key interactions and feedback mechanisms between infrastructure and surrounding environmental, economic, and social systems. One way of understanding and quantifying these interacting effects is through the use of sustainability criteria and indicators. A generic set of sustainability criteria and subcriteria and system-specific indicators is put forward. Selected indicators are quantified in a case study of the urban water system of the City of Toronto, Ontario, Canada.
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Pedestrians' emotional satisfaction when using an urban sidewalk landscapes depends on the sidewalk design elements and component ratios. It is therefore important for the design of a sidewalk to reflect pedestrians' emotional perceptions through affective engineering and design. In this study, sidewalk preference is surveyed based on principles of affective engineering and is modeled in order to understand the relationships between the design elements and the component ratios in a sidewalk landscape. Through comparisons, sidewalk design criteria are presented with the aim of developing a comfortable and pleasant sidewalk landscape. Sidewalk design elements include sidewalk width, shrub width, tree height, and tree width. Also, component area ratios for greenery, sky, roadway, sidewalk, and building are used to define the design criteria. This paper is for a Korean case study that is subject to Korean perceptions on sidewalk landscape. The research shows that it is crucial to consider affective engineering in order to design a comfortable and pleasant sidewalk landscape.
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Tree work records for ten species were analyzed to estimate average annual management costs by dbh class for six activity areas. Average annual benefits were calcu- lated by dbh class for each species with computer modeling. Average annual net benefits per tree were greatest for London plane (Platanus acerifolia) ($178.57), hackberry (Celtis sinensis) ($148.42), and Modesto ash (Fraxinus velutina 'Modesto') ($126.16) and least for pear (Pyrus calleryana cvs.) ($33.65), pistache (Pistacia chinensis) ($64.98), and camphor (Cinnamomum camphora) ($71.36). Benefit-cost ratios (BCRs) were greatest for plane (24.3:1), ginkgo (7.4:1), and cam- phor (7.3:1). Species with the lowest BCRs were sweetgum (Liquidambar styraciflua) (2.4:1), pear (2.6:1), and pistache (3.3:1). Aging of sweetgum and Modesto ash will result in reduced net benefits because BCRs decreased once trees reached the 46 cm dbh class. Uses of benefit-cost data to increase future net benefits are discussed.
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There are many factors to consider when sever- ing the roots of established trees. Factors governing root growth are discussed. Acceptable survival following severe root severance is interdependent with the condition of the top. It is important to know the location of various kinds of roots—large lateral, sinker, heart, non-woody. Key factors to successful results from severe root-pruning include: a tree species with adequate vigor, adequate moisture in the root area, healthy carbohydrate reserves, proper timing in climates with temperature extremes and knowing how to judge a tree that should not be severely root pruned. Many landscape trees appear to have a wide tolerance to root removal. Resume. II a plusieurs facteurs a considdrer lorsque les racines d'arbres a maturite doivent Stre endommagees. Les facteurs influengant la croissance des racines sont discut6s. line bonne survie d'une arbre apres des dommages aux racines est dependante de la condition de la cime. II est important de connaitre 1'emplacement des divers types de racines - les racines primaires, secondaires et les radicelles. Les facteurs-cl§s afin d'avoir des resultats positifs apres des dommages aux racines incluent: une espece d'arbre avec une bonne vigueur, une humidite adequate dans la zone racinaire, de bonnes reserves d'hydrate de carbone, le choix de la periode appropriee dans les climats avec des temperatures extremes et savior reconnaltre les arbres dont les racines ne devraient pas etre endommagees. Plusieurs arbres d'ornement semblent avoir une grande tolerance a la taille des racines.
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Although the modeling of energy-use re- duction, air pollution uptake, rainfall interception, and microclimate modification associated with urban trees depends on data relating diameter at breast height (dbh), crown height, crown diameter, and leaf area to tree age or dbh, scant information is available for common municipal tree species. In this study, tree height, crown width, crown height, dbh, and leaf area were measured for 12 common street tree species in the San Joaquin Valley city of Modesto, California, U.S. The randomly sampled trees were planted from 2 to 89 years ago. Using age or dbh as explanatory vari- ables, parameters such as dbh, tree height, crown width, crown height, and leaf area responses were modeled using two equations. There was strong corre- lation (adjusted R2 > 0.70) for total height, crown di- ameter, and leaf area with dbh. Correlations for dbh with age and crown height for several species were weaker. The equations for predicting tree sizes and leaf area are presented and applied to compare size and growth for all species 15 and 30 years after planting. Tree height, crown diameter, and dbh growth rates tended to slow during the second 15 years, but the leaf area growth rate increased for most species. Compari- sons of predicted sizes for three species common to Modesto and Santa Monica trees suggest that pruning has a significant impact on tree size and leaf area, po- tentially more than climate and soil characteristics.
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The authors estimate the relationship between trees and three crime aggregates (all crime, violent crime, and property crime) and two individual crimes (burglary and vandalism) in Portland, Oregon. During the study period (2005-2007), 431 crimes were reported at the 2,813 single-family homes in our sample. In general, the authors find that trees in the public right of way are associated with lower crime rates. The relationship between crime and trees on a house’s lot is mixed. Smaller, view-obstructing trees are associated with increased crime, whereas larger trees are associated with reduced crime. The authors speculate that trees may reduce crime by signaling to potential criminals that a house is better cared for and, therefore, subject to more effective authority than a comparable house with fewer trees.
Article
Urban forest managers often are required to make decisions about whether to retain or replace an existing tree. In part, this decision relies on an economic analysis of the benefits and costs of the alternatives. This paper presents an economic methodology that helps address the tree replacement problem. The procedures apply to analyzing the benefits and costs of existing trees as well as future replacement trees. A case study, involving a diseased American elm (Uimus americana) is used to illustrate an application of the methodology. The procedures should prove useful in developing economic guides for tree replacement/retention decisions.
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Thesis (M.L.A.)--Cornell University, August, 1990. Includes bibliographical references.
Article
At the beginning of the 1900s, the Canberra plain was largely treeless. Graziers had carried out extensive clearing of the original trees since the 1820s leaving only scattered remnants and some plantings near homesteads. With the selection of Canberra as the site for the new capital of Australia, extensive tree plantings began in 1911. These trees have delivered a number of benefits, including aesthetic values and the amelioration of climatic extremes. Recently, however, it was considered that the benefits might extend to pollution mitigation and the sequestration of carbon. This paper outlines a case study of the value of the Canberra urban forest with particular reference to pollution mitigation. This study uses a tree inventory, modelling and decision support system developed to collect and use data about trees for tree asset management. The decision support system (DISMUT) was developed to assist in the management of about 400,000 trees planted in Canberra. The size of trees during the 5-year Kyoto Commitment Period was estimated using DISMUT and multiplied by estimates of value per square meter of canopy derived from available literature. The planted trees are estimated to have a combined energy reduction, pollution mitigation and carbon sequestration value of US$20-67 million during the period 2008-2012.
Tree Roots and Infrastructure Damage
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Dimensional Relationship of Forest and Open Grown Trees in Wisconsin
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Ek, A.R., 1974. Dimensional Relationship of Forest and Open Grown Trees in Wisconsin. University of Wisconsin, School of Natural Resources, Madison, WI.
Reducing Infrastructure Damage by Tree Roots: A Compendium of Strategies. Western Chapter
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Tree Roots in the Built Environment
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Innovative Sidewalk Repair in the City of Los Angeles
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Dimensional Relationship of Forest and Open Grown Trees in Wisconsin
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Tree root growth and development. I. Form, spread, depth, and periodicity
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