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Tree monitoring is a challenging task due to the labour-intensive and time-consuming data collection methods required. We present TreeEyed, a QGIS plugin designed to facilitate the monitoring of trees using remote sensing RGB imagery and artificial intelligence models. The plugin offers several tools including tree inference process for tree segmentation and detection. This tool was implemented to facilitate the manipulation and processing of Geographical Information System (GIS) data from different sources, allowing multi resolution, variable extent, and generating results in a standard GIS format (georeferenced raster and vector). Additional options like postprocessing, dataset generation, and data validation are also incorporated.

Coastal swamp forests fill ecological niches that provide valuable environmental services, yet their extent across coastal Louisiana has diminished from logging and saltwater intrusion. Previous reforestation attempts yielded mixed results, attributed to hydrological disturbances leaving regions of the coast vulnerable to environmental stress. Environmental conditions may be improving. In the Pontchartrain Estuary, the Caernarvon Freshwater Diversion (CFD) has pulsed Mississippi River water into lower estuary wetlands since 1991, and the Mississippi River Gulf Outlet Canal closure in 2009 lowered soil salinity further upstream in the estuary on the Maurepas Landbridge (MLB). However, how hydrological restoration impacts habitat restoration remains undocumented. The Pontchartrain Conservancy planted ~80,000 saplings from 2011–2021 in two regions (CFD, MLB) within the estuary. Species included Taxodium distichum (L.) Rich, Nyssa aquatica L. Nyssa sylvatica Marshal var. biflora, Acer rubrum L. var. drummondii (Hook. & Arn. ex Nutt.) Sarg. and Fraxinus pennsylvanica, though > 80% of the saplings planted were T. distichum. We assessed survival and growth for 7.3% of saplings. Survival differed between regions; survival was lower around the CFD (63%) and higher on the MLB (82%). Growth rates also differed; growth was higher in CFD (height: 0.18–0.69 m/yr; diameter 0.66–1.62 cm/yr) and lower in MLB (height: 0.00–0.44 m/yr; diameter 0.05–0.18 cm/yr). Growth varied temporally between areas, but trends were similar. Results indicate 1) hydrological restoration benefits coastal swamp reforestation, and 2) river water increased growth. As habitat restoration, including swamp reforestation, scales-up in Louisiana, these outcomes help resource managers and planners refine restoration goals and target areas to maximize restoration success. [ABSTRACT FROM AUTHOR]

Trees outside forests (TOFs) are important landscape features that provide numerous functions (ecosystem services) that are not valued due to a lack of knowledge about these resources. The aim of this study was to evaluate the changes induced by the anthropogenic land use change in relation to their effects on TOFs. The dynamics of TOFs were examined through detailed photointerpretation mapping and characterization by land use/land cover and other environmental variables. The landscape function of TOFs and relative dynamics were analyzed, revealing landscape simplification due to the loss of TOFs, both in number and area, and a relative loss of connectivity. In 2000, TOFs accounted for 2.6% more forest area than mapped in the regional forest map; in fifteen years, about 30% of the total area has been lost, one-third of which has been converted to forest and the remainder permanently lost. The causes of the loss of TOFs are partly due to the abandonment of agricultural land, but also to the actions of farmers who remove these elements for various reasons. In protected areas (Natura 2000 network), the loss is less due to the different characteristics of land use/cover and land management. [ABSTRACT FROM AUTHOR]

Historic gardens are green spaces characterised by tree stands with several veteran specimens of high artistic and cultural value. Such valuable plant components have to cope with biotic and abiotic stress factors as well as ongoing senescence processes. Maintaining tree health is therefore crucial to preserve their ecosystem services, but also to protect the monument and visitor health. In this context, finding smart, fast and cost-effective management solutions to monitor health and detect critical conditions for both stands and individual veteran trees can promote garden conservation. For this reason, we developed a novel framework based on Sentinel2 imagery, LiDAR sources and automatic cameras to identify risk spots regarding trees in historic gardens. The pilot study area consists of two closed Italian gardens from the 16th century, which were analysed as a unique Historic Garden System (HGS). The tree health status at stand level was assessed using a criterion based on the Normalized Difference Vegetation Index weighed on tree volume (NDVI t) and validated by a visual crown defoliation assessment. At the tree level, the health status of four veteran trees defined by the NDVI t was also evaluated using green chromatic coordinates (GCC) obtained from digital images acquired by cameras at daily intervals during one growing season. The 33% of the tree population was classified as being in poor health, i.e. "at risk". Veteran trees classified as "at risk" showed an anticipation of phenological phases and a lower GCC compared to reference trees. Despite variability determined by Sentinel medium resolution, the proposed framework showed good accuracy (0.74) for monitoring historical gardens. The semi-automatic risk point mapping system tested here proved to be effective in facilitating the management of historic gardens, which in turn could be applied in the wider context of urban greening. • Senescent tree maintenance is a main issue of historic garden management. • Precision forestry techniques may simplify historic garden management. • We tested smart monitoring techniques on the tree component of two historic gardens. • A criterion to select risk spots based on Sentinel2 and LIDAR data was validated. • Images from automatic cameras were analysed for veteran tree monitoring. [ABSTRACT FROM AUTHOR]

With the increasing severity and frequency of windstorms, public administrations are increasingly dealing with damage to tree populations. The need for accurate and reliable risk assessment is growing, but currently, there is a lack of appropriate and standardised tools and methods. Recent approaches to studying wind-tree interactions include operational modal analysis and finite element modelling using detailed tree geometry. These approaches still need to be explored by the scientific community. This study investigated the advantages of the operational modal analysis approach for monitoring tree dynamics by defining the main modal parameters of two living pedunculate oaks (Quercus robur L.) The samples were monitored under free ambient sway using eleven high-sensitivity accelerometers along the trunk and main branches. The data were used to extract the tree spectral response and to estimate the main modal parameters. The trees were Lidar-scanned and reconstructed in a simulated environment to estimate modal parameters measured in the field. A reliable tree geometrical model was only obtained after more than 100 iterations of the geometry optimization procedure, focusing on optimizing the tree reconstruction. An additional 50 runs were performed to investigate the influence of mechanical material properties and stiffness of the base constraint on the main modal parameters based on literature values. The main results include the dynamic identification and detailed dynamic mode parameters under free sway at an average wind speed of less than 1 m s-1 for 20 minutes. The modal analysis highlighted the limited prominence of the peaks in frequency domain spectra and the complexity of the broadleaf behaviour in low wind and leafless conditions. Both tree models correctly simulated the dynamic parameters of the tree with satisfactory accuracy without any measured geometric and material properties as model input. The differences between the measured and simulated first sway modes are 0 to 16% for different tree and rooting stiffness values. The use of these two techniques, mainly when used in combination, allows a comprehensive study of wind-tree interaction. Further work should focus on simplifying and automating the entire research workflow and evaluating the modelling capabilities and its predictive accuracy in monitoring wind-tree interaction under high wind conditions. • Seismic accelerometers can capture tree dynamics even under low wind speed. • Operational modal analysis procedures can be applied to investigate tree dynamics. • Reconstructing complex tree geometry to solve physics problems requires guidelines. • Models developed from laser scanner can simulate tree dynamics with a good accuracy. • Tree modal parameters from numerical analysis can be validated using modal analysis. [ABSTRACT FROM AUTHOR]

A comprehensive understanding of the dynamic behavior of a tree can play a key role in the tree stability analysis. Indeed, through an engineering approach, the living tree can be modeled as a mechanical system and monitored observing its dynamic properties. In the current work, procedures of dynamic identification used in civil engineering are applied to the case study of a black locust (Robinia pseudoacacia L.). The tree was instrumented with 13 seismic, high-sensitivity accelerometers. Time histories of the tree response under ambient vibration were recorded. Three representative sections of the trunk (the collar, the diameter at breast height, and the tree fork) were equipped with three accelerometers, in order to obtain lateral and torsional vibrations. Moreover, two pairs of accelerometers were fixed on the two main branches. The results show that it is possible to identify the natural frequencies of a tree under ambient vibrations, thanks also to the support of a preliminary finite element model. Even though the optimal position is under the tree fork, the sensors fixed at the diameter at breast height allow a clear identification of the main peaks in the frequency domain. [ABSTRACT FROM AUTHOR]

Urban trees in lawns and along streets are anthropogenically constructed systems, in that these tree communities are formed by human planting and removal actions. Tree mortality studies are essential to understanding the temporal dynamism of urban forests, and in particular, it is critical to incorporate institutional records and human decision-making regarding tree removals. In this study, we investigated tree removals on a highly urbanized college campus in Philadelphia, Pennsylvania (US) by analyzing field inventories and institutional records, and by considering firsthand accounts of the University Landscape Architect. The annual mortality rate was 4.3%, higher than typical for comparable studies, which we attribute to construction pressure and proactive management to promptly remove unhealthy trees and manage risk. Capital projects and other construction caused 48.5% of all removals, other human land use decisions caused 2.0%, and tree health decline and risk management collectively accounted for 48.7%. The number of removed trees exactly equaled the number of new trees, and the campus has high taxonomic diversity, reflecting the extensive oversight by university tree and landscape professionals regarding tree removal and planting decisions. This study demonstrates the value of mixed-methods and transdisciplinary research to understand how urban forests change over time. [ABSTRACT FROM AUTHOR]

Physiological processes cause movements of tree stems and branches that occur in a circadian rhythm and over longer time periods, but there is a lack of quantitative understanding of the cause-and-effect relationships. We investigated the movement of tree branches in a long-term drought experiment and at a circadian time scale using time-series of terrestrial laser scanning measurements coupled with measurements of environmental drivers and tree water status. Our results showed that movement of branches was largely explained by leaf water status measured as leaf water potential in a controlled environment for both measured trees (R2 = 0.86 and R2 = 0.75). Our hypothesis is that changes in leaf and branch water status would cause branch movements was further supported by strong relationship between vapor pressure deficit and overnight branch movement (R2 = [0.57–0.74]). Due to lower atmospheric water demand during the nighttime, tree branches settle down as the amount of water in leaves increases. The results indicate that the quantified movement of tree branches could help us to further monitor and understand the water relations of tree communities. [ABSTRACT FROM AUTHOR]

Trees outside forests (TOFs) are important landscape features that provide numerous functions (ecosystem services) that are not valued due to a lack of knowledge about these resources. The aim of this study was to evaluate the changes induced by the anthropogenic land use change in relation to their effects on TOFs. The dynamics of TOFs were examined through detailed photointerpretation mapping and characterization by land use/land cover and other environmental variables. The landscape function of TOFs and relative dynamics were analyzed, revealing landscape simplification due to the loss of TOFs, both in number and area, and a relative loss of connectivity. In 2000, TOFs accounted for 2.6% more forest area than mapped in the regional forest map; in fifteen years, about 30% of the total area has been lost, one-third of which has been converted to forest and the remainder permanently lost. The causes of the loss of TOFs are partly due to the abandonment of agricultural land, but also to the actions of farmers who remove these elements for various reasons. In protected areas (Natura 2000 network), the loss is less due to the different characteristics of land use/cover and land management.

Recently, Internet of Things (IoT) technologies have grown rapidly and represent now a unique opportunity to improve our environmental monitoring capabilities at extremely low costs. IoT is a new system of thinking in which objects, animals or people are equipped with unique identifiers and transfer data a network without requiring human-to-human or human-to-computer interaction. IoT has evolved from the convergence of wireless technologies, microelectromechanical systems (MEMS) and the Internet. The development of these technologies in environmental monitoring domains allows real-time data transmission and numerous low-cost monitoring points. We have designed a new device, the TreeTalker©, which is capable of measuring water transport in trees, diametrical growth, spectral characteristics of the leaves and microclimatic parameters and transmit data in semi-real time. Here we introduce the device’s features, provide an example of monitored data from a field test site and discuss the application of this new technology to tree monitoring in various contexts, from forest to urban green infrastructures management and ecological research.

Abstract Comparative studies of tree dynamics can be useful for the conservation of forest fragments in the Cerrado. We tested if the successional dynamics in fragments of semideciduous forest (SF) and cerradão (CE) are influenced by edge effects (EE). Two surveys were carried out with plots allocation in both physiognomies, from the edge towards the interior of the fragments. All trees with diameter at breast height ≥ 5cm were measured, identified and classified (ecological groups). Both physiognomies showed high recruitment and mortality rates when compared with other forests in Cerrado. We found an EE on tree density (SF), and on mortality, total basal area and basal area of dead (CE), although do not so notorious on a short-term scale. Probably because EE did not influence the ecological groups and canopy cover. Our results suggest that the forest fragmentation can act as a disturbance agent, causing changes in the tree dynamics of the Cerrado forests.

ABSTRACT: Leaf hyperspectral reflectance has been used to estimate nutrient concentrations in plants in narrow bands of the electromagnetic spectrum. The aim of this study was to estimate leaf nutrient concentrations using leaf hyperspectral reflectance and verify the variable selection methods using the partial least squares regression (PLSR). Two studies were carried out using stands with Eucalyptus clones. Study I was established in Eucalyptus stands with three clones, classifying leaves into five colour patterns using the Munsell chart for plant tissues. Immediately after leaf collection, leaf reflectance was read and the chemical analysis was performed. Study II was carried out in commercial clonal stands of Eucalyptus performing the same leaf sampling and chemical analysis as used in Study I. All leaf reflectance spectra were smoothed and three more pre-processing procedures were applied. In addition, three methods of PLSR were tested. The first derivative was more accurate for predicting nitrogen ( R c v 2 = 0.95), phosphorous ( R c v 2 = 0.93), and sulphur concentration ( R c v 2 = 0.85). The estimates for concentrations of calcium ( R c v 2 = 0.81), magnesium ( R c v 2 = 0.22), and potassium ( R c v 2 = 0.76) were more accurate using the logarithm transformation. Only the estimates for iron concentrations were performed with higher accuracy ( R c v 2 = 0.35) using the smoothed reflectance. The copper concentrations were more accurate ( R c v 2 = 0.78) using the logarithm transformation. Concentrations of boron ( R c v 2 = 0.68) and manganese ( R c v 2 = 0.79) were more accurate using the first derivative, while zinc ( R c v 2 = 0.31) concentration was most accurate using the second derivative.

Urban forests provide many benefits for municipalities and their residents, including air quality improvement, urban atmosphere cooling, and pluvial flooding reduction. Monitoring the trees is one of the tasks among the several urban forest assessment procedures. Trees with a risk of falling may threaten the locals and the infrastructure of the cities, thereby being an immediate concern for forestry managers. In general, a set of measures and aspects are collected from field survey analysis to estimate whether the trees represent a risk to the safety of the urban spaces. However, gathering the tree's physical measures in fieldwork campaigns is time-consuming and laborious considering the massive number of trees in the cities. Therefore, there is an urge for new computational-based methodologies, especially those related to the latest advances in artificial intelligence, to accelerate the assessment of trees in the municipality areas. In this sense, this work aims at using several machine learning-based methods in the context of tree condition inspection. Particularly, we present the prediction of the tree failure probability by using several aspects collected over time from fieldwork campaigns, with a special focus on external physical measures of the trees. Further, we provide the samples with their respective tree failure probability values as a new open dataset for further investigations on tree status monitoring. We also present a novel dataset composed of images of trees with bounding boxes delineations of the tree, trunk, and crown for automating the tree monitoring tasks. Regarding the tree failure probability estimation, we compared several regression algorithms for estimating the tree failure likelihood. Moreover, we propose a stacking generalization approach to enhance forecast accuracy and minimize prediction errors. The results showed the viability of the proposed method as an auxiliary tool in tree analysis tasks, which attained the lowest average Mean Absolute Error of 5.6901 ± 1.1709 yielded by the stacking generalization model. • To propose using machine learning models to predict the tree failure probability. • Instead of a simple classification approach, we propose a regression task for a broader assessment of the trees. • Evaluation of the internal aspects in the machine learning algorithms' effectiveness. • The dataset and an additional image set are made available for future research. [ABSTRACT FROM AUTHOR]

Climate change forecasts higher temperatures in urban environments worsening the urban heat island effect (UHI). Green infrastructure (GI) in cities could reduce the UHI by regulating and reducing ambient temperatures. Forest cities (i.e., Melbourne, Australia) aimed for large-scale planting of trees to adapt to climate change in the next decade. Therefore, monitoring cities’ green infrastructure requires close assessment of growth and water status at the tree-by-tree resolution for its proper maintenance and needs to be automated and efficient. This project proposed a novel monitoring system using an integrated visible and infrared thermal camera mounted on top of moving vehicles. Automated computer vision algorithms were used to analyze data gathered at an Elm trees avenue in the city of Melbourne, Australia (n = 172 trees) to obtain tree growth in the form of effective leaf area index (LAIe) and tree water stress index (TWSI), among other parameters. Results showed the tree-by-tree variation of trees monitored (5.04 km) between 2016–2017. The growth and water stress parameters obtained were mapped using customized codes and corresponded with weather trends and urban management. The proposed urban tree monitoring system could be a useful tool for city planning and GI monitoring, which can graphically show the diurnal, spatial, and temporal patterns of change of LAIe and TWSI to monitor the effects of climate change on the GI of cities.

The tree is a fundamental living being. It contributes to nature and climate behaviour, as well to urban greening. It is also a source of wealth and employment. Most tree health inspection techniques are invasive or even destructive. Infrared thermography (IRT) is not invasive, and it has shown advantages when applied for inspection to trees and wood to detect deterioration or voids that could compromise its structure, stability, and durability. This study reviews the literature about IRT applied to a tree health inspection. It is framed in the context of the importance of trees for the balance of ecosystems, and the different techniques to detect tree deterioration. It highlights the difference when applied to wood or trees and the main factors that have been proven to cause disturbances in the thermal pattern of trees. The IRT, as other non-destructive methods, does not distinguish what type of damage it is, nor its causative agent. However, it enables identifying healthy and deteriorated tissues. The technology is very promising since it reveals that is efficient, fast, economical, and sustainable.

Volunteer programs can benefit from a deeper understanding of the motivations and experiences of people engaged in citizen science. Research to date has studied motivations of citizen scientists and tree-planting volunteers. Less work has focused on tree-monitoring volunteers, a role that is rapidly increasing as more cities involve the public in monitoring the urban forest. Researchers conducted an assessment of volunteers (n = 636 respondents) of the TreesCount! 2015 street tree census in New York City, New York, U.S., to understand volunteers' demographics, motivations, experiences, and levels of civic engagement. Semistructured interviews (n = 40) were also conducted on a subset of the initial assessment respondents, to deepen understanding of these factors. Like tree-planting volunteers in previous studies, volunteers were more likely to be highly educated, female, white, and with high income levels. Top self-identified motivations for participation included personal values, wanting to contribute, and a desire for education or learning. Demographics correlated with different motivations, suggesting opportunities for targeting recruitment efforts to better reach underrepresented populations. Researchers also found motivations shifted slightly in post-census interviews, also identifying a new theme of exploring the city. Street-tree monitoring presents opportunities for contributing to one's community or city, and for learning about trees and urban nature, suggesting these acts of engagement can both strengthen connections to social-ecological systems and provide personal benefits. At the same time, considering volunteer motivations, experiences, and outcomes when designing programs can positively affect participation turnout, effort, and retention. [ABSTRACT FROM AUTHOR]

This paper explores predictors of juvenile tree mortality in a newly planted cohort in Worcester, MA, following an episode of large-scale tree removal necessitated by an Asian Longhorned Beetle ( Anoplophora glabripennis, ALB) eradication program. Trees are increasingly seen as important providers of ecosystem services for urban areas, including: climate moderation and thus reduction in heating/cooling costs; air and water filtration; carbon uptake and storage; storm water runoff control; and cultural and aesthetic values. Many cities have initiated tree planting programs to receive these benefits, typically seeking to complement existing urban forest. Conversely, Worcester’s reforestation program was necessary to offset the loss of approximately 30,000 trees removed to eradicate the invasive pest ALB. Since then, more than 30,000 juvenile trees have been planted to offset the loss, creating the opportunity to study a highly dynamic urban forest. Tree planting effectiveness is contingent on high survivorship rates, particularly during the establishment phase during the first five years after planting. Using a large data set including biophysical and sociodemographic variables, this research uses Conditional Inference Trees (CIT), a machine learning technique, to explore predictors of mortality. The most important variables as determined by CIT were used to create a logistic regression to predict mortality. This analysis was run for all trees, and for several subsets of the sample based on tree type and season and year of planting, yielding twenty individual models. Results indicated that the following variables are important predictors of mortality during establishment, in descending order: adjacent home/building age, proportion renter occupancy, days since tree planted, tax parcel size, number of trees planted on property, and tax parcel value. Of these variables, proportion renter occupancy and days since tree planted were most frequently found to be significant in the logistic regression modeling. [ABSTRACT FROM AUTHOR]

Citizen science has been gaining popularity in ecological research and resource management in general and in urban forestry specifically. As municipalities and nonprofits engage volunteers in tree data collection, it is critical to understand data quality. We investigated observation error by comparing street tree data collected by experts to data collected by less experienced field crews in Lombard, IL; Grand Rapids, MI; Philadelphia, PA; and Malmö, Sweden. Participants occasionally missed trees (1.2%) or counted extra trees (1.0%). Participants were approximately 90% consistent with experts for site type, land use, dieback, and genus identification. Within correct genera, participants recorded species consistent with experts for 84.8% of trees. Mortality status was highly consistent (99.8% of live trees correctly reported as such), however, there were few standing dead trees overall to evaluate this issue. Crown transparency and wood condition had the poorest performance and participants expressed concerns with these variables; we conclude that these variables should be dropped from future citizen science projects. In measuring diameter at breast height (DBH), participants had challenges with multi-stemmed trees. For single-stem trees, DBH measured by participants matched expert values exactly for 20.2% of trees, within 0.254 cm for 54.4%, and within 2.54 cm for 93.3%. Participants’ DBH values were slightly larger than expert DBH on average (+0.33 cm), indicating systematic bias. Volunteer data collection may be a viable option for some urban forest management and research needs, particularly if genus-level identification and DBH at coarse precision are acceptable. To promote greater consistency among field crews, we suggest techniques to encourage consistent population counts, using simpler methods for multi-stemmed trees, providing more resources for species identification, and more photo examples for other variables. Citizen science urban forest inventory and monitoring projects should use data validation and quality assurance procedures to enhance and document data quality. [ABSTRACT FROM AUTHOR]

The article discusses the findings of a study which determined the accuracy of UrbanCrowns software in computing the crown volume and density of open-grown sugar maple trees under various photographic conditions and distances. It notes the processes involved in the field study including identifying photographic positions from the surroundings, and importing tree photographs to the UrbanCrowns software for crown calculation and analysis.

Monitoring of tree traits and tree response to the environment can be integrated with sensor technology. High-resolution monitoring requires a frequent data acquisition, that generally results in hourly measurements for the definition of daily processes, then scaled at monthly, seasonal and annual levels, by producing very large databases. The TreeTalker (TT) technology is an example of a tool for forest monitoring that measures hourly and simultaneously tree parameters and environmental variables, by collecting 1032 attributes per tree per day (43 variables, such as sap flow and stem diameter variation measured every hour). Therefore, we present the TreeTalkersCheck R package built to facilitate the remote checking of the functioning of the TreeTalkers devices. This package contains functions to download, process raw data obtained with TreeTalker devices, and produces a report with all the alerts detected and a complete database with preliminary processing of the data. The package was tested on a database obtained by 60 TT installed on 60 trees in three sites in Tuscany (Central Italy). [Display omitted] • TreeTalkers (TT) are useful tools to monitor tree functional traits. • Checking the functionality of TT is challenging, expensive, and time consuming. • We present an R package to remotely monitor TT devices in real time. • Downloading and primary processing of data is performed by the package. • Daily reports of TT sensors status and recorded data are produced by the package. [ABSTRACT FROM AUTHOR]

The global distribution of forest trees is essential for monitoring land-use sustainability. For this reason, FAO developed the Global Forest Survey (GFS), a systematic regional level survey with a homogeneous sampling design. Preliminary results revealed an interest in analyzing "Trees Outside Forests" (TOFs). We analyzed more than 11,150 sample GFS plots in temperate FAO-ecozones in Europe through a photo-interpretation approach using FAO's Collect Earth platform. Our results showed that forest land was the most predominant use of land (41%) in temperate FAO-ecozones in Europe in 2015. Forest IPCC land use followed a moderate upward trend from 2000 to 2015 (0.2%). Trees Outside Forests in temperate FAO-ecozones in Europe accounted for 22% of the inventoried area. Trees Outside Forests represent 30% and 48% of cropland and grassland IPCC land uses, respectively, as well as 75% in settlement uses. Comparing our results with previous studies on the Mediterranean, temperate FAO-ecozone TOFs showed a downward trend in Europe and an upward trend in the Mediterranean area, despite its smaller surface area. The greening of the Common Agricultural Policy may increase the extension of TOFs, although our results may indicate that this effect is not yet evident in the field. [ABSTRACT FROM AUTHOR]

This study shows the implementation of a new risk assessment monitoring tool, to be applied to prevent trees failure and significant damage to people and structures, in an urban archaeological site i.e. the Colosseum's Archaeological Park in Rome. Here, a network of ten TreeSavers has been recently installed to allow real-time continuous static and dynamic monitoring of the trees. These data, also linked with readings collected from a local weather station, are transmitted to an online data storage i.e. the cloud to be post-processed. The objective, in this post-processing phase, is that the online data storage system effectively works in autolearning capabilities to "become experts" in risk assessment and thus preventing dangerous situations. In this study we present the preliminary data, analyzed by relating the maximum acceleration on x-, y- and z-axis with maximum wind speed and gust events. The risk analysis was performed considering the Drag Coefficient C D and the Jerk values. The first represents the drag force generated on plants; the second describes the effect of accelerations on rigid bodies. This study has deepened the understanding of Jerk, as a novel hazard index, able to categorize the effect of accelerations on trees under dynamic wind loads for hazard control and prediction of the tree fails. Jerk has the potentiality to be an effective tool for early warning alarm which may reduce the risk of falling of trees with consequent reduction of damage to people and structures, especially in the urban archaeological sites. [ABSTRACT FROM AUTHOR]

• A novel transducer based on FBG technology is designed for trees monitoring. • The transducers are tested and optimized to accurately measure the strain of trees. • The performance of the novel transducer has been verified under a typhoon. • Monitoring systems can be established to assess the resilience of urban ecosystems. In recent decades, conventional electric instruments have been widely adopted to monitor rupture failure of trees by measuring the longitudinal strains of tree trunks. However, the good measurement accuracy is compromised by the significant difference in stiffness of the sensing element and tree trunks. Besides, the reliability of electric instruments under harsh environments, especially extreme weathers, such as thunderstorms and typhoons, is also doubtful. In this study, a novel strain gauge based on fiber Bragg grating (FBG) sensing technology was developed specifically for measuring the strain distribution of tree trunks under static or dynamic loading. The main principle of the design of the strain gauges is presented in detail. The laboratory calibration proves that the FBG-based strain gauges in polyoxymethylene (POM) and polylactic acid (PLA) backings show a better performance than those made of metal. To test the performance of this novel FBG-based strain gauge, a set of transducers were installed at different heights of a Celtis sinensis. Firstly, a pull test on this tree trunk was conducted to validate the good performance of the novel strain gauge when the tree is subjected to static loading. Secondly, the good dynamic performance of the novel strain gauge is proved by successfully recording the dynamic motion of a tree trunk during a typhoon. Furthermore, a monitor system relied on the FBG-based strain gauges is conceived to assess the resilience of urban ecosystems formed by trees to extreme weather events. [ABSTRACT FROM AUTHOR]

Climate change forecasts higher temperatures in urban environments worsening the urban heat island effect (UHI). Green infrastructure (GI) in cities could reduce the UHI by regulating and reducing ambient temperatures. Forest cities (i.e., Melbourne, Australia) aimed for large-scale planting of trees to adapt to climate change in the next decade. Therefore, monitoring cities' green infrastructure requires close assessment of growth and water status at the tree-by-tree resolution for its proper maintenance and needs to be automated and efficient. This project proposed a novel monitoring system using an integrated visible and infrared thermal camera mounted on top of moving vehicles. Automated computer vision algorithms were used to analyze data gathered at an Elm trees avenue in the city of Melbourne, Australia (n = 172 trees) to obtain tree growth in the form of effective leaf area index (LAIe) and tree water stress index (TWSI), among other parameters. Results showed the tree-by-tree variation of trees monitored (5.04 km) between 2016–2017. The growth and water stress parameters obtained were mapped using customized codes and corresponded with weather trends and urban management. The proposed urban tree monitoring system could be a useful tool for city planning and GI monitoring, which can graphically show the diurnal, spatial, and temporal patterns of change of LAIe and TWSI to monitor the effects of climate change on the GI of cities. [ABSTRACT FROM AUTHOR]

The tree is a fundamental living being. It contributes to nature and climate behaviour, as well to urban greening. It is also a source of wealth and employment. Most tree health inspection techniques are invasive or even destructive. Infrared thermography (IRT) is not invasive, and it has shown advantages when applied for inspection to trees and wood to detect deterioration or voids that could compromise its structure, stability, and durability. This study reviews the literature about IRT applied to a tree health inspection. It is framed in the context of the importance of trees for the balance of ecosystems, and the different techniques to detect tree deterioration. It highlights the difference when applied to wood or trees and the main factors that have been proven to cause disturbances in the thermal pattern of trees. The IRT, as other non-destructive methods, does not distinguish what type of damage it is, nor its causative agent. However, it enables identifying healthy and deteriorated tissues. The technology is very promising since it reveals that is efficient, fast, economical, and sustainable. [ABSTRACT FROM AUTHOR]