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Forest decline events have increased worldwide over the last decades being holm oak (Quercus ilex L.) one of the tree species with the most worrying trends across Europe. Since this is one of the tree species with the southernmost distribution within the European continent, its vulnerability to climate change is a phenomenon of enormous ecological importance. Previous research identified drought and soil pathogens as the main causes behind holm oak decline. However, despite tree health loss is a multifactorial phenomenon where abiotic and biotic factors interact in time and space, there are some abiotic factors whose influence has been commonly overlooked. Here, we evaluate how land use (forests versus savannas), topography, and climate extremes jointly determine the spatiotemporal patterns of holm oak defoliation trends over almost three decades (1987–2014) in Spain, where holm oak represents the 25% of the national forested area. We found an increasing defoliation trend in 119 out of the total 134 holm oak plots evaluated, being this defoliation trend significantly higher in forests compared with savannas. Moreover, we have detected that the interaction between topography (which covariates with the land use) and summer precipitation anomalies explains trends of holm oak decline across the Mediterranean region. While a higher occurrence of dry summers increases defoliation trends in steeper terrains where forests dominate, an inverse relationship was found in flatter terrains where savannas are mainly located. These opposite relationships suggest different causal mechanisms behind decline. Whereas hydric stress is likely to occur in steeper terrains where soil water holding capacity is limited, soil waterlogging usually occurs in flatter terrains what increases tree vulnerability to soil pathogens. Our results contribute to the growing evidence of the influence of local topography on forest resilience and could assist in the identification of potential tree decline

Air pollution, particularly tropospheric ozone (O3), whenpresent in high concentrations, affects urban tree health. This study analyzedthe ozone concentration and the potential effect on the vitality of the treeslocated in the metropolitan area of Guadalajara. Data from the Jalisco airquality monitoring network and photosynthetic activity through chlorophyllfluorescence ofFraxinus uhdei,Eucalyptus camaldulensis, andCasuarinaequisetifoliawere studied. A generalized extreme value model was fittedto estimate the atmospheric distribution and identify areas with the highestconcentration of ozone. An analysis of variance was carried out to evaluatepossible changes in the condition of the vitality due to the ozone concen-tration in the atmosphere. The areas with the highest ozone concentrationwere in Tlaquepaque, Zapopan, and the northeast of Guadalajara. Nosignificant effect of areas with higher ozone concentrations on tree vitalitywas observed., La contaminación por ozono (O3) troposférico en concentra-ciones elevadas afecta la salud de los árboles. En este estudio se analizaronlas concentraciones de O3y su efecto en la vitalidad de árboles en la zonametropolitana de la ciudad de Guadalajara. Se utilizaron datos de la red demonitoreo de la calidad del aire de Jalisco y registros de la fluorescencia declorofila deFraxinus uhdei,Eucalyptus camaldulensis, yCasuarina equiseti-folia. Se ajustó el modelo de valores extremos generalizado para estimarla distribución del O3e identificar las zonas de mayor concentración. Serealizó un análisis de varianza para determinar diferencias en la condiciónde vitalidad causadas por la concentración de O3. Las regiones con mayorconcentración de O3se localizaron en Zapopan, Tlaquepaque, y en elnoreste de Guadalajara. No se observó un efecto significativo de las zonascon mayores concentraciones de O3sobre la vitalidad del arbolado.

Urban forests and vegetation are fundamental for developing resilient cities. Thus, the effective management and protection of urban trees and greenery are essential. Nowadays, urban trees are experiencing atypical amount of natural and human-induced stresses which affects their functionality, productivity and survival. The current methods for monitoring the health of urban trees mainly comprises of manual inspection by arborists and remote sensing. However, all these methods are riddled with various challenges involving scalability, spatio-temporal resolutions and quality of assessment. The goal of this thesis was to develop a method which can autonomously measure the health of trees on a city-wide scale with high spatio-temporal resolutions at low costs. To achieve this goal, we first performed an in-depth survey and comparative analysis of the existing state-of-the-art techniques for tree health measurement, identified a research gap and based on this, developed a novel system to measure tree health autonomously from ground level in urban cities. The system can be deployed both in a drive-by sensing paradigm on moving vehicles such as taxis and garbage trucks or be carried by humans in a citizen science paradigm. A computer vision model developed using transfer learning and traditional image processing techniques were employed to fuse the data collected by low cost thermal and multispectral imaging sensors on the edge devices. The approach was evaluated through data collection experiments performed in Cambridge, USA. Comparison with parameters in ground truth datasets revealed several significant relationships. Thus, motivating various studies in the future along with potential large-scale deployment of this technique in cities and municipalities around the world., Electrical Engineering | Embedded Systems, Computer Science

Following a request from the European Commission, the EFSA Plant Health Panel performed a pest categorisation of Sphaerulina musiva, a well‐defined and distinguishable fungal species of the family Mycosphaerellaceae. Following a recent phylogenetic analysis of the genus Septoria and other closely related genera, a new name (S. musiva) was introduced for the species. The former species name Mycosphaerella populorum is used in the Council Directive 2000/29/EC. The pathogen is regulated in Annex IAI as a harmful organism whose introduction into the EU is banned. S. musiva is reported from North and South America and not known to occur in the EU. S. musiva causes Septoria leaf spots and cankers of poplar (Populus spp.). Of the poplars native to Europe, Populus nigra is reported as susceptible and Populus tremula as susceptible when planted in North America. The hybrid Populus x canadensis (arising from a cross of P. nigra and the North American Populus deltoides), widely grown in the EU, is also susceptible. The pest could enter the EU on plants for planting, cut branches, isolated bark and wood with and without bark. S. musiva could establish in the EU, as hosts are common and favourable climatic conditions are widespread, and could spread following establishment by natural dispersal and movement of infected plants for planting, cut branches, isolated bark and wood with or without bark. The pest introduction would have impacts in woodlands, plantations and nurseries. The pathogen is considered the most serious disease affecting hybrid poplar production in North America. Selection, breeding and planting of resistant species and clones are the main methods used to control the damage caused by the pathogen. There is some uncertainty on the geographical distribution of the pest in the Caucasus, the Crimean Peninsula and South America and on the level of susceptibility among Populus species native to Europe as well as Salix spp. The criteria assessed by the Panel for consid

Following a request from the European Commission, the EFSA Panel on Plant Health performed a pest categorisation of Chrysomyxa arctostaphyli, a well-defined and distinguishable fungal species of the family Coleosporiaceae. The pathogen is regulated in Council Directive 2000/29/EC (Annex IAI) as a harmful organism whose introduction into the EU is banned. C. arctostaphyli is native to North America and is the causal agent of spruce broom rust. C. arctostaphyli is a heteroecious rust with a 2-year life cycle alternating between the aecial host Picea spp. and the telial host Arctostaphylos spp. The main reported aecial host is P. engelmannii, but also P. abies, P. pungens, P. sitchensis, P. glauca, P. mariana and P. rubens (as well as Picea as a genus) are reported as hosts. The fungus is not known to occur in the EU but could enter via host plants for planting and cut branches. It could establish in the EU, as hosts are present and climatic conditions are favourable. The extent of overlap between the ranges of the telial and aecial hosts is greater in the EU than in North America. The pathogen would be able to spread following establishment by dissemination of spores and human movement of infected host plants. Should the pathogen be introduced in the EU, impacts can be expected in spruce woodland, plantations and on ornamental spruce trees, leading to reduced tree growth and associated ecosystem service provision. The main uncertainty concerns the level of susceptibility of P. abies and P. sitchensis under European conditions. The criteria assessed by the Panel for consideration as a potential quarantine pest are met. As the pest is not present in the EU, not all criteria for consideration as a regulated non-quarantine pest are met. (C) 2018 European Food Safety Authority. EFSA Journal published by John Wiley and Sons Ltd on behalf of European Food Safety Authority.

Following a request from the European Commission, the EFSA Panelon Plant Health performed a pestcategorisation of Coniferiporiasulphurascens and Coniferiporiaweirii, two well-defined and distinguishable fungal species of the family Hymenochaetaceae. The pathogens are regulated in Council Directive 2000/29/EC (Annex IAI, under the previous name Inonotusweirii for both species) as a harmful organism whose introduction into the EU is banned. The two pathogens are native to North America, where C.sulphurascens causes laminated root rot primarily in Douglas fir (Pseudotsuga menziesii) and grand fir (Abiesgrandis), while C.weirii causes cedar laminated root and butt rot mainly in cedars (Thujaplicata and Cupressusnootkatensis). C.weirii has been reported from Japan and China, and C.sulphurascens from China, Russia and Turkey. Neither species has been reported from the EU. C.sulphurascens may infect all conifers, while C.weirii is reported to mainly cause disease in tree species of Thuja spp. and Cupressus spp. The two pathogens could enter the EU mainly via wood with bark, isolated bark and plants for planting (including artificially dwarfed plants) of Pinaceae and Cupressaceae. Both fungi could establish in the EU, as hosts are present and climatic conditions are favourable. The two pathogens would be able to spread following establishment by the pathways mentioned for entry and also by dissemination of basidiospores and root contact with infected root/wood. Should the pathogen be introduced in the EU, impacts can be expected on coniferous woodlands, plantations and ornamental trees, thus leading to reduced tree growth and ecosystem service provision. The key uncertainties concern (i) the distribution of the two pathogens in Asia, (ii) the level of susceptibility of conifers native to Europe and (iii) the role of plants for planting as a pathway of entry and spread. For both pathogens, the criteria assessed by the Panelfor consideration as a potential quarantine pest are

Following a request from the European Commission, the EFSA Plant Health Panel performed a pest categorisation of Melampsora medusae, a well-defined and distinguishable fungal species of the family Melampsoraceae. The pathogen is regulated in Annex IAI of Council Directive 2000/29/EC as a harmful organism whose introduction into the EU is banned. M. medusae is a heteroecious rust fungus with Populus spp. as primary telial hosts and various conifers (Larix, Pinus, Pseudotsuga, Abies, Picea and Tsuga spp.) as secondary aecial hosts. M. medusae is native to North America and has spread to South America, Africa, Asia, Oceania, as well as the EU, where M. medusae f. sp. deltoidae has been reported with a restricted distribution and low impacts from Belgium, south-west France and southern Portugal. The pest could spread to other EU countries, via dissemination of spores, movement of host plants for planting and cut branches. Climate is assumed not to be a limiting factor for the establishment of the pathogen in the EU. M. medusae is the most widespread and important Melampsora rust in North America. In western Canada, extensive damage has been reported to conifers and Populus spp. in nurseries and plantations as well as in woodlands. M. medusae is damaging in both Australia and New Zealand. The pest could have economic and environmental impacts in the EU if aggressive isolates of M. medusae were introduced into the EU. Import prohibition of host plants for planting is an available measure to reduce the risk of further introductions. Some resistant Populus cultivars are available. Moreover, increasing the genetic diversity of poplar plantations can prevent disease impacts. The main uncertainty concerns the factors explaining the low pathogenicity of the populations of M. medusae present in the EU. The criteria assessed by the Panel for consideration as a potential quarantine pest are met (the pest is present, but with a restricted distribution, and is officially under contr

Following a request from the European Commission, the EFSA Plant Health (PLH) Panelperformed a pest categorisation of Anisogramma anomala, a well-defined and distinguishable fungal species of the family Valsaceae. The pathogen is regulated in Annex IIAI of Council Directive 2000/29/EC as a harmful organism whose introduction into the EU is banned on plants of Corylus L., intended for planting, other than seeds, originating in Canada and the USA. The fungus is native to eastern North America and causes eastern filbert blight on cultivated hazel, Corylus avellana, as well as on wild hazel (Corylus spp.). In the 1960s, the disease spread on infected plant material to Oregon, where it then threatened US hazelnut production in the Willamette Valley. The pest could enter the EU via plants for planting. Hosts and favourable climatic conditions are common in the EU, thus facilitating establishment. The pest would be able to spread following establishment through infected plants for planting and ascospore dispersal. A. anomala leads to canopy and yield loss and can cause death of Corylus trees. Should the pathogen be introduced into the EU, impacts can be expected not just on hazel as a crop and as an ornamental but also in coppices and woodlands, where Corylus species provide an important habitat. In Oregon, scouting for cankers, therapeutic pruning and copious fungicide applications are reported to be necessary (but costly measures) to continue hazelnut production in the presence of the disease. Breeding for resistance led to the selection of resistant cultivars. The main knowledge gaps concern (i) the role of deadwood and cut branches as potential entry pathways and means of spread and (ii) the susceptibility of C. avellana cultivars and of Corylus spp. in the wild in the EU. The criteria assessed by the Panelfor consideration as a potential quarantine pest are met. For regulated non-quarantine pests, the criterion on the pest presence in the EU is not met. (c) 2018 Europ

Following a request from the European Commission, the EFSA Plant Health Panelperformed a pest categorisation of Sphaerulinamusiva, a well-defined and distinguishable fungal species of the family Mycosphaerellaceae. Following a recent phylogenetic analysis of the genus Septoria and other closely related genera, a new name (S.musiva) was introduced for the species. The former species name Mycosphaerella populorum is used in the Council Directive 2000/29/EC. The pathogen is regulated in Annex IAI as a harmful organism whose introduction into the EU is banned. S.musiva is reported from North and South America and not known to occur in the EU. S.musiva causes Septoria leaf spots and cankers of poplar (Populus spp.). Of the poplars native to Europe, Populusnigra is reported as susceptible and Populus tremula as susceptible when planted in North America. The hybrid Populus x canadensis (arising from a cross of P. nigra and the North American Populus deltoides), widely grown in the EU, is also susceptible. The pest could enter the EU on plants for planting, cut branches, isolated bark and wood with and without bark. S.musiva could establish in the EU, as hosts are common and favourable climatic conditions are widespread, and could spread following establishment by natural dispersal and movement of infected plants for planting, cut branches, isolated bark and wood with or without bark. The pest introduction would have impacts in woodlands, plantations and nurseries. The pathogen is considered the most serious disease affecting hybrid poplar production in North America. Selection, breeding and planting of resistant species and clones are the main methods used to control the damage caused by the pathogen. There is some uncertainty on the geographical distribution of the pest in the Caucasus, the Crimean Peninsula and South America and on the level of susceptibility among Populus species native to Europe as well as Salix spp. The criteria assessed by the Panelfor consideration

Following a request from the European Commission, the EFSA Plant Health (PLH) Panelperformed a pest categorisation of Bretziellafagacearum, a well-defined and distinguishable fungal species of the family Ceratocystidaceae. The species was moved from the genus Ceratocystis to a new genus Bretziella following phylogenetic analysis of the species and its close relatives. The former species name Ceratocystisfagacearum is used in the Council Directive 2000/29/EC. The pathogen is regulated in Annex IAI as a harmful organism whose introduction into the EU is banned. B.fagacearum is only reported from the USA, where it causes a wilt disease on Quercus spp. Other hosts are reported based on inoculation trials, although Chinese chestnut (Castaneamollissima) is reported to be naturally infected. No North American oak species has been found to be immune to the disease. The European oak species Quercusrobur, Quercuspetraea and Quercuspubescens were found to be susceptible in inoculation experiments. The pest could enter the EU via wood (with and without bark, including wood packaging material), plants for planting and cut branches. Hosts and favourable climatic conditions are common in the EU, thus facilitating establishment. The pest would be able to spread following establishment by means of root grafts, insect vectors and movement of wood, plants for planting and other means. The pest introduction would have impacts in woodland and plantations, as oak wilt disease is often lethal in a short period of time. Wood treatment (debarking, kiln drying, fumigation), prompt removal of affected trees and creating root-free zones between affected and healthy stands are available control measures. The main knowledge gaps concern (i) the survival of the fungus in wood during transport and the association with propagation material, (ii) the presence of suitable vectors in Europe and (iii) the relative susceptibility of the oak species native to Europe under natural conditions. The criteria

Following a request from the European Commission, the EFSA Panelon Plant Health (PLH) performed a pest categorisation of Mycodiellalaricis-leptolepidis, a well-defined and distinguishable fungal species of the family Mycosphaerellaceae. The former species name Mycosphaerellalaricis-leptolepis is used in the Council Directive 2000/29/EC. The pathogen is regulated in Annex IAI as a harmful organism whose introduction into the EU is banned. M.laricis-leptolepidis is native to East Asia and causes a disease known as needle cast of Japanese larch (Larixkaempferi=Larixleptolepis) and Kurile larch (Larix gmelinii). European larch (Larix decidua) was found to be susceptible to the disease as introduced tree in Japan. The fungus could enter the EU via plants for planting and cut branches of Larix spp. It could establish in the EU, as hosts are present and climatic conditions are favourable. The pathogen would be able to spread following establishment by human movement of infected plants for planting and by dissemination of ascospores. Should the pathogen be introduced in the EU, impacts can be expected due to needle loss in larch forests and plantations, thus leading to reduced tree growth and ecosystem service provision. The use of resistant/tolerant varieties can reduce the impacts. The key uncertainties are the knowledge gaps concerning (i) the potential range of spread through ascospores and (ii) the level of impacts in the native range of the pathogen. The criteria assessed by the Panelfor consideration as a potential quarantine pest are met. For regulated non-quarantine pests, the criterion on the pest presence in the EU is not met. (C) 2018 European Food Safety Authority. EFSA Journal published by John Wiley and Sons Ltd on behalf of European Food Safety Authority.

Following a request from the European Commission, the EFSA Panel on Plant Health (PLH) performed a pest categorisation of Davidsoniella virescens, a well-defined and distinguishable fungal species of the family Ceratocystidaceae. The species was moved from the genus Ceratocystis to the genus Davidsoniella following a revision of the family. The former species name Ceratocystis virescens is used in the Council Directive 2000/29/EC. The pathogen is regulated in Annex IIAI as a harmful organism whose introduction into the EU is banned on plants (other than fruit and seeds) and wood (including wood which has not kept its natural round surface) of Acer saccharum, originating in the USA and Canada. The fungus is native to eastern North America and causes symptoms mainly on A. saccharum, but also on Liriodendron tulipifera. The fungus is also reported as a saprotroph on various hardwood species. The pest could enter the EU via wood, plants for planting and cut branches. Hosts and favourable climatic conditions are widespread in the EU. The pest would be able to spread following establishment through sap-feeding insects, root grafts and movement of infected wood and plants for planting. The pest introduction could have impacts on Acer spp. and L. tulipifera trees in the EU, by causing wilting, yellowing and the development of small leaves, as well as dieback of branches and, eventually, the death of trees. Avoiding damaging trees (as wounding facilitates infection of the fungus) and maintaining healthy trees (as tree stress facilitates the disease) are available measures to reduce impacts. The main knowledge gaps concern (i) the biology and epidemiology of the pathogen (including the saprotrophic form), (ii) the role of insect vectors for entry and spread, and (iii) the susceptibility of Acer spp. either native to or more recently established in Europe. The criteria assessed by the Panel for consideration as potential quarantine pest are met. For regulated non-quarantine pe

Following a request from the European Commission, the EFSA Panel on Plant Health (PLH) performed a pest categorisation of Stegophora ulmea, a well-defined and distinguishable fungal species of the family Sydowiellaceae. S. ulmea causes a tree disease known as black spot of elm (Ulmus spp.). The pathogen is reported from North America (native range) and Asia (Far-East Russia and China), but not from the EU. S. ulmea is regulated in Council Directive 2000/29/EC (Annex IIAI) as a harmful organism whose introduction into the EU is banned on plants of Ulmus L. and Zelkova L., intended for planting, other than seeds. The pathogen has been occasionally intercepted on imported bonsai plants (and then destroyed) in the Netherlands and the UK. It could enter the EU and spread within it via plants for planting (including bonsai) and cut branches. Hosts and favourable climatic conditions are common in the EU. The European native elm species Ulmus glabra and Ulmus laevis were found to be more susceptible to the disease than North American elm species, but information is lacking on Ulmus minor. The disease is rarely fatal, but S. ulmea can cause considerable damage, particularly in wet summers. Reduction of inoculum by the removal of leaf debris and avoiding overhead watering in nurseries can reduce the risk of spread of the pathogen. The main knowledge gaps concern (i) the distribution of the pest in Asian countries, (ii) the relative role of the means of entry/spread and (iii) the potential consequences in mature tree plantations and native woodland. The criteria assessed by the Panel for consideration as potential quarantine pest are met. For regulated non-quarantine pests, the criterion on the pest presence in the EU is not met.

Following a request from the European Commission, the EFSA Plant Health (PLH) Panelperformed a pestcategorisation of Pseudocercosporapini-densiflorae, a well-defined and distinguishable fungal species of the family Mycosphaerellaceae. The regulated harmful organism is the anamorph Cercoseptoriapini-densiflorae (synonym Cercosporapini-densiflorae) with the corresponding teleomorph Mycosphaerellagibsonii. P.pini-densiflorae causes a needle blight of Pinus spp. also known as Cercospora blight of pines or Cercospora needle blight. P.pini-densiflorae is reported from sub-Saharan Africa, Central and South America, Asia and Oceania, but not from the EU. The pathogen is regulated in Council Directive 2000/29/EC (Annex IIAI) as a quarantine organism whose introduction into the EU is banned on plants (other than fruit and seeds) and wood of Pinus. The pest could enter the EU via plants for planting and other means (uncleaned seed, cut branches of pine trees, isolated bark, growing media accompanying plants, and mycorrhizal soil inocula). Hosts are widespread in the EU and favourable climatic conditions are present in Mediterranean countries. Pinushalepensis, Pinusnigra, Pinuspinea, Pinuspinaster and Pinussylvestris are reported to be highly susceptible to the pathogen. The pest would be able to spread following establishment after introduction in the EU mainly on infected plants for planting. The pest introduction could have impacts in nurseries and young plantations. Cleaning seeds from needles and removing infected seedlings and pine litter from affected nurseries can reduce the risk of establishment in nurseries and of spread from nurseries to forests, especially given the limited scale of splash dispersal. The main knowledge gaps concern (i) the role of means of entry/spread other than plants for planting and (ii) the potential consequences in mature tree plantations and forests. The criteria assessed by the Panelfor consideration as potential quarantine pest are met. For

Following a request from the European Commission, the EFSA Panel on Plant Health (PLH) performed a pest categorisation of Stegophora ulmea, a well-defined and distinguishable fungal species of the family Sydowiellaceae. S. ulmea causes a tree disease known as black spot of elm (Ulmus spp.). The pathogen is reported from North America (native range) and Asia (Far-East Russia and China), but not from the EU. S. ulmea is regulated in Council Directive 2000/29/EC (Annex IIAI) as a harmful organism whose introduction into the EU is banned on plants of Ulmus L. and Zelkova L., intended for planting, other than seeds. The pathogen has been occasionally intercepted on imported bonsai plants (and then destroyed) in the Netherlands and the UK. It could enter the EU and spread within it via plants for planting (including bonsai) and cut branches. Hosts and favourable climatic conditions are common in the EU. The European native elm species Ulmus glabra and Ulmus laevis were found to be more susceptible to the disease than North American elm species, but information is lacking on Ulmus minor. The disease is rarely fatal, but S. ulmea can cause considerable damage, particularly in wet summers. Reduction of inoculum by the removal of leaf debris and avoiding overhead watering in nurseries can reduce the risk of spread of the pathogen. The main knowledge gaps concern (i) the distribution of the pest in Asian countries, (ii) the relative role of the means of entry/spread and (iii) the potential consequences in mature tree plantations and native woodland. The criteria assessed by the Panel for consideration as potential quarantine pest are met. For regulated non-quarantine pests, the criterion on the pest presence in the EU is not met.

Following a request from the European Commission, the EFSA Panel on Plant Health (PLH) performed a pest categorisation of Davidsoniella virescens, a well-defined and distinguishable fungal species of the family Ceratocystidaceae. The species was moved from the genus Ceratocystis to the genus Davidsoniella following a revision of the family. The former species name Ceratocystis virescens is used in the Council Directive 2000/29/EC. The pathogen is regulated in Annex IIAI as a harmful organism whose introduction into the EU is banned on plants (other than fruit and seeds) and wood (including wood which has not kept its natural round surface) of Acer saccharum, originating in the USA and Canada. The fungus is native to eastern North America and causes symptoms mainly on A. saccharum, but also on Liriodendron tulipifera. The fungus is also reported as a saprotroph on various hardwood species. The pest could enter the EU via wood, plants for planting and cut branches. Hosts and favourable climatic conditions are widespread in the EU. The pest would be able to spread following establishment through sap-feeding insects, root grafts and movement of infected wood and plants for planting. The pest introduction could have impacts on Acer spp. and L. tulipifera trees in the EU, by causing wilting, yellowing and the development of small leaves, as well as dieback of branches and, eventually, the death of trees. Avoiding damaging trees (as wounding facilitates infection of the fungus) and maintaining healthy trees (as tree stress facilitates the disease) are available measures to reduce impacts. The main knowledge gaps concern (i) the biology and epidemiology of the pathogen (including the saprotrophic form), (ii) the role of insect vectors for entry and spread, and (iii) the susceptibility of Acer spp. either native to or more recently established in Europe. The criteria assessed by the Panel for consideration as potential quarantine pest are met. For regulated non-quarantine pe

The hemlock woolly adelgid, Adelges tsugae Annand is an invasive insect that frequently causes hemlock (Tsuga spp.) mortality in the eastern United States. Studies have shown that once healthy hemlocks become infested by the adelgid, nutrients are depleted from the tree, leading to both tree decline and a reduction of the adelgid population. Since A. tsugae is dependent on hemlock for nutrients, feeding on trees in poor health may affect the ability of the insect to obtain necessary nutrients and may consequently affect their physiological and population health. Trees were categorized as lightly or moderately impacted by A. tsugae based on quantitative and qualitative tree health measurements. Population health of A. tsugae on each tree was determined by measuring insect density and peak mean fecundity; A. tsugae physiological health was determined by measuring insect biomass, total carbon, carbohydrate, total nitrogen, and amino nitrogen levels. Adelges tsugae from moderately impacted trees exhibited significantly greater fecundity than from lightly impacted trees. However, A. tsugae from lightly impacted hemlocks contained significantly greater levels of carbohydrates, total nitrogen, and amino nitrogen. While the results of the physiological analysis generally support our hypothesis that A. tsugae on lightly impacted trees are healthier than those on moderately impacted trees, this was not reflected in the population health measurements. Adelges tsugae egg health in response to tree health should be verified. This study provides the first examination of A. tsugae physiological health in relation to standard A. tsugae population health measures on hemlocks of different health levels.

The hemlock woolly adelgid, Adelges tsugae Annand is an invasive insect that frequently causes hemlock (Tsuga spp.) mortality in the eastern United States. Studies have shown that once healthy hemlocks become infested by the adelgid, nutrients are depleted from the tree, leading to both tree decline and a reduction of the adelgid population. Since A. tsugae is dependent on hemlock for nutrients, feeding on trees in poor health may affect the ability of the insect to obtain necessary nutrients and may consequently affect their physiological and population health. Trees were categorized as lightly or moderately impacted by A. tsugae based on quantitative and qualitative tree health measurements. Population health of A. tsugae on each tree was determined by measuring insect density and peak mean fecundity; A. tsugae physiological health was determined by measuring insect biomass, total carbon, carbohydrate, total nitrogen, and amino nitrogen levels. Adelges tsugae from moderately impacted trees exhibited significantly greater fecundity than from lightly impacted trees. However, A. tsugae from lightly impacted hemlocks contained significantly greater levels of carbohydrates, total nitrogen, and amino nitrogen. While the results of the physiological analysis generally support our hypothesis that A. tsugae on lightly impacted trees are healthier than those on moderately impacted trees, this was not reflected in the population health measurements. Adelges tsugae egg health in response to tree health should be verified. This study provides the first examination of A. tsugae physiological health in relation to standard A. tsugae population health measures on hemlocks of different health levels.

Identification of fungi and the International Code of Nomenclature underpinning this process, rests strongly on the characterisation of morphological structures. Yet, the value of these characters to define species in many groups has become questionable or even superfluous. This has emerged as DNA-based techniques have increasingly revealed cryptic species and species complexes. This problem is vividly illustrated in the present study where 105 isolates of the Botryosphaeriales were recovered from both healthy and diseased woody tissues of native Acacia spp. in Namibia and South Africa. Thirteen phylogenetically distinct groups were identified based on Internal Transcribed Spacer (ITS) rDNA PCR-RFLP and translation elongation factor 1-α (TEF1-α) sequence data, two loci that are known to be reliable markers to distinguish species in the Botryosphaeriales. Four of these groups could be linked reliably to sequence data for formerly described species, including Botryosphaeria dothidea, Dothiorella dulcispinae, Lasiodiplodia pseudotheobromae and Spencermartinsia viticola. Nine groups, however, could not be linked to any other species known from culture and for which sequence data are available. These groups are, therefore, described as Aplosporella africana, A. papillata, Botryosphaeria auasmontanum, Dothiorella capri-amissi, Do. oblonga, Lasiodiplodia pyriformis, Spencermartinsia rosulata, Sphaeropsis variabilis and an undescribed Neofusicoccum sp. The species described here could not be reliably compared with the thousands of taxa described in these genera from other hosts and regions, where only morphological data are available. Such comparison would be possible only if all previously described taxa are epitypified, which is not a viable objective for the two families, Botryosphaeriaceae and Aplosporellaceae, in the Botryosphaeriales identified here. The extent of diversity of the Botryosphaeriales revealed in this and other recent studies is expected to reflect that of ot

Fire is one of the main agents controlling composition, structure, and function of mixed conifer forests in the Sierra Nevada, CA. Over the past century, there has been a dramatic shift in the role of fire in these forests as fire regimes shifted from low intensity, frequent fires prior to European settlement in the region, to extended periods of fire exclusion due to a policy of active fire suppression. This led to many unintended consequences such as increased stand density, shifts in species composition towards more shade tolerant species such as white fir, and an increase in fire severity and extent when fires do occur due to increased fuels and changing climate. In the past several decades, prescribed fire has become one of the most important tools for forest restoration and management, yet its effects are still not fully understood. This uncertainty is especially true for sugar pine, a species that is being affected not only by changing forest conditions, but also by the introduced pathogen white pine blister rust. These multiple factors, and potential interactions among them, have led to population declines of sugar pine in some areas and have raised concerns about potential mortality during prescribed fire. The goal of this research was to better understand what processes were most important in controlling post-fire mortality of sugar pine, use this information to produce more accurate predictive models of post-fire mortality, and to evaluate simple management actions that could ameliorate the risk of mortality following fire.The first chapter serves as an introduction to the mixed conifer ecosystem and sugar pine in particular. It discusses the main factors that control mortality following prescribed fire and highlights some of the main findings of this research. In the second chapter, structural equation modeling (SEM) was used to assess the direct and indirect effects of multiple variables related to tree health, beetle activity, blister rust, and fire ef

The United Company’s corporate headquarters resides on 65 acres in a residential area just east of downtown Bristol, Virginia. The main office complex on the south side of campus is accented by a mixed landscape of trees, shrubs, and lawns. In 2008, foresters with Virginia Cooperative Extension and Virginia Tech were contracted to develop a landscape tree management plan for the corporate campus. A complete tree inventory was conducted in summer 2008 to assess campus tree composition and maintenance needs. The inventory provided the basis for developing the management plan, which describes the priorities, goals, and objectives that should guide landscape tree management on the United Company corporate campus over the next decade and beyond. The inventory enumerated 630 landscape trees consisting of 67 different species. Flowering dogwood, yellow-poplar, and eastern white pine were the three most abundant species, each accounting for about 15% of the total population. The campus landscape is dominated by mature and geriatric trees. Despite the “graying” of the tree population, it is in fair to good condition overall. Structural defects that may threaten tree stability were commonly observed in the inventoried trees. Fortunately, most of these defects were mild to moderate and do not pose a significant threat to the landscape. However, critical defects were observed in several trees and should be attended to immediately. An assortment of disorders that may threaten tree health were also observed in campus trees. Prevalent disorders included trunk wounds, soil compaction, buried root collars, and inadequate mulching. These disorders can threaten tree health and should be addressed through a systematic tree maintenance program. In this paper, general recommendations for tree planting, maintenance, and removal are provided based on the primary goal of attaining a safe, attractive, and sustainable campus forest. In addition, specific management recommendations are provide

Vermont Hardwood Tree Health in 1991 Compared to 1986

Analysis of Rates of Intensification of Douglas-Fir Dwarf Mistletoe in Mixed Conifer Stands in the Southwest

Highway Salting Influences on Ponderosa Pine Seedlings

Management Plan for Dead and Defective Trees on the Olympic National Forest

Station Note No. 38; Tree defects and stand conditions on the Hacker Creek Experimental Area Morgan-Monroe State Forest Indiana

Station Note No. 49; Tree defects common in the upland forests of southern Illinois

The Groundwood and Sulfate Pulping of Pole-Blighted and Healthy Western White Pine