Update on the 35‐year expansion of the invasive root pathogen,Phytophthora lateralis,across a landscape of Port Orford cedar (Chamaecyparis lawsoniana)

Port Orford cedar (Chamaecyparis lawsoniana) is endemic to northern California and southwestern Oregon and is considered a foundation species that plays critical roles in riparian areas and on nutrient‐poor soils. Since 1952, a non‐native, pathogenic oomycete (Phytophthora lateralis) has been spreading throughout the range of the cedar. Most spread occurs by vehicles carrying infested soil along gravel roads primarily used for timber harvest. In a previous study conducted in 1998 and 1999, Port Orford cedar and P. lateralis were censused in a 37‐km² study area and dendrochronology was used to reconstruct the history of pathogen invasion. That work, which represents the only detailed analysis of spread rates for P. lateralis, showed that the first successful invasion into the study area took place in 1977 and that 43% of the susceptible host sites (stream crossings) were infested by 1999. In the work presented here, all sites that were uninfested in 1999 were re‐censused in 2012, extending the historical reconstruction of P. lateralis spread to 35 years. Two new infestations were initiated between 1999 and 2012, suggesting that the rate of spread of P. lateralis has slowed greatly. Between 1980 and 1989, the average number of new site infestations was 1.8 infestations per year, while between 1990 and 1999 the average was 0.4 infestations per year and between 2000 and 2009 the average was 0.2 infestations per year. Several potential explanations for the reduced number of new infestations are discussed.     

<Emphasis Type="Italic">Philaenus spumarius</Emphasis>: when an old acquaintance becomes a new threat to European agriculture

The unique color pattern polymorphism and the foamy nymphal case of the meadow spittlebug Philaenus spumarius have attracted the attention of scientists for centuries. Nevertheless, since this species has never been considered a major threat to agriculture, biological, ecological and ethological data are missing and rather scattered. To date this knowledge has become of paramount importance, in view of the discovery of P. spumarius main role in the transmission of the bacterium Xylella fastidiosa in Italy, and possibly in other European countries. The aim of this review is to provide a state of the art about this species, with particular focus on those elements that could help developing environmental friendly and sustainable control programs to prevent transmission of X. fastidiosa. Moreover, recent findings on the role of the meadow spittlebug as vector of the fastidious bacterium within the first reported European bacterium outbreak in Apulia (South Italy) will be discussed.     

ABT新型植物生长调节剂在云南松飞机播种造林中应用的试验初报

本文对ABT植物生长调节剂在云南松种子飞播造林试验应用中表明,种子萌芽期可提前7天,苗全期提前8天,而且种子出苗整齐,根系发达,同时由于种子发芽期提前,减少了鸟、鼠、危害种子时间。     

Detection and quantification of Phytophthora species which are associated with root-rot diseases in European deciduous forests by species-specific polymerase chain reaction

Oligonucleotide primers were developed for the polymerase chain reaction (PCR)-based detection of selected Phytophthora species which are known to cause root-rot diseases in European forest trees. The primer pair CITR1/CITR2, complementing both internal transcribed spacer regions of the ribosomal RNA genes, gave a 711 bp amplicon with Phytophthora citricola. The Phytophthora cambivora specific primer pair CAMB3/CAMB4, producing a 1105bp amplicon, as well as the Phytophthora quercina specific primer pair QUERC1/QUERC2, producing a 842 bp amplicon, were derived from randomly amplified polymorphic DNA (RAPD)-fragments presented in this paper. All three primer pairs revealed no undesirable cross-reaction with a diverse test collection of isolates including other Phytophthora species, Pythium, Xerocomus, Hebeloma, Russula, and Armillaria. Under the PCR conditions described the detection of a well discernable amplicon was possible down to 100 pg (P. cambivora), 4pg (P. quercina), and 2pg (P. citricola) target DNA. This diagnostic PCR system was able to detect P. citricola, P. quercina, and P. cambivora in seedlings of pendunculate oak (Quercus robur) and European beech (Fagus sylvatica) which were artificially infected under controlled conditions.     

Root recovery rates for Phytophthora cinnamomi and rate of symptom development from root rot on Abies fraseri trees over 7 years

Phytophthora root rot on Abies fraseri trees was monitored from 2001 to 2007 within the disease front of a 12‐year‐old Virginia plantation where trees had been dying of the disease since 1994. After a slow increase in early foliage symptom development from July 2001 to September 2002, the frequency of A. fraseri trees with early symptoms accelerated for about 15 months. While the slow increase occurred during a 18.7% lower than normal rainfall period and the acceleration occurred during a 31.2% higher than normal rainfall period, the percentage of trees with early symptoms continued to increase during the mid‐winter months (December–February) when the estimated mean minimum daily soil temperature (25 cm depth) was unfavourable (<10°C) to Phytophthora cinnamomi pathogenic activity. The time required for trees to progress from early foliage symptoms to completely dead foliage, from November 2000 to October 2007, was highly variable, ranging from 4 to 35 months. Root recovery rates for P. cinnamomi, assayed on a selective medium, were 6.4 times greater for symptomatic foliage trees than for asymptomatic foliage trees in this deep, silt‐loam soil. Following an atypical cold period in February 2007, when the mean minimum daily soil temperature was 0.8°C, symptomatic roots yielded only a low level of germinable propagules of P. cinnamomi. Further, during an atypical midsummer in 2007 (June–August), when the soil water potential was at or below ?9 bars for 68 of 92 days, symptomatic roots yielded no germinable propagules of P. cinnamomi. Addition of thiophanate‐methyl to the selective medium aided P. cinnamomi isolation by inhibiting many undesired pythiaceous colonies growing from symptomatic roots.     

Decline of Mediterranean oak trees and its association with Phytophthora cinnamomi: a review

Mortality events in cork and holm oaks have occurred in the Mediterranean basin since the beginning of the XX century, but severity of decline increased during the 1980s. By that time, the exotic soil borne pathogen Phytophthora cinnamomi was often recovered from declining stands and since then it has been considered the main factor associated with decline. This work analyses data concerning P. cinnamomi surveys in cork and holm oaks trees, pathogenicity tests carried out in controlled experiments, studies about the influence of site characteristics in tree decline and approaches to control the disease. Results of field surveys showed that the pathogen is widespread and pathogenicity tests suggested that host susceptibility to the pathogen is moderate when seedlings are in appropriate watering conditions, particularly cork oaks. Occurrence of decline is also associated with soil characteristics that interfere with root expansion and water retention. We assessed the relative importance of each factor involved in decline and revised the role of P. cinnamomi in cork and holm oak decline.     

The Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3): customization of the Archive Index Database for European Union countries

Key message

The purpose of this report is to increase the transparency of applications of the CBM-CFS3 model by climate-related policy-makers and researchers. The report provides explicit information on the parametrization of a new Archive Index Database used with this model to simulate forest carbon dynamics in 26 EU countries. The database can be accessed at https://data.europa.eu/89h/jrc-cbm-eu-aidb , primary metadata are available in Kull et al. (2017), and additional metadata are available at https://metadata-afs.nancy.inra.fr/geonetwork/srv/fre/catalog.search#/metadata/df48155b-973f-4169-a722-100bb6bfc76c .The Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3) has been adapted, tested, and applied to forests of 26 EU countries over the last 7 years for EU policy making and scientific research. The overall purpose of this exercise is to increase the transparency of how the EU Archive Index Database (EU-AIDB) was parameterized while supporting both the policy making and research communities interested in applying the CBM-CFS3 with ecological parameters specific to the EU context. In addition to preparing model input data reflecting various management and disturbance scenarios for CBM-CFS3 projects, an essential step was to update the original AIDB with information specific to the EU context and create an EU-AIDB. The AIDB is the Microsoft Access database behind the CBM-CFS3 that stores default ecological information and parameters pertaining to the forest ecosystems of a country, among other functions. The EU-AIDB incorporates 1034 spatial units resulting from the intersection of 204 European administrative regions and ecological boundaries representing 35 climatic units. It also contains updated parameters for 192 of the main tree species reported by the National Forest Inventories of each EU country. The release of this database allows CBM-33 CFS3 users in the EU to apply European administrative and ecological units and tree species in forest carbon modeling projects.

     

RFLP analysis as a tool for identification of lignicolous basidiomycetes: European polypores

Restriction fragment length polymorphisms were generated for 52 species of lignicolous European polypores belonging to 31 different genera. An enzymatically amplified portion of the nuclear-encoded ribosomal DNA was found to be about 1800–1900 bp long for most taxa. After digestion with Hpa II, 44 distinct phenotypes were detected for the species under study; application of the additional restriction endonucleases, Hin 6 I and Hinf I, resulted in 48 species-specific and two genera-specific phenotypes. The procedure described should allow for a reliable identification of unknown mycelia of lignicolous fungi.     

Phosphorus Nutrition of Lodgepole Pine and Sitka Spruce Stands as indicated by a Root Bioassay

A bioassay for determining P-deficiency, based on the rate ofuptake of ³²P-labelled phosphorus by roots from a standard solutionand developed on pot grown tree seedlings, has been appliedto roots from 10–18 year old lodgepole pine and Sitkaspruce stands in field fertilizer trials on peat. Rates of ³²-phosphorusuptake by roots were negatively related to quantities of P fertilizerpreviously given and to tree heights. The P content of firstwhorl needle samples were generally high but were not significantlydifferent between fertilizer treatments nor related to treeheights. There was, however, a general relationship between rates of³²P uptake by roots and P content of needles over all sitesand tree species. The bioassy, however, rapidly detects changesin internal P status of the tree which takes time to manifestitself in a change of needle P content. Preliminary work suggests that the bioassay detects a P-statusin trees, not identifiable from needle analyses. A number offactors which might influence the results of the bioassay andtherefore the field applicability of the method are discussed.     

THz-imaging: a new method for density mapping of wood

Summary This paper presents a new technique for fast and non-intrusive density mapping of wood based on far-infrared spectroscopy. The transmission of a piece of beech 1.7 mm thick is investigated between 0.1 and 2.5 THz. In this spectral range we find wood to be fairly transparent, but density inhomogeneities and structural details such as annual rings become visible in the transmission profile. The measured absorption correlates well with the wood density independently obtained by the gravitometric-volumetric method. Thus it finally becomes possible to transform the THz images into 2-dimensional density maps.The skillful technical help of Mrs. M. Rinas is greatly appreciated.     

A review of habitat thresholds for dead wood: a baseline for management recommendations in European forests

In contemporary forest management, also of commercial forests, threshold values are widely used for consideration of biodiversity conservation. Here, we present various aspects of dead-wood threshold values. We review published and unpublished dead-wood threshold data from European lowland beech–oak, mixed-montane, and boreo-alpine spruce–pine forests separately to provide managers of European forests with a baseline for management decisions for their specific forest type. Our review of dead-wood threshold data from European forests revealed 36 critical values with ranges of 10–80 m³ ha⁻¹ for boreal and lowland forests and 10–150 m³ ha⁻¹ for mixed-montane forests, with peak values at 20–30 m³ ha⁻¹ for boreal coniferous forests, 30–40 m³ ha⁻¹ for mixed-montane forests, and 30–50 m³ ha⁻¹ for lowland oak–beech forests. We then expand the focus of dead-wood threshold analyses to community composition. We exemplify the two major statistical methods applied in ecological threshold analysis to stimulate forest researchers to analyze more of their own data with a focus on thresholds. Finally, we discuss further directions of dead-wood threshold analysis. We anticipate that further investigations of threshold values will provide a more comprehensive picture of critical ranges for dead wood, which is urgently needed for an ecological and sustainable forestry.     

Disease biology and histopathology of bronze leaf disease: a threat to cultivated aspens,white poplars and their hybrids

Bronze leaf disease (BLD) of species and hybrids of aspens, grey and white poplars (Genus Populus, section Populus) is a systemic disease incited by the fungus Apioplagiostoma populi (E.K. Cash & A.M. Waterman) M.E. Barr that results in a characteristic bronze to dark brown pigmentation of infected leaves in late summer and early fall. Branches on affected trees die over a period of several years, disfiguring trees and eventually leading to mortality of susceptible trees planted in landscapes. In this study, we describe the histopathology of the disease and fungus development relative to external symptoms on affected trees. A. populi hyphae were observed in leaf vessels, lateral veins and xylem vessels of stems and roots of affected trees. Hyphae were also observed in veins and vessels of asymptomatic leaves. Xylem vessels of growth rings on dead branches were completely occluded with A. populi near the vascular cambium and together with the ray parenchyma were stained a bronze colour. Evidence of putative toxin damage to mesophyll cells, not colonized by hyphae, was observed and may contribute to the characteristic tissue staining observed. The development of the fungus was consistent with previous reports, but in this study, we report additional details including perithecial development and ascospore release from predominantly abaxial leaf surfaces. We also report for the first time the isolation and growth of the pathogen in pure culture and systemic infection of roots.     

Biological invasion of European tomato crops by Tuta absoluta: ecology, geographic expansion and prospects for biological control

The tomato leafminer Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is a devastating pest of tomato originating from South America. After its initial detection in eastern Spain in 2006, it rapidly invaded various other European countries and spread throughout the Mediterranean basin. If no control measures are taken, then the pest can cause up to 80–100% yield losses in tomato crops in recently invaded areas and may pose a threat to both greenhouse and open-field tomato production. The exceptional speed and extent of T. absoluta invasion have called for studies documenting its biology and ecology, while indicating an urgent need for efficient and sustainable management methods. The development of approaches to manage T. absoluta would be facilitated through a detailed revision of information on this pest in its area of origin. This review combines information on the invasion by T. absoluta, its ecology, and potential management strategies, including data that may help the implementation of efficient biological control programs. These programs, together with a variety of other management tactics, may allow efficient integrated pest management of T. absoluta in Europe and Mediterranean Basin countries.     

Description of a new species and new distributional data for two species of Aphytis(Hymenoptera: Aphelinidae) from China

Aphytis tridentatus Gao and Li sp. nov. is described and illustrated from southwest China, and A.bangalorensis Rosen and De Bach is newly recorded from China. New distributional data for A. chionaspis Ren are also provided.     

Forestry operations in the European mountains: a study of current practices and efficiency gaps

Timber production is an important ecosystem service of European mountain forests. This paper aimed to assess the current practices in logging operations and to identify the efficiency gaps in timber production. The study was located in 7 case study areas from representative European mountain ranges, where 632 logging operations were analysed. The focus was on road infrastructure, transport systems, harvesting methods and extraction technologies. Often inappropriate technology was used in steep terrain; there was no correlation between the average slope and the selection of harvesting systems (HS). Skidding was the most common extraction method (75%), while cable yarding and forwarding had shares of 15% and 8%. The mean road density was 18.5?m?ha^?1. The mean extraction distance was 501?m. The mean harvesting and extraction productivity were 9.0 and 10.2?m³?h^?1; the mean costs were 11.1 and 11.7?€?m^?³, respectively. Non-mechanized and obsolete HS reported the lowest efficiency and the highest environmental footprint, while fully mechanized systems reported the highest efficiency, the lowest number of accidents and the lowest stand damage. Cable yarders are the appropriate extraction technology in steep terrain, but they require a well-developed road network. Higher mechanization degree, improved quality of the road networks, knowledge transfer to practice and training of forest workers are some of the necessary measures to overcome the efficiency gaps in timber production in European mountain forests.