Search

Understanding the factors that structure soil microbial communities and their relative importance in determining local community assemblages is fundamental to understanding how human activities, such as forest management, may impact soil ecosystems. We studied fungal communities in soil and litter under multiple sites dominated by spruce, beech and oak in a central European forest ecosystem to further understand the relative importance of vegetation and abiotic variables within a temperate forest. We sampled four times over a one-year period to determine if fungal community composition varied over time and whether the determination of driving factors was temporally dependent. We found that fungal community composition differed between litter and soil and among stand types but that community structure (richness, functional-guilds) was similar. In litter communities, composition was strongly coupled to dominant tree species; while in soil communities, both dominant tree and abiotic variables such as pH were important - with each variable explaining a separable portion of the variation in the fungal community composition. Further analyses showed that the relative importance of dominant tree species and abiotic drivers differed among functional groups subsets of the community. Across our sampled sites, both the litter and soil communities of a given stand type were well-characterized by a set of low-abundance indicator species with consistent presence, regardless of location, suggesting stand type is an important local filter on the occurrence of these taxa within the spatial context of our study (100 km 2 ). The marked difference in annual leaf break and leaf fall between coniferous and deciduous stands were not found to correlate with temporal changes in fungal community composition; however, a time-dependent trend was found across all soil communities and among all soil functional-group subsets regardless of the dominant tree type. [ABSTRACT FROM AUTHOR]

Pseudodidymella fagi is a leaf blotch pathogen of Fagus crenata in Japan. This pathogen is now reported for the first time on F. sylvatica in Switzerland and Germany. Species identity was verified by morphological assessment of the asexual and sexual morphs and by comparing the internal transcribed spacer ( ITS) sequence of the type material from Japan and of freshly collected samples from Europe. ITS sequences proofed to be completely identical. The asexual morph Pycnopleiospora of Ps. fagi is formed on necrotic leaf spots during summer and autumn. In early spring, its sexual morph is formed in the litter of F. sylvatica. The connection between sexual and asexual morphs was verified by sequencing the ITS region of single conidium and ascospore isolates. The pathogenicity of Ps. fagi on F. sylvatica was tested by inoculations on detached leaves in vitro and Koch's postulates were fulfilled. The second pathogen we report in central Europe for the first time is Petrakia deviata, which causes a leaf blotch disease of field maple ( Acer campestre). This species was collected only once in the central Caucasus region in 1929 and was never found again after its first discovery. Now it was rediscovered in two different locations in Switzerland on field maple ( A. campestre) and on the new host Norway maple ( A. platanoides). Species identity was verified by morphology and by comparison with the ITS sequence of the holotype specimen and freshly collected samples. Phylogenetic analysis based on ITS sequences suggested that Ps. fagi and P. deviata are closely related to each other. Whether these species were simply overlooked so far, profit from climate change, or represent newly introduced invasive species remains to be studied. Moreover, deeper phylogenetic analysis using multiple sequence markers should be conducted to verify species identities. [ABSTRACT FROM AUTHOR]

Understanding how species-specific disturbances affect the dynamics of mixed forests is becoming increasingly important due to rapidly changing disturbance regimes. This study estimated the effect of Norway spruce ( Picea abies (L.) Karst.) mortality on the disturbance processes in two mixed beech stands of the Western Carpathians that were affected by a bark beetle outbreak. We evaluated the size distribution, fraction of canopy and expanded gaps, the characteristics of gapmakers and the contribution of different species to gap size. The measured canopy gap fraction was <5%, and most canopy gaps were small (<100 m). Spruce was the most abundant gapmaker, and its share among gapmakers was 3-6 times higher than its share in the canopy. We found that the increase in spruce mortality due to the outbreak resulted in a fine-scale mortality pattern. However, spruce gapmakers did not contribute much to gap area size, as shown by a weak correlation between the number of spruce gapmakers and the area of expanded gaps. Diameter distribution of living versus recently dead trees showed that beech mortality occurred disproportionately in large size classes. However, dead spruce trees were equally frequent in all diameter classes, which means beetles did not exclusively attack larger trees in these stands during the outbreak. We conclude that spruce mortality may have influenced successional processes by giving a competitive advantage to two other species that were not affected by the outbreak, provided that a high deer browsing intensity does not hinder the regeneration of new seedlings. [ABSTRACT FROM AUTHOR]

We investigated the potential for human-mediated range expansion of an exotic beech leaf-mining weevil, Orchestes fagi (Linnaeus) (Coleoptera: Curculionidae: Curculioninae: Rhamphini) (formerly known as Rhynchaenus fagi) on timber or firewood, which for eight to nine months of the year may harbour adults in diapause. In both relatively low-density and high-density populations, adults were found on the base, middle, and upper boles of the primary host, American beech (Fagus grandifolia Ehrhart; Fagaceae), as well as red maple (Acer rubrum Linnaeus; Sapindaceae) and red spruce (Picea rubens Sargent; Pinaceae) in the vicinity. Comparatively few individuals were found on tree branches, or in the moss, duff, or soil collected beneath beech trees. Overwintering adults appeared to favour parts of trees with relatively high bark roughness. Our study suggests that, between the months of July through May, any woody stems near areas having O. fagi outbreaks are likely to harbour adults. Moreover, as all of the trees studied are common sources of timber or firewood, the harvest and transport of wood from these areas may facilitate outbreak spread; this may explain the multiple, distantly distributed populations of O. fagi that have been reported in eastern Nova Scotia, Canada in recent years. [ABSTRACT FROM PUBLISHER]

The present work focused on the influence of leaf-mining weevil (Orchestes fagi L.) on the leaves of common beech (Fagus sylvatica L.). The study investigated the changes of the oxidative stress markers malone dialdehyde (MDA), total peroxides and free proline in beech trees located at two different altitudes (680 m asl and 1400 m asl) at the Petrohan Training and Experimental Forest Range, Western Balkan Mountains. Levels of infestation as well as the studied parameters were highly dependent on the location. The conditions at low altitude were favorable for the rapid development of O. fagi which resulted in significant changes of leaf growth and physiology. The peak of the invasion was reached in May - June, 2015. Malone dialdehyde was the most reliable oxidative marker among the examined parameters. The heavily damaged leaves at 680 m asl contained higher amount of MDA - 24% - 35% more than that in the leaves at the higher altitude. Statistically significant correlation between content of MDA and degree of infestation was established. However, the increased level of lipid peroxidation was not accompanied by the corresponding enhancement of total peroxides. The damage caused by O. fagi invasion was also manifested by the increase of free proline content, especially in the leaves at 680 m asl. In general, the herbivory resulted in serious biochemical changes occurring in the leaves, indicating a shift in the oxidative status of the beech trees. [ABSTRACT FROM AUTHOR]

Biscogniauxia nummularia is a xylariaceous fungus known as a common endophyte of European beech, living in plant tissues without development of symptoms, or even inducing strip-cankers and wood decay on trees stressed by drought. We studied the presence of the fungus in apparently healthy beech trees, growing in two different bioclimatic zones characterized by Continental and Mediterranean climates. Asymptomatic twigs were collected in each zone over the season and evaluated for the presence of B. nummularia infections using both cultural and qPCR methods. Results from qPCR indicated differences in the detection of B. nummularia among the seasons and between the study sites. In both sites the highest frequency of detection was in summer. B. nummularia was more frequently detected in the Mediterranean bioclimatic area, where drought is more common. These results suggest that B. nummularia may be a possible bioindicator of beech health stands. [ABSTRACT FROM AUTHOR]

Fungal attacks on beech wood (Fagus sylvatica L.) samples (25 x 25 x 3) mm were performed using the brown-rot fungus Coniophora puteana over a period of 8 weeks, without or with their previous accelerated ageing in a Xenotest and a drying oven. Due to the fungal and ageing-fungal attacks, respectively, the top surfaces of the reference beech samples obtained a darker yellow-red shade according to the CIE-L*a*b* colour system. Similar changes in the colour coordinates L*, a*, and b* were found for the beech wood modified with the essential oils which were less fungicidal efficient--lavender, sage, tea-tree, and the oil-mixture. On the other hand, the colour changes in the beech wood modified with those essential oils which had a better fungicidal efficiency--birch, clove, oregano, sweet lag, savory, and thyme--were less significant, confirmed by Duncan's test. Linear correlations with greater or lesser significance were established between the changes in the colour parameters (ΔL*; Δa*; Δb*; ΔE*) and the corresponding mass losses (Δm) of attacked beech wood, the best for positive Δb* which identified its yellowing. [ABSTRACT FROM AUTHOR]

Copyright of Acta Silvatica et Lignaria Hungarica is the property of Sciendo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The authors mapped occurrence of three biotic vectors of beech (Fagus sylvatica L.) bark necrotic disease: beech lice Cryptococcus fagi Bärensp. and moths Bucculatrix ulmella Zeller and Ectoedemia liebwerdella Zim. in several countries in Central and South-Eastern Europe. The role of these species in European beech pathology is discussed. We have found a massive occurrence of C. fagi in all the localities, with frequency values reaching up to 100%. The occurrence of beech lice was not limited by the locality altitude. The butterfly E. liebwerdella generally occurred in most localities, with exception of Poland and Romania. In contrast to C. fagi, occurrence of E. liebwerdella was limited by altitude. The upper occurrence limit in Slovakia was 800 m a.s.l., in Bulgaria it was 1,220 m a.s.l. (32%) and infrequent in 1,380 m a.s.l. (only 4%). The butterfly B. ulmella occurred everywhere, apart from Poland. Its frequency was always lower than that of C. fagi and E. liebwerdella. The maximum value (91%) was found in Slovakia in a beech stand strongly affected with airborne pollutants in the past. Our results show that the upper occurrence limit for this species was 900 m a.s.l. in Slovakia and 1,250 m a.s.l. (4%) in Bulgaria. [ABSTRACT FROM AUTHOR]

Copyright of Forestry Chronicle is the property of Canadian Institute of Forestry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To increase grafting success rate, a hot callus grafting system was designed and implemented as part of a multiagency collaborative project to manage beech bark disease (BBD) through the establishment of regional BBD-resistant grafted seed orchards. Five years of data from over 2000 hot callus graft attempts were analyzed using a logistic regression model to determine which factors were important in graft success. Variables having the largest influence included scion genotype, technical problems, health issues (such as chlorosis or dwarfing), and contamination. Very few genotypes had significantly lower success compared with the average genotype, indicating that this method should be widely applicable. Comparison of the hot callus method with traditional grafting demonstrated that the odds of success using the hot callus method were 17 times greater than traditional grafting methods. Hot callus grafting is an efficient method for propagating American beech selections resistant to BBD for the establishment of seed orchards and superior clones with value as ornamentals. [ABSTRACT FROM AUTHOR]

There were studied particular biochemical and physiological characteristics of European beech (Fagus sylvatica L.) saplings of different origin, responding to different water supply. Three different provenances (PV1, PV2, and PV3) representing the lower margin, the upper margin of beech distribution range and the optimal growth and environmental conditions for this species were investigated in a control (well-watered) and a drought treatment. For each provenance, the water potential values (Ψw) towards the end of the experiment were found low, indicating a severe water stress. However, there were not observed significant differences in decreasing Ψw values between the studied provenances. There were also recorded significant decreasing osmotic potential values (Ψs) influenced by drought. In the saplings of the PV2 provenance, the plants deprived of watering (drought treatment) showed the largest decrease of osmotic potential values. All provenances showed significant impacts of drought on the content of assimilatory pigments (Chl a, Chl b, Chl a + b, Chl a/b, Chl/Car). Nevertheless, the observed changes in individual provenances did not differ significantly. The analysis of the response to the controlled water deficit confirmed that the proline content increased significantly for all provenances. The largest increase in the proline concentration was observed in PV2 provenance. These results imply that the most sensitive to water deficit was the provenance PV2 from the optimal ecological beech area. [ABSTRACT FROM AUTHOR]

Identification and quantification of spatial genetic structure (SGS) within populations remains a central element of understanding population structure at the local scale. Understanding such structure can inform on aspects of the species' biology, such as establishment patterns and gene dispersal distance, in addition to sampling design for genetic resource management and conservation. However, recent work has identified that variation in factors such as sampling methodology, population characteristics and marker system can all lead to significant variation in SGS estimates. Consequently, the extent to which estimates of SGS can be relied on to inform on the biology of a species or differentiate between experimental treatments is open to doubt. Following on from a recent report of unusually extensive SGS when assessed using amplified fragment length polymorphisms in the tree Fagus sylvatica, we explored whether this marker system led to similarly high estimates of SGS extent in other apparently similar populations of this species. In the three populations assessed, SGS extent was even stronger than this previously reported maximum, extending up to 360 m, an increase in up to 800% in comparison with the generally accepted maximum of 30-40 m based on the literature. Within this species, wide variation in SGS estimates exists, whether quantified as SGS intensity, extent or the Sp parameter. Consequently, we argue that greater standardization should be applied in sample design and SGS estimation and highlight five steps that can be taken to maximize the comparability between SGS estimates. [ABSTRACT FROM AUTHOR]

Elevated temperature has potential to influence the biological mechanisms regulating ecosystem-atmosphere carbon exchange. The relationship between warming and heterotrophic microbial respiration remains poorly understood, not least in terms of the differential sensitivity of microbial groups to temperature and the complexity of interactions with other biota. Cord-forming basidiomycete fungi are dominant primary decomposers in temperate woodland. Decomposition rates are determined by the composition of the decomposer community, ecophysiological relationships between these fungi and abiotic variables and interactions with other organisms. Amongst the latter, a major determinant is the balance between mycelial growth and removal by soil invertebrate grazers, which can themselves be affected by elevated temperature. We investigated the impact of elevated temperature on fungal foraging and decomposition of beech ( Fagus sylvatica) wood in soil microcosms to which the invertebrate grazers, Folsomia candida and Protophorura armata (Collembola), were added in factorial combinations with five basidiomycete fungi. Species-specific impacts on mycelial development and function resulted from differential sensitivity of fungi to warming and grazing. Temperature impacts on collembola abundance were resource-specific, causing increased grazing pressure by both species, but on different fungi. Grazing often counteracted warming-induced stimulation of mycelial growth, but occasionally amplified the temperature effect, with implications for colonization rates of new resources. High grazing pressure did not prevent increased fungal-mediated decomposition of colonized wood, as fungi utilized more resource-derived energy to maintain explorative growth. Impacts of elevated temperature on decomposition are likely to depend on local composition of the fungal and invertebrate decomposer community. [ABSTRACT FROM AUTHOR]

A new milkcap species, Lactariusfuscomarginatus, was found in the subtropical region of central Veracruz (eastern Mexico) associated with two relict populations of Fagus grandifolia var. mexicana. The species is characterized macroscopically by its dark pileus and stipe and by its distant and whitish lamellae with blackish to blackish brown edges. A molecular phylogenetic analyses based on ITS and LSU nucDNA sequences confirms the delimitation of this new taxon and places L. fuscomarginatus in subgenus Gerardii. A detailed morphological comparison is given with similar species. [ABSTRACT FROM AUTHOR]

Abstract: Liming is a known forest management procedure used to amend nutrient-poor soils such as soils of acidic forests to rectify cation deficiencies and to restore soil pH. However, although this procedure is well known for its beneficial effect on the forest trees, its relative impact on the functional and taxonomic diversity of the soil bacterial communities has been poorly investigated. In this study, we characterized the ability of the soil bacteria to weather soil minerals and to hydrolyze chitin. A collection of 80 bacterial strains was isolated from the Scleroderma citrinum ectomycorrhizosphere and the adjacent bulk soil in two stands of mature beeches (Fagus sylvatica) developed on very acidic soil and presenting two levels of calcium (Ca) availability: a control plot as well as a plot amended with Ca in 1973. All the bacterial isolates were identified by partial 16S rRNA gene sequence analysis as members of the genera Burkholderia, Bacillus, Dyella, Kitasatospora, Micrococcus, Paenibacillus, Pseudomonas, and Rhodanobacter. Using a microplate assay for quantifying the production of protons and the quantity of iron released from biotite, we demonstrated that the bacterial strains from the amended plot harbored a significant higher mineral weathering potential that the ones isolated from the control plot. Notably, the weathering efficacy of the ectomycorrhizosphere bacterial isolates was significantly greater than that of the bulk soil isolates in the control treatment but not in the amended plot. These data reveal that forest management, here mineral amendment, can strongly affect the structure of bacterial communities even over the long term. [Copyright &y& Elsevier]

Fungal endophyte assemblages in leaves of Japanese beech (Fagus crenata Blume) trees were investigated in pure beech stands at four localities with different summer temperatures covering the natural distribution range of the species. Ascochyta fagi Woronich was dominant at every site, and the infection density (ID) of this fungus was higher at sites with low maximum air temperatures. The growth rate of A. fagi on potato dextrose agar was inhibited by temperatures above 30 °C. These results suggest that the population density of A. fagi on Japanese beech leaves is influenced by summer temperatures. However, the number of species and Shannon index of diversity (H′) of endophytic fungi increased with increasing air temperature and a negative correlation was observed between the ID of A. fagi and the diversity of other endophytes. The species composition of minor endophytes was site-specific and may reflect geographic and genetic distances between beech stands. [ABSTRACT FROM AUTHOR]

Beech scale, Gryptococcusfagisuga Lindinger, is a non-native invasive insect associated with beech bark disease. A quantitative method of measuring viable scale density at the levels of the individual tree and localized bark patches was developed. Bark patches (10 cm2) were removed at 0, 1, and 2 m above the ground and at the four cardinal directions from 13 trees in northern New York and 12 trees in northern Michigan. Digital photographs of each patch were made, and the wax mass area was measured from two random 1-cm2 subsamples on each bark patch using image analysis software. Viable scale insects were counted after removing the wax under a dissecting microscope. Separate regression analyses at the whole tree level for the New York and Michigan sites each showed a strong positive relationship of wax mass area with the number of underlying viable scale insects. The relationships for the New York and Michigan data were not significantly different from each other, and when pooling data from the two sites, there was still a significant positive relationship between wax mass area and the number of scale insects. The relationships between viable scale insects and wax mass area were different at the 0-, 1-, and 2-m sampling heights but do not seem to affect the relationship. This method does not disrupt the insect or its interactions with the host tree. [ABSTRACT FROM AUTHOR]

Abstract: Two cultivation-based isolation techniques – the incubation of leaf fragments (fragment plating) and dilution-to-extinction culturing on malt extract agar – were compared for recovery of foliar endophytic fungi from Fagus sylvatica near Greifswald, north-east Germany. Morphological-anatomical characters of vegetative and sporulating cultures and ITS sequences were used to assign morphotypes and taxonomic information to the isolates. Data analysis included species-accumulation curves, richness estimators, multivariate statistics and null model testing. Fragment plating and extinction culturing were significantly complementary with regard to species composition, because around two-thirds of the 35 fungal taxa were isolated with only one of the two cultivation techniques. The difference in outcomes highlights the need for caution in assessing fungal biodiversity based upon single isolation techniques. The efficiency of cultivation-based studies of fungal endophytes was significantly increased with the combination of the two isolation methods and estimations of species richness, when compared with a 20-years old reference study, which needed three times more isolates with fragment plating to attain the same species richness. Intensified testing and optimisation of extinction culturing in endophyte research is advocated. [Copyright &y& Elsevier]

During the past decade, and in particular after the wet year 2002 and the dry year 2003, an increasing number of trees and stands of European beech ( Fagus sylvatica L.) in Bavaria were showing symptoms typical for Phytophthora diseases: increased transparency and crown dieback, small-sized and often yellowish foliage, root and collar rot and aerial bleeding cankers up to stem heights of >20 m. Between 2003 and 2007 134 mature beech stands on a broad range of geological substrates were surveyed, and collar rot and aerial bleeding cankers were found in 116 (86.6%) stands. In most stands the majority of beech trees were declining and scattered or clustered mortality occurred. Bark and soil samples were taken from 314 trees in 112 stands, and 11 Phytophthora species were recovered from 253 trees (80.6%) in 104 stands (92.9%). The most frequent species were P. citricola, P. cambivora and P. cactorum. Primary Phytophthora lesions were soon infected by a series of secondary bark pathogens, including Nectria coccinea, and wood decay fungi. In addition, infected trees were often attacked by several bark and wood boring insects leading to rapid mortality. Bark necroses were examined for their probable age in order to determine whether the onset of the current Phytophthora epidemic was correlated to rainfall rates recorded at 22 Bavarian forest ecosystem monitoring stations. A small-scale survey in nine Bavarian nurseries demonstrated regular infestations of all beech fields with the same range of Phytophthora species. The results indicate that (1) Phytophthora species are regularly associated with beech decline and may also be involved in the complex of ‘Beech Bark Disease’, (2) excessive rainfalls and droughts are triggering the disease, and (3) widespread Phytophthora infestations of nursery stock might endanger current and future silvicultural projects aiming on the replacement of non-natural conifer stands by beech dominated mixed stands. [ABSTRACT FROM AUTHOR]

Exotic pests and pathogens, through direct and indirect effects on forest structure and species composition, have the potential to significantly alter forest ecosystem processes, including C cycling. Throughout the northern hardwood forest, beech bark disease (BBD) is causing widespread disruption in forest structure and composition. In the Catskill Mountains of New York, some forests formerly codominated by American beech (Fagus grandifolia Ehrh.) and sugar maple (Acer saccharum Marsh.) are shifting to sugar maple dominance. The effects of BBD and a subsequent shift in species composition on annual aboveground net primary production and soil CO2 efflux were examined in eight forest plots selected to represent a gradient of BBD impact. There were no significant trends in aboveground net primary production across this gradient. However, growing season soil CO2 efflux decreased linearly along the BBD gradient, declining by 40%. Although the mechanism controlling this decline is uncertain, the decrease in soil CO2 efflux with BBD impact and a shift to greater composition of sugar maple in litterfall could significantly alter C cycling in northern hardwood stands in the Catskill Mountains. [ABSTRACT FROM AUTHOR]

We investigated the relationship between time since death and morphological characteristics of Abies alba Mill. (European silver fir) and Fagus sylvatica L. (European beech) stumps in two forest stands in the central Apennines. At each site, 15 or 16 living trees were selected, and increment cores were collected to build master ring-width chronologies. For both sites, cross sections were collected from stumps. Samples were assigned to visually discernible decay classes, and their death date dendrochronologically determined. Using cross-dating techniques, stumps cross-dated significantly with standard chronologies, and it was possible to assign a year of death to 77% and 69% of sampled A. alba and F. sylvatica stumps, respectively. Analysis of the time since death of the stumps suggests that the two species have similar decay rates, although A. alba was faster in passing from class 2 to class 3. However, this study revealed a continuum through decay classes and showed a high variability in the transition rate from one class to another. Overall, information obtained using dendrochronological techniques was valuable for assessing deadwood decomposition rates. The variability found in stump decomposition rates indicates that existing decay classification schemes, although providing information on decomposition timing, are hardly applicable to these forest stands and that the relationship between qualitatively assessed decay classes and time since death of trees appears to be rather weak. [ABSTRACT FROM AUTHOR]

1. The degree of infestation by New Zealand sooty beech scale insects ( Ultracoelostoma assimile, Homoptera: Margarodidae) varies dramatically among adjacent southern beech trees ( Nothofagus spp., Fagaceae), but has previously been assumed to be uniformly or randomly distributed within individual host trees. In this study, a full-census survey was conducted from ground level to canopy level on 14 naturally occurring, canopy-dominant red beech ( Nothofagus fusca) trees (size range 38.7–107.6 cm diameter at breast height) to determine the degree of within-tree heterogeneity in herbivore density. 2. The within-tree distribution of the sooty beech scale was vertically stratified and highly heterogeneous, with the greatest densities occurring on bark surfaces in the canopy rather than on the trunk, and on the lower rather than upper sides of the branches. The spatial distribution was strongly negatively correlated with trunk and branch diameter, and increasing bark thickness (as a function of diameter) provides a plausible explanation for differences in the establishment and population density of sooty beech scale insects with trunk and branch size. Furthermore, there was a significant change in the spatial distribution of scale insect populations on trunks and branches of trees of increasing diameter at breast height. This indicates a strong temporal component to the spatial dynamics of the sooty beech scale insect driven by changing host phenology. Future studies on phytophagous insects infesting large host trees need to consider more explicitly changes in population dynamics through space and time. 3. Because of the high degree of within-tree heterogeneity in population density, the total population size of scale insects on an individual tree could not be predicted from any measure of population density low on the trunk. However, the dry weight biomass of sooty mould fungi growing on the ground beneath infested trees was a remarkably accurate predictor of the total population size of scale insects. The use of sooty mould fungi as a relative measure of population size could be incorporated into studies of other honeydew-producing hemipterans, since the growth of sooty mould is a distinctive feature synonymous with high concentrations of honeydew production worldwide. [ABSTRACT FROM AUTHOR]

The effect of nitrogen fertilization on fungistatic phenolic compounds in fine roots of beech and Norway spruce growing in afforestation plots was analysed. The plots were situated at two sites in Switzerland on acidic soil with low base saturation. For 9 years, the trees have been treated with dry ammonium nitrate to give 0, 10, 20, 40, 80, 160 kg N ha−1 year−1, respectively. The phenolic compounds responded differently to fertilization. Fine roots of beech showed a significant decrease of (−)-epicatechin and piceatannol with increasing nitrogen fertilization. The concentration of protocatechuic acid was increased with fertilization. Roots of fertilized Norway spruce showed significantly decreased concentrations of 4-hydroxyacetophenone and piceatannol. The mycelial growth of three isolates each of Heterobasidion annosum s.l. and Cylindrocarpon destructans was tested on agar media containing various phenolic compounds in concentrations found in fine roots of Norway spruce ( Picea abies) and beech ( Fagus sylvatica). All three H. annosum isolates were inhibited by p-coumaric acid and (−)-epicatechin. Two isolates were inhibited by another four phenolic compounds (p-hydroxybenzoic acid, 4-hydroxyacetophenone, piceatannol and protocatechuic acid), one by (+)-catechin. Two of three C. destructans isolates were inhibited by all phenolic compounds except for (+)-catechin which affected only one isolate, one isolate did not respond at all. [ABSTRACT FROM AUTHOR]

Several studies have demonstrated the relationship between black bear (Ursus americanus) reproductive success and the availability of hard mast. Beech bark disease (BBD) has been shown to reduce mast production in beech trees; however, no studies have investigated the relationship between bear foraging preferences of beech trees and the presence of BBD. To investigate this, we measured the severity of Nectria fungus and beech scale insect on freshly clawed and unclawed trees in pooled beech stands in northern Vermont. Our results suggest that bears do not have a strong preference for climbing healthier beech trees in aftermath forests. Changes in landscape composition and in cultural values appear to have been more important processes affecting black bear populations today than has BBD; however, we still advocate management strategies to minimize the impacts of this disease. [ABSTRACT FROM AUTHOR]

Reports on the observation of a disorder in a 76-year-old Japanese beech (Fagus crenata) bonsai with symptoms including marginal scorch of leaves bordered by a chlorotic halo, as well as a premature leaf browning and defoliation. Reaction of leaf midrib extracts from the affected bonsai with an antiserum specific to Xylella fastidiosa in an enzyme-linked immunosorbent assay; Detection of a 472-bp polymerase chain reaction (PCR) product; Confirmation of the PCR product to be the predicted X. fastidiosa product by sequencing and sequence comparison with the reported genomic sequence of X. fastidiosa.

The distribution and severity of beech bark disease (BBD) in the Catskill Mountains of southeastern New York state, U.S.A., were measured between 1997 and 2000. Forest composition was measured using wedge prism surveys and fixed-area plot counts of canopy species. BBD severity on individual trees was ranked from 1 (no disease) to 5 (dead) based on bark health and canopy loss. These data were analyzed at multiple spatial scales to determine possible controls of disease distribution and severity. BBD was present on almost all Fagus grandifolia Ehrh. (American beech) individuals encountered >10 cm diameter at breast height, but was most severe in larger diameter classes. Mortality due to BBD also increased with diameter class. A strong positive relationship was found between BBD severity and relative beech basal area at the tract (hundreds of hectares) and 100-m elevation band spatial scales, but not found at smaller scales. Successful long-range dispersal of the disease may therefore be dependent upon host density, while local conditions may control BBD severity within individual stands. The current status of BBD in the Catskills suggests these forests are entering the aftermath phase of the disease's progression and that BBD has become an endemic component of these forests. La distribution et la sévérité de la maladie corticale du hêtre dans les monts Catskills du sud-est de l'État de New York aux États-Unis ont été mesurées entre 1997 et 2000. La composition de la forêt a été évaluée par un inventaire au prisme et le décompte des espèces dominantes dans des placettes à aire fixe. La sévérité de la maladie a été classée de 1 (sain) à 5 (mort) sur chaque arbre en se basant sur l'état de santé de l'écorce et la perte de cime. Ces données ont été analysées à plusieurs échelles spatiales pour déterminer les facteurs potentiels qui régissent la distribution et la sévérité de la maladie. La maladie était présente sur presque tous les hêtres à grandes feuilles (Fagusgrandifolia Ehrh.) présents de plus de 10 cm au diamétre à hauteur de poitrine mais elle était plus sévère dans les plus fortes classes de diamètre. La mortalité due à la maladie augmentait aussi avec la classe de diamètre. Une relation positive étroite a été observée entre la sévérité de la maladie et la surface terrière relative des hêtres à l'échelle spatiale de la parcelle (centaines d'hectares) et de la bande de 100 m d'altitude mais pas à de plus petites échelles. La dispersion de la maladie sur de longues distances est par conséquent possiblement dépendante de la densité de l'hôte tandis que les conditions locales contrôlent vraisemblablement la sévérité de la maladie dans chaque peuplement. La situation présente de la maladie dans les Catskills indiquent que ces forêts entrent dans la phase finale de la progression de la maladie et que celle-ci est devenue une composante endémique de ces forêts.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

The seasonal occurrence of Mycosphaerella buna in leaves and contiguous organs of Fagus crenata was studied in a Japanese beech forest, Ibaraki, Japan, in 1998 and 1999. Mycosphaerella buna was not isolated from newly developed leaves in May, but it was isolated from asymptomatic leaves after June. The frequency of its occurrence gradually increased until leaffall. In contrast, M. buna was not isolated from overwintered buds, leaf petioles, or contiguous current-year twigs. The spermogonia and pseudothecia were observed in dead leaves after leaffall. The mature pseudothecia were found on dead leaves from May to July. The ascospores produced in the pseudothecia were suggested to infect newly developed leaves. [ABSTRACT FROM AUTHOR]

Presents a study that examined the indirect effects of beech bark disease on sugar maple seedling survival. Method of the study; Results and discussion; Conclusion.

Beech canker caused by Nectria ditissima was abundant in many plots of a large beech provenance trial in Germany. In 149 plots a total of 9015 plants were assessed. No difference in susceptibility of individual provenances was established. However, significant spatial correlation was found between canker incidence in the plantation and the distance to neighbouring diseased shelterwood. The latter evidently served as a source of inoculum. Predominant juveniles tended to be more infected presumably by being more exposed to the inoculum. Trees planted up to 20 m from diseased shelterwood were most significantly infected, up to 48% per plot. In order to ascertain the role of wind for dispersing inoculum, distance zones were combined with locally predominant wind directions. The resulting wind dispersal zones served better for modelling disease dispersal than the distance zones. [ABSTRACT FROM AUTHOR]

Summary Leaves of Japanese beech (Fagus crenata) were collected monthly during the vegetation period at five sites in the Tohoku district in Japan to isolate endophytic fungi. Leaves were also collected only once at two additional sites. Two endophytic fungi were dominant, a Discula species and a sterile mycelium. This result strongly suggests that these two fungi are generally associated with leaves of the Japanese beech at different sites. At most sites the isolation frequency of Discula sp. was greatest in June and gradually decreased from July to October whereas the isolation frequency of the sterile mycelium increased during the vegetation period and remained at a high isolation frequency in October. Spores of Discula sp. were released for a very short time in late May, just after the disappearance of the snow cover on the forest floor. These spores may be important for the infection of newly sprouting leaves. [ABSTRACT FROM AUTHOR]

In 1994 and 1995, the degree of infestation by the beech scale (Cryptococcus fagisuga Lind.) was recorded on 120 beech trees (Fagus sylvatica L.) in the Pless Forest near Göttingen, Germany. Simultaneously, the trees were characterized genetically and compounds of primary and secondary metabolism of beech bark were analyzed. A correlation was established between beech scale infestation and the genotype of the host trees, based on gene locus A of isocitrate dehydrogenase (IDH-A). The fraction of infested beech trees was higher in the heterozygous genotype A2A3 group than in the homozygous genotype A2A2 and A3A3 groups, whereas the fraction of beech trees with decreasing infestation from one year to the next was lower in the heterozygous genotype A2A3 group than in the homozygous genotype A2A2 and A3A3 groups. [ABSTRACT FROM PUBLISHER]

Back transmission trials on young forest plants with isolates of purified viruses from the same tree species were performed using different inoculation techniques. Spruce seedlings and willow plants were successfully infected with tobacco necrosis virus (TNV) by the conventional method of mechanical inoculation of virus suspension mixed with celite as abrasive. Cherry leaf roll virus (CLRV) was transmitted to birches only after adding poIy-L-ornithine (PLO) to the inoculum. The same method was successful with brome mosaic virus (BMV) on beech seedlings. PLO also improved the rate of infection on TNV in willows. In only one case, was CLRV transmitted conventionally to a white ash seedling. The infection of white ash was increased when frozen powders of infected ash leaves were directly rubbed onto leaves. BMV could not be transmitted to beech seedlings by carborundum pressure-inoculation. Stem slashing-inoculation of BMV and CLRV was successful with CLRV in one beech out of 60 seedlings. [ABSTRACT FROM AUTHOR]

The forest of Lyons (Eure) is one of the French forests where beech bark disease is worst. Harvest of seeds in 1976 provided the opportunity to raise progenies of 12 mature trees in 1979, half of which had bark disease. Two isolates of Nectria coccinea, introduced into bark wounds, produced bark necrosis on one-year-old beeches. The size of the necrosis was assessed monthly from December 1979 to June 1980. According to the size of the necrosis in May 1980, the progenies could be separated into two groups of susceptibility. Classification of progenies is in good agreement with the mother trees' health. All progenies of bark disease trees arc in the most susceptible category. Nevertheless no relation can be found between susceptibility of progenies and development of the disease as noticed on mother trees between 1977 and 1980. Now the method used to determine susceptibility of progenies has been applied on young beeches free of beech scale. The insect's role in lowering of resistance to fungal invasion, has a prominent influence on the course of the disease. Subsequent development of the disease, after N. coccinea infection, depends more on the level of insect infestation than on the susceptibility of beech to N. eoccinea. As demonstrated previously for N. ditissima causing beech canker, susceptibility of beech to N. coccinea has a genetic origin. This result, in addition with the demonstration of genetic origin of beech susceptibility to Cryptococcus fagisuga by WAINHOUSE and DEEBLE (1980) substantiate the value of early elimination of diseased trees. [ABSTRACT FROM AUTHOR]

The article studies rot of beechnuts caused by Rhizoctonia solani Kühn. It discusses disease incidence after the 1974 and 1976 mast years. Also discussed is curative seed treatment before storage. Rot of beechnuts by Rhizoctonia solani Kühn, occurred throughout French beech forests after the masts of 1974 and 1976. The site conditions and the climatic conditions of November and December determine the incidence of disease which is notably reduced by soil cultivation before the mast. Thermotherapy, 24 hours at 36-38°C at 100% relative humidity, was shown to be a curative treatment of seeds before storage.

This article examines the effect of low SO[sub2]-concentrations on the activities of some glycosidases in the foliage of clonal forest trees. The aim of the study has been to find an early indicator of latent SO[sub2] injuries in a beech and a spruce clone. It has been found that the activities of β-glucosidase in the beech and β-galactosidase in the spruce clone and β-1, 3-glucanase in both species were significantly raised after an exposure to 0.0, 0.05, 0.1 and 0.2 ppm. As the beech clone was very sensitive to SO[sub2], an indication of latent injury could be ascertained only in the 0.05 ppm treatment where the rise of the β-glucosidase activity appeared some days before necroses.

Studies the incidence and spatial pattern of Nothofagus cunninghamii attacked by Platypus subgranosus or the mountain pinhole borer in a temperate rain forest in Tasmania. Proportion of myrtle trees attacked by the disease; Decrease in disease attack after increasing myrtle density; Description of attacked trees.

Seasonal and annual change of folivorous insects of beech associated with outbreaks of the beech caterpillar, Quadricalcarifera punctatella, were investigated in northern Japan from 1988 through 1992. Lepidopteran larvae sampled from branches and fallen frass were used for the analysis. Sixty-nine species were found over a 5 year period. Most species in the families Tortricidae, Geometridae, and Noctuidae infested in early seasons in the year, while Notodontidae fed in late seasons. Although the number of species decreased, the size of those infesting became larger in later seasons. There were three peaks in seasonal changes of falling frass: the first was in June and was constant over the years and locations; the second, caused mainly by Q. punctatella in August, varied greatly among years; and the third peak was sometimes ambiguous. Total frass was strongly influenced by Q. punctatella density. The density of this species changed with a magnitude of 10000, but the weight of frass produced by the other folivorous insects was estimated to fluctuate 10 times at most. The frass of other insects decreased the year following conspicuous defoliation by Q. punctatella. The results indicate that delayed induced response of the Siebold beech caused by Q. punctatella influenced not only the species itself but also other folivorous insects. Q. punctatella was the main factor determining the biomass of folivorous insects in the beech forests in northern Japan during the period studied. [ABSTRACT FROM AUTHOR]

The carabid beetle, Calosoma maximowiczi, is a conspicuous predator of the beech caterpillar, Quadricalcarifera punctatella. The beech caterpillar population gradually increased in all study plots from the time our research began and a severe defoliation was found in 1990. Seasonal and annual change in beetle abundance was investigated in the beech forests where this defoliation was observed. Adult carabids appeared from late July to mid-August when larvae of the caterpillar were full grown, and their abundance showed a strong relationship with the caterpillar density. Though carabid larvae are usually scarce in forests, they were abundant the year that catches of adult beetles were heavy. [ABSTRACT FROM AUTHOR]

During a survey of seed diseases of Fagus crenata, a new fungal disease of the seeds was found with high frequency in Akita, northern Japan. Main symptoms are often expressed as browning of the cracked parts from exposed cotyledons and complete loss of viability of infected seeds. Reddish perithecia and whitish yellow sporodochia were occasionally observed symptoms and determined that they were anamorph-telemorph relationship on the basis of both cultural observations. Inoculation studies confirmed that this fungus was the cause of seed rot. The fungus is morphologically identical with Neonectria ramulariae (anamorph: Cylindrocarpon obtusiusculum) that is well known as the soil-born fungi around the world. Sequences between the authentic isolate of Neo. ramulariae (CBS 151.29) and the pathogenic fungus based on ITS, LSU and tub showed high similarity. Thus, 'seed rot', the new disease of beech seeds caused by Neo. ramulariae (anamorph: Cyl. obtusiusculum) was proposed in this study. [ABSTRACT FROM AUTHOR]

The article reports on disease outbreaks of American beeches (Fagus grandifolia). Topics discussed include views of Lynn Carta, plant disease specialist with the U.S. Department of Agriculture (USDA), on the disease, views of David McCann, plant pathologist of the Ohio Department of Agriculture, on worms streaming from infected beech leaves and finding of an undescribed beetle on European beech trees by U.S. Forest Service researchers.