Home About us Contact
|
Home About us Contact | ||
|
|
||
F. Sylvatica (f + sylvatica)
Selected AbstractsEarly infection of Fagus sylvatica by Heterobasidion annosum sensu strictoFOREST PATHOLOGY, Issue 5 2008Akomy Summary Heterobasidion annosum sensu stricto is the most important damaging agent in Scots pine stands planted on the former agricultural lands in Poland. The routine action in pine stands which have lost stability because of H. annosum root rot is to change stand management, including species conversion. In many cases, the Fagus sylvatica is used for this purpose. This study was the first assessment of widespread infection by H. annosum in young F. sylvatica plantations. Disease symptoms included atrophy and yellowing of leaves, wilting and the presence of pathogen sporocarps around the root collars of young trees. Heterobasidion annosum s. s. was observed on both 4- and 17-year-old beech. Based on annual increments, the disease could be present for 3,4 years before tree death. A high incidence of H. annosum in pine stumps of previous stands (80,100%) and dry periods in recent years may be the main reasons for such common infection of F. sylvatica. This work also showed that mice and frost were not the main killing factors F. sylvatica in plantations. [source] Spatial patterns and environmental factors affecting the presence of Melampsorella caryophyllacearum infections in an Abies alba forest in NE SpainFOREST PATHOLOGY, Issue 3 2006A. Solla Summary The presence of trunk swellings caused by the rust fungus Melampsorella caryophyllacearum was systematically surveyed in an Abies alba forest (Irati, NE Spain), using 1237 circular plots (diameter = 18 m). The relationship between fungal presence and several abiotic (aspect, elevation, distance to the nearest river and slope) and biotic factors (basal area of A. alba and/or Fagus sylvatica, shrub, fern and herb cover) was assessed through correlation and ordination analyses. Additionally, the spatial pattern of the presence of diseased trees was described using Ripley's K function. Southern-aspect plots had a significantly lower presence of diseased trees than plots-oriented north, east and west. Plots with diseased trees were located at a significantly lower elevation, and at a shorter distance to the river than plots without infections. Plots with diseased trees had almost twice the average A. alba basal area, and less average F. sylvatica basal area than plots without diseased trees. However, similar mean values of slope and shrub, fern and herb cover were found in both types of plots. The disease showed spatial aggregation in patches with a mean radius of ca. 900 m. The implications of the results for disease management are discussed. Résumé La présence de renflements sur les troncs causés par l'agent de la rouille, Melampsorella caryophyllacearum, a étéétudiée de façon systématique dans une forêt d'Abies alba (Irati, NE Espagne), en utilizant 1237 placettes circulaires (diamètre de 18 m). Les relations entre la présence du champignon et divers facteurs abiotiques (orientation, altitude, distance à la rivière la plus proche, pente) et biotiques ( surface terrière de A. alba et/ou Fagus sylvatica, abondance de la couverture herbacée et abondance d'arbustes et fougères) ont étéétudiées par analyses de corrélation et d'ordination. D'autre part, la structure spatiale de la présence d'arbres infectés a été décrite en utilizant la fonction K de Ripley. Les placettes exposées au sud présentent moins fréquemment des arbres malades que celles exposées au nord, à l'est ou à l'ouest. Les placettes avec des arbres malades sont situées à une altitude significativement plus faible et à une distance plus faible d'une rivière que les placettes sans infections, et elles présentent une surface terrière 2 fois plus forte en moyenne pour A. alba, et plus faible pour F. sylvatica, que les placettes non-infectées. Toutefois, des valeurs moyennes équivalentes pour la pente, la couverture herbacée et l'abondance d'arbustes et fougères, sont observées pour les deux types de placettes. La maladie montre une agrégation spatiale en foyers d'un rayon moyen de 900 m. Les résultats sont discutés dans une perspective de gestion de la maladie. Zusammenfassung Das Vorkommen von durch den Rostpilz Melampsorella caryophyllacearum verursachten Stammdeformationen wurde in einem Abies alba - Wald (Irati, NO-Spanien) auf 1237 kreisförmigen Probeflächen (Durchmesser 18 m) systematisch erfasst. Die Beziehung zwischen dem Pilzvorkommen und mehreren abiotischen (Exposition, Meereshöhe, Distanz zum nächsten Fluss, Hangneigung) und biotischen Faktoren (Deckungsgrad von A. alba und/oder Fagus sylvatica, Strauch-, Farn- und Krautschicht) wurden durch Korrelations- und Ordinations-Analysen überprüft. Zudem wurden räumliche Muster der befallenen Bäume mit Hilfe von Ripley's K-Funktion beschrieben. In südexponierten Probeflächen kamen signifikant weniger erkrankte Bäume vor als in nach Norden, Osten und Westen orientierten Standorten. Flächen mit Befall lagen in signifikant geringerer Meereshöhe und kürzerer Distanz zum nächsten Fluss als solche ohne Befall. Zudem hatten sie beinahe die doppelte Basalfläche mit A. alba und eine durchschnittliche geringere Basalfläche mit F. sylvatica. Die durchschnittlichen Werte für die Strauch-, Farn- und Krautschicht sowie die Hangneigung unterschieden sich jedoch nicht in den Flächen mit und ohne Befall. Erkrankte Bäume waren räumlich aggregiert mit einem mittleren Radius von ca. 900 m. Die Bedeutung dieser Befunde für das Krankheitsmanagement wird diskutiert. [source] Rapid climate change-related growth decline at the southern range edge of Fagus sylvaticaGLOBAL CHANGE BIOLOGY, Issue 11 2006ALISTAIR S. JUMP Abstract Studies on Fagus sylvatica show that growth in populations toward the southern limit of this species' distribution is limited strongly by drought. Warming temperatures in the Mediterranean region are expected to exacerbate drought where they are not accompanied by increases in precipitation. We studied levels of annual growth in mature F. sylvatica trees over the last half-century in the Montseny Mountains in Catalonia (northeast Spain). Our results show significantly lower growth of mature trees at the lower limit of this species' distribution when compared with trees at higher altitudes. Growth at the lower Fagus limit is characterized by a rapid recent decline starting in approximately 1975. By 2003, growth of mature trees had fallen by 49% when compared with predecline levels. This is not an age-related phenomenon, nor is it seen in comparable populations at higher altitudes. Analysis of climate-growth relationships suggests that the observed decline in growth is a result of warming temperatures and that, as precipitation in the region has not increased, precipitation is now insufficient to ameliorate the negative effects of increased temperatures on tree growth. As the climate-response of the studied forest is comparable with that of F. sylvatica forests in other southern European regions, it is possible that this growth decline is a more widespread phenomenon. Warming temperatures may lead to a rapid decline in the growth of range-edge populations and a consequent retreat of the species distribution in southern Europe. Assessment of long-term growth trends across the southern range edge of F. sylvatica therefore merits further attention. [source] ORIGINAL ARTICLE: Towards an understanding of the Holocene distribution of Fagus sylvatica L.JOURNAL OF BIOGEOGRAPHY, Issue 1 2007Thomas Giesecke Abstract Aim, Understanding the driving forces and mechanisms of changes in past plant distribution and abundance will help assess the biological consequences of future climate change scenarios. The aim of this paper is to investigate whether modelled patterns of climate parameters 6000 years ago can account for the European distribution of Fagus sylvatica at that time. Consideration is also given to the role of non-climatic parameters as driving forces of the Holocene spread and population expansion of F. sylvatica. Location, Europe. Methods, European distributions were simulated using a physiologically-based bioclimatic model (STASH) driven by three different atmospheric general circulation model (AGCM) outputs for 6000 years ago. Results, The three simulations generally showed F. sylvatica to have potentially been as widespread 6000 years ago as it is today, which gives a profound mismatch with pollen-based reconstructions of the F. sylvatica distribution at that time. The results indicate that drier conditions during the growing season 6000 years ago could have caused a restriction of the range in the south. Poorer growth conditions with consequently reduced competitive ability were modelled for large parts of France. Main conclusions, Consideration of the entire European range of F. sylvatica showed that no single driving force could account for the observed distributional limits 6000 years ago, or the pattern of spread during the Holocene. Climatic factors, particularly drought during the growing season, are the likely major determinants of the potential range. Climatic factors are regionally moderated by competition, disturbance effects and the intrinsically slow rate of population increase of F. sylvatica. Dynamic vegetation modelling is needed to account for potentially important competitive interactions and their relationship with changing climate. We identify uncertainties in the climate and pollen data, as well as the bioclimatic model, which suggest that the current study does not identify whether or not climate determined the distribution of F. sylvatica 6000 years ago. Pollen data are better suited for comparison with relative abundance gradients rather than absolute distributional limits. These uncertainties from a study of the past, where we have information about plant distribution and abundance, argue for extreme caution in making forecasts for the future using equilibrium models. [source] The drought tolerance limit of Fagus sylvatica forest on limestone in southwestern GermanyJOURNAL OF VEGETATION SCIENCE, Issue 6 2008Stefanie Gärtner Abstract Question: What components of drought influence the drought limit of Fagus sylvatica forests? This study contributes to the ongoing discussion regarding the future of Fagus as a major component of central European forests. Location: The drought limit of F. sylvatica at its ecotone with forest dominated by Quercus pubescens, Q. petraea and their hybrids in two limestone regions (Klettgau, Schwäbische Alb) in southwestern Germany was compared. Methods: Vegetation relevés were classified and a gradient analysis was performed. The vegetation pattern was analysed with several drought relevant variables. Classification trees were used to determine the drought limits of the Fagus forest. Results: The Fagus, Quercus and the ecotone forests were floristically characterized. The lower humidity in the submontane Klettgau, compared to the montane Schwäbische Alb, was compensated for by greater soil moisture (ASWSC). Therefore, Fagus forest in the Schwäbische Alb grew on sites with ASWSC values similar to those of ecotone forest in Klettgau. Conclusions: The interaction between climatic and edaphic drought related factors demonstrates that drought is a complex edaphic-climatic factor. Both components contribute to limiting the distribution of Fagus. For the two regions in southwestern Germany, and under the existing climatic conditions, it could be shown that Fagus is able to dominate forests on soils with very low ASWSC (, 68 l.m -2). [source] Extensive spatial genetic structure revealed by AFLP but not SSR molecular markers in the wind-pollinated tree, Fagus sylvaticaMOLECULAR ECOLOGY, Issue 5 2007ALISTAIR S. JUMP Abstract Studies of fine-scale spatial genetic structure (SGS) in wind-pollinated trees have shown that SGS is generally weak and extends over relatively short distances (less than 30,40 m) from individual trees. However, recent simulations have shown that detection of SGS is heavily dependent on both the choice of molecular markers and the strategy used to sample the studied population. Published studies may not always have used sufficient markers and/or individuals for the accurate estimation of SGS. To assess the extent of SGS within a population of the wind-pollinated tree Fagus sylvatica, we genotyped 200 trees at six microsatellite or simple sequence repeat (SSR) loci and 250 amplified fragment length polymorphisms (AFLP) and conducted spatial analyses of pairwise kinship coefficients. We re-sampled our data set over individuals and over loci to determine the effect of reducing the sample size and number of loci used for SGS estimation. We found that SGS estimated from AFLP markers extended nearly four times further than has been estimated before using other molecular markers in this species, indicating a persistent effect of restricted gene flow at small spatial scales. However, our SSR-based estimate was in agreement with other published studies. Spatial genetic structure in F. sylvatica and similar wind-pollinated trees may therefore be substantially larger than has been estimated previously. Although 100,150 AFLP loci and 150,200 individuals appear sufficient for adequately estimating SGS in our analysis, 150,200 individuals and six SSR loci may still be too few to provide a good estimation of SGS in this species. [source] | ||||||||||