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Scots Pine Trees (scots + pine_tree)
Selected AbstractsPhytophthora cinnamomi and other fine root pathogens in north temperate pine forestsFEMS MICROBIOLOGY LETTERS, Issue 1 2007Didier Chavarriaga Abstract A number of fine root pathogens, including Phytophthora cinnamomi, Pythium ultimum var. ultimum, Pythium undulatum, Pythium violae, Fusarium sp., and two incompletely identified Verticillium species, were isolated from soils taken from under Scots pine trees at five sites in north Scotland, including semi-natural forests and plantations. At least two root pathogens were recovered from each forest. Morphological and molecular data supported the identification of Phytophthora cinnamomi from three of the sites investigated. Isolates of Phytophthora cinnamomi, Pythium ultimum var. ultimum and an incompletely identified Fusarium sp. caused growth reductions of Scots pine seedlings, as determined by dry weight; the most virulent species were Phytophthora cinnamomi and Fusarium sp. The most severe disease symptoms were caused by a mixed inoculum containing Phytophthora cinnamomi, Pythium ultimum var. ultimum and Fusarium sp., or by the Fusarium isolate alone. These nonspecific pathogens may persist on the roots of understorey and herbaceous plants in the pine forests. [source] Distribution of early-arriving saproxylic beetles on standing dead Scots pine treesAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 2 2010í Foit 1The community composition of early-arriving saproxylic beetles on 80 standing and recently deceased Scots pine trees (Pinus sylvestris L.) was examined. 2In total, 34 species of saproxylic beetles were found, comprising at least four well-defined groups of species identified by correspondence analysis. 3Bark thickness, trunk/branch diameter and height above ground significantly affected community composition, with bark thickness being the most important factor. 4Overall, 13.7% of the variance in species composition was explained by section of the tree that was sampled, a variable that encompasses the three aforementioned parameters. [source] Feeding on roots in the humus layer by adult pine weevil, Hylobius abietisAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 4 2006Kristina Wallertz Abstract 1,The consumption by adult pine weevil, Hylobius abietis, of the bark of roots present in the humus layer was assessed in a field study conducted in southern Sweden during two years (1998 and 2002). The study sites were divided into two areas: (i) a shelterwood where 80,100 mature Scots pine trees per hectare remained after cutting and (ii) a clearcut where no trees were left. 2,On average, 3741 m2 per hectare of root bark was present in the humus layer, of which 135 m2 was not coniferous but comprised species such as bilberry and broadleaved trees. 3,The mean area debarked by pine weevils was 2.9 m2 per hectare; 2.6 m2 of conifer roots and 0.3 m2 of bilberry roots. Roots of broadleaved trees were almost never consumed. No clear preferences for roots of a specific level of vitality were observed. 4,No consistent difference between the shelterwood and clearcut was found, either in the amount of root bark area available or in the extent of root feeding by pine weevil. 5,A weak negative correlation between debarked areas on roots and seedlings was found, indicating that root feeding may have reduced damage to seedlings. 6,It is concluded that conifer roots in the humus layer constitute a major food source for the pine weevil and can be utilized for a considerable period in both clearcuts and shelterwoods. [source] Tree root and soil heterotrophic respiration as revealed by girdling of boreal Scots pine forest: extending observations beyond the first yearPLANT CELL & ENVIRONMENT, Issue 8 2003BHUPINDERPAL-SINGH ABSTRACT Limitations in available techniques to separate autotrophic (root) and soil heterotrophic respiration have hampered the understanding of forest C cycling. The former is here defined as respiration by roots, their associated mycorrhizal fungi and other micro-organisms in the rhizosphere directly dependent on labile C compounds leaked from roots. In order to separate the autotrophic and heterotrophic components of soil respiration, all Scots pine trees in 900 m2 plots were girdled to instantaneously terminate the supply of current photosynthates from the tree canopy to roots. Högberg et al. (Nature 411, 789,792, 2001) reported that autotrophic activity contributed up to 56% of total soil respiration during the first summer of this experiment. They also found that mobilization of stored starch (and likely also sugars) in roots after girdling caused an increased apparent heterotrophic respiration on girdled plots. Herein a transient increase in the ,13C of soil CO2 efflux after girdling, thought to be due to decomposition of 13C-enriched ectomycorrhizal mycelium and root starch and sugar reserves, is reported. In the second year after girdling, when starch reserves of girdled tree roots were exhausted, calculated root respiration increased up to 65% of total soil CO2 efflux. It is suggested that this estimate of its contribution to soil respiration is more precise than the previous based on one year of observation. Heterotrophic respiration declined in response to a 20-day-long 6 °C decline in soil temperature during the second summer, whereas root respiration did not decline. This did not support the idea that root respiration should be more sensitive to variations in soil temperature. It is suggested that above-ground photosynthetic activity and allocation patterns of recent photosynthates to roots should be considered in models of responses of forest C balances to global climate change. [source] Effects of growth and virulence of associated blue-stain fungi on host colonization behaviour of the pine shoot beetles Tomicus minor and T. piniperdaPLANT PATHOLOGY, Issue 1 2001H. Solheim The pine shoot beetles Tomicus minor and T. piniperda are common in the Nordic countries. Of these, T. piniperda may attack and kill living but severely stressed trees, whereas T. minor has never been reported to be individually responsible for killing live trees. Both species are associated with blue-stain fungi: T. minor with Ophiostoma canum and T. piniperda with Leptographium wingfieldii and Ophiostoma minus. The growth of these fungi was studied in phloem and sapwood of live Scots pine trees, on malt agar, and on malt agar under oxygen-deficient conditions. Leptographium wingfieldii was more virulent (i.e. caused more extensive host symptoms) grew more quickly on malt agar, and was less affected by oxygen-deficient growth conditions than either O. minus or O. canum. Ophiostoma canum was least virulent. In low-density inoculations it induced lesions similar to those induced by sterile control inoculations; it grew very slowly on malt agar and stopped growing after ,30 mm under oxygen-deficient conditions. Ophiostoma minus was intermediate in all respects. The different virulence of the blue-stain fungi associated with the two pine shoot beetles may explain the lower level of aggressiveness in T. minor. [source] | ||||||||||