bluuebunny/crossref_metadata_2025 huggingface dataset:
Inhibition of pathogenicSalmonellaenteritidisgrowth mediated byEscherichia colimicrocin J25 producing strains
Authors: Portrait V , Gendron-Gaillard S , Cottenceau G , Pons A M
Published: April 2011

For the first time, microcin-producing strains showing inhibitory activities against enteropathogen Salmonella enteritidis were isolated from poultry intestinal contents. Among the numerous strains isolated, two strains of Escherichia coli, named J02 and J03, showing the greatest activities against S. enteritidis, were studied. Biochemical tests and purification identified the main antagonist compound produced as microcin J25. In order to evaluate the protective potential of E. coli J02 and J03 against S. enteritidis infection, the ability of these strains to inhibit growth of S. enteritidis was investigated in mixed culture. A strong antagonist activity was obtained with a preculture phase of the active strain in minimal medium before incubation with S. enteritidis. In a bioreactor experiment simulating the chicken gastric and intestinal tract environment, a mixture of the two strains E. coli J02 and J03, provided an enhanced inhibitory effect. Microcinogenic strain activities were not affected by bile, pancreatic enzymes addition, or acidic conditions. These results suggest the relevant role of microcin-producing microorganisms in microbial intestinal ecology. To conclude, this study shows that microcin J25 strains could exert a beneficial protective effect against S. enteritidis growth in situ.Key words: microcin J25, Salmonella, mixed cultures.
Biological control of fusarial wilt of pigeon pea by Bacillus brevis
Authors: Bapat Sangita , Shah A K
Published: April 2011

A virulent strain of pigeon pea wilt pathogen was isolated from wilted pigeon pea plants and was identified as Fusarium oxysporum f. sp. udum. Many bacterial cultures showing antagonism to the pathogen were isolated from various ecological niches. When tested under pot and field conditions, development of fusarial wilt symptoms was prevented in pigeon pea seeds treated with one such antagonist, Bacillus brevis. A formulation of B. brevis with vermiculite as a carrier had a shelf life of at least 6 months. Bacillus brevis produced an extracellular antagonistic substance which induced swelling of the pathogen's hyphal tips, and cells were bulbous and swollen with shrunken and granulated cytoplasm. The antagonistic substance also inhibited germination of conidia, and was fungicidal to the vegetative mycelia of the pathogen. Comparison of the properties of our antagonistic substance with that of known antibiotics produced by B. brevis suggests that our antagonistic substance is a novel compound. The observations reported here indicate that this strain of B. brevis may have potential as a biocontrol agent against fusarial wilt in pigeon pea. Key words: antibiosis, Bacillus brevis, biological control, fusarial wilt, pigeon pea.
Multiple environmental factors regulate the expression of the carbohydrate-selective OprB porin ofPseudomonas aeruginosa
Authors: Adewoye Lateef O , Worobec Elizabeth A
Published: April 2011

In response to low extracellular glucose concentration, Pseudomonas aeruginosa induces the expression of the outer membrane carbohydrate-selective OprB porin. The promoter region of the oprB gene was cloned into a lacZ transcriptional fusion vector, and the construct was mobilized into P. aeruginosa OprB-deficient strain, WW100, to evaluate additional environmental factors that influence OprB porin gene expression. Growth temperature, pH of the growth medium, salicylate concentration, and carbohydrate source were found to differentially influence porin expression. This expression pattern was compared to those of whole-cell [14C]glucose uptake under conditions of high osmolarity, ionicity, variable pH, growth temperatures, and carbohydrate source. These studies revealed that the high-affinity glucose transport genes are down-regulated by salicylic acid, differentially regulated by pH and temperature, and are specifically responsive to exogenous glucose induction.Key words: Pseudomonas aeruginosa, OprB porin, glucose transport, regulation.
Chitinolytic bacteria in the minke whale forestomach
Authors: Olsen M A , Blix A S , Utsi THA , Sørmo W , Mathiesen S D
Published: April 2011

Minke whales consume large amounts of pelagic crustaceans. Digestion of the prey is initiated by indigenous bacteria in a rumen-like forestomach system. A major structural component of the crustacean exoskeleton is chitin, the β-1,4-linked polymer of N-acetyl-D-glucosamine. The exoskeletons appear to dissolve completely in the non-glandular forestomach. Bacteria in the forestomach fluid of six krill-eating minke whales were enumerated and isolated using an anaerobic habitat-simulating culture medium. Median viable population densities ranged between 6.0 × 106and 9.9 × 109bacterial cells per mL forestomach fluid. Bacterial isolates (n = 44) cultured from the forestomach fluid of one minke whale mainly resembled strains of Eubacterium (25%),Streptococcus (18%), Clostridium (14%), and Bacteroides (11%). As much as 12% of the bacterial isolates were chitinolytic, while β-N-acetylglucosaminidase activity was demonstrated in 54% of the isolates, and utilisation of N-acetyl-D-glucosamine was observed in 73%. The chitinolytic isolates resembled strains of Bacteroides, Bacteroidaceae, Clostridium, and Streptococcus. Scanning and transmission electron microscopy of partly digested krill from the minke whale forestomach revealed bacteria close to and inside the chitinous exoskeleton. The bacterial chitinase may act on the chitinous crustacean exoskeletons, thereby allowing other bacteria access to the nutritious soft inner tissues of the prey, and thus initiating its degradation and fermentation.Key words: chitinase, β-N-acetylglucosaminidase, cetacea, symbiotic microbial digestion.
Effects of iron and manganese availability on growth and production of superoxide dismutase byStreptococcus suis
Authors: Niven Donald F , Ekins Andrew , Al-Samaurai Aws A-W
Published: April 2011

A complex medium supported good growth of the type strain of Streptococcus suis irrespective of the presence or absence of a high concentration (1 mM) of the iron chelating agent, ethylenediamine di-o-hydroxyphenylacetic acid. Good growth was also obtained using a complex medium that had been treated with Chelex-100 to reduce the iron content, but only if this medium was supplemented with manganese; supplementation with iron had little effect. Collectively, these results indicate that S. suis requires manganese, but not iron, for growth. Polyacrylamide gel electrophoresis of cell extracts followed by activity staining revealed the presence of a single manganese-cofactored superoxide dismutase; activity staining and enzyme assays revealed that manganese availability during growth affected the activity of the superoxide dismutase in cell extracts. The results are discussed with respect to the capacity of S. suis to avoid damage by reactive oxygen species.Key words: Streptococcus suis, iron, manganese, superoxide dismutase.
IsFusarium culmorumisotrichodermin-15-hydroxylase different from other fungal species?
Authors: Zamir Lolita Ora , Farah Carole Abi
Published: April 2011

Fusarium spp. are ubiquitous fungi infecting cereals and grains, and therefore constitute a major problem for agriculture. Their trichothecene metabolites, and in particular deoxynivalenol and its 3-acetylated derivative, are the mycotoxins involved. The major metabolite produced by Fusarium culmorum is 3-acetyldeoxynivalenol. Studies in vivo with Fusarium culmorum have established that its tricyclic intermediate, isotrichodermin, is a major biosynthetic precursor, which is hydroxylated at position 15 to give 15-deacetylcalonectrin, prior to being converted to the product. In a preliminary in vitro investigation of the cell-free system involved in this transformation, we suggested that cytochrome P450 enzymes are not involved. In this paper, the isotrichodermin-15-hydroxylase from the microsomal fraction of Fusarium culmorum was solubilized and partially purified (60 fold). Our studies with cofactors indicate that this enzyme is a flavoprotein, and the inducers tested highly indicate that indeed the hydroxylase is not attached to cytochrome P450. This is particularly interesting, since the only other enzyme catalyzing the same reaction isolated from Fusarium sporotrichiodes is attached to cytochrome P450. Key words: trichothecene, Fusarium culmorum, cell-free system, isotrichodermin, 15-deacetylcalonectrin, flavoprotein.
The effects of ultraviolet radiation on the moderate halophileHalomonas elongataand the extreme halophileHalobacterium salinarum
Authors: Martin E L , Reinhardt R L , Baum L L , Becker M R , Shaffer J J , Kokjohn T A
Published: April 2011

Both the moderately halophilic bacterium, Halomonas elongata, and the extremely halophilic archaea, Halobacterium salinarum, can be found in hypersaline environments (e.g., salterns). On complex media, H. elongata grows over a salt range of 0.05-5.2 M, whereas, H. salinarum multiplies over a salt range of 2.5-5.2 M. The purpose of this study was to illustrate the effect that solar (UV-A and UV-B) and germicidal radiation (UV-C) had on the growth patterns of these bacteria at varied salt concentrations. Halomonas elongata grown on a complex medium at 0.05, 1.37, and 4.3 M NaC1 was found to be more sensitive to UV-A and UV-B radiation, as the salt concentration of the medium increased. Halobacterium salinarum grown on a complex medium at 3.0 and 4.3 M NaC1 did not show a significant drop in viability after 39.3 kJ·m-2of UV-A and UV-B exposure. When exposed to UV-C, H. elongata exhibited substantially more sensitivity than H. salinarum. In H. elongata, differential sensitivity to UV-C was observed. At 0.05 M NaCl, H. elongata was less sensitive to UV-C than at 1.37 and 4.3 M NaCl. Both bacteria showed some photoreactivation when incubated under visible light following both UV-A, UV-B, and UV-C exposure. Mutagenesis following UV-C exposure was demonstrated by both organisms.
Tween 80 enhanced TNT mineralization by Phanerochaete chrysosporium
Authors: Hodgson Jonathan , Rho Denis , Guiot Serge R , Ampleman Guy , Thiboutot Sonia , Hawari Jalal
Published: April 2011

The effect of a nonionic surfactant (Tween 80) on 2,4,6-trinitrotoluene (TNT) mineralization by the white-rot fungus Phanerochaete chrysosporium strain BKM-F-1767, was investigated in a liquid culture at 20, 50, and 100 mg TNT·L-1. The presence of 1% (w/v) Tween 80, at 20 mg·L-1 TNT, added to a 4-d-old culture, allowed the highest TNT mineralization level, that is 29.3% after 24 d, which is two times more than the control culture, without Tween 80 (13.9%). The mineralization of TNT resumed upon additional Tween 80 supplementation, consequently, 39.0% of the TNT was respired on day 68. Orbital agitation of the fungal culture was found detrimental to TNT mineralization, with or without Tween 80 in the culture medium. The surfactant also stimulated the growth of P. chrysosporium without any notable effect on either the glycerol consumption rate or the extracellular LiP and MnP activity levels. Respirometric assays highlighted some differences between the oxygen uptake rate of the fungal culture supplemented with or without Tween 80. Key words: 2,4,6-trinitrotoluene, TNT, surfactant, white-rot fungus, Phanerochaete chrysosporium, lignin peroxidase, manganese peroxidase.
Isolation and characterization of aPseudomonassp. strain PH1 utilizing meta-aminophenol
Authors: Kutty Razia , Purohit Hemant J , Khanna Purushottam
Published: April 2011

Pseudomonas sp. strain PH1 was isolated from soil contaminated with pharmaceutical and dye industry waste. The isolate PH1 could use m-aminophenol as a sole source of carbon, nitrogen, and energy to support the growth. PH1 could degrade up to 0.32 mM m-aminophenol in 120 h, when provided as nitrogen source at 0.4 mM concentration with citrate (0.5 mM) as a carbon source in the growth medium. The presence of ammonium chloride as an additional nitrogen source repressed the degradation of m-aminophenol by PH1. To identify strain PH1, the 16S rDNA sequence was amplified by PCR using conserved eubacterial primers. The FASTA program was used to analyze the 16S rDNA sequence and the resulting homology patterns suggested that PH1 is a Pseudomonas.Key words: m-aminophenol, resorcinol, DNA sequencing.
Stimulation of the ionic transport system in Brassica napus by a plant growth-promoting rhizobacterium (Achromobacter sp.)
Authors: Bertrand H , Plassard C , Pinochet X , Touraine B , Normand P , Cleyet-Marel J C
Published: April 2011

A plant growth-promoting rhizobacterium belonging to the genus Achromobacter was isolated from the oilseed-rape (Brassica napus) root. Growth promotion bioassays were performed with oilseed rape seedlings in a growth chamber in test tubes containing attapulgite and mineral nutrient solution, containing NO3- as N source. The presence of this Achromobacter strain increased shoot and root dry weight by 22-33% and 6-21%, respectively. Inoculation of young seedlings with the Achromobacter bacteria induced a 100% improvement in NO3- uptake by the whole root system. Observations on the seminal root of seedlings 20 h after inoculation showed that there was an enhancement of both the number and the length of root hairs, compared to non-inoculated seedlings. Electrophysiological measurements of NO3- net flux with ion-selective microelectrodes showed that inoculation resulted in a specific increase of net nitrate flux in a root zone morphologically similar in inoculated and non-inoculated plants. The root area increased due to root hair stimulation by the Achromobacter bacteria, which might have contributed to the improvement of NO3- uptake by the whole root system, together with the enhancement of specific NO3- uptake rate. Moreover, inoculated plants showed increased potassium net influx and proton net efflux. Overall, the data presented suggest that the inoculation of oilseed-rape with the bacteria Achromobacter affects the mineral uptake.Key words: Brassica napus, plant growth-promoting rhizobacteria, Achromobacter sp., mineral uptake, root morphology.
Characterization of chitinases excreted byBacillus cereusCH
Authors: Mabuchi Naoto , Hashizume Ichiro , Araki Yoshio
Published: April 2011

Bacillus cereus CH was shown to excrete chitinases into the culture supernatant when cultivated in a medium containing 0.2% colloidal chitin, whereas the removal of colloidal chitin resulted in a low activity. After concentration of the culture supernatant by precipitation with ammonium sulfate, the induced chitinases were purified by sequential chromatography. Four different chitinases, A, B1, B2, and B3 with molecular masses of 35, 47, 58, and 64 kDa, respectively, were separated. All chitinases showed similarities in their kinetic parameters when observed with colloidal chitin, including an optimal pH of 5.0-7.5, and an optimal temperature between 50-60°C. Chitinase A hydrolyzed glycol chitin and p-nitrophenyl-di-N-acetyl-beta-chitobioside at similar rates to that of colloidal chitin, whereas group B chitinases hydrolyzed both substrates in much lower rates. From analyses of the reaction products, it is most likely that chitinase A and all group B chitinases hydrolyze the substrates tested in an endo-fashion. However, group B chitinases were distinct from chitinase A in possessing high transglycosylation activity. From amino terminal sequencing, chitinases B1, B2, and B3 were shown to have almost identical sequences, which differed from that of chitinase A. The similarities in the reaction modes and amino terminal sequences among chitinases B1, B2, and B3 suggest that these chitinases may be derived from a presumptive precursor protein through C-terminal processing.Key words: Bacillus cereus, chitinase, purification, characterization.
Factors affecting the freeze-fracture morphology of in vivo polyhydroxyalkanoate granules
Authors: Sudesh Kumar , Fukui Toshiaki , Iwata Tadahisa , Doi Yoshiharu
Published: April 2011

Interesting morphologies were observed when Comamonas acidovorans containing polyhydroxyalkanoates (PHA) of various compositions was freeze-fractured at temperatures far below the glass transition temperatures of PHA. In vivo granules of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) comparatively showed the most ductility, and could be stretched extensively. Contrary to the uniform needle-type deformation shown by the poly(3-hydroxybutyrate) homopolymer when fractured at -110°C, copolymers containing 3-hydroxyvalerate units showed various deformation structures. Similar observations were made when in vivo granules of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) were freeze-fractured, although the ductility of the latter was much reduced. In addition, it was found that fracturing at -160°C resulted in decreased ductility of the PHA granules with the concomitant increase in the number of mushroom-type deformation structures. Our results suggest that PHA granules with higher resistance to freeze-fracture deformation show less ductility, and therefore produce the mushroom-type morphology. This is the first report on the freeze-fracture morphology of PHA copolymers containing short-chain-length monomers.Key words: polyhydroxyalkanoates, freeze-fracture electron microscopy, poly(4-hydroxybutyrate), Comamonas acidovorans, biodegradable plastic.
Testing accuracy of log volume calculation procedures against water displacement techniques (xylometer)
Authors: Filho Afonso Figueiredo , Machado Sebastião Amaral , Carneiro Maurício Ricardo Araújo
Published: April 2011

The accuracy of three traditional formulas to calculate log volumes (Smalian, Huber, and Newton) and three recent methods (cubic splines, centroid sampling, and overlapping bolts) were compared and tested against volumes determined by the water-displacement technique (xylometer). Fifty-two felled trees were measured in a Pinus elliottii Engelm. plantation. The accuracy of these six procedures was analyzed considering total and merchantable outside bark volumes with 1-, 2-, 4-, and 6-m log lengths. The results showed that Huber's formula was superior for all volumes and log lengths considered. Centroid and Newton had a similar performance to Huber but with some higher errors. As expected, Smalian was the procedure with the worst performance. When log lengths of 1 and 2 m were employed, all procedures used to calculate total volume presented errors lower than 4.77%. However, the errors increased when the merchantable volume involves a large top diameter (veneer volumes, for example) or for calculating volumes from trees with large diameters. The results of this and other research have shown that Huber's formula has been accurate for several species, ages, geographic regions, etc. Thus, Huber's formula could be used in the majority of circumstances with log lengths greater than 2 m, reducing drastically the costs and sampling effort.
Colonization and growth promotion of outplanted spruce seedlings pre-inoculated with plant growth-promoting rhizobacteria in the greenhouse
Authors: Shishido Masahiro , Chanway Christopher P
Published: April 2011

Seeds of two hybrid spruce (Picea glauca (Moench) Voss × Picea engelmannii Parry ex Engelm.) ecotypes were inoculated with one of six plant growth-promoting rhizobacteria (PGPR) strains previously shown to be able to stimulate spruce growth in controlled environments. The resulting seedlings were grown in the greenhouse for 17 weeks before outplanting at four reforestation sites. Inoculation with five of the six strains caused significant seedling growth promotion in the greenhouse, which necessitated analysis of relative growth rates (RGR) to evaluate seedling performance in the field. Four months after outplanting, most strains enhanced spruce shoot or root RGRs in the field, but seedling growth responses were strain specific. For example, Pseudomonas strain Ss2-RN significantly increased both shoot and root RGRs by 10-234% at all sites, but increases of 28-70% were most common. In contrast, Bacillus strain S20-R was ineffective at all outplanting sites. In addition, seedlings inoculated with four of the six strains had significantly less shoot injury than control seedlings at all sites. Evaluation of root colonization by PGPR indicated that bacterial population declines were not related to spruce growth response variability in the field. Our results indicate that once plant growth promotion is induced in the greenhouse, seedling RGR can increase by more than 100% during the first growing season in the field. However RGR increases of 21-47% were more common and may be more representative of the magnitude of biomass increases that can result from PGPR inoculation.
Shrubland fire behaviour modelling with microplot data
Authors: Fernandes Paulo M , Catchpole Wendy R , Rego Francisco C
Published: April 2011

Fire behaviour modelling has been based primarily on experiments involving the measurement of a certain number of fires, where each variable is represented by an average value per fire. The main objective of this study was to examine if data collected from a microplot sampling design could be used to derive meaningful fire behaviour models. Three burns were conducted in low shrubland of Erica umbellata Loefl., and Chamaespartium tridentatum (L.) P. Gibbs in northeastern Portugal. Wind speed and aerial dead fuel moisture content varied from 5 to 27 km/h and from 14 to 21%, respectively. Rate of spread and flame length ranged from 0.3 to 14.1 m/min and from 0.2 to 3.1 m, respectively. Rate of fire spread could be described effectively in terms of an empirical model with wind speed and fuel height as independent variables. The coefficients that describe the effects of wind speed and fuel height on fire propagation were consistent with published values for similar fuel types. Flame length was strongly related to Byram's fireline intensity. Microplot sampling is not free from methodological problems, which are discussed, but can be effectively used in field studies of fire behaviour.
Influence of millipedes on litter decomposition, N mineralization, and microbial communities in a coastal forest in British Columbia, Canada
Authors: Cárcamo H A , Abe T A , Prescott C E , Holl F B , Chanway C P
Published: April 2011

Laboratory experiments were conducted with the millipede Harpaphe haydeniana haydeniana Wood (Polydesmida: Xystodesmidae) to determine (i) its litter feeding preferences, (ii) rates of leaf litter consumption, (iii) feeding effects on available nitrogen, and (iv) functional microbial diversity. The millipede exhibited a preference for Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and, to a lesser extent, Sitka spruce (Picea sitchensis (Bong.) Carrière) litter compared with western hemlock (Tsuga heterophylla (Raf.) Sarg.) and western redcedar (Thuja plicata Donn ex D. Don) litter when given a choice. When only one litter type was provided, millipedes consumed considerably more western redcedar than Douglas-fir, Sitka spruce, or western hemlock. Among the six broadleaf species tested, paper birch (Betula papyrifera Marsh.), bigleaf maple (Acer macrophyllum Pursh), vine maple (Acer circinatum Pursh), and red alder (Alnus rubra Bong.) were consumed at much higher rates than swordfern (Polystichum munitum (Kaulf.) Presl.) or salal (Gaultheria shallon Pursh). Daily rates of conifer litter consumption ranged between 10 and 20% of the millipede's fresh biomass and may translate to 36% of the annual litter fall. Our results suggest that transformation of conifer litter into millipede frass can increase rates of litter decomposition and N mineralization, as well as influence microbial activity and diversity in coastal forests.
Stand structure, invasion, and growth dynamics of bog pine (Pinus uncinata var. rotundata) in relation to peat cutting and drainage in the Jura Mountains, Switzerland
Authors: Freléchoux François , Buttler Alexandre , Schweingruber Fritz H , Gobat Jean-Michel
Published: April 2011

A description of bog pine stands (Pinus uncinata Ramond var. rotundata (Link) Antoine) on uncut oligotrophic mires affected by drainage and nearby peat cuttings at three sites of the Jura Mountains (Switzerland) is given. In all sites, three situations were chosen: (i) central parts of the bogs, (ii) surfaces near cutting walls and bog margins, and (iii) intermediate situations. Population structures were characteristic for each situation. In the open and wet central parts of the bogs, trees were scattered, small, and uneven aged. In the intermediate situations, tree density was higher, and the stand was multilayered with taller and uneven-aged individuals. Near the edges of the bogs or close to the peat cutting walls, the trees were tall, even-aged, and younger with a high growth rate. The nonsynchronous colonization of the bog pine trees on the three sites indicates that local factors such as drainage and peat cuttings in the vicinity of the uncut surfaces were more influential than climate factors. Radial growth patterns, very similar between the sites and the various pinewood stands, and the numerous common pointer years reflect local and regional climate fluctuations. The pinewood development on uncut bogs in the Jura Mountains thus represents a recent dynamics, which is strongly linked to human activities.
Tree recruitment from burn edges
Authors: Greene D F , Johnson E A
Published: April 2011

We developed and tested a wind-dispersal model of tree recruitment into burns from living sources at the fire edge or from small unburned residual stands. The model was also tested on recruitment of serotinous Pinus banksiana Lamb. within a burn. The model assumed that source strength is proportional to basal area density and that an individual (point source) recruitment curve can be expressed as a lognormal distribution. The model made significant predictions of the recruitment curves of Engelmann spruce (Picea engelmannii Parry ex Engelm.), white spruce (Picea glauca (Moench) Voss), and balsam fir (Abies balsamea (L.) Mill.) to distances as great as 2.0 km, although it tended to underpredict Abies and overpredict Picea. The model gave significant prediction of recruitment for jack pine (Pinus banksiana) within burns with seeds derived from aerial seed banks, and of white spruce and tamarck (Larix laricina (Du Roi) K. Koch) up to 100 m from residual stands. By forestry standards, burns are poorly stocked by those species that must obligately recruit from edges. In large fires, adequate stocking by a species such as white spruce that had 5 m2/ha of basal area would be limited to about 70 m from the edge. Small residual stands are expected to supply about half of all the recruits of white spruce or fir at distances exceeding about 800 m from a nominal burn edge.
Establishment of tree seedlings and water-soluble nutrients in coarse woody debris in an old-growth Picea-Abies forest in Hokkaido, northern Japan
Authors: Takahashi Masamichi , Sakai Yoshimi , Ootomo Reiko , Shiozaki Masao
Published: April 2011

Forest floor microsite conditions and tree seedling establishment were studied at an old-growth Picea-Abies forest in Hokkaido Island, northern Japan. Tree seedlings were established abundantly on coarse woody debris (CWD) from decay class III, a class indicating moderate decay, to class V, the most advanced decay class. The height-class distribution of tree seedlings indicates that the recruitment of Picea glehnii (Fr. Schm.) Masters and Picea jezoensis (Sieb. et Zucc.) Carr. seedlings on CWD started on decay class II and was mostly restricted to CWD decay class III. Seedlings of Abies sachalinensis (Fr. Schm.) Masters also favored establishment on CWD but had a wide adaptability to most of the microsites. Although CWD functioned as a suitable seedbed, water extracts from CWD were acidic and had quite low mineral nutrient concentrations. Tree seedling establishment did not necessarily require high levels of nutrient content in microsites. Although the forest floor was largely covered by CWD, with 2056 m2·ha-1 of the total projected area covered by CWD, CWD decay class III covered only 366 m2·ha-1 of the forest floor, indicating that CWD as a functioning seedbed is limited by time and space on the forest floor.
Litter decomposition in a transect of Norway spruce forests: substrate quality and climate control
Authors: Berg Björn , Johansson Maj-Britt , Meentemeyer Vernon
Published: April 2011

We used a climatic transect of 14 stands of Norway spruce (Picea abies (L.) Karst.) at which locally collected needle litters was incubated. Our purpose was to show that climate is not necessarily the main rate-regulating factor even in a long climatic transect. The sites are found in Sweden from 56 to 66°N. There was virtually no relationship between climate (AET ranging between 371 and 545 mm) and first-year mass loss (range 19.4-32.8%). Instead, substrate quality (litter Mn concentration) explained 27% of the site-to-site variation in first-year mass loss. For the later stages of decomposition (second to fifth year), the sites could be divided into two groups; one in which lignin concentration regulated litter mass-loss rates, and one in which lignin concentration was not an important control. In this latter group, Mn concentrations were the component best correlated with litter mass loss. When combining all data, Mn concentration gave the best linear relationship. We repeated this procedure using first- to fifth-year mass-loss values and found the same pattern. We concluded that litter Mn concentrations is a key factor for Norway spruce litter decomposition because of its influence on lignin degradation and that the very early stage is short or nonexistant.
Influence of canopy structure on the understory environment in tall, old-growth, conifer forests
Authors: Pelt Robert Van , Franklin Jerry F
Published: April 2011

The effect of the spatial distribution of trees and foliage on understory conditions was examined in six tall old-growth forests along the Pacific Coast: two sites each in Washington, Oregon, and California. Detailed field measurements of crown parameters were collected on over 9000 trees encompassing over 14.5 ha in the stands. Crown parameters were used to construct a spatially explicit model useful in analyzing the variability of crown distributions in both vertical and horizontal dimensions. Sapwood measurements of over 400 trees in combination with published equations and 240 hemispherical photos were used to assess leaf area and understory light levels, respectively. Shrub and herb cover was used as a biological indicator of growing conditions in the understory. Although leaf area is often assumed to be correlated with the amount of light penetrating the canopy, this is not the case in tall, old-growth forests. The semivariance of the horizontal distribution of canopy volume was strongly correlated with shrub cover and understory light levels and was an overall predictor of canopy structure. This variability gives rise to potentially higher understory light levels and shrub cover values when compared with a forest lacking this vertical heterogeneity and may allow the stand to support a higher volume of foliage.
The contribution of beech bark disease-induced mortality to coarse woody debris loads in northern hardwood stands of Adirondack Park, New York, U.S.A.
Authors: McGee Gregory G
Published: April 2011

The objective of this study was to adjust previously published estimates of coarse woody debris (CWD) volume and basal areas in northern hardwood forests to account for elevated CWD inputs due to beech bark disease (a disease complex of the scale insect, Cryptococcus fagisuga Lindinger, and a fungus, Nectria spp., on American beech, Fagus grandifolia Ehrh.). Ratios of snags/live tree densities and downed CWD volume/live tree basal area were compared between beech and the codominant, shade-tolerant sugar maple (Acer saccharum Marsh.). The differences between the beech and the sugar maple ratios were used to define the elevated mortality from beech bark disease. Estimated volumes of downed CWD (stumps [Formula: see text] 1.0 m tall and logs), adjusted for effects of beech bark disease, were 108 ± 18 and 48 ± 11 m3·ha-1in old-growth and even-aged, 90- to 100-year-old maturing stands, respectively, representing reductions of 22 and 21%, respectively, compared with observed volumes. Similarly, snag densities were adjusted from 59.7 ± 21.7 to 41.1 ± 26.3 per hectare in the old-growth stands and from 96.3 ± 48.0 to 87.3 ± 46.5 per hectare in the maturing stands. Snag basal areas were reduced 21 and 17% from their observed values to 6.8 ± 3.5 and 3.5 ± 0.6 m2·ha-1in the old-growth and maturing stands, respectively. The adjusted CWD estimates presented here are more historically accurate and ecologically meaningful than previous observations made in diseased northern hardwood forests and, therefore, provide more appropriate target levels for managing CWD in these forest types.
Clonal and annual variation of flower production and composition of gamete gene pool in a clonal seed orchard ofPinus densiflora
Authors: Kang Kyu-Suk
Published: April 2011

The numbers of female and male strobili were assessed for 99 clones in a Pinus densiflora Sieb. et Zucc. seed orchard for four consecutive years. The data showed that differences for the production of both female and male strobili among clones were very large and statistically significant for all years examined. The most abundant quartile of clones produced 48.1 and 37.3% of the total female and male strobili, respectively, averaged over the 4-year period. Differences in female strobilus production among clones were more variable than in male. Pearson's correlations between years for flower production were positive for all combinations of years. Spearman's rank correlation coefficients between years with moderate female flowers were highly significant. Both correlations between female and male flowers were moderate and positive for all 4 years. Broad-sense heritabilities for flower production on an individual ramet basis varied from 0.19 to 0.41, while those on a clone-mean basis were much higher, from 0.57 to 0.80. Maleness index showed that sexual symmetry in good and poor flower years deviated more from the ideal panmictic situation than that in intermediate years. Parental balance curves showed that orchard clones contributed more equally to the seed crop when flower production was moderate.
Predicting the date of leaf emergence for sugar maple across its native range
Authors: Raulier Frédéric , Bernier Pierre Y
Published: April 2011

A combined winter chilling and spring warming model is presented for predicting the date for the onset of foliation of sugar maple (Acer saccharum Marsh.) trees. The model is calibrated using both local data obtained in two sugar maple stands during two consecutive years with contrasting foliation dates and data obtained from the literature and chosen to span the full range of sugar maple distribution. Despite the disparity of the data used, more than 84% of the variation for the observed foliation date is explained by the model. Forty-one days separate the earliest and the latest foliation dates, and on average, the predicted date is within an interval of ±1.5 days of the observed date. Unusual events like exceptionally cool or warm springs are also well represented by the model. The counts for chilling days and degree-days are both started on December 1, but choosing any other date between November 1 and April 1 would yield nearly as good a fit to the foliation data. Temperature thresholds for chilling days and degree-days are both set at 10°C. Although this temperature gives the best fit to the foliation data, any temperature down to about 3°C would give good results as long as both threshold temperatures are the same.
The relationship between tree diameter growth and climate for coniferous species in northern California
Authors: Yeh Hui-Yi , Wensel Lee C
Published: April 2011

The difference between actual and predicted growth rates for the conifer regions of northern California has been observed to vary with climatic changes. This study presents a method to investigate the relationship between growth and climate. Growth variations attributable to biological and cultural factors were removed by using the CACTOS (California conifer timber output simulator) program. The remaining variation was then associated with relative precipitation and temperature for the projected period and the CACTOS calibration period. Climatic data from the current and preceding years were considered. Elevation, stand density, and species were also investigated to determine their effects on the format and magnitude of the relationship between growth and climate. The results of this study, which included tests of stem analysis data taken over 15 years, indicate that growth variation is associated with the climatic changes of winter precipitation and summer temperatures for the region, in addition to biological and cultural factors. Winter precipitation and summer temperatures affect growth in the current and the subsequent years. Moreover, the relationship between climate and growth changes by densities and species. This study provides a basis for using short-term growth data to make long-term growth projections with growth adjusted to long-term climatic conditions.
Genetic gains and levels of relatedness from best linear unbiased prediction selection ofEucalyptus urophyllafor pulp production in southeastern China
Authors: Wei Xianming , Borralho Nuno MG
Published: April 2011

Breeding values for diameter at breast height (DBH), tree height (HT), relative bark thickness (BKR), and pilodyn penetration (PP) in Eucalyptus urophylla St. Blake plantations were predicted with best linear unbiased prediction (BLUP) approach. These values along with their economic weights derived from a previous study were then used to estimate economic genetic gains for three breeding objectives (pulp, woodchips, and wood volume) in southeastern China. The results showed substantial gain can be expected from selecting top 5% trees, with a reduction of up to US$35 for producing a tonne of ovendry pulp. However, actual gains can be strongly influenced by how the breeding objectives have been defined and whether the key traits have been included in the selection criteria. This study also showed that problem in the increase of coancestry associated with selection on BLUP would not be serious, with average coancestry amongst the selected population was less than 1%. More importantly, an unrestricted multiple-trait BLUP selection did not result in the same increase in relatedness in the selected population than it does for the single trait situation.
Use of false rings in Austrian pine to reconstruct early growing season precipitation
Authors: Wimmer Rupert , Strumia Giorgio , Holawe Franz
Published: April 2011

As a consequence of dry conditions, coniferous trees may produce radially smaller diameter tracheids within their tree rings before regular latewood formation starts. The resulting structures, which are commonly called false rings, have demonstrated utility as an environmental indicator. However, the climatic patterns behind false rings and their potential use in climate reconstruction models have been barely explored. The study is based on 313 Austrian pines (Pinus nigra Arn.) sampled at 29 sites in the Viennese basin, an area with low annual rainfall, extended dry periods during the growing season and usually severely cold winters. False rings relate significantly to May precipitation, and in years with higher false-ring proportions, a relationships with the combination of wet April, dry May, and wet June is often seen. In linear regressions, the presence-absence of false rings was used as a "dummy" variable and, together with earlywood width, explained 31% of variation in May precipitation. Years with high false-ring proportions were found when May precipitation was less than half its long-term average. False-ring trends during the past 100 years were closely associated with changing May rainfall pattern. Overall, false rings are shown to be a useful tree-ring feature and may be applied successfully in dendroclimatic studies, i.e., in the reconstruction of very low rainfall months in early growing seasons during pre-instrumental periods.
Phosphorus forms and related soil chemistry of Podzolic soils on northern Vancouver Island. II. The effects of clear-cutting and burning
Authors: Cade-Menun Barbara J , Berch Shannon M , Preston Caroline M , Lavkulich L M
Published: April 2011

When cedar-hemlock (CH) forests of northern Vancouver Island are clear-cut and replanted, growth of replanted trees is often poor. This growth check can be overcome with nitrogen (N) and phosphorus (P) fertilization, suggesting that it may be because of deficiencies of these elements. A widely used site-preparation tool in these forests is slash burning. Because fire is known to alter nutrient cycling in forests, this burning may be contributing to the problem of poor seedling growth. Thus, the objective of this study was to compare P in forest floor and soils from clear-cut CH stands 10 years, 5 years, and immediately after burning to P concentrations and forms in undisturbed old growth CH stands. Analytical methods included extraction and digestion procedures, fractionation and31P nuclear magnetic resonance spectroscopy. Soon after burning, an "ashbed effect" was noted, with increased pH and higher concentrations of available P in surface soil horizons. Available P concentrations and pH returned to preburn levels within 10 years. However, destruction of organic matter appeared to disrupt illuviation processes throughout the soil profile, producing long-term changes in organic matter, organic P, and organically complexed Fe and Al in lower mineral horizons. Total P concentrations were unchanged, but there was a shift from organic to inorganic P forms and changes in P forms with time at depth in the profile. These changes in P distribution and movement in the soil may contribute to the growth check observed in these forests.
Provenances and families show different patterns of relationship between bud set and frost hardiness in Picea abies
Authors: Johnsen Øystein , Skrøppa Tore
Published: April 2011

We have compared bud set and frost hardiness among Norway spruce (Piceas abies (L.) Karst.) provenances and families in two cold-acclimation regimes in a phytotron; low light intensity and high night temperatures (LL-HNT), and high light intensity and low night temperatures (HL-LNT) under shortening day lengths. Nine provenances from 59-66°N and altitude 100-700 m within Norway, and nine open-pollinated families from a single stand (61°N, 270 m elevation) were used. Both provenances and families started bud set and frost hardening earlier in LL-HNT than in HL-LNT. Correlations between the same trait expressed in two regimes were high for both bud set and hardiness at the provenance level and slightly lower at the family level. The variation among family means in bud set and hardiness was large. The differences found between the family extremes were up to 75% of those found between provenance extremes. The relationship between bud set and frost hardiness was strong among the provenance means within both environments (r = 0.92) but weak for the families (r = 0.22-0.44). Causal factors influencing phenotypic variation within traits and covariation among traits may differ for provenances and families within stands. The strong relationships among traits that are found at the provenance level cannot be generalized to the levels of families or clones.
Aboveground and belowground interactions in mixed plantations of Eucalyptus globulus and Acacia mearnsii
Authors: Bauhus J , Khanna P K , Menden N
Published: April 2011

This study investigated whether increased productivity in mixed plantations of Eucalyptus globulus Labill. and Acacia mearnsii de Wild when compared with monocultures could be explained by niche separation of the fine-root systems. For this purpose fine-root architecture, nutrient concentration, and fine-root distribution were examined in two horizons (0-15 and 15-30 cm) of mixed and pure stands. Investigations were carried out in 6.5-year-old plantations consisting of 100% eucalypts, 75% eucalypts + 25% acacia, 50% eucalypts + 50% acacia, 25% eucalypts + 75% acacia, and 100% acacia. Aboveground the two species interacted synergistically. Stem volume and tree height was highest in the 50:50 mixtures. For acacias, intraspecific competition was stronger than interspecific competition with eucalypts. Fine-root biomass and length density were similar for all species combinations, and there was no synergistic effect. The vertical distribution of fine roots and fine-root architecture were similar for acacias and eucalypts. This indicated that soil exploitation strategies may be similar, which can result in strong competition for soil resources. Fine-root nitrogen concentrations of eucalypts were highest in the 50:50 mixture. Improved productivity of mixtures appears to be a result of both canopy stratification and improved N nutrition of eucalypts through N fixation by acacias.
The impacts of broadcast burning after clear-cutting on the diversity of ectomycorrhizal fungi associated with hybrid spruce seedlings in central British Columbia
Authors: Mah Karen , Tackaberry Linda E , Egger Keith N , Massicotte Hugues B
Published: April 2011

Morphological and molecular (polymerase chain reaction  restriction fragment length polymorphism) methods were used to assess ectomycorrhiza (ECM) diversity in naturally regenerating and planted Picea engelmannii Parry ex Engelm. × Picea glauca (Moench) Voss seedlings in two recently clear-cut sites, two clear-cut and broadcast burned sites, and two mature forests (>100 years) in central British Columbia. Based on 24 characterized ECM, burning did not affect overall diversity (Shannon, Simpson, Shannon evenness, and Margalef indices). However, the occurrence and relative abundance of some ECM morphotypes varied significantly. Hebeloma and a Russulaceae type 1 were more abundant and Cenococcum was less abundant in planted seedlings from cut-burned sites compared with those from clear-cut sites. E-strain, MRA, and Amphinema were more abundant in planted seedlings from both cut-burned and clear-cut sites compared with naturally regenerating seedlings from mature sites. ECM diversity of regenerating seedlings was significantly greater in mature forests compared with clear-cut sites and was greater in planted seedlings than naturally regenerating seedlings in clear-cut sites. Molecular analysis of the internal transcribed spacer region of the nuclear-encoded ribosomal RNA gene repeat showed no significant differences among treatments or seedling type. Twenty-two genotypes were identified from eight common morphotypes: Cenococcum (one), Thelephora (two), E-strain, Tuber, Hebeloma, and Russulaceae type 1 (three each), MRA (four), and Amphinema (six). Hebeloma genotypes matched three for Amphinema; genotypes from unidentified lightly colonized tips matched those for E-strain, MRA, and Amphinema-Hebeloma.
Analysing the Finnish pulpwood market under alternative hypotheses of competition
Authors: Kallio A Maarit I
Published: April 2011

Efficient functioning of the wood market is crucial in a country where the forest sector is of strong macroeconomic importance. We investigate the possibility of noncompetitive behavior of the buyers in the Finnish pulpwood market. We simulate the buyers' behavior under alternative competition structures (perfect competition, Cournot oligopsony, and monopsony) and compare the simulated equilibria with the observed behavior in the years 19881997. In the static models the pulp industry firms are assumed to maximize their short-run variable profits either under fixed production capacity or, hypothetically, under variable capacity. The results suggest that, during the boom years, the industry has been capacity constrained, sometimes even for monopsony output. During the recession years, the actual wood prices have often been between simulated Cournot oligopsony and monopsony prices. Hence, noncompetitive behavior of the buyers is possible during the recessions. The capacity investment behavior of the industry is explored with dynamic models. The conclusions from these models depend on the price elasticity of pulpwood supply used.