bluuebunny/crossref_metadata_2025 huggingface dataset:
Fertile sporophore production of Typhula phacorrhiza in the field is related to temperatures near freezing
Authors: Yang Y , Chen F , Hsiang T
Published: April 2006

Two field tests and one lab test were conducted to examine the environmental factors affecting sporophore production in Typhula phacorrhiza and to compare these results with those documented for T. ishikariensis and T. incarnata. In the 2001 lab test where lighting, soil moisture, and soil–sand media were tested in 50 mL screw-cap tubes incubated at 4 °C, the limiting factor for Typhula sporophore production was found to be moisture. In the fall 2001 field test, 100 sclerotia of six isolates from three Typhula spp. were placed into pots filled with a sand and soil mixture. The pots were monitored weekly, and maximum sporophore production for all six isolates and for watered and unwatered pots was observed at 11 weeks, which was soon after mean daily temperatures fell below 0 °C. In the second field test in fall 2003, five isolates of the three species were tested with similar procedures, but peak sporophore production was observed after 6 weeks, and again only after mean daily temperatures fell below 0 °C. In the field, sporophore production of T. phacorrhiza seems to require the same environmental cues as those of T. ishikariensis or T. incarnata, namely high moisture and temperatures near freezing.Key words: snow mold, fruiting, basidiocarp, cold.
Variation in thenodgene RFLPs, nucleotide sequences of 16S rRNA genes, Nod factors, and nodulation abilities ofBradyrhizobiumstrains isolated from ThaiVignaplants
Authors: Yokoyama Tadashi , Tomooka Norihiko , Okabayashi Masanori , Kaga Akito , Boonkerd Nantakorn , Vaughan Duncan A
Published: April 2006

The analysis of nod genes and 16S rRNA gene regions, Nod factors, and nodulation abilities of Brady rhizobium strains isolated from tropical Thai Vigna species is reported. A total of 55 Bradyrhizobium strains isolated from two cultivated and six wild Vigna species growing in central and northern Thailand were evaluated. Thai Vigna spp. Bradyrhizobium strains showed higher levels of nod gene RFLP diversity compared with Thai soybean Brady rhizobium strains or temperate strains of Bradyrhizobium japonicum and Bradyrhizobium elkanii. Analysis of the 16S rRNA gene region using selected strains also suggests a high genetic diversity of the Thai Vigna–Bradyrhizobium association. Based on thin-layer chromatography analysis, Nod factors produced by tropical Thai Vigna spp. Brady rhizobium strains are more diverse than temperate Japanese and US strains of B. japonicum and B. elkanii. Thai Vigna spp. Bradyrhizobium strains showed variation in nodulation ability and affinity, estimated by the number of normal nodules versus green nodules in an inoculation study. There are some Bradyrhizobium–host combinations that could not form any nodules, suggesting that some genetic differentiation has evolved in their host range. However, most of the Thai Vigna spp. Bradyrhizobium strains formed nodules on the cultigens soybean (Glycine max), mungbean (Vigna radiata), azuki bean (Vigna angularis), and cowpea (Vigna unguiculata). This is the first study on Bradyrhizobium strains associated with a range of cultivated and wild Vigna and reveals that these Bradyrhizobium strains are diverse and may provide novel sources of useful variation for the improvement of symbiotic systems.Key words: Bradyrhizobium, Vigna, common nod gene, 16S rRNA genes, RFLP, Thailand.
Effect of organic N source on bacterial growth, lipo-chitooligosaccharide production, and early soybean nodulation by Bradyrhizobium japonicum
Authors: Supanjani S , Lee Kyung D , Almaraz Juan J , Zhou Xiaomin , Smith Donald L
Published: April 2006

Production of Bradyrhizobium japonicum inoculants is problematic because high inoculation rates are necessary but expensive, while production of rhizobial Nod factors (lipo-chitooligosaccharides (LCOs)), key signal molecules in the establishment of legume–rhizobia symbioses, may be inhibited at high culture cell densities. We conducted experiments to determine the effects of growth medium N source on B. japonicum growth, LCO production, and early nodulation of soybean. We found that 1.57 mmol ammonium nitrate·L–1 resulted in less rhizobial growth and rhizobial capacity to produce LCOs (on a per cell basis) than did 0.4 g yeast extract·L–1, which contained the same amount of N as the ammonium nitrate. Increasing yeast extract to 0.8 g·L–1 increased rhizobial growth and LCO production on a volume basis (per litre of culture) and did not affect cell capacity to produce LCOs; however, at 1.4 g yeast extract·L–1 per cell, production was reduced. A mixture of 0.8 g yeast extract·L–1 and 1.6 g casein hydrolysate·L–1 resulted in the greatest bacterial growth and LCO production on a volume basis but reduced LCO production per cell. Changes in organic N level and source increased production of some of the measured LCOs more than others. LCO production was positively correlated with cell density when expressed on a volume basis; however, it was negatively correlated on a per cell basis. We conclude that although quorum sensing affected Nod factor production, increased levels of organic N, and specific compositions of organic N, increased LCO production on a volume basis. Greenhouse inoculation experiments showed that the medium did not modify nodule number and N fixation in soybean, suggesting that it could have utility in inoculant production.Key words: Nod factor, casein hydrolysate, yeast extract, quorum sensing.
Morphology and lipid body and vacuole dynamics during secondary conidia formation inColletotrichum acutatum: laser scanning confocal analysis
Authors: Barbosa Ariani Corrêa , Carmo Anousca Evelyn do , Graf Letícia , Tomaz Roberto , Souza Caroline Fogaça de , Mendes Jeane , Randi Marco Antonio Ferreira , Buchi Dorly , Schadeck Ruth Janice Guse
Published: April 2006

Colletotrichum acutatum may develop one or more secondary conidia after conidial germination and before mycelial growth. Secondary conidia formation and germination were influenced by conidia concentration. Concentrations greater than 1 × 105conidia/mL were associated with germination decrease and with secondary conidia emergence. Secondary conidia can form either alone or simultaneously with germ tubes and appressoria. Confocal analysis showed numerous lipid bodies stored inside ungerminated conidia, which diminished during germ tube and appressoria formation, with or without secondary conidia formation. They were also reduced during secondary conidia formation alone. While there was a decrease inside germinated conidia, lipid bodies appeared inside secondary conidia since the initial stages. Intense vacuolization inside primary germinated conidia occurred at the same time as the decrease in lipid bodies, which were internalized and digested by vacuoles. During these events, small acidic vesicles inside secondary conidia were formed. Considering that the conidia were maintained in distilled water, with no exogenous nutrients, it is clear that ungerminated conidia contain enough stored lipids to form germ tubes, appressoria, and the additional secondary conidia replete with lipid reserves. These results suggested a very complex and well-balanced regulation that makes possible the catabolic and anabolic pathways of these lipid bodies.Key words: secondary conidia, lipid bodies, vacuoles, confocal microscopy, Colletotrichum.
Application of DNA microarray technology for detection, identification, and characterization of food-borne pathogens
Authors: Kostrzynska M , Bachand A
Published: April 2006

DNA microarrays represent the latest advance in molecular technology. In combination with bioinformatics, they provide unparalleled opportunities for simultaneous detection of thousands of genes or target DNA sequences and offer tremendous potential for studying food-borne microorganisms. This review provides an up-to-date look at the application of DNA microarray technology to detect food-borne pathogenic bacteria, viruses, and parasites. In addition, it covers the advantages of using microarray technology to further characterize microorganisms by providing information for specific identification of isolates, to understand the pathogenesis based on the presence of virulence genes, and to indicate how new pathogenic strains evolved epidemiologically and phylogenetically.Key words: DNA microarrays, food-borne pathogens, detection.
Characterization of an extracellular protease and its cDNA from the nematode-trapping fungus Monacrosporium microscaphoides
Authors: Wang Miao , Yang Jinkui , Zhang Ke-Qin
Published: April 2006

To better exploit the biocontrol potential of nematophagous fungi, it is important to fully understand the molecular background of the infection process. In this paper, several nematode-trapping fungi were surveyed for nematocidal activity. From the culture filtrate of Monacrosporium microscaphoides, a neutral serine protease (designated Mlx) was purified by chromatography. This protease could immobilize the nematode Penagrellus redivivus in vitro and degrade its purified cuticle, suggesting that Mlx could serve as a virulence factor during infection. Characterization of the purified protease revealed a molecular mass of approximately 39 kDa, an isoelectric point of 6.8, and optimum activity at pH 9 at 65 °C. Mlx has broad substrate specificity, and it hydrolyzes protein substrates, including casein, skimmed milk, collagen, and bovine serum albumin. The gene encoding Mlx was also cloned and the nucleotide sequence was determined. The deduced amino acid sequence contained the conserved catalytic triad of aspartic acid – histidine – serine and showed high similarity with two cuticle-degrading proteases (PII and Aoz1), which were purified from the nematode-trapping fungus Arthrobotrys oligospora. Research on infection mechanisms of nematode-trapping fungi has thus far only focused on A. oligospora. However, little is known about other nematode-trapping fungi. Our report is among the first to describe the purification and cloning of an infectious protease from a different nematode-trapping fungus.Key words: extracellular serine protease, Monacrosporium microscaphoides, nematode-trapping fungus, nematocidal activity.
Purification and characterization of phosphotriesterases fromPseudomonas aeruginosaF10B andClavibacter michiganensesubsp.insidiosumSBL11
Authors: Das Subhas , Singh Dileep Kumar
Published: April 2006

A microbial biodegradation of monocrotophos was studied in the present investigation. The monocrotophos-degrading enzyme was purified and characterized from two soil bacterial strains. The cells were disrupted and the membrane-bound fractions were studied for purification and characterization. Solubilization of the membrane-bound fractions released nearly 80% of the bound protein. Phase separation further enriched the enzyme fraction 34–41 times. The enzyme phosphotriesterase (PTE) from both the strains was purified to more than 1000-fold with 13%–16% yield. Purified PTE from Clavibacter michiganense subsp. insidiosum SBL11 is a monomeric enzyme with a molecular mass of 43.5 kDa (pI of 7.5), while PTE from Pseudomonas aeruginosa F10B is a heterodimeric enzyme with a molecular mass of 43 and 41 kDa (pI of 7.9 and 7.35). Both purified enzymes are stable enzymes with peak activity at pH 9.0. The enzyme from strain F10B was more thermostable (half-life = 7.3 h) than that from SBL11 (half-life = 6.4 h at 50 °C), while both showed the same temperature optimum of 37 °C. Inhibitors like dithiothreitol and EDTA inhibited the purified enzyme, while p-chloromercuribenzoic acid and indoleacetic acid had a very little effect.Key words: biodegradation, monocrotophos, phosphotriesterase, Pseudomonas aeruginosa F10B, Clavibacter michiganense subsp. insidiosum SBL11.
Solubilization of potassium-bearing minerals by a wild-type strain of Bacillus edaphicus and its mutants and increased potassium uptake by wheat
Authors: Sheng Xia Fang , He Lin Yan
Published: April 2006

Two potassium (K)-bearing minerals, Nanjing feldspar and Suzhou illite, were used to investigate K mobilization by the wild-type strain NBT of Bacillus edaphicus, also labeled MPs+, selected for high activity in mobilizing potassium from minerals, and by four of its UV + LiCl mutants, MPs++, MPs+1, MPs+2, and MPs–. In liquid cultures, the five bacterial strains showed better growth on Suzhou illite than on Nanjing feldspar. Suzhou illite was the better potassium source for the growth of the wild type and the MPs++, MPs+1, and MPs+2 mutants. Solubilization of K from its sources by the wild-type NBT and the MPs++ mutant resulted mostly from the action of organic acids and capsular polysaccharides. Oxalic acid seemed to be a more active agent for the solubilization of Nanjing feldspar. Oxalic and tartaric acids were likely involved in the solubilization of Suzhou illite. The MPs– mutant did not produce any organic acid or capsular polysaccharide when grown on the above two K sources. In a pot experiment, wheat (Triticum aestivum L.) 'Yangmai-158' was grown in a yellow–brown soil that had low available K. After inoculation with bacterial strains, B. edaphicus NBT and its four mutants, MPs++, MPs+1, MPs+2, and MPs– (in separate tests), the root growth and shoot growth of wheat were significantly increased by B. edaphicus NBT and the mutants MPs++ and MPs+1. Bacterial inoculation also resulted in significantly higher N, P, and K contents of plant components. The bacteria were able to survive in the wheat rhizosphere soils after root inoculation.Key words: Bacillus edaphicus, potassium release, organic acids, potassium nutrition.
Biochemical and taxonomic characterization of bacteria associated with the crucifer root maggot (Delia radicum)
Authors: Lukwinski Angelina T , Hill Janet E , Khachatourians George G , Hemmingsen Sean M , Hegedus Dwayne D
Published: April 2006

The crucifer root maggot, Delia radicum, is an important pest of cruciferous crops; however, little is known about its digestive biochemistry or resident gut microbiota. A culturing approach was used to survey the types of micro organisms associated with eggs, midgut, and faeces of larvae feeding on rutabaga. All bacteria isolated from the midgut and faecal materials were Gram-negative bacilli. Nine types of culturable bacteria were identified within the midgut based on analysis of 60 kDa chaperonin sequences and were generally γ-Proteobacteria, primarily Enterobacteriaceae. Carbohydrate utilization patterns, select biochemical pathways, and hydrolytic enzymes were examined using the API®system for each of the nine groups, revealing an exceptionally broad metabolic and hydrolytic potential. These studies suggest that resident alimentary tract microorganisms have the potential to contribute to host nutrition directly as a food source as well as by providing increased digestive potential.Key words: Delia radicum, crucifer root maggot, midgut-associated bacteria.
Technological properties of Enterococcus faecium isolated from ewe's milk and cheese with importance for flavour development
Authors: Abeijón María C , Medina Roxana B , Katz Marta B , González Silvia N
Published: April 2006

Eight Enterococcus faecium strains isolated from ewe milk and artisanal cheese from northwest Argentina were screened for biotechnological properties relevant to flavour development. The API ZYM test showed absence of proteases, presence of high amounts of peptidases, and high esterase-lipase activities. Low extracellular proteolytic activity was observed. Most strains produced diacetyl in milk, with E. faecium OvL 214 and OvL 254 being the best producers. Biomass and growth rate increased when citrate was added to the medium, suggesting that these strains could use citrate as a main energy source. After 24 h of incubation, citrate was completely consumed in complex medium supplemented with glucose and citrate. An average of 17% residual citrate was detected in complex media supplemented with citrate. For all strains, esterase activity was detected up to α-naphthyl-caproate. They hydrolyzed α-naphthyl derivatives of fatty acids in this order: C3 > C6 > C4 > C8 > C2. Post-electrophoretic detection of esterase activities revealed the presence of multiple esterases. Hydrolysis of tributiryn, tricaprylin, and milk fat was observed in cell-free extracts. Enterococcus faecium strains isolated from ewe milk and artisanal cheese from northwest Argentina present the metabolic potential to contribute to cheese flavour development.Key words: flavour compounds, enterococci, ewe milk cheese.
Archaeal habitats — from the extreme to the ordinary
Authors: Chaban Bonnie , Ng Sandy Y.M , Jarrell Ken F
Published: April 2006

The domain Archaea represents a third line of evolutionary descent, separate from Bacteria and Eucarya. Initial studies seemed to limit archaea to various extreme environments. These included habitats at the extreme limits that allow life on earth, in terms of temperature, pH, salinity, and anaerobiosis, which were the homes to hyper thermo philes, extreme (thermo)acidophiles, extreme halophiles, and methanogens. Typical environments from which pure cultures of archaeal species have been isolated include hot springs, hydrothermal vents, solfataras, salt lakes, soda lakes, sewage digesters, and the rumen. Within the past two decades, the use of molecular techniques, including PCR-based amplification of 16S rRNA genes, has allowed a culture-independent assessment of microbial diversity. Remarkably, such techniques have indicated a wide distribution of mostly uncultured archaea in normal habitats, such as ocean waters, lake waters, and soil. This review discusses organisms from the domain Archaea in the context of the environments where they have been isolated or detected. For organizational purposes, the domain has been separated into the traditional groups of methanogens, extreme halophiles, thermoacidophiles, and hyperthermophiles, as well as the uncultured archaea detected by molecular means. Where possible, we have correlated known energy-yielding reactions and carbon sources of the archaeal types with available data on potential carbon sources and electron donors and acceptors present in the environments. From the broad distribution, metabolic diversity, and sheer numbers of archaea in environments from the extreme to the ordinary, the roles that the Archaea play in the ecosystems have been grossly underestimated and are worthy of much greater scrutiny.Key words: Archaea, methanogen, extreme halophile, hyperthermophile, thermoacidophile, uncultured archaea, habitats.
Dendroecology of American chestnut in a disjunct stand of oakchestnut forest
Authors: McEwan Ryan W , Keiffer Carolyn H , McCarthy Brian C
Published: April 2006

American chestnut (Castanea dentata (Marsh.) Borkh.) was once an important hardwood species in the forests of eastern North America. Following the chestnut blight fungus (Cryphonectria parasitica (Murrill) Barr) pandemic of the early 20th century, C. dentata remains only as sprouts throughout much of its range. We conducted a dendroecological analysis of a large naturalized stand of mature C. dentata to evaluate the species' growth capacity, ecology, and restoration potential. Eestablishment of C. dentata was sporadic in the first 40 years of our chronology, followed by a disturbance-associated recruitment pulse. The species appears to be tolerant of suppression in the understory, but responded to release with rapid radial growth (>10 mm·year1). Although its climategrowth relationships are similar to those of other hardwood species, mean radial growth of C. dentata was nearly twice that of other hardwood species found in the stand (4.7 ± 0.21 vs. 2.5 ± 0.16 mm·year1). Chestnut blight has recently infected this stand, resulting in a sharp depression in the growth chronology of C. dentata, even when outward signs of infection were not yet visible. Observed establishment and growth patterns suggest that blight-resistant C. dentata is likely to attain dominance rapidly in forests where restoration efforts include canopy manipulations that increase light availability.
Nitrogen availability in soil and forest floor of contrasting types of boreal mixedwood forests
Authors: Jerabkova Lucie , Prescott Cindy E , Kishchuk Barbara E
Published: April 2006

Boreal mixedwood forests with varying proportions of coniferous and deciduous species are found throughout the North American continent. Maintenance of a deciduous component within boreal forests is currently favoured, as deciduous species are believed to promote faster nutrient turnover and higher nutrient availability. Results of comparisons of deciduous and coniferous forests are, however, inconsistent in supporting this generalization. We compared indices of soil nitrogen (N) availability in the forest floor and mineral soil of deciduous, mixed, and coniferous stands of boreal mixedwood forest in northwestern Alberta. Deciduous stands had higher N availability, reflected by higher pools of NH4-N and inorganic N in the forest floor. Forest floors of deciduous stands also tended to have higher concentrations of microbial N but did not have higher levels of NO3-N or higher rates of net nitrification. Mixed stands showed the highest rates of net N mineralization. Soil N availability was more closely related to litter N content than to litter decomposition rate. The variation among the forest types is likely attributable to vegetation, as topography is fairly uniform, stands do not differ in soil texture, and N-availability indices correlated directly with the proportion of deciduous trees.
Effects of serial grafting, ontogeny, and genotype on rooting ofQuercus rubracuttings
Authors: Zaczek James J , Steiner Kim C , Heuser, Jr. Charles W , Tzilkowski Walter M
Published: April 2006

Bud grafts, up to three series over 3 years, were made on seedling and tree rootstocks using scions from juvenile and mature northern red oak (Quercus rubra L.). Serial grafts on juvenile rootstock used buds collected from shoots developed from grafted scions of prior years. Rooting trials were performed in years 2 and 3 with shoot cuttings developed in situ on seedlings and trees and developed from successful grafts. Without grafting, cuttings from seedlings rooted more frequently and had more roots than cuttings from trees. Significant variation within maturation groups due to genotype and ontogeny obscured absolute between-group differences. Grafting scions of juvenile origins onto seedling rootstock had little effect on percent rooting and the number of roots for cuttings. Grafting onto seedling rootstock tended to increase rooting and the number of roots for cuttings from mature origins, but the effect was not progressive with increasing grafting series. Grafting onto mature rootstock did not affect rooting of cuttings from juvenile or mature origins collected in the first growing season after grafting, but cuttings from juvenile scions collected in the second growing season exhibited reduced percent rooting compared with cuttings from seedling controls. Results suggest that northern red oak buds are predetermined in their developmental fate relative to rooting parameters and are only minimally influenced by grafting. The true effect of grafting on the subsequent rooting of cuttings may be mediated through processes other than rejuvenation.
Plant community attributes 12 to 14 years following precommercial thinning in a young lodgepole pine forest
Authors: Lindgren P M.F , Ransome D B , Sullivan D S , Sullivan T P
Published: April 2006

We investigated plant community responses (abundance, species diversity, and structural diversity) to a range of precommercial thinning densities in young lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) stands 12 to 14 years after thinning, with both unthinned and old-growth stands for comparison. Abundance of understory plants, especially herbs, appeared to increase dramatically in the thinned stands. The moss layer was significantly more abundant in old-growth stands than in the young pine stands. Of a total of 108 species sampled, only three were introduced species, all of which occurred more frequently in the low-density stands than in any of the other stands. Thinning treatments appeared to increase the abundance of late-seral species. Our results suggest that by disrupting canopy closure, thinning decreased the dominance of tall trees and increased the abundance of herbs, shrubs, and trees in the understory height classes. As a result, thinning to low densities significantly increased the structural richness of the tree layer and caused an increase in total structural diversity, which, although only marginally significant (p = 0.06), was likely biologically important. Our results suggest that thinning will enhance the abundance, species diversity, and structural diversity of the plant community 12 to 14 years postthinning.
Quantifying the coarse-root biomass of intensively managed loblolly pine plantations
Authors: Miller Ashley T , Allen H Lee , Maier Chris A
Published: April 2006

Most of the carbon accumulation during a forest rotation is in plant biomass and the forest floor. Most of the belowground biomass in older loblolly pine (Pinus taeda L.) forests is in coarse roots, and coarse roots persist longer after harvest than aboveground biomass and fine roots. The main objective was to assess the carbon accumulation in coarse roots of a loblolly pine plantation that was subjected to different levels of management intensity. Total belowground biomass ranged from 56.4 to 62.4 Mt·ha1and was not affected by treatment. Vegetation control and disking increased pine taproot biomass and decreased hardwood taproot biomass. Pines between tree coarse roots were unaffected by treatment, but hardwoods between tree coarse roots were significantly reduced by vegetation control. Necromass was substantially lower than between-tree biomass, indicating that decomposition of coarse-root biomass from the previous stand was rapid for between-tree coarse roots. Total aboveground biomass was increased by vegetation control, with the lowest production on the least intensively managed plots (180.2 Mt·ha1) and the highest production on the most intensively managed plots (247.3 Mt·ha1). Coarse-root biomass ranged from 19% to 24% of total biomass. Silvicultural practices increasing aboveground pine productivity did not increase total coarse-root biomass carbon because of the difference in root/shoot allocation between pine and hardwood species.
Welfare impacts of the 1996 United States - Canada softwood lumber agreement: an update
Authors: Zhang Daowei
Published: April 2006

This research note provides updated estimates on the market and welfare impacts of the 1996 United States  Canada Softwood Lumber Agreement (SLA). Using the aggregate price model in Zhang (2001), the anticipated change in lumber price is estimated at US$30 (based on 1997 dollars), or 7.4%, on average for the first 4 years under the SLA; this is smaller than the previous estimate. In the fifth year, the price impact was negative because of a decline in lumber demand, oversupply in the United States, and excessive supply from Canada due to the structure and expected expiration of the SLA. The consequent gains to US producers of softwood lumber and the losses to US consumers are reestimated.
Spatial information for scheduling core area production in forest planning
Authors: Wei Yu , Hoganson Howard M
Published: April 2006

Forest core area is the portion of the forested landscape that is free from edge effects from surrounding areas. Forest core area is important for specific plant communities and wildlife species. Identifying spatial interdependencies of site-specific management decisions is an important step for recognizing core area production in forest management scheduling models. A forest-wide map layer of influence zones can be used to identify the interdependencies. Each influence zone is a potential area for producing core area. Each is unique in terms of the specific combination of management units that interact to influence core area production. A raster-based approach is presented for identifying influence zones and estimating their area. Tests considered the need for precision in terms of the size of the raster cells for accurately identifying influence zones and estimating their size. Tests, using a 100 m buffer width for defining core area, show that scheduling results were relatively insensitive to gains in precision from using raster cell widths less than 30 m.
Landscape-scale spatial patterns of winter injury to red spruce foliage in a year of heavy region-wide injury
Authors: Lazarus Brynne E , Schaberg Paul G , Hawley Gary J , DeHayes Donald H
Published: April 2006

Red spruce (Picea rubens Sarg.) winter injury is caused by freezing damage that results in the abscission of the most recent foliar age-class. Injury was widespread and severe in the northeastern United States in 2003 and was assessed at multiple elevations at 23 sites in Vermont and adjacent states. This paper presents a spatial analysis of these injury assessments. Relationships between winter injury on dominant and codominant spruce trees and elevation, latitude, longitude, slope, and aspect were investigated with least squares regression and geographically weighted regression. Results of these analyses indicate that injury increased (1) with elevation; (2) from east to west; (3) with the degree to which plots faced west, except at the highest elevations, where injury was uniformly severe; (4) with increases in slope steepness at higher elevations, or with decreases in slope steepness at lower elevations; and (5) with the degree to which plots faced south, except at the highest elevations in northern locations, where injury was uniformly severe. Because injury was greater in areas that have historically received higher levels of acid and nitrogen deposition  western portions of the study region, west-facing slopes, and higher elevations  observed patterns of injury support the hypothesis that acidic and (or) nitrogen deposition act on a landscape scale to exacerbate winter injury. Greater injury on south-facing slopes suggests that sun exposure exacerbates injury or its expression.
Mountain pine beetle population sampling: inferences from Lindgren pheromone traps and tree emergence cages
Authors: Bentz Barbara J
Published: April 2006

Lindgren pheromone traps baited with a mountain pine beetle (Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae, Scolytinae)) lure were deployed for three consecutive years in lodgepole pine stands in central Idaho. Mountain pine beetle emergence was also monitored each year using cages on infested trees. Distributions of beetles caught in pheromone traps and emergence cages were compared. Each year, mountain pine beetle emergence from infested trees occurred within a 30-d period, although beetles were caught in pheromone traps over a period as long as 130 d. A large proportion of the total number of beetles caught in pheromone traps occurred prior to and following peak emergence from infested trees. Beetles caught in pheromone traps during the main emergence period from infested trees had greater whole-body lipids compared to beetles caught early and late in the flight season. Low lipid content of beetles caught before and after the main emergence period could be the result of a long-distance flight caused by fewer sources of pheromone attraction on the landscape and (or) some proportion of reemerged parents in the sample. Results suggest that pheromone traps disproportionately sample mountain pine beetle populations and that natural pheromone sources may influence the number and timing of beetles caught in synthetically baited traps.
Soil-solution chemistry in a coniferous stand after adding wood ash and nitrogen
Authors: Ring Eva , Jacobson Staffan , Nohrstedt Hans-Örjan
Published: April 2006

Wood-ash applications have been proposed to promote the long-term sustainability of forest production at increased harvest intensities. Effects of wood-ash and nitrogen (N) application on soil-solution chemistry were studied for 9 years following application in a coniferous stand in Sweden. Crushed, self-hardened wood ash was applied at 3, 6, and 9 Mg·ha1 alone, the lowest dosage both with and without 150 kg N·ha1. Pelleted wood ash (3 Mg·ha1) and N were also applied alone. The soil solution was sampled by suction cups at 50 cm depth. The crushed, self-hardened ash readily dissolved in water, as reflected in increased soil-solution concentrations of sodium and sulphate. Significant (p < 0.05) elevations were also found for potassium, calcium, aluminum, and total organic carbon. Vanadium, chromium, manganese, nickel, copper, zinc, arsenic, and lead were not significantly affected by the ash treatments, but cadmium tended to increase in the treatments with ash alone. From the fourth year onwards, the pH of the soil solution was lowered and the aluminum concentration raised in the plots given 9 Mg crushed ash·ha1. Fertilization with N alone temporarily increased concentrations of inorganic N, cadmium, aluminum, and zinc and decreased the pH. The crushed ash generally had longer lasting effects than N fertilization.
Nonparametric estimation of stem volume using airborne laser scanning, aerial photography, and stand-register data
Authors: Maltamo M , Malinen J , Packalén P , Suvanto A , Kangas J
Published: April 2006

In forest management planning and forestry decision-making there is a continuous need for higher quality information on forest resources. The aim of this study was to improve the quality of forest resource information acquired by airborne laser scanning by combining it with aerial images and current stand-register data. A k-MSN (most similar neighbor) application was constructed for the prediction of the plot and stand volumes of standing trees. The application constructed used various data sources, including laser scanner data, aerial digital photographs, class variables describing a stand, and updated old stand volumes. The ability of these data sources to predict stem volume was tested together and separately. In the airborne laser scanner data based k-MSN application, characteristics of canopy quantiles were used as independent variables. The results show that with respect to individual plot and stand volume estimation approaches, the laser-based technique is a superior one. The results were improved further when other information sources were used together with the laser scanner data. Using a combination of laser scanner data, aerial images, and class variables (on the grounds of the current forest database) improved the root mean square error (RMSE) of the estimated plot volume by 15% (from 16% to 13%) as compared to using laser scanner data on their own. When the results were averaged at the stand level, the accuracy improved considerably, but the use of other information sources together with airborne laser scanner data did not further improve the results as it did at the plot level. The RMSE of stand volume was about 6% in all data combinations where airborne laser scanning information was used. One conclusion is that making use of additional available data sources together with laser material improves the reliability of plot volume estimates. As these additional data typically mean no extra material costs (since they are available in any case), making combined use of these data and laser scanner data improves the cost efficiency of a forest inventory.
Impacts of harvesting and postharvest treatments on soil bulk density, soil strength, and early growth ofPinus taedain the Gulf Coastal Plain: a Long-Term Soil Productivity affiliated study
Authors: Carter Mason C , Dean Thomas J , Wang Ziyin , Newbold Ray A
Published: April 2006

At four sites in the Gulf Coastal Plain, mechanical whole-tree harvesting (MWT) removed more biomass and nutrients than hand-fell bole-only harvesting (HFBO). Soil compaction and loblolly pine (Pinus taeda L.) regeneration growth varied among sites. At one location, MWT increased soil bulk density by 0.1 Mg·m3, from 1.14 to 1.24 Mg·m3, with no effect on tree growth. At a second location, where bulk density increased by 0.1 Mg·m3, from 1.41 to 1.51 Mg·m3, pine growth was reduced significantly. Soil strength at 1520 cm depth increased by 0.30.5 MPa at both locations. However, where MWT reduced pine growth, herbaceous weed control mitigated the effect. Fertilization with N and P, where P was limiting, increased pine growth irrespective of other treatments. Where P was not limiting, addition of a complete fertilizer reduced the mitigating effect of weed control. Bedding reduced soil compaction without improving early tree growth; however, bedding was not tested on the two sites where soil compaction appeared to be at critical levels. Broadcast burning increased survival but reduced pine growth irrespective of harvesting method. Our results suggest that the impact of intensive management on site productivity varies among sites, is potentially accumulative, and is subject to change over time.
Exotic bark- and wood-boring Coleoptera in the United States: recent establishments and interceptions
Authors: Haack Robert A
Published: April 2006

Summary data are given for the 25 new species of exotic bark- and wood-boring Coleoptera first reported in the continental United States between 1985 and 2005, including 2 Buprestidae (Agrilus planipennis and Agrilus prionurus), 5 Cerambycidae (Anoplophora glabripennis, Callidiellum rufipenne, Phoracantha recurva, Sybra alternans, and Tetrops praeusta), and 18 Scolytidae (Ambrosiodmus lewisi, Euwallacea fornicatus, Hylastes opacus, Hylurgops palliatus, Hylurgus ligniperda, Orthotomicus erosus, Phloeosinus armatus, Pityogenes bidentatus, Scolytus schevyrewi, Tomicus piniperda, Xyleborinus alni, Xyleborus atratus, Xyleborus glabratus, Xyleborus pelliculosus, Xyleborus pfeilii, Xyleborus seriatus, Xyleborus similis, and Xylosandrus mutilatus). In addition, summary interception data are presented for the wood-associated beetles in the families Bostrichidae, Buprestidae, Cerambycidae, Curculionidae, Lyctidae, Platypodidae, and Scolytidae, based on the USDA Animal and Plant Health Inspection Service "Port Information Network" database for plant pests intercepted at US ports of entry from 1985 to 2000. Wood-associated insects were most often intercepted on crating, followed by dunnage and pallets. The five imported products most often associated with these 8341 interceptions were tiles, machinery, marble, steel, and ironware. A significantly higher proportion of the most frequently intercepted true bark beetles have become established in the United States compared with the less frequently intercepted species.
Effective heat of combustion for flaming combustion of conifers
Authors: Babrauskas Vytenis
Published: April 2006

The heat of combustion of burning trees is often used in forest-fire hazard modeling to relate mass-loss results to the heat produced; therefore reliable values are needed. Experimental results for the effective heat of combustion of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees are presented as a function of moisture content. It is also shown that during a forest fire, the effective heat of combustion does not correspond to the oxygen-bomb-test value. Instead, the value will always be lower, since the heat of combustion of char is higher than that of the pyrolysate vapors, and char mostly remains unburned during a forest fire. These are the first and only experimental results obtained from testing of actual trees. But results from benchmark testing and studies on wood products by other investigators are broadly consistent with our findings. It is further shown that moisture content has a major effect on the effective heat of combustion. A quantitative expression for the effective heat of combustion, as a function of moisture content, is obtained. Benchmark testing by earlier researchers established that generally there is only a slight species effect on the heat of combustion; therefore the present Douglas-fir results can be applied in more general forest-fire modeling.
Quantifying size-asymmetric growth among individual beech trees
Authors: Nord-Larsen Thomas , Damgaard Christian , Weiner Jacob
Published: April 2006

We modelled the growth of individual trees in populations of European beech (Fagus sylvatica L.) grown under different thinning regimes using a modified Richards equation. The effect of competition on growth was modelled by coupling the n individual equations simultaneously with a saturation term. By assuming that the growth of an individual within the population is a function of its size to a power a, a measure of the growth advantage of larger individuals (size-asymmetric growth) is provided. If a > 1, larger trees have a disproportionate advantage in growth and by inference, in competition. The degree of size-asymmetric growth, a, exceeded one in stands with large size variability and increased significantly at increasing density. This suggests that the predominant mode of competition is size asymmetric and that this size asymmetry increases with density. A measure of growth asymmetry is more informative than static measures of size inequality in understanding the growth dynamics of managed forest stands. Since a provides a measure of the relative importance of above- versus below-ground competition, it may be useful in interpreting the growth dynamics of forest stands and may provide an additional level of information for modellers of forest growth.
Effects of harvesting and soil disturbance on soil CO2 efflux from a jack pine forest
Authors: Fleming Robert L , Laporte Michael F , Hogan Gary D , Hazlett Paul W
Published: April 2006

We measured organic matter removal and soil compaction effects on soil surface CO2 efflux (F) from a jack pine (Pinus banksiana Lamb.) forest and developed an analytical framework involving multiplicative response functions to interpret response. Treatments included stem-only harvest (OM0C0), full-tree harvest (OM1C0), full-tree harvest with surface soil removal (OM2C0), full-tree harvest with surface soil removal and soil compaction (OM2C2), and uncut forest (UF). Mean F and calculated F at 10 °C under nonlimiting soil moisture conditions (F10) were greatest in treatments with intact organic surfaces and often larger in the OM2C0 than in the OM2C2. F10 showed strong linear relationships with detrital production in harvested plots, with total near-surface carbon in all plots, and was positively correlated with understory cover. F increased exponentially with soil temperature, with the most and least pronounced responses found in the UF and OM2C0 treatments, respectively. F also responded in parabolic fashion to relative soil water content. In the UF, F was often low in May because of cold soils, but subsequently attained rates equivalent to those of the OM0C0 and OM1C0, despite lower soil temperatures. Three to five growing seasons after treatment, soil temperature and moisture, together with F10, explained 71%87% of the plot-level variation in F.
Risk of extirpation for vertebrate species on an industrial forest in New Brunswick, Canada: 1945, 2002, and 2027
Authors: Higdon Jeff W , MacLean David A , Hagan John M , Reed J Michael
Published: April 2006

The risk of extirpation was assessed for 157 vertebrate species for a ca. 190 000 ha forest in New Brunswick, Canada, based on land cover in 1945, 2002, and 2027. Data from 1945, prior to intensive forest management, were derived from detailed spatial 19441947 timber-cruise data and maps. Extirpation risk was determined by species, using a categorical system called the species-sorting algorithm whereby each species was assigned to one of four risk classes based on four variables: potential abundance, proportion of the landscape suitable for occupancy, species-specific habitat connectivity, and population growth potential. Data for these variables were derived from species-specific spatial landscape assessments and published life-history parameters. Forest management from 1945 to 2002 decreased the mixed hardwoodsoftwood forest area from 37% to 18%, increased the area of tolerant hardwoods from 10% to 25%, and decreased the area of forest >70 years old from 86% to 44%. Projections for 2027 showed further declines in old softwood, hardwood, and mixedwood habitats. Twenty-seven vertebrate species were ranked as class I (highest extirpation risk) in 1945 versus 20 in 2002 and 26 in 2027; 35 species (22%) were ranked as class I at least once and 15 species in all 3 years. Sensitivity analyses demonstrated that habitat availability was the most important ranking variable for determining extirpation risk, and that changes in habitat threshold values for assigning risk scores significantly altered results. The forest was less sensitive to habitat thresholds in 1945 than in 2002 or 2027 because of greater homogeneity. Low cover of old-forest habitat, especially mixedwood in large patches with adequate connectivity, resulted from both management and natural disturbances, and was the primary factor determining extirpation risk for vertebrates on the landscape.
Suillus tomentosus tuberculate ectomycorrhizal abundance and distribution in Pinus contorta woody debris
Authors: Paul Leslie R , Chapman Bill K , Chanway Christopher P
Published: April 2006

Tuberculate ectomycorrhizae (TEM) have been observed in decaying coarse woody debris (CWD) and may play a role in the nitrogen economy of forests. This study evaluates the occurrence of Suillus tomentosus (Kauff.) Singer, Snell and Dick TEM within CWD in Pinus contorta Dougl. ex Loud. var. latifolia Engelm. stands and relates their occurrence to CWD and soil characteristics as well as stand age. TEM were more abundant in the basal end of CWD incorporated in the forest floor than in the middle and top portions. Tubercle abundance was positively correlated with moisture and texture of CWD, degree of incorporation of CWD into the forest floor, and the amount of roots within CWD. There were significantly more TEM in CWD in young stands than in old stands and on sites with granitic soils than on sites with basaltic soils. Highly degraded CWD that is well incorporated in the forest floor appears to be an important microhabitat for the formation and occurrence of TEM.
Intermediate wind disturbance in an old-growth beech-fir forest in southeastern Slovenia
Authors: Nagel Thomas A , Diaci Jurij
Published: April 2006

We studied the immediate effects of two successive storms in 1983 and 2004 in an old-growth Fagus sylvatica L.  Abies alba Mill. forest in the Dinaric Alps, southeastern Slovenia. In the 1983 and 2004 storms the density and basal area of wind-killed trees were 27.4·ha1 and 5.98 m2·ha1 and 11.2·ha1and 4.02 m2·ha1, respectively. In both storm events, mid-sized to large stems were more prone to wind mortality than small stems, and A. alba was more susceptible than F. sylvatica. In the 2004 storm, 70% of wind-killed trees were uprooted and 30% were snapped. Tree size (diameter at breast height) was more important than species in determining damage type, smaller stems being more prone to uprooting and larger stems to snapping. The combined mortality due to the two storms was similar to a decade of baseline mortality, and wind-killed trees were larger than trees that died from background mortality processes. In both storms, wind-killed trees had a clumped spatial distribution, which resulted in the formation of many multiple-tree-fall gaps up to 1500 m2 in size. We suggest that intermediate wind disturbance occurs at time intervals similar to or less than the life expectancy of most canopy tree species in central Europe, and may play a more important role in forest dynamics than previously thought.