bluuebunny/crossref_metadata_2025 huggingface dataset:
Gene inactivation system extension into a unique sequence outside of the II →> I insertional duplication in Aspergillus nidulans
Authors: Meilus M , Castro-Prado MAA
Published: April 2011

The first report of the gene inactivation system (GIS) in Aspergillus nidulans came from crosses involving a II Gene inactivation system extension into a unique sequence outside of the II →> I insertional duplication. Duplicated segments trigger the GIS that acts through the methylation of cytosines present within repeats. Duplicated genes are probably inactivated during the premeiotic period between fertilization and karyogamy, but reactivation may occur spontaneously or after 5-azacytidine treatment. The aim of the present study was to determine the action of GIS on a single copy gene located near a duplicated segment. Aspergillus nidulans strains bearing the Dp(II,I) duplication were used in meiotic crosses homozygous for the y+ gene and yellow (y) segregants were recovered among the progenies. Data show that the GIS can act on a closely linked gene outside the duplicated segment, promoting reversible inactivation. Reduction of ascospore numbers and viability were observed in crosses parented by duplication strains. Inactivation of the w+ gene in a w/w+ duplication strain is also shown.Key words: Aspergillus nidulans, gene inactivation, DNA methylation, chromosomal duplication.
Duplication of insertion element IS50 associated with Tn5 transposition in Azospirillum brasilense
Authors: Tripathi Anil K , Tripathi Rachna , Ganguli Abhijit , Bazzicalupo Marco
Published: April 2011

The characterization of a DNA fragment with a Tn5 insertion in a regulatory nif gene of Azospirillum brasilense is reported. Restriction endonuclease mapping, Southern hybridization with a Tn5 probe, and nucleotide sequencing revealed that IS50 had duplicated in Tn5. The duplication of an IS50 element suggests the occurrence of a replicative mechanism of transposition. A strategy, based on the bacterial ability of homologous recombination that was used to precisely eliminate Tn5 along with the duplicated IS50 element, is presented.Key words: Tn5, IS50, Azospirillum brasilense, recombinant DNA.
Biofilms, infectious agents, and dental unit waterlines: a review
Authors: Barbeau Jean , Gauthier Carl , Payment Pierre
Published: April 2011

Aquatic biofilms, which are widespread not only in nature but also in medical and dental devices, can be the source of serious nosocomial infections. In these hardy microbial communities, pathogens like nontuberculous mycobacteria, Pseudomonas aeruginosa, Legionella pneumophila, and other bacteria not only survive but proliferate and lie in wait for susceptible hosts. Not only are these organisms intrinsically resistant to high temperatures and biocides, but the biofilms they inhabit enhance their resistance. This should be of concern to infection control practitioners. The bacterial colonization of dental unit waterlines can be used as a model to investigate the problem of waterborne biofilms in health care settings.Key words: dental unit waterlines, biofilm, nosocomial pathogens, drinking water.
Naphthalene uptake by a Pseudomonas fluorescens isolate
Authors: Whitman Brian E , Lueking Donald R , Mihelcic James R
Published: April 2011

TThe uptake of naphthalene has been investigated in the metabolizing cells of Pseudomonas fluorescens utilizing [1-14C]naphthalene. The uptake displayed an affinity constant (Kt) of 11 μM and a maximal velocity (Vmax) of 17 nmol·h-1·mg-1 cellular dry weight. Naphthalene uptake was not observed in a mutant strain, TG-5, which was unable to utilize naphthalene as a sole source of carbon for growth. Uptake was significantly inhibited (~90%) by the presence of growth-inhibiting levels of either azide or 2,4-dinitrophenol and was sensitive to the presence of structural analogues of naphthalene. The intracellular levels of ATP were not significantly reduced by the presence of either azide or 2,4-dinitrophenol. The presence of alpha-naphthol was found to noncompetitively inhibit naphthalene uptake, displaying a Ki of 0.041 μM. It is concluded that the first step in the utilization of naphthalene by Pseudomonas fluorescens is its transport into the cell by a specific energy-linked transport system.Key words: naphthalene, PAH, biodegradation, transport.
Computer-assisted restriction endonuclease analysis of plasmid DNA in field strains of Salmonella enteritidis
Authors: Rychlik Ivan , Karpiskova Renata , Faldynova Marcela , Sisak Frantisek
Published: April 2011

Computer-assisted restriction endonuclease analysis of plasmid DNA in field strains of Salmonella enterica serovar Enteritidis (S. enteritidis) is described. The procedure consists of plasmid DNA purification, its digestion with restriction endonuclease TaqI, electrophoresis, charge-coupled device camera scanning of the gels, and an analysis of the restriction patterns with the software Gel Manager. The system allowed us to analyse, in detail, results of plasmid profiling in more than 600 field strains of S. enteritidis. In addition to plasmid-free and virulence plasmid only containing strains, 15 additional plasmid types were detected. All the images and detailed protocols are available at the Web site http://www.clark.cz/vri/salmon.htm.Key words: computer analysis, plasmid type, Salmonella, DNA fingerprinting, epidemiology.
Studies on pullulan extracellular production and glycogen intracellular content in Aureobasidium pullulans
Authors: Simon L , Bouchet B , Bremond K , Gallant D J , Bouchonneau M
Published: April 2011

Pullulan is a well known extracellular polysaccharidic product of the hyphomycete Aureobasidium pullulans coming into more and more frequent use in commercial and industrial applications. Nevertheless, its cellular origin and biosynthesis pathways still remain uncertain. As pullulan synthesis is increasing while glycogen production is decreasing during growth, it should be possible that the kinetics of production of both polysaccharides, whose cellular locations differ, might be correlated. To check this hypothesis, we have performed biochemical analyses and microscopic studies of the biomass removed at regular intervals during growth. The ultrastructural data have shown that glycogen units were present in all the different cellular types (conidia, swollen cells, chlamydospores) and at all the stages of cellular development. Moreover, analytical studies have shown that glycogen level is time dependent, decreasing in the early exponential stage, whereas the extracellular pullulan content increases. The correlation coefficient (r) calculated between intracellular glycogen and extracellular pullulan levels by the chi2 method suggests that these products are inversely correlated. Ultrastructural and confocal fluorescence data indicate that glycolipids could be implicated in the pullulan biosynthetic pathway.Key words: Aureobasidium pullulans, pullulan, glycogen, metabolism, microscopy.
Phosphorus forms and related soil chemistry of Podzolic soils on northern Vancouver Island. I. A comparison of two forest types
Authors: Cade-Menun Barbara J , Berch Shannon M , Preston Caroline M , Lavkulich L M
Published: April 2011

When cedar-hemlock (CH) and hemlock - amabalis fir (HA) forests of northern Vancouver Island are clearcut and replanted, growth of replanted trees is often poor on CH clearcuts but not adjacent HA clearcuts. This poor growth can be overcome with nitrogen (N) and phosphorus (P) fertilization, which suggests differences in nutrient cycling between CH and HA forests. The objective of this study was to investigate soil P in mature, uncut stands of CH and HA forests. The results suggest that there are no inherent differences in soil P concentration between the CH and HA forests. The diversity of P forms as revealed by 31P-NMR spectroscopy was typical of cool, moist acidic forests with high P immobilization. Diester phosphates were found throughout the soil profile, albeit at very low levels in the mineral horizons. Phosphorus forms and cycling were vertically stratified down the profile. Most of the P in the LF horizon was in organic forms typical of litterfall. In the more humified H horizon the P forms were more typical of soil organisms. The high C/N and C/P ratios in the LF and H horizons at the CH site are consistent with microbial immobilization. In the upper Bhf horizon, inorganic P was predominantly nonoccluded. Organic P was present, mainly as orthophosphate monoesters, which were probably adsorbed on soil colloids. In the lower Bhf horizon, most P was occluded in amorphous sesquioxides, with low levels of organic P, mainly as orthophosphate monoesters.
Estimating error in wind speed measurements for experimental fires
Authors: Sullivan A L , Knight I K
Published: April 2011

Most experimental fires, by nature, are small scale ([Formula: see text]100 m), and rate of spread measurements are taken over periods of several minutes. The aim of empirical fire modellers is to ascribe a single measure of rate of forward spread over a period to a single scalar measure of wind. The actual wind affecting the fire is unmeasurable; its value must be estimated from remote anemometry. Observation and consideration of the spatial and temporal statistics of the wind has allowed confidence limits to be placed upon the accuracy with which the measured wind reflects the wind acting on the fire front. Experimental data to verify these estimates was gathered during Project Vesta, a study into high-intensity fires in dry eucalypt forests. An equation that quantifies the accuracy of the estimate of wind affecting the fire front is given. The accuracy increases with time scale, size of the fire front, and density of anemometry. When applied to a measured wind speed taken some distance from the fire, it gives a useful estimate of the likely variation of the corresponding wind at the fire front.
Direct carbon emissions from Canadian forest fires, 1959-1999
Authors: Amiro B D , Todd J B , Wotton B M , Logan K A , Flannigan M D , Stocks B J , Mason J A , Martell D L , Hirsch K G
Published: April 2011

Direct emissions of carbon from Canadian forest fires were estimated for all Canada and for each ecozone for the period 19591999. The estimates were based on a data base of large fires for the country and calculations of fuel consumption for each fire using the Canadian Forest Fire Behaviour Prediction System. This technique used the fire locations and start dates to estimate prevailing fire weather and fuel type for each of about 11 000 fires. An average of 2 × 106 ha·year1 was burned in this period, varying from 0.3 × 106 ha in 1978 to 7.5 × 106 ha in 1989. Ecozones of the boreal and taiga areas experienced the greatest area burned, releasing most of the carbon (C). The mean area-weighted fuel consumption for all fires was 2.6 kg dry fuel·m2 (1.3 kg C·m2), but ecozones vary from 1.8 to 3.9 kg dry fuel·m2. The mean annual estimate of direct carbon emissions was 27 ± 6 Tg C·year1. Individual years ranged from 3 to 115 Tg C·year1. These direct fire emissions represent about 18% of the current carbon dioxide emissions from the Canadian energy sector, on average, but vary from 2 to 75% among years. Post-fire effects cause an additional loss of carbon and changes to the forest sink condition.
Organic acid exudation by Laccaria bicolor and Pisolithus tinctorius exposed to aluminum in vitro
Authors: Cumming Jonathan R , Swiger Troy D , Kurnik Betsy S , Panaccione Daniel G
Published: April 2011

Ectomycorrhizal fungi exhibit varying degrees of aluminum (Al) tolerance and often confer Al tolerance to their host trees. The mechanisms of Al tolerance operating in ectomycorrhizae have yet to be elucidated. We exposed cultures of Laccaria bicolor (Maire) P.D. Orton and Pisolithus tinctorius Coker & Couch to Al in vitro and assessed organic acid production and the accumulation of Al and other nutrients in mycelia. Both L. bicolor and P. tinctorius were tolerant of Al in culture media at concentrations up to 500 µM. Aluminum did not significantly alter patterns of organic acid exudation in L. bicolor. Exposure to Al changed organic acid exudation profiles of P. tinctorius, altering patterns of tartrate, glycolate, and formate production and inducing oxalate production. Although growth was unaffected by Al in media, the concentrations of Ca, Mg, and Fe in mycelia were significantly reduced by exposure to Al in both species. The concentration of Al in mycelia increased with media Al concentration, with P. tinctorius accumulating four times more Al than L. bicolor. These results suggest that organic acid production may not be involved in Al tolerance in these ectomycorrhizal fungi, since patterns of exudation were not affected by Al in L. bicolor and the production of oxalate by P. tinctorius was ineffective at ameliorating Al-induced changes in ion accumulation by mycelia of this species.
Relation between Collybia fusipes root rot and growth of pedunculate oak
Authors: Marçais Benoit , Caël Olivier
Published: April 2011

Collybia fusipes (Bull. ex Fr.) is the cause of a root rot on oak, mainly pedunculate oak, Quercus robur L., and northern red oak, Quercus rubra L. The disease is associated with a deterioration of the crown of affected trees in some, but not all, stands. We investigated the relationship between the level of root damage induced by C. fusipes and past growth of the infected trees at four sites of pedunculate oaks and one site of red oaks in northeastern and central France. The severely infected oaks showed poor growth for 1550 years depending on the site. At one site where C. fusipes was not associated with a deterioration of the affected tree crowns, the basal area increments of severely root damaged oaks has nevertheless been poor for more than 30 years. Severe infection by C. fusipes was associated with a 3050% reduction of basal area increment in the last 10 years preceding the study at all the sites. In contrast, in all the sites, trees lightly damaged by C. fusipes had basal area increments similar to the undamaged trees. The data would be consistent with a disease that develops slowly on vigorous trees and affects their growth only late in the infection process.
Feasibility of estimating stem size distribution from measurement on the largest trees in even-aged pure stands
Authors: Osawa Akira , Abaimov Anatoly P
Published: April 2011

Reconstruction of the size distribution of trees in stands provides critical information for assessing the effects of environmental changes on forests and for forest management. For furthering a method of such reconstruction, feasibility of estimating size distribution in stem volume from measurement of the largest trees was examined for even-aged pure stands of Pinus banksiana Lamb.and Larix gmelinii (Rupr.) Rupr. We tested what percentage of the largest trees should be included in obtaining a frequency distribution in stem volume that is not statistically different from the observed size distribution patterns. The 3/2 power, beta-type, and adjusted beta-type distribution functions were applied. Comparison of the observed stem frequencies and those estimated from measurement of the largest trees in a stand suggested that (i) the 3/2 power distribution, beta-type distribution, or adjusted beta-type distribution may be used for reconstruction of stem size variation in pure stands, if the overall size variation could be approximated by one of these functions; (ii) we can be at least 95% sure that the tree size pattern be expressed successfully with the 3/2 power distribution with tree samples of only the largest 20% in the stand, or with the beta-type distribution with the largest 30% in the stand; and (iii) the reliability decreases somewhat for the adjusted beta-type distribution. The second observation implies that reconstruction of the temporal changes in stand structure may be reliable up to the time when the stand density was about five times that of the trees used for fitting the 3/2 power distribution curve. Reliability may be warranted up to the stand density of about three times as the number of trees used for fitting the beta-type distribution. Other considerations and limitations are also discussed.
Frost heaving in a boreal soil in relation to soil scarification and snow cover
Authors: Bergsten Urban , Goulet France , Lundmark Tomas , Löfvenius Mikaell Ottosson
Published: April 2011

Vertical uplift of seedlings and rods on the soil surface and at a depth of 5 cm, and of reference trees, was monitored using a theodolite from autumn to spring in two adjacent field experiments on a silt soil in northern Sweden. Treatments involving scarification (control and square patches of 0.1, 0.2, 0.4, and 0.8 m at natural snow cover) and snow cover (simulated maximum cover, snow free, and natural cover for control and 0.4-m patches) were compared. For snow free and natural snow cover, diurnal variation of soil surface temperature, duration and magnitude of freezing temperatures, and uplift increased with patch size. At the end of the winter under natural snow cover, uplift of the soil surface and shallow soil was between 4.4 and 5.3 cm for the control treatment without scarification and the 0.1-m patch while the uplift for the 0.4- and 0.8-m patches reached 7.611.5 cm. The highest uplift value, 14.6 cm, was observed for the snow-free treatment with 0.4-m patches. Maximum uplift of trees averaged 4.4 cm, which was similar to values observed for seedlings and rods with an intact humus layer and a natural snow cover, indicating that the highest observed uplift was mainly due to needle and soil surface ice. In conclusion, size of the scarified area and duration and thickness of snow cover largely influence frost heaving of tree seedlings in a susceptible soil.
Shoot fluctuating asymmetry: a new and objective stress index in Norway spruce (Picea abies)
Authors: Kozlov Mikhail V , Zvereva Elena L , Niemelä Pekka
Published: April 2011

We showed that difference in length of two opposite second-order lateral shoots on first-order branches of Norway spruce (Picea abies (L.) Karst.) can be classified as fluctuating asymmetry (FA). The FA was higher (i) in trees from a heavily polluted site than in trees from an unpolluted site, (ii) in shaded trees from the understorey of a dense stand than in trees from an open site, and (iii) after needle clipping (simulated herbivory). This is the first study to demonstrate that FA of woody plants can be assessed by measuring skeletal elements (branches) rather than photosynthetic organs (leaves or needles). Our finding significantly improves the possibilities to study plant developmental stability, in particular by allowing fast and accurate assessment of the past stress levels by using information stored in branch architecture. We concluded that FA based on shoot measurements is a practicable objective stress index in Norway spruce.
Temperature thresholds of shoot elongation in provenances of Pinus contorta
Authors: Chuine Isabelle , Aitken Sally N , Ying Cheng C
Published: April 2011

Periodicity of shoot elongation in seedlings of Pinus contorta Dougl. ex Loud. was assessed during one growing season in two extremely different environments (Cowichan Lake, and Red Rock, British Columbia) for 109 provenances sampled range wide. Analysis of variance of total elongation and growth parameters showed significant differences among geographic regions and among provenances within each region. Our study also revealed tremendous genotype-by-environment interaction for growth and phenological traits. The response of growth to temperature of each provenance was assessed from their growth curve using an original methodology. The estimated temperature threshold of the provenance growth responses (i.e., the temperature for which the response reaches half of its maximum) varied between 4.1 and 6.5°C among regions. Threshold temperatures showed less variation than total elongation, and only the northern provenances showed thresholds significantly different from the other regions. Our results show that, across highly contrasting environments, relationship between phenology and growth may not be as important as the relationship between growth and number of internode priomordia. This tempers the results of studies, carried out in one or few similar environments, that have shown that phenological differences were important in determining total height growth in lodgepole pine.
Water relations, cuticular transpiration, and bud characteristics of air-slit containerizedPicea glaucaseedlings in response to controlled irrigation regimes
Authors: Stowe Debra C , Lamhamedi Mohammed S , Margolis Hank A
Published: April 2011

White spruce seedlings (Picea glauca (Moench) Voss) were grown in air-slit containers (IPL 25-350A) in a tunnel under four different irrigation regimes (IR-15%, IR-30%, IR-45%, and IR-60%, v/v; (cm H2O)3·(cm substrate)3). At the end of the first growing season the water-relation variables of the shoots were determined. Seedling morphology, the rates of cuticular transpiration and terminal bud development, as well as the number of needle primordia were also measured. Irrigation regime had no significant effect on any of the water-relation variables. Seedlings grown under the IR-15% were smaller and completed bud development more quickly than seedlings grown under IR-30%, IR-45%, and IR-60%. The formation of needle primordia was enhanced under IR-30%. Both the irrigation regime and the amount of time the detached shoots were left to transpire had a significant effect on the rate of cuticular transpiration. A comparison of the water-relation variables at the end of the first (1998) and second (1999) growing seasons showed that the younger seedlings had more negative osmotic potential at tissue saturation and greater maximum modulus of elasticity values. None of the other water-relation variables were significantly affected by seedling age, but the absolute values of all the variables were greater in the younger (1+0) seedlings.
Prospects for the Mass Production of Improved Stock of Forest Trees by Cell and Tissue Culture
Authors: Durzan D. J. , Campbell R. A.
Published: April 2011

An annotated chronological bibliography of cell and tissue culture studies with forest tree species is presented. The current status of cell and tissue culture as a tool for tree improvement is considered against the background of work with other plant species. Techniques and strategies which have been used to induce differentiation in plant cultures are outlined. The main methods seem to be sequential treatments of growth regulators or nutrients, simplification of media, and growth regulator balances. Additional unexploited treatments such as spatial and temporal gradients, and environmental variables are suggested. There is a new prospect of adding traits and producing genetic combinations which could not be obtained by sexual crossing. This would involve mutation, transcession, transduction, transformation, and somatic cell hybridization. Invitro methods can also be used in forestry for preservation of gene resources, production of homozygous specimens, prediction of phenotypic expression, production of disease-free specimens, study of host-parasite relations, and study of mycorrhizae. We conclude that cell and tissue culture has a great potential value to forestry.
Seasonal Changes in Phenol-bound Sugars in Bark of Some Deciduous Forest Trees
Authors: Parker Johnson
Published: April 2011

The prominent phenol-bound sugars in bark of the five tree species studied declined from winter to summer on a fresh, but not on a dry weight basis. Rhamnose was the phenol-bound sugar occurring in greatest quantity in Quercusvelutina and Caryaglabra, xylose in Betulalenta, and glucose in Fraxinusamericana and Acersaccharum. Glucose was a common phenol-bound constituent of all these species. Rhamnose, bound to phenols in Quercusvelutina, made up as much as 2.5% of fresh weight in winter. Galactose and fructose, found in hydrolyzed ethanol–water extracts, originated largely from oligosaccharides.
Suggestions and Criteria for More Effective Regression Sampling
Authors: Demaerschalk J. P. , Kozak A.
Published: April 2011

Techniques are developed for more effective sampling for simple linear regression, making use of the relative frequency distribution of the observations over the range of the independent variable. A basis for testing the efficiency of a given sampling design is also provided.
Economic Implications of Stocking and Budworm Attacks for Jack Pine Management
Authors: Rose Dietmar W.
Published: April 2011

Regional growth and supply projections under selected management alternatives are crucial in planning necessary steps to meet increasing demands on a shrinking timber resource base. Knowledge about the growth and stocking conditions of second-growth stands is essential in such long-term projections especially if large geographical areas are considered. Two second-growth stocking assumptions were selected to illustrate the effect of stocking on management variables for the jack pine (Pinusbanksiana Lamb.) inventory of northwestern Wisconsin and to indicate plausible ranges for future growth, growing stock, and harvest volumes. These stocking effects were studied in a deterministic environment and with the occurrence of stochastic infestations of jack pine budworm (Choristoneurapinuspinus Freeman). The analysis illustrated the strong sensitivity of system's variables to assumptions about stocking for two contrasting rotation alternatives. The sensitivity of the model was increased considerably when budworm infestations were simulated because jack pine budworm populations movements are strongly influenced by the stocking conditions of the host stand. Policies were identified for which more reliable projections of minimum expected growth and yields are possible than for presently-used policies for jack pine in the Lake States.
A Simple Technique for Seed Transfer in X-ray Analysis of Seed
Authors: Wang B. S. P.
Published: April 2011

Using X-radiography both for the follow-up study of germination and the correlation of tree seed germinability with embryo and endosperm (or megagametophyte) development often involve seed transfer by hand. Such a procedure is tedious and time-consuming and errors of seed displacement occur frequently. Conventional germination procedures also make counting germinants and evaluating seedling vigor difficult due to the shifting of positions of germinating seeds. A simple technique of using a combination of mechanized vacuum counting plate and perforated Plexiglas templates was devised to overcome these difficulties. It decreased by 40 times the time needed to transfer 400 seeds by hand. It also reduced errors of seed displacement.
Potassium et magnésium: deux éléments limitant la croissance en hauteur du pin rouge au Québec
Authors: Phu Truong Dinh
Published: April 2011

Relations between the site index of red pine (Pinusresinosa, Ait.) and foliar concentrations in N, P, K, Mg, Ca, and Mn, the soil content in O.M., total N, available P, exchangeable K, HNO3 extractable K, exchangeable Mg and Ca, and the percentage of silt plus clay of 23 sample plots on fluvio-marine or associated deposits in the St-Lawrence plain were studied. The site index varies between 28 and 42 at 20 years b.h. There are significant and positive linear correlations between the site index and concentrations in K, Mg, and Ca in the needles. The linear correlation for Mn is significant but negative. However, multiple regression analysis indicate that only potassium and magnesium were significantly associated with the regressions.There are significant and positive linear correlations between the site index and the soil content in HNO3 extractable K, exchangeable K and Mg. However, multiple regression analysis indicate that only HNO3 extractable K has a significant contribution to variations of site index and the contribution of exchangeable Mg is almost significant at 0.05. There are also significant and positive linear correlations between the foliar concentrations of potassium and magnesium and the respective soil contents in HNO3 extractable K and exchangeable Mg. Height growth of red pine in St-Lawrence plain is closely related to the nutrient status of potassium and magnesium in the sites under investigation.
Effect of Thinning on the Production of High-quality Wood in a Quebec Northern Hardwood Stand
Authors: Roberge M. R.
Published: April 2011

In 1963, two intensities of thinning were carried out in a 60-year-old northern hardwood stand of fire origin. Yellow birch (Betulaalleghaniensis Britt.) made up as much as 40% of the total number of trees 9 cm d.b.h. and up. By 1973, both sugar maple (Acersaccharum Marsh.) and yellow birch had responded to thinning, the former more than the latter. The percentages of yellow birch trees had not changed regardless of treatment. There were between 120 and 129 trees/ha of the 25–39 cm diameter class in the unthinned as well as in the thinned areas. Basal area of the trees 9 cm d.b.h. and up had increased by 5.4, 7.6, and 8.1 m2/ha in the unthinned, 20% thinned, and 40% thinned area, respectively. A decrease in stem quality was not observed, even at the 40% thinning intensity. Both thinning intensities were thus successful except that they somewhat favored sugar maple at the expense of yellow birch.
Effects of cold- and warm-water extractives from decayed and nondecayed western hemlock heartwood on the growth of Fomesannosus
Authors: Edmonds R. L.
Published: April 2011

Western hemlock (Tsugaheterophylla (Raf.) Sarg.) heartwood is extremely susceptible to decay by Fomesannosus (Fr.) Karst. Cold-water extracts from nondecayed heartwood mildly inhibited growth of F. annosus in culture, but cold-water extracts from incipient and advanced decayed heartwood stimulated growth slightly. Compounds in cold-water extracts were not identified. Warm-water extracts generally stimulated growth of F. annosus. Phenolic compounds that were extracted by warm-water treatments from nondecayed heartwood were catechin, leucocyanidin, hydroxymatairesinol, and matairesinol. Ultraviolet spectrophotometry and paper chromatography revealed that F. annosus was capable of modifying and (or) utilizing these phenolic compounds. However, concentrated leucocyanidin in culture slightly inhibited growth of F. annosus. The high susceptibility of western hemlock heartwood to decay by F. annosus is apparently related to the absence of strongly fungitoxic heartwood extractives.
Association of western white pine cone crops with weather variables
Authors: Eis S.
Published: April 2011

Twenty-one-year records of western white pine cone counts were analyzed with seven meteorological variables to find if any combinations of available weather factors were associated with the induction of reproductive buds and successful development of the strobili. The weather in three periods before the physical initiation of the potentially reproductive cycle showed association with cone counts: (1) sunny weather in June, 39 months before cone maturation; (2) warm, sunny, dry weather in September and October, 36 and 35 months before cone maturation; and (3) warm, sunny, dry weather with wide daily temperature range in June and July, 27 and 26 months before cone maturation, appeared to promote differentiation of potentially reproductive buds. During and after the initiation of bud primordia, the weather in four periods appeared to be associated with cone production: (1) warm and possibly wet weather in August, September, and October, 25 to 23 months before cone maturation; (2) rain in the third quarter of July, 4 weeks after pollination and 14 months before cone maturation; (3) warm temperatures in September, October, and November, 12 to 10 months before cone maturation; and (4) sunny, warm, dry weather in May, 4 months before cone maturation, appeared to be beneficial to cone development.
Effets d'un engrais chimique sur la croissance de semis d'épinette noire en godets
Authors: D'Aoust André L.
Published: April 2011

Growth of Piceamariana (Mill) BSP seedlings was studied under greenhouse conditions. A fertilization regime from a balanced commercial fertilizer in solution was tested with two containers of different diameter. The best results were obtained with weekly addition of balanced macroelements and microelements equivalent to 50–100 ppm of total nitrogen. Although roots were always longer than the shoots, fertilization resulted in the accumulation of dry matter in the shoots. An adequate fertilization regime, for a short growing period, counteracted the small dimension of the Walters bullet (23 cm3) as compared with the 'Plantube' which has a volume of 180 cm3.
A low-cost unit for measuring carbon dioxide evolution from organic matter under field conditions
Authors: Piene Harald , Cleve Keith Van
Published: April 2011

A chamber was constructed and tested to determine respiration rates from forest floor L-layer material under field conditions. Seasonal trends in CO2 evolution closely followed seasonal trends in moisture content in the organic matter. Maximum respiration rates were encountered over a moisture range from about 65 to 100%.During laboratory calibration tests, no depression of respiration rates as a result of oxygen depletion in the chambers was detected except at 32 °C, where depression occurred after about 6 h incubation. Regardless of temperature, the KOH in the chambers absorbed nearly all (99.6 to 100%) of CO2 that evolved during incubation periods of up to 48 h duration.
Effects of exposure on water relations and photosynthesis of western hemlock in habitat forms
Authors: Keller R. A. , Tregunna E. B.
Published: April 2011

Measurements of relative turgidity, transpiration rates, and photosynthetic rates on sun-grown and shade-grown western hemlock (Tsugaheterophylla (Raf.) Sarg.) were used to indicate effects of varying degrees of exposure.The sun-adapted form had low photosynthetic rates but maintained its water content under conditions of high evaporative demand. The shade-adapted form desiccated under exposed conditions, and in contrast with the sun-adapted form, its water vapour diffusion resistance decreased with increasing light intensity.
Méthode d'évaluation de la protection accordée au sapin baumier par les pulvérisations aériennes contre la tordeuse des bourgeons de l'épinette
Authors: Dorais Louis G. , Hardy Yvan J.
Published: April 2011

An index (I) based on the presence of apical buds and defoliation of the current growth is proposed to measure the vigor of balsam fir, Abiesbalsamea Mill., trees attacked by the spruce budworm, Choristoneurafumiferana (Clem.). This index is used to evaluate in terms of foliage protection the efficacy of aerial spray programs conducted against the spruce budworm. By comparing the index (I) as measured before and after treatment, the annual loss of vigor (PVA) observed on balsam fir is established, while a comparison of the annual loss of vigor inside and outside the spray areas leads to an appreciation of the overall protection (P) to the trees by the spray operation.
Mise au point d'un test rapide de germination des faînes (Fagussylvatica)
Authors: Bonnet-Masimbert Marc , Muller Claudine
Published: April 2011

The use of gibberellic acid (GA3) to break dormancy has enabled us to develop a new and quick germination test for Fagussylvatica L. nuts. The test procedure involves removing the external pericarps, sterilizing the nuts, removing the internal coats, and germinating the bare nuts on cotton wool moistened with a solution of GA3 (200 mg/l) in darkness at 20 °C. Under these test conditions, it was possible to obtain good results after 3 to 4 weeks as compared with those obtained after 3 to 4 months by conventional methods.
Epidemiology of comandra rust on jack pine and comandra in Minnesota
Authors: Bergdahl D. R. , French D. W.
Published: April 2011

In the greenhouse, comandra plants (Comandraumbellata (L.) Nutt. ssp. umbellata Piehl) inoculated with aeciospores of Cronartiumcomandrae Pk. became infected after only 6 h in a mist chamber. Plants became infected if misting was not delayed more than 8 days after inoculation with aeciospores.Rust developed on comandra more rapidly in open areas than in shaded areas. In open areas in the field, uredia occurred as early as May 17, and telia, as early as June 30. Some uredia were present until about July 28 and telia were present up to mid-August, by which time rust-infected comandra leaves had abscissed.Aeciospores were produced as early as May 13 on all twig, limb, and main-stem infections, but peak aeciospore production coincided with jack pine (Pinusdivaricata (Ait.) Dumont = P. banksiana Lamb.) pollination. Rodent damage to rust infections was associated with production of spores, especially of pycniospores. The period of maximum infection on 4-week-old pine seedlings occurred from mid-July through mid-August. The 4-week-old pine seedlings exposed during this period had up to 4.4 times more infection than older seedlings.
Seedling input, death, and growth in uneven-aged northern hardwoods
Authors: Leak William B. , Graber Raymond E.
Published: April 2011

Seedling input, death, and diameter growth equations, covering a broad range in stand densities, were developed from short-term remeasured plot data in northern hardwood stands in New Hampshire. Long-term simulated changes in stand structure based on these equations exhibited logical constrained behavior.
A comparative study of crosses between and within two geographically diverse sources of eastern Cottonwood
Authors: Dhir N. K. , Mohn C. A.
Published: April 2011

Eastern cottonwood sources of Minnesota (Mn.) and Missouri (Mo.) origin were latitudinally the most diverse seed sources among the material identified to be adapted to Minnesota growing conditions by an earlier study. Crosses were made within and between these two sources to form four experimental populations: Mn. (seed parent) × Mn. (pollen parent), Mn. × Mo., Mo. × Mn, and Mo. × Mo. Greenhouse performance of these populations was evaluated on the basis of seven traits. The four populations showed significant differences in all traits and the between-sources crosses group was generally found to have a higher performance level (heterosis) than within-source crosses group. The two populations within each of the two groups also differed from each other in most traits. The crossbred progenies of the two sources were suggested to have potential as additional or alternate base populations for eastern cottonwood improvement.
Balsam fir death and deterioration in eastern Canada following girdling
Authors: Basham J. T. , Hudak J. , Lachance D. , Magasi L. P. , Stillwell M. A.
Published: April 2011

Balsam fir (Abiesbalsamea (L.) Mill.) trees lived from 2 to 30 months following girdling in five regions of eastern Canada. Girdled trees died fastest in the eastern Ontario plot (2 to 16 months), whereas in Newfoundland all of the 22 girdled trees were still alive 1 year after girdling; these regional variations were related to precipitation during the growing season, the length and mean temperature of the growing season, and to the level of bark beetle populations. Once dead, the sapwood of balsam fir in the three easternmost provinces developed sap stain more extensively than in western and eastern Ontario; however, the sapwood of trees in the latter areas was affected by sap rot far more rapidly than those in New Brunswick, Quebec, and Newfoundland. The principal cause of these observed differences appears to be regional differences in intensity of attack by the three major insects that invade weakened and dead balsam fir, which in turn may at least partly be due to regional climatic differences. The results of this study can be used as an aid in predicting the rate and pattern of deterioration of killed balsam fir in connection with salvage operations in eastern Canada.
An improved method for extraction of indole-3-acetic acid from shoots of Douglas fir
Authors: Deyoe David R. , Zaerr Joe B.
Published: April 2011

Comparison of extraction by diethyl ether solvent and by centrifugation into 20% methanol has revealed that the latter method was more effective in removing indole-3-acetic acid (IAA) from terminal and primary lateral shoots of Douglas fir (Pseudotsugamenziesii (Mirb.) Franco). The quantity of endogenous IAA extracted by centrifugation was 1.38 mg/kg and 2.36 mg/kg fresh weight for spring 1972 and spring 1971 collections, respectively, compared with 0.68 mg/kg and 0.72 mg/kg fresh weight acquired by the classic method of solvent extraction in diethyl ether. Centrifugation was rapid and provided an extract essentially free of pigments and interfering plant constituents, which permitted more efficient preparation of extracts for analysis by gas–liquid chromatography and mass spectrometry. The quantity of IAA present and its seasonal fluctuation in Douglas fir were verified.
Evaluation of chemically controlling the collembolan Bourletiellahortensis on germinating Sitka spruce and western hemlock in the nursery
Authors: Marshall V. G. , Ilnytzky S.
Published: April 2011

Three concentrations of the insecticides diazinon, fonofos, malathion, and oxamyl and one concentration of the herbicidal mineral oil Shell AWK No. 1® were tested on Sitka spruce [Piceasitchensis (Bong.) Carr.] and western hemlock [Tsugaheterophylla (Raf.) Sarg.] for controlling the collembolan Bourletiellahortensis (Fitch) in nursery trials in 1972 and 1973. All insecticides were effective against the insect, but low spring populations of the collembolan prevented full evaluation of the trials. A 4-m diazinon-sprayed surround was adequate to keep the insect from migrating to adjacent plots. Certain nursery practices, such as application of the herbicidal mineral oil Shell AWK, the herbicide propazine, and sodium fluosilicate for weevil control, temporarily suppressed B. hortensis populations but did not provide effective control against this insect. Shell AWK, applied when the radicle was emerging from the seed, was apparently phytotoxic to Sitka spruce.
A clustering technique for land management models
Authors: Williams Douglas H. , Yamada Michael M.
Published: April 2011

Cluster analysis was used to aggregate land units into efficient data sets for land management models. The descriptive variables of the land units were chosen for their importance in the structure of the model. The land units were grouped such that the error of aggregation was minimized. Data sets were prestratified for a specific management purpose and aggregated by a procedure of cluster formation and allocation.
Shoot apical growth and cataphyll initiation rates in provenances of Pinusconforta in Scotland
Authors: Cannell Melvin G. R.
Published: April 2011

The dynamics of terminal bud development on seven 3-year-old nursery-grown provenances of Pinuscontorta Dougl. were monitored by sampling buds at 1- to 3-weekly intervals during one growing season. Differences in rates of cataphyll initiation occurred which were analysed in terms of (a) the projected areas of the apical domes, which changed over the season, (b) the relative rates at which the apical domes expanded radially during a plastochrone (square millimetres per square millimetre), as shown by the extent to which the new cataphyll primordia receded away from the domes, and (c) the projected areas of the tissues used to form new cataphyll primordia. Component a was a measure of the size of the apical dome meristems and b was a measure of their rates of 'activity.' A model-matching method is described to measure b.Those provenances which produced most cataphylls during the growing season developed and maintained large apical domes (component a above). There were unexpectedly small provenance differences in the apical dome 'activity' in midsummer (component b defined above), although differences occurred in spring and autumn. Differences in the projected areas of the new cataphyll primordia (component c) were inversely related to cataphyll initiation rates. Apical dome tissue doubling times in midsummer were estimated to be less than 120 h, irrespective of provenance.Inland provenances had small but relatively 'active' apical domes in spring, but they produced cataphyll primordia as products of this growth rather than reinvesting in apical dome 'capital.' Consequently, their apical domes remained small. Coastal Alaskan provenances, on the other hand, developed large apical domes, but these domes ceased to be very 'active' after the end of August. The apical domes on south coastal provenances did not become 'active' until early summer, but their domes were relatively large even in spring, became much larger by late summer, and they remained 'active' until mid-September.Implications are noted regarding cross-breeding of complementary genotypes to increase needle production and height growth.
Stomatal control and the development of water deficit in Engelmann spruce seedlings during drought
Authors: Kaufmann Merrill R.
Published: April 2011

The effects of soil drying on water relations of Engelmann spruce (Piceaengelmannii Engelm.) were studied by withholding water from 4-year-old potted seedlings in full sunlight and under a shade screen transmitting 55–60% light. During a period of 2 months, xylem pressure potential, water vapor conductance, and transpirational flux density gradually declined compared with well watered controls, with drying being more rapid in full sunlight. As drying progressed, xylem pressure potential at 0 transpiration (predawn potential) decreased and the slope of the relationship between xylem pressure potential and transpirational flux density became more negative. Hysteresis in the relationship occurred when predawn xylem pressure potential was −6 bars (1 bar = 105 Pa) or lower. Needle conductance during daylight hours decreased as the absolute humidity difference from leaf to air increased but conductances were lower in September than in August for given humidity differences. Xylem pressure potentials between −15 and −19 bars had no clear effect on conductance in August but apparently caused significant stomatal closure in September. Because of humidity-induced stomatal closure, evaporative demand had little effect on transpirational flux density over a broad range of humidity gradient. Thus increased leaf-to-air vapor gradients for transpiration are not always accompanied by increased transpiration.
Mycorrhizae and growth of white fir seedlings in mineral soil with and without organic layers in a California forest
Authors: Alvarez Isabel F. , Rowney David L. , Cobb Jr. Fields W.
Published: April 2011

White fir (Abiesconcolor (Gord. et Glend.) Lindl.) seedlings appear to survive and grow better in mineral soil alone than in mineral soil with organic layers. To determine whether the better growth observed in seedlings in mineral soil (M), compared with those in mineral soil with organic layers (MO), could be related to the incidence of mycorrhizae in their root systems, natural M and MO seedlings were examined from five sites in the north central Sierra Nevada. Statistical analysis of the data showed that seedling dry weight was significantly related to total length of roots, number of main lateral roots, and presence of mycorrhizae on the roots. Dry weight, total length of roots, total number of mycorrhizal tips, and number of mycorrhizal tips per centimetre of roots were significantly higher for M compared with MO seedlings. Age, number of main lateral roots, and number of mycorrhizal tips per centimetre of roots are highly significant in distinguishing M from MO seedlings. The data indicate that mycorrhizae play an important role in the growth of white fir seedlings, and that both growth and presence of mycorrhizae are favored by the absence of organic layers.