bluuebunny/crossref_metadata_2025 huggingface dataset:
Sensitivity analysis of ice motion near Adams Island
Authors: Sykes J. F. , Miller-Cushon J. D.
Published: May 2008

The time-averaged motion of shore-fast ice near a small Arctic island is analysed through the solution of the momentum equation for the ice cover using the Galerkin finite element method coupled with an adjoint sensitivity formulation. A linear-viscous rheology is used. Shore boundaries were modeled by prescribing ice velocity components such that the ice velocity vectors at shore boundaries were directed towards the ice cover, normal to the shoreline. A sensitivity analysis using the adjoint methodology showed that the velocity of the ice near the island is strongly influenced by the magnitude of the prescribed boundary velocities. The surface shear stresses from wind and ocean currents and the ice viscosities over part of the modeled domain also have a significant influence. The influence of Coriolis acceleration and the mass of the ice are not significant. Key words : ice mechanics, momentum, viscous rheology, finite elements.
Progressive failure of the Carsington Dam: a numerical study
Authors: Chen Z. , Morgenstern N. R. , Chan D. H.
Published: May 2008

The mechanism of progressive failure is well understood as one which involves nonuniform straining of a strain-weakening material. Traditional limit equilibrium analysis cannot be used alone to obtain a rational solution for progressive failure problems because the deformation of the structure must be taken into account in the analysis. The failure of the Carsington Dam during construction in 1984 has been attributed to progressive failure of the underlying yellow clay and the dam core materials. The dam was monitored extensively prior to failure, and an elaborate geotechnical investigation was undertaken after failure. The limit equilibrium analysis indicated that the factors of safety were over 1.4 using peak strength of intact clay material or 1.2 based on reduced strength accounting for preshearing of the yellow clay layer. Factors of safety were found to be less than unity if residual strengths were used. The actual factor of safety at failure was, of course, equal to one. By using the finite element analysis with strain-weakening models, the extent and degree of weakening along the potential slip surface were calculated. The calculated shear strength was then used in the limit equilibrium analysis, and the factor of safety was found to be 1.05, which is very close to the actual value of 1.0. More importantly, the mechanism of failure and the initiation and propagation of the shear zones were captured in the finite element analysis. It was also found that accounting explicitly for pore-water pressure effects using the effective stress approach in the finite element and limit equilibrium analyses provides more realistic simulations of the failure process of the structure than analyses based on total stresses. Key words : progressive failure, strain softening, finite element analysis, dams.
Numerical modelling of heat and moisture transport through bentonite–sand buffer
Authors: Radhakrishna H. S. , Crawford A. M. , Kjartanson B. , Lau K. C.
Published: May 2008

A computer code TRUCHAM developed to model the coupled heat and moisture flow through a porous medium is used to assess the thermohydraulic performance of the clay-based engineered barrier encapsulating nuclear waste containers in a deep geological disposal vault in the borehole emplacement concept. This paper contains an overview of the development of the numerical model and its application to the buffer–container experiment at the Underground Research Laboratory of Atomic Energy of Canada Limited Research. The thermohydraulic transport parameters required for the analysis were determined by specially designed laboratory experiments. The needs for further development of the model and the material properties are identified. Key words : buffer, clay barrier, coupled heat and moisture, heater experiment, numerical model, nuclear waste disposal, thermal diffusivity, unsaturated soil.
Landslides at Rock Glacier Site, Highwood Pass, Alberta
Authors: McAffee R P , Cruden D M
Published: May 2008

Twenty topples are described from Rock Glacier Site, 2 km north of the summit of the Highwood Pass in the Front Ranges of the Rocky Mountains in Alberta. In situ field testing and laboratory tests indicated that the external force driving the toppling process is frost action within a weathered shale zone. A stability analysis of the slope included examining rock falls, rupture surface formation, and slides. Rock falls were the dominant mode of landsliding. Surfaces of rupture develop when the amount of angular rotation of the toppling rock mass is over 16°. Slides along continuous surfaces of rupture are possible in rock masses with no cohesion and reduced friction angles. Topples cause rock falls, which lead to shallow slides in the rock-fall colluvium.

Key words: topple, rupture surface, rock fall, rock slide, Rocky Mountains, slope stability.
Measurement of two-fluid saturations in a fine to medium sand
Authors: Gravelle C F , Knight M A , Mitchell R J
Published: May 2008

The infiltration of a light nonaqueous phase liquid (LNAPL) into an unsaturated porous medium will result in varying amounts of water, LNAPL, and air within the soil voids. A simple and reliable method of determining the percent saturation of each fluid is needed to analyze laboratory infiltration experiments. This note reviews the available methodologies for determining the oil content in porous media and presents an experimental study of a simple and reliable method for determining water and oil contents in an unsaturated fine to medium sand.

Key words: fluid saturations, oil content, gravimetric, extraction, assay.
Allozyme diversity in the endangered shrub Linderamelissifolia (Lauraceae) and its widespread congener Linderabenzoin
Authors: Godt Mary Jo W. , Hamrick J.L.
Published: May 2008

Allozyme diversity was assessed in 15 populations of the endangered clonal shrub Linderamelissifolia (Walt.) Blume (pondberry; Lauraceae) throughout its range in the southeastern United States and in five populations of spicebush (Linderabenzoin (L.) Blume), a sexually reproducing, co-occurring congener. Low levels of allozyme variation characterize both dioecious species. Although genetic diversity was moderately high (HT = 0.239) at polymorphic loci for L. benzoin, few of the 42 loci were polymorphic (Ps = 35%; Pp = 25%), and thus overall estimates of genetic diversity were relatively low (Hes = 0.083; Hep = 0.070). Little genetic variation was detected at 27 loci within L. melissifolia (Hes = 0.025; Hep = 0.015). Nine L. melissifolia loci (33%) were polymorphic but genetic diversity was low (HT = 0.074) at these loci, and few were polymorphic within populations (mean = 6.7%). The number of multilocus genotypes detected in L. melissifolia populations ranged from 1 to 18, with a mean of 4.5. Mean genetic identities between populations within each species were high (I = 0.98 and 0.99 for L. benzoin and L. melissifolia, respectively), a result of the high numbers of monomorphic loci. Despite the high genetic similarity of populations, estimates of gene flow were low to moderate (Nm = 0.82 and 1.25 for L. melissifolia and L. benzoin, respectively). The lower genetic diversity within L. melissifolia may be primarily due to bottlenecks during its evolutionary history. The recent loss of populations and of genets within populations have probably further eroded genetic diversity. To reduce the risk of extinction, effective population sizes of L. melissifolia could be enhanced by increasing genotypic diversity within populations.
The effect of nursery blackout application on Sitka spruce seedlings
Authors: Hawkins C.D.B. , Eastham A.M. , Story T.L. , Eng R.Y.N. , Draper D.A.
Published: May 2008

Sitka spruce (Piceasitchensis (Bong.) Carrière) seedlings were cultured using two nursery methods of blackout (short photoperiod) application: static treatment (constant day length of 14.28 h) and dynamic treatment (day length varying over length of experiment, with a mean of 14.28 h). Both methods when compared with a control (natural day length) reduced seedling height by inducing terminal bud set, increased seedling root weight, and decreased shoot to root and sturdiness ratios. Both static and dynamic blackout treatment seedlings had 26 and 30% lammas flush, respectively. Compared with control, both methods accelerated cold hardiness acquisition. After winter storage at −2 °C, treated seedlings flushed sooner than did control stock under light:dark temperatures of 25:20 °C. Under a cooler regime, 15:5 °C, differences among treatments were not significant. After planting in a common garden trial, terminal bud phenology had a range of treatment responses. Control seedlings flushed later and set bud sooner. Dynamic treatment seedlings' bud set phenology was nearest to that of controls. At a common garden trial and a reforestation site, blackout-treated seedlings had greater first-season terminal height increment. Planting check was observed for all treatments in the field during the second and third growing seasons. After five field seasons there was no height difference among treatments, and survival averaged 87%. Groundline stem diameter was never different among treatments. Biologically, the dynamic treatment is intermediate between the static and control treatments, but the static treatment is recommended because it is easier to apply in the nursery, and differences between the dynamic and static treatments were minimal.
The association of young weevil-killed pine and spruce terminals with Phellinuspini in western Canada
Authors: Mallett Kenneth I. , Langor David W.
Published: May 2008

Terminals of jack pine (Pinusbanksiana Lamb.), lodgepole pine (Pinuscontorta Dougl. ex Loud. van latifolia Engelm.), and white spruce (Piceaglauca (Moench) Voss), killed by either Pissodesstrobi (Peck) or Pissodesterminalis Hopping, were sampled from 17 sites in Alberta, Saskatchewan, Manitoba, and the Northwest Territories. The weevil-killed terminals were examined for decay caused by Phellinuspini (Brot.:Fr.). Wood chips taken from the terminals were placed on agar media in an attempt to isolate P. pini. No decay was observed in the terminals. Of 192 isolations from freshly killed terminals, 32% were sterile. Phellinuspini was not isolated from any of the terminals. The predominant fungi found were Aureobasidiumpullulans (de Bary) Arn., Hormonemadematioides Lagerberg & Melin, and Phialemoniumdimorphosporum W. Gams & W.B. Cooke. Weevil-killed terminals from lodgepole pine and white spruce that had been dead for up to 6 years were sampled for the presence of P. pini. The fungus was not found in any of the decayed wood in the terminals, although several other unidentified Basidiomycete species were isolated.
The Toxic Effects of Fatty Acids and Their Salts on the Balsam Woolly Aphid, Adelgespiceae (Ratz.)
Authors: Puritch George S.
Published: May 2008

Fatty acids and their potassium soaps were screened for their toxicity to different life stages and eggs of the balsam woolly aphid (Adelgespiceae (Ratz.)). The most effective fatty acids for causing aphid mortality were in two major groups, one centering around capric acid (C10) within the low-chain saturated fatty acid series and the other around oleic acid (C18:1), within the unsaturated 18-carbon fatty acids. The potassium soaps were better aphicides than the corresponding acids; the soaps of caprylic, capric, oleic, and linoleic acids were the most effective. Eggs were less sensitive to the soaps than later stages of the aphid, and there was a large variation in their response to the soap treatments. The possibility of using fatty acids and soaps as a control for the balsam woolly aphid is discussed.
Site Quality Evaluation Models for Aspen (Populustremuloides Michx.) in Wisconsin
Authors: Fralish James S. , Loucks Orie L.
Published: May 2008

Soil and site relationships were studied in 32 mature quaking aspen (Populustremuloides Michx.) communities in north central Wisconsin. Multiple linear regression techniques indicated that soil texture, available water-holding capacity, water-table depth, and stand exposure were the most important factors controlling site index. Two models developed from combinations of these factors accounted for 62% of the variation in site index. Values for soil calcium, magnesium, potassium, and phosphorus were corrected for bulk density and summed to 12-, 24-, 36-, and 60-in. depths. When included in additional models, only magnesium to a 60-in. depth was found to have additional effect on aspen growth over and above that implicit in available water-holding capacity. The models were validated using 10 additional mature aspen stands and then applied to data from 10 stands in early stages of deterioration.
Mode of Shoot Growth in 12-year-old Black Spruce Provenances
Authors: Logan K. T. , Pollard D. F. W.
Published: May 2008

Number of primordia in the buds of 12-year-old black spruce provenances are compared with number of needles on the expanded shoots. In contrast with earlier findings on younger black spruce, the spring flush was generally not supplemented by needles initiated in the current year, and primordia number was now correlated with height increment.
Total and Soluble Nitrogen in Douglas Fir in Relation to Plant Nitrogen Status
Authors: Driessche R. Van Den , Webber J. E.
Published: May 2008

Concentrations of total N, ninhydrin-positive compounds, and monosubstituted guanidino compounds were determined in current and 1-year-old foliage and twigs, and in roots of 3-year-old Douglas fir (Pseudotsugamenziesii (Mirb.) Franco.). These plants were grown in a trial where levels of N (0, 255, and 675 kg N/ha), and sources of N (nitrate, ammonium, and urea) had been applied factorially. N fertilizer treatment increased soluble N levels by as much as 19 times control values, whereas total N was increased at most 40%. Total N in 1-year-old foliage, current twigs, and roots, and guanidino compounds in 1-year-old twigs were consistently different for different N treatment levels. Sixty percent of the variance in plant size measurements could be explained by six N measurements, including total N, in multiple regression.In a second experiment, concentrations of arginine and proline, in addition to concentrations of ninhydrin-positive compounds, guanidino compounds, and total N, were determined in foliage of 3-year-old Douglas fir grown in growth chambers at 10 and 21 °C. Four provenances, to which three moisture-stress treatments were factorially applied, were represented at each temperature. Concentration of soluble N compounds was higher at 21 °C than at 10 °C, but not concentration of total N. Moisture stress increased concentration of soluble N compounds, in particular proline, and there were some differences between provenances in concentrations of soluble N compounds and total N.
Distribution of Radial Growth During the Development of Red Pine Root Systems
Authors: Fayle D. C. F.
Published: May 2008

The patterns of ring width throughout the root systems and stems of several 32- to 36-year-old, plantation-grown red pine were analyzed. All root systems showed a basic similarity in their radial sequences of ring width. Within a root system, individual sequences ranged from those similar to the radial sequence at the stem base to ones apparently dissimilar. At the stem–root base, the increasing distance to the tree crown with time and changes in mechanical stresses with increasing tree size appeared to play major roles in the development of the basic pattern. The position and type of root, the environment of its apices, and changes in the transportation pathways in the xylem and phloem at branching points may all have influenced the pattern in individual roots. The pattern of deposition of xylem at branching points was visualized as an interaction between the stream of growth regulators and assimilates towards the root tips and the stream of xylem water (and (or) dissolved substances) towards the root base. Discontinuities in the growth layers did not occur in the stem but increased with time in the roots, particularly in the surface horizontal roots. Moisture availability modified the radial sequence patterns and probably influenced the shifts in longitudinal distribution of radial increment from year to year within and between the stem and the root system. The maximum current annual increment in root wood volume occurred before that in the stem.
Litter Fall and Nutrient Cycling in the Forest Floor of Birch and Aspen Stands in Interior Alaska
Authors: Cleve Keith Van , Noonan Laraine L.
Published: May 2008

During a 4-year period the biomass and mass of selected chemical elements were measured in litter fall from young, intermediate, and mature age classes of quaking aspen and paper birch in interior Alaska.Average annual deposition of biomass and mass of Mg, Fe, and Mn were consistently greater in birch than in aspen stands of similar age. Mass of Ca was consistently greater in aspen stands (range 4.02 to 4.80 g m−2) than in birch stands (3.18 to 3.45 g m−2) regardless of age class. Trends in mass of chemical elements returned to the forest floor in litter fall were generally reflected in the average percentage composition of the organic matter.Turnover time for forest-floor biomass was about the same for both the 50- and 120-year age classes of birch (16.7 years) and of aspen (12.7 years to 13.0 years). For both species Fe had the maximum turnover time in the forest floor (167 to 280 years), with K (6.9 years to 9.7 years) and Zn (5.5 years to 11.6 years) having minimum times.Linear correlations between biomass and mass of selected nutrient elements in litter fall provide an efficient means of conducting short- and long-term assessments of differences in nutrient content of litter within and between forest vegetation types.
Tree mortality and radial growth losses caused by the western spruce budworm in a Douglas-fir stand in British Columbia
Authors: Alfaro R. I. , Sickle G. A. Van , Thomson A. J. , Wegwitz E.
Published: May 2008

The effects of defoliation by western spruce budworm (Choristoneuraoccidentalis (Freeman)), on Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) radial growth at breast height and tree mortality are given. Four hundred and twenty trees were marked in an 81-year-old stand, and their defoliation levels were recorded annually from 1970 to 1980 in an outbreak that lasted from 1970 to 1974, inclusive. Forty-one trees were felled and dissected in 1977, 3 years after recovery began. The number of stems per hectare was reduced by 39.3% and basal area by 11.6% through mortality, most occurring among the small diameter, suppressed, and intermediate trees. Relationships were established between mortality and defoliation. Radial increments were examined, and the presence of four outbreaks during the life of the stand was detected. The combined effect of these infestations amounted to a loss of about 12% of the estimated potential diameter had not the insects been active. The most recent outbreak (1970–1974) caused a total of 10 years of subnormal growth, including 5 years due to defoliation and 5 years of recovery. The relationship between radial increment losses and defoliation intensity and duration is studied and quantified.
Evaluation of forest-canopy photographs with diode-array scanner OSIRIS
Authors: Olsson Lars , Carlsson Kjell , Grip Harald , Perttu Kurth
Published: May 2008

Fish-eye pictures are often used to characterize forest canopies. The sky-obscuration factor (SOF), defined as the relative area of sky obscured by vegetational elements for a certain solid angle when observed from below, is evaluated by means of the interactive, computer-supported, diode-array scanner OSIRIS (now commercially available), with high geometric and photometric resolution. The SOF in each picture element is calculated by linear interpolation between the frequency peaks of completely covered and uncovered sky. This method gives good results when the two peaks show small skewness and limited width and are clearly separated. Compared with OSIRIS results (from nonideally exposed pictures), manual evaluation and radiation measurements gave a somewhat higher SOF, while precipitation–throughfall analysis agreed in the zenith-angle interval 0–10°. To facilitate and improve evaluation, a standardized photographic technique is recommended including usage of high contrast film, carefully controlled exposure, and identical development. An artificial horizon and north position indicated by lamps mounted within the depth of field of the fish-eye lens is also recommended.
Architectural approach to analysis of North American temperate deciduous forests
Authors: Oosterhuis L. , Oldeman R. A. A. , Sharik T. L.
Published: May 2008

The architectural approach to the analysis of forest structure and dynamics, which originated in the tropics, has increasingly been applied to temperate forests during recent years, especially in Europe. However, few examples are available for this continent. To test the usefulness in North American temperate deciduous forests, an architectural analysis was conducted in a series of Appalachian oak forest stands. Central to the analysis are profile diagrams and plans of forest sample plots, five of which are presented here in detail. The interpretation of the diagrams focuses on the growth and development of the individual tree as well as the forest community, and thereby reveals certain phenomena which may not be detected by traditional plot sampling techniques. The architectural approach adds a new dimension to the existing array of research methods and its application is expected to be of great value in basic and applied studies of forest ecology.
Copper requirements of container-grown conifer seedlings
Authors: Lambert D. H. , Weidensaul T. C.
Published: May 2008

Blue spruce (Piceapungens Engelm.), Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco, Noble fir (Abiesprocera Rehd.), and eastern white pine (Pinusstrobus L.) seedlings grown in the greenhouse in peat–vermiculite medium were fertilized with nutrient solutions containing 0.00–0.64 ppm Cu. Maximum growth generally occurred at levels higher than the conventional fertilizer rates of 0.02–0.06 ppm, particularly for Douglas-fir, with subsequent shoot or needle concentrations of 3 or more ppm. Optimum growth of Douglas-fir in a peat–vermiculite medium treated with a single initial drench of 0–100 ppm Cu/L mix occurred over a broad range of foliar Cu concentrations greater than 4 ppm. Supplemental Cu for container-grown conifers thus appears necessary in some cases, but not harmful in others.
Modelling probability of root disease center occurrence in northern Idaho forests
Authors: Williams Ralph E. , Marsden Michael A.
Published: May 2008

A data screening algorithm (SCREEN) identified stand age, average stand diameter, timber type, soil type, aspect, habitat type, and elevation as forest stand or site characteristics strongly associated with root-disease occurrence in northern Idaho forests. The logistic regression model was used to predict root disease center occurrence. A second algorithm (RISK) was used to compute the estimates for the coefficients and to test different prediction equations. On wet aspects, highest probability of root disease centers was found on soils with lowest year-round moisture availability. The reverse was true on dry aspects. Increased slope was associated with increased root disease. Root disease center frequency was inversely related to elevation and directly related to occurrence of Pseudotsugamenziesii (Mirb.) Franco and Abiesgrandis (Dougl.) Lindl. Expression of disease centers was maximum at 60–100 years of stand age on all habitat types. A habitat-type–age interaction was observed in oldest aged stands.
Phosphorus and lime response of Sitka spruce, western hemlock seedlings, and romaine lettuce on two coastal Washington soils
Authors: Anderson S. , Zasoski R. J. , Gessel S. P.
Published: May 2008

Greenhouse growth tests using Sitka spruce (Piceasitchensis (Bong.) Carr), western hemlock (Tsugaheterophylla (Raf.) Sarg.), and romaine lettuce (Lactucasativa) and soil analysis were used to evaluate the fertility status of two soils from the coastal region of Washington State. Available N determined by aerobic incubation was low (5–12 ppm). Nitrification in these acid soils (pH = 4.1 and 4.2) was negligible even after 2 months of incubation. Neither the lettuce nor the conifer seedlings responded to N addition in spite of the low available N. Extractable soil P was low and a growth response to added P was observed. Lettuce was not an adequate predictor of conifer growth. In the growth study, the soils were amended with lime and combinations of N, P, S, K, and Mg. Both Sitka spruce and western hemlock grew best in treatments with lime and P added. The lime response was smaller than the P effect. Mycorrhizal development on the spruce and hemlock was quite limited and may have enhanced the phosphorus response.
Effects of drying soils on survival of young Piceaglauca seedlings
Authors: Tear E. C. , Higginbotham K. O. , Mayo J. M.
Published: May 2008

Drought stress is often suggested as a factor preventing successful field establishment of seedlings of white spruce (Piceaglauca (Moench) Voss) during their first growing season. In this study the combined effects of water stress and seedbed type on 1- and 3-month-old seedlings were examined. Shoot xylem pressure potential decreased to −1.5 MPa in seedlings grown in a greenhouse soil mixture in 9.5 days but took 18.5 days to reach this level in peat. Mortality reached 100% for 1-month-old seedlings grown in greenhouse mix 11 days after watering ceased, while it took 23 days to reach this level in peat. Shoot xylem pressure potentials can be used to predict mortality potential on the two seedbed types. Three-month-old seedlings on either seedbed survived for at least 31 days without watering, indicating development of capability for control of water loss with time.
Sucker regeneration in some deteriorating Utah aspen stands: development of independent root systems
Authors: Schier George A.
Published: May 2008

Root-sucker regeneration in deteriorating Utah aspen (Populustremuloides Michx.) stands was examined for the occurrence of adventitious roots. Suckers in only 1 of 12 clones examined had well developed independent root systems. Most new roots died the same year they were initiated.
Use of the ectomycorrhizal fungus Laccarialaccata in forestry. III. Effects of commercially produced inoculum on container-grown Douglas-fir and ponderosa pine seedlings
Authors: Hung Ling-Ling L. , Molina Randy
Published: May 2008

Inoculation of container-grown Douglas-fir and ponderosa pine seedlings with vegetative inoculum of Laccarialaccata (Scop.:Fr.) Berk. & Br., prepared by Sylvan Spawn Laboratory, yielded ectomycorrhizae in a research greenhouse experiment; however, in two container nurseries, ectomycorrhizae were observed only on inoculated Douglas-fir seedlings. Successfully colonized seedlings had more short roots than did the controls. The percentage of L. laccata ectomycorrhizae increased with increasing inoculation rates. Inoculation rate for best seedling growth and ectomycorrhiza formation differed between nurseries. Inoculation at an "optimal" rate resulted in quality seedlings and abundant ectomycorrhiza formation at each nursery. Inoculation of Douglas-fir with L. laccata in a commercial nursery application is feasible.
Seasonal and diurnal trends of heat pulse velocity in Douglas-fir and ponderosa pine
Authors: Lopushinsky W.
Published: May 2008

Seasonal trends of heat pulse velocity in the trunks of 55-year-old ponderosa pine (Pinusponderosa Dougl. ex Laws.) and Douglas-fir (Pseudotsugamenziesii var. glauca (Beissn.) Franco) trees showed large yearly variations related to weather patterns. Onset of sap movement in the spring, seasonal variations, and summer declines in response to decreasing moisture were similar for Douglas-fir and ponderosa pine. When soil moisture was not limiting, rates of heat pulse velocity in both species were significantly related to air temperature, solar radiation, and vapor pressure deficit. As soil moisture decreased during the summer, rates of heat pulse velocity no longer followed evaporative demand. In both species, sap movement also occurred at night. Diurnal trends of heat pulse velocity also were similar in both species. During early summer, maximum heat pulse velocity occurred at midday; in the fall, maximum rates occurred earlier. The similarity of seasonal and diurnal trends of heat pulse velocity and responses to variation in site conditions suggest that on the site studied, transpiration behavior in ponderosa pine and Douglas-fir trees generally is similar.
Decomposition of Douglas-fir and red alder wood in clear-cuttings
Authors: Edmonds Robert L. , Vogt Daniel J. , Sandberg David H. , Driver Charles H.
Published: May 2008

Decomposition rates of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) and red alder (Alnusrubra Bong.) wood (simulating logging residues) were determined in clear-cuttings at the Charles Lathrop Pack Experimental Forest of the University of Washington, which is located approximately 120 km south of Seattle, WA. The influence of diameter (1–2, 4–6, and 8–12 cm), vertical location (buried, on the soil surface, and elevated), season of logging (summer and winter), aspect (north and south), and wood temperature, moisture, and chemistry on wood decomposition rates were determined. Red alder wood decomposed faster (k = 0.035–0.517 year−1) than Douglas-fir wood (k = 0.006–0.205 year−1). In general, buried wood decomposed faster than surface wood, which decomposed faster than elevated wood. Small diameter wood generally decomposed faster than larger diameter wood. Aspect and season of logging had little influence on decomposition rates. Moisture and temperature were the dominant factors related to Douglas-fir wood decomposition, with initial chemistry playing a minor role. Initial wood chemistry, particularly soda solubility, was the dominant factor related to red alder wood decomposition.
Effect of aluminum on 32P uptake and translocation by red spruce seedlings
Authors: Cumming Jonathan R. , Eckert Robert T. , Evans Lance S.
Published: May 2008

32P uptake and translocation was simultaneously studied in 11-week-old red spruce (Picearubens Sarg.) seedlings that had been pretreated for 24 h in hydroponic culture with or without 10 mg Al L−1. Aluminum in solution enhanced the accumulation of 32P in roots by more than two orders of magnitude over uptake in control seedlings, while the translocation of 32P to apical buds and mature primary needles was reduced to 20.0 and 9.1% of control levels, respectively. Kinetic analysis of 32P uptake indicated that P absorption is mediated by an uptake system exhibiting Michaelis–Menten behavior from solutions ranging from 0.01 to 5.00 mM KH2PO4; uptake at 10.0 mM KH2PO4 was inconsistent with this model. Changes in the patterns of 32P uptake and translocation in seedlings treated with Al suggest that Al in solution altered accumulation processes.
The use of mark–recapture to evaluate a pheromone-based mass trapping program for ambrosia beetles in a sawmill
Authors: Shore Terry L. , McLean John A.
Published: May 2008

Trypodendronlineatum (Olivier) and Gnathotrichussulcatus (LeConte) beetles (Coleoptera: Scolytidae) were marked with fluorescent powder and released in a sawmill area during a pheromone-based mass trapping program for ambrosia beetles. Trapping efficiency was estimated at 5.9% for T. lineatum and 5.5% for G. sulcatus. This technique had good potential for obtaining information on trapping efficiency, population size, and beetle dispersal patterns. Suggestions are given for improving the accuracy of the information obtained and for additional uses of mark-recapture in evaluating and optimizing mass trapping programs for ambrosia beetles.
Susceptibility of lodgepole pine provenances to geographically separate western gall rust spore sources
Authors: Kamp B. J. van der
Published: May 2008

Seven lodgepole pine (Pinusconforta Dougl.) provenances collected along an east–west transect from the Cypress Hills, Saskatchewan, to Vancouver, British Columbia, were inoculated as 1-year-old seedlings with one coastal and three British Columbia interior western gall rust (Endocronartiumharknessii (J.P. Moore) Y. Hiratsuka) spore sources in a factorial design. Infection levels ranged from 4 to 95% (average 56.4%, based on 1032 inoculated seedlings). ANOVA of arc sine transformed percent seedlings infected demonstrated a significant interaction between provenance and spore source (P = 0.029). Provenance, spore source, and their interaction accounted for 70, 14, and 6% of the variation, respectively.
Control of sex expression in potted Piceaengelmannii grafts by gibberellin A4/7 and the auxin, naphthaleneacetic acid
Authors: Ross Stephen D.
Published: May 2008

Three concentrations each of gibberellin A4/7 (GA4/7) and naphthaleneacetic acid (NAA) were tested in factorial combination on shoots in the upper and lower crown of young, potted Piceaengelmannii grafts. There was no interaction between the two growth regulators, both of which promoted flowering but affected sex expression differently. GA4/7 at 125 and 625 μg/shoot increased similarly the production of seed-cone buds without affecting male flowering. NAA promoted male flowering at the expense of seed-cone buds when applied at 5 μg/shoot, but was phytotoxic at 25 μg/shoot. GA4/7 was more effective in promoting seed-cone buds on shoots in the upper than the lower crown, whereas the male flowering response to NAA was independent of crown position. Present results indicate that sex expression in P. engelmannii can be manipulated practically by application of appropriate growth regulators to facilitate pollen and seed-crop management in indoor-potted orchards.
Reformulated self-thinning exponents as applied to black spruce
Authors: Newton Peter F. , Smith V. G.
Published: May 2008

Five self-thinning exponents (ηi, i = 1,…,5) for the asymptotic total stem volume – density relationship within black spruce (Piceamariana (Mill.) B.S.P.) stands were estimated and compared: (i) the empirically observed value (η1); (ii) η2 = −[(2 + α)/2β] + 1, where α and β are species-specific allometric exponents for the relationship between stem height and stem diameter, and crown basal diameter and stem diameter, respectively; (iii) η3 = −(2.5/2β) + 1; (iv) η4 = −{l/[2(0.5 − 0.5δ)]} + 1, where δ is the allometric exponent for the relationship between mean stem height and mean stem volume; and (v) η5 = −[(ε + 1)/ζ] + 1, where ε and ζ are stem and crown form exponents, respectively. Employing data derived from 27 permanent and 21 temporary sample plots situated on medium sites throughout central Newfoundland, thinning, allometric, and form exponents were estimated. Resultant exponents were as follows: η1 = −0.618 estimated by principal component analysis; η2 = −1.633, where α = 0.682 and β = 0.509; η3 = −1.454; η4 = −0.470, where δ = 0.320; and η5 = −0.528, where ε = 2.144 and ζ = 2.058. Hence two numerically distinct sets of thinning exponents were obtained: A = {η1, η4, η5} and B = {η2, η3}. Set A corresponds to commonly observed or expected values, whereas set B exhibits substantial departure. It is proposed that the underlying allometric relationships employing stem diameter are partially responsible for these set differences.
Field growth of Pinussylvestris following nursery inoculation with mycorrhizal fungi
Authors: Stenström Elna , Ek Mats
Published: May 2008

Growth of Pinussylvestris L. seedlings inoculated with a number of forest mycorrhizal fungi (Amanitamuscaria (L. ex Fr.) Hooker, Lactariusrufus (Scop.) Fr., Suillusvariegatus (Swartz ex Fr.) O. Kuntze, Tricholomaalbobrunneum (Pers. ex Fr.) Kummer, and an unknown mycorrhizal fungus) in the nursery was studied for 3 years after field planting. At outplanting, 10–40% of the root tips were mycorrhizal, consisting of both the inoculated fungi and an indigenous nursery mycorrhiza, Thelephoraterrestris (Ehrh.) Fr. In the field the target fungi were replaced by several indigenous forest mycorrhizal fungi, which also rapidly colonized the remaining uncolonized root system. At outplanting, some of the inoculated seedlings were substantially smaller than the uninoculated seedlings. However, after 2.5 years seedlings in some of the treatments were up to 50% larger in volume than control seedlings. Even at low initial mycorrhizal colonization rates some mycorrhizal species stimulated seedling growth. The most noticeable response occurred in seedlings inoculated with A. muscaria; although they were about 50% smaller than the control seedlings at outplanting, they grew so rapidly that 18 months later they were about 20% larger than the controls. This observation contradicts previous reports on the importance of seedling size at outplanting. Possible explanations for the observed effects are discussed.
Decomposition of aspen (Populustremuloides) leaf litter modified by leaching
Authors: Parsons William F. J. , Taylor Barry R. , Parkinson Dennis
Published: May 2008

In a Rocky Mountain aspen forest, the detailed pattern of mass loss from decomposing leaf litter of trembling aspen (Populustremuloides Michx.) during the first 6 months of decay was compared with that from aspen leaves modified to produce a more recalcitrant litter type by removal of leachable material (31.7% of original mass). Leaching litter removed substantial quantities of N (24%) and P (54%), but did not change the litter's C/N ratio (77:1); and leached leaves still contained 33% labile (benzene alcohol soluble) material. Decomposition of intact aspen litter was best described by a double exponential model (k1 = −7.91/year, k2 = −0.21/year), except during the first 2 weeks, when an extremely rapid mass loss (14.2%) apparently resulted from leaching. Microbial metabolism was probably responsible for most of the subsequent decay (35% total in 6 months). In contrast, decomposition of leached aspen showed no exponential trend and was best described by a simple linear regression with a slope of −19.7%/year. Additional data from a 2nd year (12–15 months decay) reduced the regression estimates of decay rates but did not alter the best fit models. Fits were improved slightly if temperature sum replaced time in the regressions, especially if 2nd-year data were included.
Effect of nursery culture on morphological development of western hemlock seedlings during field establishment. I. Flushing, shoot elongation, and bud development
Authors: O'Reilly Conor , Owens J.N. , Arnott J.T. , Dunsworth B.G.
Published: May 2008

Western hemlock (Tsugaheterophylla (Raf.) Sarg.) seedlings grown in two different container cavity sizes that received four different dormancy induction treatments, short (SD) or long days (LD), in combination with moisture stress (D) or no moisture stress (W), in the greenhouse, and lifted and placed in cold storage (November, January, or March) were planted on two adjacent coastal reforestation sites on Vancouver Island, British Columbia, and monitored for phenological responses during the first growing season. The SD seedlings flushed sooner and began bud development later than the LD seedlings, although the effect on flushing was small for those lifted in March. Moisture stress and SD together in the greenhouse reduced shoot elongation rates but had little impact on field bud development. Cold storage of seedlings lifted in November and January delayed flushing, reduced shoot elongation rates, and advanced bud development compared with the March-lifted stock. The influence of cavity size was generally small on most variables measured. Shoot elongation was slightly faster on the southeast site than on the northwest site, whereas bud development was more rapid on the northwest site. The effect of site on date of flushing varied with nursery treatment.
Sealed-bid versus oral-auction timber offerings: implications of imperfect data
Authors: Schuster Ervin G. , Niccolucci Michael J.
Published: May 2008

The central issue regarding sealed-bidding versus oral-auction timber offerings focuses on the question of revenue generation. On this point, the literature provides no consistent answer. This study measured the difference'in bid price between sealed-bid and oral-auction timber offerings in the Northern Region of the U.S. Forest Service. A two-step estimation process, involving a probit model followed by a linear regression model, was used. That two-step process did not produce the expected results because the timber offering data used did not correspond to quality expectations; specifically, sale method was not always assigned on the basis of offering characteristics. Subsequent analyses indicated that when timber offerings in the Northern Region are randomly assigned a sale method, sealed-bid sales generated about $6 per 103 board ft (1 board ft = 2.4 dm3) more than oral auction sales. When the sale method is based on offering characteristics, oral auction sales produced revenues of about $9 per 103 board ft higher than sealed-bid offerings. Recommendations for handling data quality problems are provided.
Population differences in water-use efficiency of well-watered and water-stressed western larch seedlings
Authors: Zhang Jianwei , Marshall John D.
Published: May 2008

Gas exchange, water-use efficiency (WUE), and carbon-isotope discrimination (Δ) were compared among 14 populations of western larch (Larixoccidentalis Nutt.), a deciduous conifer. Seedlings grown from seed collected across the natural distribution of the species were maintained under water-stressed and well-watered conditions. No differences in gas exchange or instantaneous water-use efficiency (WUEi) were detected among populations. However, population differences in Δ, a second measure of water-use efficiency, were observed. WUE measured as the rate of dry matter accumulation per cumulative water transpired (WUET) was different among populations at the P = 0.07 level. The three measures of WUE were intercorrelated and all were higher among water-stressed seedlings than among well-watered seedlings. Overall means were 4.30 ± 0.08 (± SE) and 3.61 ± 0.07 g dry matter accumulation per kg water transpired (WUET), 2.80 ± 0.09 and 2.02 ± 0.06 μmol CO2 uptake per μmol H2O transpired (WUEi), and Δ was 18.24 ± 0.08‰ and 20.26 ± 0.10‰ under the water-stressed and well-watered treatments, respectively. Population differences in the two integrated measurements, WUET and Δ, were significantly correlated with the altitude at which seed was collected. No interaction between genotype and watering treatment was observed, which means that despite pronounced shifts in WUE between watering treatments, population rankings remained unchanged. These results provide evidence of genotypic differences in long-term measures of WUE among native populations of western larch.
Shoot growth from the bud bank in black oak
Authors: Wilson Brayton F. , Kelty Matthew J.
Published: May 2008

The bud bank in black oak (Quercusvelutina Lam.) trees is composed of four bud types, with the first three occurring on current shoots: (i) large buds in terminal clusters; (ii) large intercluster buds; (iii) small leafless buds; and (iv) preventitious buds on older shoots. Leafless buds may grow and preventitious buds may form epicormic shoots after injuries to large buds. We applied clipping treatments to small trees growing in either shade or light to test for crown recovery of leaf number, leaf area, leaf weight, shoot number, and total shoot length. Removing the terminal bud cluster almost doubled the proportion of intercluster buds that produced shoots and did not affect crown parameters, compared with control trees. Removing all large buds increased epicormic shoot production, but did not affect crown parameters. Removing current shoots reduced only leaf area and leaf number in the shade. The more extreme clipping treatments released primarily 2-year-old preventitious buds, but only a few older buds. Buds of all ages could be forced on isolated stem segments. Mortality of buds from the 1st to 2nd year was more than 90% for buds with leaves and about 50% for leafless buds.
Potential for biological protection against blue stain in Populustremuloides with a hyphomycetous fungus, Stachybotryscylindrospora
Authors: Hiratsuka Y. , Chakravarty P. , Miao S. , Ayer W.A.
Published: May 2008

Interactions between a blue-stain fungus, Ophiostomacrassivaginatum (H.D. Griffin) T.C. Harrington, and a hyphomycetous fungus, Stachybotryscylindrospora C.N. Jensen, from Populustremuloides Michx. were studied. Stachybotryscylindrospora inhibited the in vitro growth of O. crassivaginatum when grown in dual culture. A culture filtrate of S. cylindrospora reduced the growth of O. crassivaginatum on both agar media and in liquid culture. Stachybotryscylindrospora, previously inoculated on P. tremuloides wood chips, prevented colonization of O. crassivaginatum on the same chips. Two known fungitoxic compounds, trichodermin and trichodermol, were isolated and identified from culture filtrates of S. cylindrospora. Both of these compounds significantly inhibited the growth of O. crassivaginatum in vitro. Stachybotryscylindrospora can be considered as a candidate for biological protection of wood chips and wood products of aspen from the stain-producing fungus, O. crassivaginatum.
A site-index model remodified
Authors: Payandeh Bijan , Wang Yonghe
Published: May 2008

A previously reported site index model with unconstrained parameter estimates may not be amenable to extrapolation. A modification is presented that is more robust and has no apparent shortcomings. Results of fitting both models to white spruce (Piceaglauca (Moench) Voss) and aspen (Populustremuloides Michx.) data sets are presented and discussed.
Initial deposits and persistence of forest herbicide residues in sugar maple (Acersaccharum) foliage
Authors: Thompson Dean G. , Pitt D. G. , Buscarini T. , Staznik B. , Thomas D. R. , Kettela E. G.
Published: May 2008

Initial deposition and subsequent fate of herbicide residues in sugar maple (Acersaccharum Marsh.) foliage were quantified following applications of three different formulations of glyphosate (VISION®, TOUCHDOWN®, MON14420) and one formulation of triclopyr ester (RELEASE®) in a comparative field study. Maximum initial residues were 529, 773, 777, and 1630 mg of acid equivalent per kilogram dry mass, respectively. Initial foliar residues were dependent upon application rate (r2 = 0.63 to 0.87) and increased by a similar factor (233 to 313 mg•kg−1) for each kilogram per hectare applied, irrespective of formulation type. Foliar residues dissipated following a negative exponential pattern with time, rates of which varied with initial concentration. Mean times to 50% dissipation were 2 days for all glyphosate formulations, 1.5 days for triclopyr ester, and 4 days for triclopyr acid. Mean times to 90% dissipation were <16 days for glyphosate formulations, 9 days for triclopyr ester, and 33 days for triclopyr acid. Multivariate analyses of intercept and rate parameter estimates indicated significant (p = 0.02) differences in dissipation patterns among treatments. Orthogonal contrasts confirmed a priori hypotheses that glyphosate residue dissipation was independent of the salt formulation applied, and that triclopyr ester dissipated faster than either glyphosate (p = 0.004) or triclopyr acid residues (p = 0.07). Results are considered in terms of the exposure and resultant potential toxicity to forest songbirds inhabiting or foraging in treated hardwood canopies.
HIGHER DIMENSIONAL OPERATORS AND THEIR EFFECTS IN (NON)SUPERSYMMETRIC MODELS
Authors: GHILENCEA D. M.
Published: May 2008

It is shown that a 4D N = 1 softly broken supersymmetric theory with higher derivative operators in the Kahler or the superpotential part of the Lagrangian and with an otherwise arbitrary superpotential, can be re-formulated as a theory without higher derivatives but with additional (ghost) superfields and modified interactions. The importance of the analytical continuation Minkowski–Euclidean space–time for the UV behaviour of such theories is discussed in detail. In particular it is shown that power counting for divergences in Minkowski space–time does not always work in models with higher dimensional (derivative) operators.