bluuebunny/crossref_metadata_2025 huggingface dataset:
Mitogen‐activated protein kinases regulate palytoxin‐induced calcium influx and cytotoxicity in cultured neurons
Authors: Vale C , Gómez‐Limia B , Vieytes M R , Botana L M
Published: July 2007

Background and purpose:

Palytoxin (PLT) is a potent toxin that binds to the Na,K‐ATPase. Palytoxin is highly neurotoxic and increases the cytosolic calcium concentration ([Ca2+]c) while decreasing intracellular pH (pHi) in neurons (Vale et al., 2006; Vale‐Gonzalez et al., 2007). It is also a tumour promoter that activates several protein kinases.

Experimental approach:

The role of different protein kinases in the effects of palytoxin on [Ca2+]c, pHi and cytoxicity was investigated in cultured neurons.

Key results:

Palytoxin‐induced calcium load was not affected by inhibition of calcium‐dependent protein kinase C (PKC) isoforms but it was partially ameliorated by blockade of calcium‐independent PKC isozymes. Inhibition of the extracellular signal‐regulated kinase (ERK) 2 eliminated the palytoxin‐induced rise in calcium and intracellular acidification, whereas inhibition of MEK greatly attenuated the palytoxin effect on calcium without modifying the PLT‐evoked intracellular acidification. Blockade of c‐Jun N‐terminal protein kinases (JNK) somewhat decreased the palytoxin‐effect on calcium, whereas inhibition of the p38 mitogen activated protein kinases (MAPKs) delayed the onset of the palytoxin‐evoked rise in calcium and acidification. Furthermore, the cytotoxicity of palytoxin was completely blocked by inhibition of ERK 2 and partially prevented by inhibition of MEK. PLT increased phosphorylated ERK immunoreactivity in a concentration‐dependent manner.

Conclusions and implications:

MAPKs, specifically ERK 2, link palytoxin cytotoxicity with its effects on calcium homeostasis after inhibition of the Na,K‐ATPase. Binding of palytoxin to the Na,K‐ATPase would alter signal transduction pathways, even in non‐dividing cells, and this finding is related to the potent neurotoxicity of this marine toxin.

British Journal of Pharmacology (2007) 152, 256–266; doi:10.1038/sj.bjp.0707389
Pollination Biology and the Impact of Floral Display, Pollen Donors, and Distyly on Seed Production in Arcytophyllum lavarum (Rubiaceae)
Authors: García‐Robledo C. , Mora F.
Published: July 2007

Abstract: In animal‐pollinated plants, two factors affecting pollen flow and seed production are changes in floral display and the availability of compatible mates. Changes in floral display may affect the number of pollinator visits and the availability of compatible mates will affect the probability of legitimate pollination and seed production. Distyly is a floral polymorphism where long‐styled (pin) and short‐styled (thrum) floral morphs occur among different individuals. Distylous plants frequently exhibit self and intra‐morph incompatibility. Therefore changes in morph abundance directly affect the arrival of compatible pollen to the stigmas. Floral morph by itself may also affect female reproductive success because floral morphs may display differences in seed production. We explored the effects of floral display, availability of neighboring compatible mates, and floral morph on seed production in the distylous herb Arcytophyllum lavarum. We found that floral display does not affect the mean number of seeds produced per flower. There is also no effect of the proportion of neighboring legitimate pollen donors on seed production in pin or thrum flowers. However, floral morphs differed in their female reproductive success and the thrum morph produced more seeds. Hand pollination experiments suggest that differences in seed production between morphs are the result of pollen limitation. Future research will elucidate if the higher seed production in thrum flowers is a consequence of higher availability of pollen donors in the population, or higher efficiency of the pin morph as pollen donor.
Genome Size Estimations On Ulmus minor Mill., Ulmus glabra Huds., and Celtis australis L. Using Flow Cytometry
Authors: Loureiro J. , Rodriguez E. , Gomes Â. , Santos C.
Published: July 2007

Abstract: The Ulmaceae family is composed of nearly 2000 species widely distributed in the northern hemisphere. Despite their wide distribution area, there are only four native species in the Iberian Peninsula. In this work the genome size of three of those species (Ulmus minor, U. glabra, and Celtis australis) was estimated using flow cytometry. The nuclear DNA content of C. australis was estimated as 2.46 ± 0.061 pg/2C, of U. minor as 4.25 ± 0.158 pg/2C, and of U. glabra as 4.37 ± 0.103 pg/2C of DNA. No statistically significant differences were detected among individuals of the same species. These species revealed to be problematic for flow cytometric analyses, due to the release of mucilaginous compounds into the nuclear suspension. Despite that, the modified protocol here presented ensured high quality analyses (low coefficient of variation and background debris and nuclear fluorescence stability), opening good perspectives on its application to estimate the genome size of species with similar problems.
On the lattice parameters of GaN
Authors: Darakchieva V. , Monemar B. , Usui A.
Published: July 2007

The lattice parameters of low-defect density, undoped bulk GaN fabricated by hydride vapor phase epitaxy (HVPE) on (0001) sapphire and subsequent substrate removal, are precisely determined using high-resolution x-ray diffraction. The obtained values, c=5.18523Å and a=3.18926Å, are compared with the lattice parameters of freestanding HVPE GaN from different sources and found to be representative for state-of-the-art undoped HVPE bulk GaN material. A comparison with bulk GaN fabricated by the high-pressure technique and homoepitaxial GaN is made, and significant differences in the lattice parameters are found. The observed differences are discussed and a possible explanation is suggested.
Modeling the interactions between compliant microcapsules and pillars in microchannels
Authors: Zhu Guangdong , Alexeev Alexander , Kumacheva Eugenia , Balazs Anna C.
Published: July 2007

Using a computational model, we investigate the motion of microcapsules inside a microchannel that encompasses a narrow constriction. The microcapsules are composed of a compliant, elastic shell and an encapsulated fluid; these fluid-filled shells model synthetic polymeric microcapsules or biological cells (e.g., leukocytes). Driven by an imposed flow, the capsules are propelled along the microchannel and through the constricted region, which is formed by two pillars that lie in registry, extending from the top and bottom walls of the channels. The tops of these pillars (facing into the microchannel) are modified to exhibit either a neutral or an attractive interaction with the microcapsules. The pillars (and constriction) model topological features that can be introduced into microfluidic devices or the physical and chemical heterogeneities that are inherently present in biological vessels. To simulate the behavior of this complex system, we employ a hybrid method that integrates the lattice Boltzmann model (LBM) for fluid dynamics and the lattice spring model (LSM) for the micromechanics of elastic solids. Through this LBM/LSM technique, we probe how the capsule’s stiffness and interaction with the pillars affect its passage through the chambers. The results yield guidelines for regulating the movement of microcarriers in microfluidic systems and provide insight into the flow properties of biological cells in capillaries.
Fabrication of nonaging superhydrophobic surfaces by packing flowerlike hematite particles
Authors: Cao Anmin , Cao Liangliang , Gao Di
Published: July 2007

The authors demonstrate the fabrication of nonaging superhydrophobic surfaces by packing flowerlike micrometer-sized hematite (α-Fe2O3) particles. Although hematite is intrinsically hydrophilic, the nanometer-sized protrusions on the particles form textures with overhanging structures that prevent water from entering into the textures and induce a macroscopic superhydrophobic phenomenon. These superhydrophobic surfaces do not age even in extremely oxidative environments—they retain the superhydrophobicity after being stored in ambient laboratory air for 4months, heated to 800°C in air for 10h, and exposed to ultraviolet ozone for 10h.
Investigation of meticillin-resistant Staphylococcus aureus in pigs used for research
Authors: Sergio Darvi Michell Bufete , Koh Tse Hsien , Hsu Li-Yang , Ogden Bryan Emmett , Goh Angela L. H. , Chow Pierce K. H.
Published: July 2007

Meticillin-resistant Staphylococcus aureus (MRSA) was unexpectedly isolated from a pig used for streptozotocin-induced diabetes research. To investigate the possible source of the MRSA isolate, nasal swabs were obtained from the animal herd, and from animal holding rooms, and veterinary and research staff involved in the handling of the animals. Overall, four MRSA isolates were cultured from three pigs and from a clinician/scientist. Two were ST22-MRSA-IV, a human strain type associated with epidemic spread. The other two were ST398-MRSA-V, a strain type associated with pigs. Thus, care should be taken to prevent cross-transmission of MRSA.
Renal tumors: The good, the bad, and the ugly
Authors: Flanigan Robert C
Published: July 2007

Abstract:  Renal cancers comprise a wide variety of neoplasms with quite different genetic and molecular characteristics and clinical behaviors. Several issues of significant note have arisen in association with our increased understanding of these tumors, including questions regarding early diagnosis, the evaluation of cystic lesions, the behavior of tumors occurring in young patients, and insights regarding the prognosis and best follow‐up strategies for these tumors.
Characterization of binder and mix properties to detect reclaimed asphalt pavement content in bituminous mixtures
Authors: Chen J S , Chu P Y , Lin Y Y , Lin K Y
Published: July 2007

Abstract: The purpose of this study was to recommend a testing procedure to detect the content of reclaimed asphalt pavement (RAP) used in hot-mix asphalt mixtures. Asphalt was extracted from RAP for use in blending with new binder and aggregate. The recovered binders were blended with virgin asphalt (AC-10) at 10 different concentrations. A concept called relative energy loss was proposed to determine the engineering properties of recycled asphalt concrete (RAC). The relative energy loss was found to be directly related to the resistance of RAC to moisture-induced damage. A noticeable increase in relative energy loss with as much as 50% RAP was observed. At 20% RAP, there was not enough RAP to change binder or mixture properties. The predicted performance of mixtures containing up to 40% RAP by weight was shown to be similar to that of virgin material mixtures. A model was developed to estimate the RAP content in terms of penetration, viscosity, and relative energy loss. Key words: reclaimed asphalt pavement, relative energy loss, moisture sensitivity.
Hydrodynamic and physical assessment of ice-covered conditions for three reaches of the Athabasca River, Alberta, Canada
Authors: Katopodis C , Ghamry H K
Published: July 2007

Water is needed for oil sand developments in the lower Athabasca River basin of northern Alberta, Canada, and is also a key consideration from an ecological and fish habitat perspective, particularly in winter when river flows are at their lowest. Efforts to establish an appropriate flow management regime for the lower Athabasca included revision of River2D, a fixed bed, depth-averaged finite element model, available from www.river2d.ca, to predict hydraulics with a partial or total ice cover. Hydrometric surveys from three reaches of the Athabasca River were used to test the model, assess different model calibration methods, and simulate hydrodynamics for ice-covered conditions. Calibrating bed roughness from ice-free data, assuming the same bed roughness for ice-covered conditions, or the reverse, provided a close fit to the surveyed water surface elevations. The applied ice and composite roughness heights differed according to the applied method of calibration. This may have implications for local velocity estimates possibly affecting fish habitat suitability. A range of bed and composite grain roughness heights, corresponding to different bed substrates and ratios of bed and composite roughness heights to water depths, are provided for model calibration purposes. Key words: hydrodynamics, hydraulics, ice, ecology, environment, fish habitat, winter, oil sands.
Cellulose Yields from Decayed Wood of Western Hemlock
Authors: Munro Donald D.
Published: July 2007

Because of the large volumes of decayed western hemlock wood available in British Columbia forests a small laboratory study was undertaken to assess the potential quantity of cellulose available from western hemlock wood decayed by Echinodontiumtinctorium. Alpha cellulose and holocellulose yields were determined for a total of 57 wood samples from five trees. On the basis of these limited investigations it appears that holocellulose and alpha cellulose yields from western hemlock wood decayed by E. tinctorium should be nearly equivalent to yields obtained from equal volumes of soundwood. Further investigation of cellulose yields from decayed wood is warranted.
Trials in Rooting of Douglas-fir Cuttings by a Paired-Cutting Technique
Authors: Brix H. , Barker H.
Published: July 2007

Cuttings from mature Douglas-fir trees, normally difficult to root, can be stimulated into rooting by grafting them at the stem base with cuttings from seedlings of the same species. This stimulation originates from roots of seedling cuttings; their tops did not affect the final rooting success although they increased the rate of rooting.
Properties of Some Common Newfoundland Forest Soils and their Relation to Forest Growth
Authors: Page G.
Published: July 2007

The morphological, physical, and chemical properties of nine, important, broadly defined Newfoundland forest soil types are described in this paper. The soils of the Avalon Peninsula are generally stonier, more compacted, and richer in silt and clay than those of western Newfoundland. Gleysols and gleyed podzols are the common soils on the Avalon Peninsula whereas orthic and peaty podzols are the common soils in western Newfoundland. In both sample areas the growth of balsam fir and black spruce stands is best on brunisols and poorest on gleysols and deep peats. Only a very small proportion of the total nutrient supply in the various soils is in an available form, but amounts are considered adequate to maintain the nutrient cycle and its associated forest growth at their present levels more or less indefinitely, provided there is no severe disturbance involving the permanent removal of some of the available nutrients. To achieve lasting increases in forest productivity it will be necessary to increase the rate of nutrient cycling by appropriate cultural treatments.
Inoculation and Development of Eutypella Canker of Maple
Authors: Lachance Denis
Published: July 2007

Possible ways by which infection with Eutypellaparasitica can occur on sugar and red maple were investigated using various artificial infection courts and different inocula. Close to 50% of wound-inoculated sugar maple trunks became infected, using either mycelium or ascospore inoculum. Red maple was much less susceptible to infection than sugar maple, as only 6% of the tests were positive. Fifteen to 25% of sugar maple branches, 0.25 to 0.5 in. (0.6 to 1.2 cm) in diameter, inoculated with ascospore suspension, became infected when they had received one of the following wounds: knife cut, bruised bark, or incomplete breakage of the branch. No infection occurred when inoculations were attempted at axils of nonwounded 1- to 2-year-old twigs. On many successful trunk inoculations, a slight swelling of the stem and the characteristic mycelial fans of the fungus under the bark were observed 2 years after inoculation. Where rapid extension of the canker occurred, the initial advance of the fungus was in the bark tissue and subsequently in the underlying cambium and xylem. This fungus development corresponds to that observed in naturally infected trees.
Grazing Values as Related to Tree-Crown Covers
Authors: Dodd C. J. H. , McLean A. , Brink V. C.
Published: July 2007

Studies were undertaken to determine if approximations of herbage productivity could be made from estimates of tree-crown cover, also whether or not estimates from aerial photographs would be accurate enough for this purpose. Results suggest that there is a sufficiently close relationship between herbage production and crown cover in coniferous stands to make the technique useful in range surveys. Estimation of herbage yields from the ground is too slow to be useful in surveys where large acreages have to be covered in a very short time. Similar results were obtained from ground estimates of crown canopy and those made from aerial photographs. Estimates of herbage yields on a pasture made as a result of the survey were almost identical to those established from an earlier grazing trial.
Effects of Light Intensity on Early Periderm and Xylem Development in Pinusresinosa, Fraxinuspennsylvanica, and Robiniapseudoacacia
Authors: Borger G. A. , Kozlowski T. T.
Published: July 2007

The influence of light intensity on development of the first periderm and xylem in seedlings of Pinusresinosa, Fraxinuspennsylvanica, and Robiniapseudoacacia up to 56 days after seed germination was studied. Dark-grown seedlings of all three species lacked periderm at the end of the experimental periods, emphasizing the essentiality of light for periderm development. P. resinosa seedlings grown for 56 days following germination at 70 ft-c (1 ft-c = 10.76 lm/m2) of light and R. pseudoacacia seedlings grown at 70 or 300 ft-c of light for 30 days following germination failed to develop periderm. Seedlings of F. pennsylvanica grown at 70, 300, 600 or 1200 ft-c of light for 30 days following germination developed periderm. Periderm increments did not differ in 56-day-old P. resinosa seedlings grown at 600 or 1200 ft-c or in 30-day-old F. pennsylvanica seedlings grown at 70 or 300 ft-c of light. Phellogen formed sooner and was more active in 30-day-old R. pseudoacacia seedlings grown at 1200 ft-c than in those grown at 600 ft-c. Time to periderm initiation decreased and phellem increment increased in 30-day-old F. pennsylvanica seedlings with each increase in light intensity from 300 to 1200 ft-c. Secondary xylem was absent in dark-grown seedlings of all three species and in P. resinosa and F. pennsylvanica seedlings grown at 70 ft-c of light. In other treatments xylem increment increased significantly with each increase in light intensity up to 1200 ft-c.
Ultrastructural Changes in Leaf Tissues of Populusdeltoides spp. angulata Ait. Infected with Poplar Mosaic Virus
Authors: Navratil S. , Boyer M. G.
Published: July 2007

Ultrastructural observations on the foliar cells of Populusdeltoides spp. angulata Ait. infected by poplar mosaic virus revealed a high content of virus particles in the cytoplasm of most but not all young cells from chlorotic areas. Mature cells from necrotic areas contained far fewer virions while in symptomless green portions no virions were observed. Virus particles were not found in mature sieve elements or in mature nonliving xylem cells.Changes in the cytoplasm and in chloroplasts were followed. Healthy, mature chloroplasts contained well developed thylakoid systems. In infected cells, a disintegrative process at necrotization resulted in the dissolution of the thylakoid system into individual electron dense sacs which were released when the chloroplast membrane dissolved. Cytoplasmic changes were characterized by increased vacuolation. Cisternae of the endoplasmic reticulum and vesiculate bodies were also more numerous. Necrotization was accompanied by dissolution of the cell organelles.
Increase of Dwarf Mistletoe Infections on Young Lodgepole Pine
Authors: Muir John A.
Published: July 2007

Field studies in southern Alberta revealed a rapid increase in the incidence of dwarf mistletoe (Arceuthobiumamericanum Nutt. ex Engelm.) in young lodgepole pine (Pinuscontorta Dougl. var. latifolia Engelm.). In 10 areas of infected trees, the number of infections increased exponentially at a mean rate (base 10 logarithm) of 0.24 per year (range: 0.19–0.29 among areas). Differences in rates of increase among areas were not significant.
Effect of Nitrogen Nutrition Upon Sugar Content and Dry Weight of Juvenile Lodgepole Pine and White Spruce
Authors: Etter Harold M.
Published: July 2007

A factorial experiment was conducted in which Pinuscontorta var. latifolia and Piceaglauca (Moench) Voss seedlings were grown for 6 weeks under controlled environmental conditions with deficient and normal supplies of nitrate and ammonium. Free sugars (sucrose, fructose and glucose), starch (as glucose) and pectic sugars (galactose, arabinose, mannose and xylose) were quantitated. Effects of nitrogen form and nitrogen level, and their interactions, upon sugar contents and dry weights of the two species were examined. Growth responses to nitrogen occurred mainly in the shoots. For most parameters the two species reacted similarly to changes in nitrogen level and form, although the concentration of individual sugars differed between the species. In the shoots there were level × species interactions in the dry weight and the sum of free sugars plus starch. Plants grown under nitrogen deficiency were characterized by higher starch contents throughout and lower free sugars in the shoots. Supplying nitrate instead of ammonium lowered glucose levels, particularly in the shoots. Pectic sugar contents were unaffected by nitrogen nutrition. These compositional and growth responses to the nutritional regime implied changes in carbohydrate metabolism and physiological processes that are described by the C/N ratio of the plant.
Effects of Osmotic Water Stress and Gibberellic Acid on Initial Growth of Oak Seedlings
Authors: Larson M. M. , Palashev I.
Published: July 2007

Red and white oak seeds were treated and untreated with gibberellic acid (GA) and then watered with graded polyethylene glycol 400 solutions to simulate various soil water stress conditions. Seedling growth decreased as the osmotic potential of the soil solution decreased from −1/3 bars to −4 bars to −8 bars (the low, moderate, and high osmotic stress conditions, respectively). Seedling dry weights at high stress condition averaged only 11% of seedling dry weights at low stress condition. At high stress condition, shoot growth was more suppressed than root growth. White oak roots grew somewhat better than red oak roots at high stress condition.Treatment of seed with GA prior to germination stimulated stem elongation and number of leaves per plant but inhibited formation of lateral roots and other aspects of shoot and root growth, especially among white oak seedlings. The GA-stimulated stem growth observed at the low stress condition was completely suppressed at moderate and high stress conditions. GA-white oak seedlings appeared to be less tolerant of soil stress than untreated seedlings.
Sequence of Formation and Resin Content of Scleroderris Cankers
Authors: Dorworth C. E.
Published: July 2007

Scleroderrislagerbergii Gremmen (= Gremmeniellaahietina (Lagerb.) Morelet) infects branches of Pinnsresinosa Ait. largely within 0.8 m of the ground and predominantly on the north side of the tree. The fungus may grow the length of the branch, at approximately one internode per year, into the bole where it incites formation of a canker of which 60% is above and 40% below the point of stem invasion.Resin content of the cankers was twice that of the adjacent noncankered wood, with the greatest increase in the benzene fractions, as compared with the petroleum ether or chloroform/methanol fractions.
Estimation of Pielou's Nonrandomness Index in Conjunction with Large-scale Aerial Photo Cruising
Authors: Payandeh Bijan
Published: July 2007

Simple procedures are proposed for estimating Pielou's nonrandomness index in conjunction with large-scale aerial photo cruising. Such indices were calculated on crown maps of 48-acre (19.2-ha) tracts, one in each of the five major forest types of the Pacific northwest. Density figures were obtained both by complete enumeration and by the Bitterlich point sampling. Pielou's indices ranged from 1.139 to 1.713 and indicated significant clustering in four of the forest stand types studied. Point sampling produced very accurate density estimates and is recommended in conjunction with Pielou's nonrandomness index.
Kraft Pulping of Young Trembling Aspen from Manitoba
Authors: Bella I. E. , Hunt K.
Published: July 2007

The unscreened kraft pulp yields at permanganate No. 14 for 7-, 13-, and 22-year-old trembling aspen (Populustremuloides Michx.) trees from Manitoba for effective alkali applications of 14% were 56.2, 55.7, and 54.8% (o.d. wood), respectively. Specific gravity data for green and ovendry wood are presented, but no relationship with tree height could be established. Pulp strength values from the 7-, 13-, and 22-year-old aspen were, respectively, 60, 67, and 65 for tear factor; 67, 71, and 72 for burst factor; and 10.1, 10.4, and 10.7 (km) for breaking length, respectively. These data indicate that trees of any of the three ages will make a kraft pulp comparable in yield and strength to commercial hardwood–softwood pulp.
Survival of the Weevil, Hylobiuswarreni Wood, in Lodgepole Pine Stumps
Authors: Cerezke H. F.
Published: July 2007

Survival of the weevil, Hylobiuswarreni Wood, in lodgepole pine stumps was examined over a 5-year period in a clearcut area near Robb, Alberta. Larvae continued to develop in the stumps for 2 years after tree removal, although an estimated 88.4% of the larval population apparently died, but none were found in the third year. In the fourth year after cutting, an increase in weevil abundance occurred in adjacent uncut trees. Numbers of newly developed adults in the clearcut areas one year after cutting were about the same as in the uncut areas, but were much higher than in the uncut areas in the second year. The increased rate of weevil development and high numbers of adults in clearcut areas during the second season was attributed to higher temperatures in the larval feeding zone of the stumps. The effects of clearcutting on the surviving adult weevils are discussed and recommendations are made for using clearcutting as a method for weevil control.
Wind–Snow Relations at Marmot Creek, Alberta
Authors: Storr D.
Published: July 2007

Wind patterns are crucial factors to be considered in the design of artificial clearings in the forest to trap and retain snow. Winds at Marmot Creek during snowfall are predominantly southeasterly but are quite light; over 80% of the snow falls with winds less than 4.5 m/s. Maximum winds occur between snowfalls, and favor the southwest to northwest quadrant. The average maximum hourly wind per month is less than 7 m/s in the lower reaches but increases with elevation to 16 m/s at treeline.
The Ectomycorrhizal Association, Alnusrubra + Lactariusobscuratus
Authors: Froidevaux Lucien
Published: July 2007

The mycorrhizal association, Alnusrubra + Lactariusobscuratus, was confirmed by comparing mycorrhiza mantle with sporocarp stipe base mycelium for morphology, reaction to chemical reagents, and autofluorescence in long-wave ultraviolet light.
Markov models of forest-type secondary succession in coastal British Columbia
Authors: Bellefleur Pierre
Published: July 2007

Sample plots of five biogeoclimatic subzones of the British Columbia coastal forest were classified into forest types at 5-year intervals during 40 years. Matrices of transition probabilities from one forest type to another were calculated and stationary Markov models were built for each subzone. Simulation runs were tested against observations. The time and composition of steady state were predicted to evaluate the likelihood of the models. Succession and behaviour of forest types were discussed within and between subzones. It was concluded that forest succession was not Markovian for reasons that depended on the data set and on properties of stationary Markov models. The future of a forest type cannot be determined solely on the basis of its present state, and its prediction necessitates a sound knowledge of how the forest got there in the first place.
A provenance test of red spruce in nine environments in eastern Canada
Authors: Morgenstern E. K. , Corriveau A. G. , Fowler D. P.
Published: July 2007

Survival and total height of red spruce (Picearubens Sarg.) at ages 15 and 22 years from seed are reported. Twelve provenances distributed from North Carolina to Quebec were grown in three experiments each in Ontario, Quebec, and New Brunswick; seven additional provenances were only partially represented. Variance, correlation, and regression analyses were made. Results at both ages were very similar. Provenance differences in survival were small at individual sites and significant only when the results from all nine sites were combined. Provenance differences in height were well expressed and significant in each of the three groups of tests, with northern provenances growing best. Several provenances were also relatively stable and performed well from site to site. Correlation and regression analyses showed that variation in height was more closely related to the degree of introgressive hybridization with black spruce (Piceamariana (Mill.) B.S.P.) than to latitude, elevation, or precipitation at the place of seed origin. These results were conditioned by development on open sites which are not typical red spruce sites.In contrast with expectations when the study was initiated, it is now apparent that provenances from the southern Appalachian Mountains in West Virginia and North Carolina are less variable than expected and not suitable for reforestation in Canada.
Isoenzyme uniformity in western red cedar seedlings from Oregon and Washington
Authors: Copes Donald L.
Published: July 2007

Isoenzymes of newly germinated western red cedar seedlings (Thujaplicata Donn ex D. Don) from western Oregon and eastern and western Washington lacked variation in band patterns of nine enzymes. The isoenzyme results indicate that western red cedar populations contain very little genetic polymorphism. Management of the species will likely be more productive if concentrated on cultural practices rather than on intensive genetic improvement.
Duration-dependent discounting?
Authors: Binkley Clark S.
Published: July 2007

Because economic analysis of forest management decisions depends so critically on the choice of discount rate, the appropriate value of this parameter remains controversial. Recently several economists have suggested, in one form or another, that the discount rate depends on the duration of the investment. However, empirical evidence marshalled to support this position can be explained by a model of asset markets where future returns are uncertain. Consequently, adjusting the discount rate as a function of the duration of the investment may be inappropriate. Alternative analytical techniques are required for comparing timber investments with other assets.
Effect of cluster sampling in biomass tables construction: ratio estimators models
Authors: Kotimaki T. , Cunia T.
Published: July 2007

To minimize field costs, it is ordinarily efficient to select sample trees by cluster sampling; that is, to select several trees from the same geographical location. But when the sample trees are used to construct biomass tables, it is also customary to use regression techniques based on the simple random sampling assumption. This procedure gives rise to errors in the statistical analysis that are largely ignored.A method is shown to evaluate the validity of the regression analysis when the undefined relationship between a dependent variable y and an independent variable x can be sufficiently well approximated by a line of the form y = βx. This method is then applied to two samples of trees selected in clusters of approximately five trees. The regression of nine variables y (various biomass components) on six variables x (functions of tree diameter and height) are then considered. It is shown that analyzing data selected by cluster sampling as data selected by simple random sampling results in relatively large errors in the interval estimates of β. More specifically, the confidence intervals based on the random sampling assumption are ordinarily found to be between 60 and 80% of those based on the cluster sampling assumption. Within the regression model used, however, the point estmates of β remained unchanged.
Mortality of balsam fir and white spruce following a spruce budworm outbreak in the Ottawa River watershed in Quebec
Authors: Blais J. R.
Published: July 2007

Spruce–fir stands in the Ottawa River watershed in Quebec were subjected to defoliation by spruce budworm, Choristoneurafumiferana (Clem.), between 1967 and 1975. Eighteen study plots were established in mixed and coniferous mature stands to determine impact of the infestation on balsam fir, Abiesbalsamea Mill., and white spruce, Piceaglauca (Moench) Voss, and the protracted mortality of these two species following the end of the infestation. The plots were established in 1975, the last year of defoliation, and revisted each year until 1979. Between 1975 and 1979, fir mortality increased from 44 to 91%, and spruce mortality from 17 to 52%. Thus, more than 50% of the trees of both species that died did so during the 4 years after cessation of defoliation. Mortality for both spruce and fir was as high for mixed (hardwoods and budworm hosts) as for coniferous (predominantly spruce and fir) stands. A survey along 710 km of forest roads conducted in the study area in 1980 indicated the degree of mortality observed in the plots was representative of that for the whole region, and that mortality in young stands (20–50 years) was almost as high as in mature fir stands. Since the beginning of the twentieth century, intervals between budworm outbreaks lasted about 30 years in the Ottawa River watershed. However, the high incidence of mortality of white spruce and of immature fir that occurred during the recent infestation was not observed during earlier infestations. Regeneration of fir is plentiful throughout the area, but it will take some time before these young trees attain maturity and become susceptible to budworm attack. The interval between this recent and the next budworm infestation should therefore be longer than preceding ones.
The effects of rationing on the demand for production factors: the case of the Swedish roundwood market
Authors: Löfgren Karl-Gustaf
Published: July 2007

This paper, which is inspired by the tendency of permanent excess demand in the Swedish roundwood market during the late seventies, contains theoretical results on how rationing of roundwood affects the demand for nonrationed production factors. The typical corporation within the forest industry has more than one plant, and the analysis also contains results on how the rationed resource is allocated between low-cost and high-cost plants. The corporation is assumed to work under perfect competition, but it is also hinted at how the results are affected by monopolistic market conditions.
Stem eccentricity in coastal western hemlock
Authors: Kellogg Robert M. , Barber Francis J.
Published: July 2007

Stem eccentricity in second-growth western hemlock (Tsugaheterophylla (Raf.) Sarg.) from southern coastal British Columbia appears to be the rule rather than the exception. Although the difference was small, the average eccentricity ratios (ratios of minimum diameter inside bark (DIB) to maximum DIB) for two Lower Mainland sites were significantly larger than those of two Vancouver Island sites. The average eccentricity ratio of all 87 trees studied was 0.929, with a standard deviation of 0.0231. The angular rotation of the major axis of the stem cross section varied greatly, and was positively related to the average stem eccentricity ratio within 5-m log lengths for each stem. Average eccentricity of the whole stem was relatively independent of diameter at breast height (DBH), age, stem height, and eccentricity at breast height. It does not appear that a practical field technique could be devised for the rapid estimation of average stem eccentricity in western hemlock.
Effect of urea fertilizer on leaching of micronutrient metals and aluminum from forest soil columns
Authors: Otchere-Boateng J. , Ballard T. M.
Published: July 2007

The effects of urea fertilization (0, 112, and 448 kg N/ha) on N transformations, pH, and leaching of Al, Cu, Fe, Zn, and Mn from Ap horizon material of a scarified forest plantation soil were studied in the greenhouse for 15 weeks. Replicated tension lysimeter columns were used, in which seedlings of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) and western hemlock (Tsugaheterophylla (Raf.) Sarg.) were grown. Large amounts of the metal elements were released from columns treated with 448 kg N/ha. Amounts released with the 112 kg N/ha treatment were not significantly different (0.05 level) from the controls. Maximum leaching of Cu and Fe occurred soon after urea application, apparently because of mobilization of metal–organic complexes. In contrast, the major Mn and Zn leaching losses occurred later, effected by the increased acidity caused by nitrification. Al leaching showed a pronounced early peak and a large late peak, and apparently was strongly influenced by both mechanisms.
On computing topographic characteristics of a mountainous catchment
Authors: Tajchman Stanislaw J.
Published: July 2007

This report provides a theory and results of its application for a topographic analysis of a mountain catchment in the Appalachian Mountains, U.S.A. The catchment was divided into triangular segments ([Formula: see text]; 1 acre = 0.405 ha) that were analyzed in the three-dimensional coordinate system; topographic parameters of each triangle were computed and their distribution was represented by isolines. Areas included in specified ranges of inclination and azimuth are given in a tabular form in hectares, and they can be located on maps with isolines of azimuth and inclination.The average gradient of slope inclination is greater on northeast- and north-facing slopes (0.32°/m) than on southwest- and south-facing slopes (0.17°/m).The method has potential for application in land ecological, hydrological, and meteorological studies where a mathematical description of land-surface configuration is needed. The development of a system for automatic reading the coordinates from maps and storing them for computer processing would bring nearer the possibility of using this method for detailed biogeophysical analyses of large mountain regions.
The power function as a simple stem profile examination tool
Authors: Forslund R. R.
Published: July 2007

Formulae are presented for calculating the volume, surface area, centre of gravity, centre of mass, form, taper, and instantaneous slope of the power function. A profile plotting technique is also used that allows visual comparisons between average stem profiles independent of the size and taper of individual stems. The technique is used to demonstrate that the position near 30% of the height from the base of the stem is a position of form stability for volume estimation. Using the paracone profile model (a power function midway between a paraboloid and a cone) with the diameter at the 30% position and the total stem height, individual stem volume estimates within 10% of the true volume (95% confidence) are obtained once again using a sample of 50 yearling aspen (Populustremuloides Michx.). The plotting technique is then applied to the aspen sample, and the average profiles support the hypothesis that juvenile stems may begin life as paraboloids. The average centre of gravity, the average centre of mass, the sectional form, the average form, and the taper of the stems are also examined and are shown to be quantitative indicators of the plotted profile characteristics.
Methods of detecting past spruce beetle outbreaks in Rocky Mountain subalpine forests
Authors: Veblen Thomas T. , Hadley Keith S. , Reid Marion S. , Rebertus Alan J.
Published: July 2007

We examined the use of dendrochronological techniques and stand age structure for detecting past outbreaks of spruce beetle (Dendroctonusrufipennis Kirby) in subalpine forests in the Colorado Rocky Mountains. The methods were based on the observation that following beetle-caused mortality of canopy trees, growth rates of subcanopy Engelmann spruce (Piceaengelmannii (Parry) Engelm.) and subalpine fir (Abieslasiocarpa (Hook.) Nutt.) increase severalfold and remain high for several decades or more. Although inspection of unstandardized individual tree ring-width chronologies is useful for detecting past disturbance, standardized mean chronologies based on ≥20 cores assure adequate sample sizes and improve interpretability. Standardization of ring-width series by fitting the observed data to a horizontal line passing through the mean ring width facilitates detection of past outbreaks better than other standardization models such as polynomial or cubic spline functions. The incorporation of samples from dead-standing trees increases sample sizes and reveals patterns in the early history of a stand that may not be detectable if samples only from live trees are used. Patterns of release frequencies based on nearly all the trees in a stand were helpful in confirming interpretations not always clear from the chronologies alone. Variations in tree population age structures were related to the history of disturbance by beetle outbreak, but age structure alone was not a reliable means of detecting past outbreaks.
Early detection of membrane injury in black spruce (Piceamariana)
Authors: Zwiazek Janusz J. , Blake Terence J.
Published: July 2007

Electrolyte leakage, electrical impedance to 1 and 10 kHz alternating current, and xylem sap osmolarity methods were compared to detect membrane injury in black spruce (Piceamariana (Mill.) B.S.P.) rooted cuttings after subjecting them to four levels of osmotic stress. Although relatively time-consuming, the electrolyte leakage method offered the highest sensitivity and detected injury in plants subjected to a mild stress with polyethylene glycol (15% 3350 polyethylene glycol treatment for 2 days). Change in the electrical impedance of stems subjected to 10 kHz alternating current was a less sensitive indicator of injury than the electrolyte leakage method, but it detected injury earlier than the impedance to 1 kHz current or the xylem sap osmolarity method. Early injury of plants in response to stress was poorly reflected by changes in osmotic potentials of the xylem sap expressed from shoots under high pressure.
Growth-curve differentiation among Japanese larch provenances
Authors: Magnussen S. , Park Y. S.
Published: July 2007

Height–age regression models were fitted to observed heights at ages 7, 11, 15, 22, and 29 years in 20 Japanese larch (Larixleptolepis (Sieb. & Zucc.) Gord.) provenances. A generalized least squares approach with maximum-likelihood estimation of the autocorrelation function and the variance function (heteroscedasticity) is proposed as a framework for growth-curve analysis. Ignoring autocorrelation and variance heteroscedasticity led to serious bias of error estimates that may invalidate statistical comparisons. Normality of log-transformed heights and homogeneity of covariance matrices were confirmed statistically. Cluster analyses followed up by likelihood-ratio tests identified three significantly different growth patterns. Ten provenances belonged to a fast-growing group, nine to a slow-growing group, and one was deemed aberrant (very slow growing). Discriminant analyses on geographic variables and clusters achieved a 95% posterior rate of correct classification. The growth-curve approach was extended to the analyses of age to age correlations and compared with observed correlations. It is concluded that a multivariate approach to growth-curve analysis is preferable to the univariate approach owing to correlations among estimated regression coefficients.
Reconstruction of mixed hemlock–spruce stands in coastal southeast Alaska
Authors: Deal Robert L. , Oliver Chadwick Dearing , Bormann Bernard T.
Published: July 2007

Stands of western hemlock (Tsugaheterophylla (Raf.) Sarg.) and Sitka spruce (Piceasitchensis (Bong.) Carr.) on low-elevation, upland sites in coastal southeast Alaska develop as single-generation stands after stand-replacing disturbances and as multiple-generation stands after minor disturbances. Both stand types were studied. Spruce grew rapidly after major and minor windthrow events and reached the mid to upper canopy of the stand. Hemlock showed variable growth patterns and occupied both upper and lower canopy positions. Unlike forested regions containing more tree species, the species compositions and stand structures were similar among both the single- and multiple-generation stands. Hemlock and spruce occupied unique yet similar canopy and stand structural positions in both single- and multiple-generation stands because they had distinctly different regeneration and development patterns. Regardless of the frequency or intensity of the disturbance, spruce usually regenerated on mineral or mixed-soil microsites created by wind-throw events, and hemlock usually regenerated on organic substrates. Hemlock regeneration was prolific and tended to dominate sites by sheer number. Mortality rates were extremely high, but the large number of hemlock seedlings guaranteed many surviving stems. Spruce regeneration was much lower, but this species had higher survival rates and generally more rapid height growth. An important stand component was the advance hemlock regeneration that existed prior to the new stand; they formed a significant and dominant position in the future stand.
Seasonal and clonal variations in drought tolerance of Populusdeltoides
Authors: Gebre G. Michael , Kuhns Michael R.
Published: July 2007

Water relations of three field-grown eastern cottonwood (Populusdeltoides Bartr.) clones were compared for the 1989 growing season. Clonal and seasonal variations in leaf water potential, leaf osmotic potential, dry weight fraction, and injury index were measured. The injury index was calculated from conductivity changes due to electrolyte leakage during rehydration of dehydrated and nondehydrated leaves. When samples were measured after dry periods, dry weight fraction increased and injury index and predawn osmotic potential declined. There were significant negative correlations between dry weight fraction and osmotic potential for all clones. There were no significant differences between clones from Nebraska (Platte) and Indiana (Tippecanoe) throughout the season in osmotic potential and injury index. The clones Platte and Tippecanoe had significantly lower osmotic potentials than a clone from Ohio (Ohio Red) on most sample dates. When injury index values increased following favorable weather conditions, Platte and Tippecanoe had a significantly lower injury index than Ohio Red. Since all clones had lower osmotic potential, higher dry weight fraction, and lower injury index during dry periods, it was concluded that all had drought hardened during the period, indicating that all clones have some degree of drought tolerance.