bluuebunny/crossref_metadata_2025 huggingface dataset:
An Ectromelia Virus Protein That Interacts with Chemokines through Their Glycosaminoglycan Binding Domain
Authors: Ruiz-Argüello M. Begoña , Smith Vincent P. , Campanella Gabriele S. V. , Baleux Françoise , Arenzana-Seisdedos Fernando , Luster Andrew D. , Alcami Antonio
Published: November 2007

Poxviruses encode a number of secreted virulence factors that modulate the host immune response. The vaccinia virus A41 protein is an immunomodulatory protein with amino acid sequence similarity to the 35-kDa chemokine binding protein, but the host immune molecules targeted by A41 have not been identified. We report here that the vaccinia virus A41 ortholog encoded by ectromelia virus, a poxvirus pathogen of mice, named E163 in the ectromelia virus Naval strain, is a secreted 31-kDa glycoprotein that selectively binds a limited number of CC and CXC chemokines with high affinity. A detailed characterization of the interaction of ectromelia virus E163 with mutant forms of the chemokines CXCL10 and CXCL12α indicated that E163 binds to the glycosaminoglycan binding site of the chemokines. This suggests that E163 inhibits the interaction of chemokines with glycosaminoglycans and provides a mechanism by which E163 prevents chemokine-induced leukocyte migration to the sites of infection. In addition to interacting with chemokines, E163 can interact with high affinity with glycosaminoglycan molecules, enabling E163 to attach to cell surfaces and to remain in the vicinity of the sites of viral infection. These findings identify E163 as a new chemokine binding protein in poxviruses and provide a molecular mechanism for the immunomodulatory activity previously reported for the vaccinia virus A41 ortholog. The results reported here also suggest that the cell surface and extracellular matrix are important targeting sites for secreted poxvirus immune modulators.
The First Hypervariable Region of the gp120 Env Glycoprotein Defines the Neutralizing Susceptibility of Heterologous Human Immunodeficiency Virus Type 1 Isolates to Neutralizing Antibodies Elicited by the SF162gp140 Immunogen
Authors: Ching Lance K. , Vlachogiannis Giorgos , Bosch Katherine A. , Stamatatos Leonidas
Published: November 2007

Current vaccine efforts to elicit cross-reactive neutralizing antibodies (NAbs) against human immunodeficiency virus (HIV) focus on the engineering of soluble mimetics of the trimeric HIV Env glycoprotein (commonly termed gp140 immunogens). Such immunogens are thought to be more effective than previously tested monomeric gp120 immunogens at eliciting cross-reactive NAbs. Still, the breadth of neutralizing antibody responses elicited by gp140 immunogens is narrow. Understanding why antibodies elicited by gp140 immunogens fail to neutralize a wide range of heterologous primary HIV isolates is necessary for improving the design of such immunogens. We previously reported that antibodies elicited in macaques by SF162 Env-derived gp140 immunogens fail to neutralize several heterologous “neutralization-resistant” primary HIV type 1 isolates, such as JRFL, ADA, and YU2. Here we show that by replacing the V1 region of Env on these heterologous viruses with that of SF162, we render them highly susceptible to neutralization by the SF162gp140-elicited antibodies. We observed that viral neutralization was mediated not only by vaccine-elicited anti-V1 but also by anti-V3 antibodies and antibodies directed against as yet unidentified Env regions, depending on the heterologous Env background. Our study indicates that common neutralization epitopes are differentially exposed on diverse primary HIV isolates and that the V1 loop contributes to this differential exposure. Therefore, the antibody responses elicited by soluble gp140 immunogens will have to overcome several distinct obstacles in order to neutralize diverse primary HIV isolates.
Clonal growth in spire-shaped Engelmann spruce and subalpine fir trees
Authors: Shea Kathleen L. , Grant Michael C.
Published: November 2007

The existence of multitrunk clusters in all-aged stands of spire-shaped Engelmann spruce and subalpine fir trees was documented and their origin was investigated using starch gel electrophoresis. Identical genotypes at nine variable loci demonstrated that most of the multitrunk clusters resulted from clonal growth of one individual. Significant differences in allele frequencies between clonal and nonclonal individuals in fir, but not spruce, suggest that there is a genetic component to clonal growth. Comparisons of sizes and ages among individuals with clonal growth and (or) sexual reproduction showed significant size and age differences, depending on mode of propagation, in spruce, and significant size differences in fir. In both species seed production was the predominant method of propagation and trees with seed production or seed production plus clonal growth were larger in size, but not necessarily older, than nonreproductive trees or those with clonal growth only. The fact that some trees had only clonal growth, some trees had only seed production, and some trees had both suggests that each type of propagation is advantageous under certain microenvironmental conditions. Results showing that it was impossible to determine visually if a given multitrunk cluster was composed of a single or multiple genets have implications for demographic and genetic studies in these and related conifer species.
Intraspecifïc variation in gel electrophoresis patterns of soluble mycelial proteins of Phytophthora megasperma isolated from alfalfa
Authors: Faris M. A. , Sabo F. E. , Cloutier Y.
Published: November 2007

The electrophoretic patterns of the buffer-soluble proteins of 26 isolates of Phytophthora megasperma f. sp. medicaginis from diseased alfalfa plants and soil were studied. On the basis of the protein patterns, the isolates were divided into two groups which correlated with cardinal temperatures for growth, pathogenicity, and oogonia size. Group 1 (seven isolates) has minimum growth at 5 °C, optimum at 25–30 °C, and maximum at 35 °C, and is a highly pathogenic pathotype with small oogonia. Group 2 (19 isolates) has minimum growth at less than 5 °C, optimum at 20 °C, and maximum at 30 °C, and is a less pathogenic pathotype with large oogonia. The electrophoresis technique was useful in identifying differences among the Phytophthora isolates.
Early events in the embryo sac after intraspecific and interspecific pollinations in Rhododendron kawakamii and R. retusum
Authors: Kaul V. , Rouse J. L. , Williams E. G.
Published: November 2007

Early events in the embryo sac of Rhododendron kawakamii and R. retusum have been studied after compatible self-pollinations and eight interspecific crosses, using sectioned ovaries, pistil squashes, and seed-set data. Ovules of Rhododendron kawakamii and R. retusum are anatropous, unitegmic, and tenuinucellate, with a typical eight-nucleate, seven-celled embryo sac. Fertilization normally occurs 4–5 days after pollination. The zygote lays down a callose wall but remains undivided during the first 13–15 days after pollination. The primary endosperm nucleus divides soon after fertilization, and development is cellular ab initio. Crosses of R. kawakamii (♂) with R. santapaui and R. retusum and crosses of R. retusum (♂) with R. kawakamii, R. santapaui, R. ovatum, and R. tashiroi showed apparently normal fertilization in a majority of ovules entered by pollen tubes. In crosses of R. kawakamii (♂) with R. quadrasianum and Kalmia latifolia entry of pollen tubes into ovules was delayed and frequently abnormal. Apart from compatible self-pollinations of R. kawakamii an R. retusum, only the cross of R. kawakamii (♂) with R. santapaui produced healthy seedlings. Of the remaining seven interspecific crosses only three showed significant embryo development in control pistils left to mature in situ. Similarities and differences in the breeding behaviour of R. kawakamii and R. retusum are discussed with reference to their taxonomic grouping within subsection Pseudovireya.
Fine structure of root hair infection leading to nodulation in the Frankia–Alnus symbiosis
Authors: Berry A. M. , McIntyre L. , McCully M. E.
Published: November 2007

Root hair infection by Frankia (Actinomycetales) is the means by which nitrogen-fixing root nodules are initiated upon the actinorhizal host, Alnus rubra. Structural details of the infectious process and the changes in host root hair cells are demonstrated at the prenodule stage for the first time using light and transmission electron microscopy. The Frankia hypha is the infective agent, extending from the rhizosphere through the root hair wall in a highly deformed region of the hair. There is no evidence of pleomorphism of the Frankia hypha. The primary wall fibrils of the root hair appear disorganized at the site of penetration. There is extensive secondary wall formation in the infected hair. At the site of penetration, root hair cell wall ingrowths occur that are structurally consistent with transfer cell wall formation. The ingrowths are continuous with the encapsulating wall layer surrounding the Frankia hypha The host cytoplasm is rich in ribosomes, secretory products, and organelles, including Golgi bodies, mitochondria, plastids, and profiles of endoplasmic reticulum. In an aborted infection sequence, some structural features of the host response to Frankia are observable, while other aspects of successful infection do not occur. Limited transfer cell wall is formed at the site of near infection. The root hair cytoplasm is senescent, however, and a callosic plug appears to surround the pathway of infection.
Differences in standing live and dead crops in estuarine marshes on Vancouver Island
Authors: Kennedy K. A. , Brink V. C.
Published: November 2007

There was marked variation in the dynamics of the standing crops of tidal marshes on the east coast of Vancouver Island, British Columbia. Carex lyngbyei Homem. stands did not have standing dead crops for the final 5 months of the 7-month study, though Carex lyngbyei stands produced the most matter (i.e., a peak standing live crop of 1450 g dry matter m−2). In a Salicornia virginica L. stand, the standing dead crop exceeded the standing live crop throughout the study and the stand had the greatest amount of dead matter with a peak standing dead crop of 1470 g dry matter m−2. This suggested that vascular plant matter produced in the Carex lyngbyei stands was more likely to enter the detrital food web of an estuary than was matter produced in the Salicornia virginica stand.
Plant community pattern analysis: a cartographic approach applied in the Lac des Deux-Montagnes area (Québec)
Authors: Vincent Gilles , Bergeron Yves , Meilleur Alain
Published: November 2007

Following quantitative sampling of riparian and forest plant communities bordering on Lac des Deux-Montagnes, a classification and a plant community pattern analysis were made. First a community classification was established by using an hierarchic agglomeration cluster analysis technique. These communities were mapped at a 1:10 000 scale. Second, by superimposing on this map, soil and topographic maps of the same region, a systematic sampling of the maps was done. The variables considered were elevation, drainage, aspect, slope, soil great groups, soil series, deposit, soil texture, stoniness, parent rock, and topography. The discrimination potential of these abiotic variables over the classification was investigated by means of information theory. The variables which most controlled the plant community pattern distribution in the studied area were soil texture, slope, elevation, and aspect. To study relationships among the abiotic variables and their relation to the plant communities, contingency tables, based on the map sampling, were prepared. By analysing each box of these tables it was possible to characterize each of the plant communities and establish the toposequence for nine communities. These communities were dominated respectively by Acer saccharum, A. saccharinum – Cephalanthus occidentalis, A. saccharinum – Fraxinus pennsylvanica, A. saccharinum – Matteuccia struthiopteris, A. saccharinum – Phalaris arundinacea, Pinus strobus, Quercus bicolor, Q. rubra, and Salix sp.
Effect of potato spindle tuber viroid on sexual reproduction and viroid transmission in true potato seed
Authors: Grasmick M. E. , Slack S. A.
Published: November 2007

The effect of potato spindle tuber viroid infection on pollen viability, fruit-set, botanical seed set, seed weight, and seed germination in potatoes was determined. Pollen collected from the infected cultivar 'Monona' was less viable than pollen collected from healthy plants. Pollen collected from infected plants reduced seed set significantly but did not reduce fruit development or seed set in all cultivars tested. For some cultivars, infected maternal plants increased the frequency of fruit development and seed weight compared with healthy controls. True potato seed from viroid-infected 'Katahdin' × 'Superior' crosses germinated at a higher rate than did seed from comparable uninfected parents. Progeny from viroid-infected parents that exhibited potato spindle tuber viroidlike symptoms did not always test positive for potato spindle tuber viroid by bioassay or polyacrylamide gel electrophoresis tests. Efficiency of potato spindle tuber viroid detection by bioassay was highest for seedlings 2 weeks after imbibition. Potato spindle tuber viroid was detected in 100% of the progeny tested after true potato seed was stored at 4 °C for 12 years. Tests on selfed true potato seed from the viroid-infected cultivar 'Monona' demonstrated a transmission rate of 100% after subinoculation of initial bioassay plants.
Somatic embryogenesis and plant regeneration from cell suspension derived protoplasts of Solanum melongena (eggplant)
Authors: Gleddie S. , Keller W. A. , Setterfield G.
Published: November 2007

Cell suspension cultures of eggplant (Solanum melongena L.) were initiated from embryogenic callus cultures and maintained in medium supplemented with either 1-naphthaleneacetic acid (NAA) or 2,4-dichlorophenoxyacetic acid (2,4-D). Higher yields of protoplasts were obtained from cells grown in 2,4-D than in NAA. The efficiency of cell division was also greater in protoplast cultures derived from cells grown in the presence of 2,4-D. Protoplast-derived cells formed somatic embryos in modified Kao or Nagata and Takebe media which were supplemented with 1 mg/L 2,4-D. Early stages of embryogenesis were observed in liquid medium; however, these embryos and associated cell colonies were transferred onto agar-solidified medium for subsequent regeneration. Mature plants were established in soil in the greenhouse.
Vegetational gradients in relation to environmental conditions in northwestern European mires
Authors: Malmer Nils
Published: November 2007

Floristically characterized gradients related to (i) mire surface microtopography, (ii) marginal versus central areas, (iii) ombrotrophy and minerotrophy ("poor and rich mires"), and (iv) distance from the sea can be recognized in the mire vegetation of northwestern Europe. Along these gradients variation occurs in (i) oscillations in the water level, (ii) origin and flow of water, and (iii) supply of minerals. These conditions influence the decay processes and the resulting peat accumulation rate, pH, mineral nutrient supply, and productivity. The differences between marginal and open areas result from differences in nutrient supply (N,P,K), while the differences between "poor and rich" mires are due to differences in the reactions of the peat. In Sphagnum-dominated vegetation, most floristic variation results from effects of differences in peat accumulation rates. Climatic conditions, other than atmospheric supply of minerals, are most important in establishing the regional floristic differences in the bog vegetation.
Raised bogs in eastern North America: transitions in landforms and gross stratigraphy
Authors: Glaser Paul H. , Janssens Jan A.
Published: November 2007

A regional survey of 60 raised bogs was made in eastern North America to determine the geographic patterns of bog landforms and gross peat stratigraphy. Three major types of bogs were identified: (i) midcontinental forested bogs with a longitudinal crest, radiating lines of forest growth, and an actively growing surface of loose Sphagnum hummocks, (ii) non-forested northern or maritime bogs with a convex or plateau shape, various networks of pools, hollows, and firm compact hummocks, and a more slowly growing surface that produces deeply humified bands or recurrence surfaces throughout the peat profile, and (iii) semiforested continental bogs with a forested crest, networks of linear hummocks and flat hollows on the lower flanks, and shallow expanding pools on the hollows. The peat stratigraphy on these semiforested bogs is also intermediate, with recurrence bands in the compact upper portions of the profile, becoming looser and more irregular toward the bottom. The geographic changes in landform patterns and gross peat stratigraphy indicate that forested bogs with a linear crest represent an early stage of bog development and are replaced in time by a nonforested plain with pools as changes in the slope and the hydrologic properties of the surficial layers of peat restrict runoff and infiltration, producing a rise in the water table. Thus on a regional scale autogenic bog processes may be as important as climate in controlling bog patterns and peat stratigraphy.
The bryophyte flora and major peat-forming mosses at Red Lake peatland, Minnesota
Authors: Janssens Jan A. , Glaser Paul H.
Published: November 2007

Red Lake peatland, a vast mire complex in northern Minnesota, contains 21 Sphagnum species, 47 other mosses, and 17 liverwort taxa in its present flora, and several other species present only as fossils in the peat. Four broad vegetation types are recognized: (i) bogs, (ii) poor fens, (iii) forested rich fens, and (iv) rich-fen pools (flarks). These vegetation types are differentiated by water chemistry and bryophyte associations. Most of the major peat-forming moss species are common, circumboreally distributed taxa, and they are distinct in their ecology. Shifts in some of their habitat requirements, however, are evident among different geographic regions of the northern hemisphere. In bogs the major peat-formers are Sphagnum species, while on minerotrophic sites in Red Lake peatland they belong mainly to the family Amblystegiaceae.
Prairie marshes in western Canada, with specific reference to the ecology of five emergent macrophytes
Authors: Shay Jennifer M. , Shay C. Thomas
Published: November 2007

Prairie marshes in western Canada occur in the Manitoba, Saskatchėwan, and Alberta plains, from 49 to between 50 and 53° N. They are dynamic habitats characterized by fluctuations in water levels and water chemistry. Marsh habitats form an east–west gradient that involves a decrease in precipitation (525 – 350 mm year−1) and an increase in its variability. Within the region, water salinity ranges from fresh to hypersaline. Water levels and chemistry coupled with life history features influence the distribution and successional role of emergent macrophytes. Five dominant emergents have aboveground standing crops of between 425 (Scirpus lacustris ssp. glaucus) and 1750 g m−2 (Typha latifolia). They vary in reproductive strategy and tolerance to water levels and salinity. Scirpus lacustris ssp. glaucus grows in deep water with conductivities < 15 mS cm−1, and spreads vegetatively. Typha latifolia, tolerant of water fluctuations and salinity < 10 mS cm−1, spreads both vegetatively and by seed, particularly under drawdown. Phragmites australis tolerates a wide range of moisture conditions and salinities (< 20 mS cm−1). It propagates primarily by rhizomes and runners. Scirpus lacustris ssp. validus thrives under unstable water regimes but is saline intolerant (< 2 mS cm−1). It is short lived (±3 years) and reproduces primarily by seed. Scirpus maritimus var. paludosus, which dominates western wetlands, tolerates hypersaline conditions (±45 mS cm−1), prefers changing water levels, and spreads both vegetatively and by seed. These environmental and life history features help elucidate wetland dynamics.
Salt marshes of Atlantic Canada: their ecology and distribution
Authors: Roberts Bruce A. , Robertson Alexander
Published: November 2007

This paper reviews the status of research on the Atlantic salt marshes of eastern Canada. The floristics, habitats, and biophysical aspects of the Atlantic salt marshes are described and aspects relating to anthropogenic influences on the Atlantic marshes are discussed in the context of contemporary rural settlement and vulnerability to offshore oil development. Guidelines for environment management, protection, and rehabilitation research are proposed. Such guidelines are deemed important since more than half the 33 000 ha of salt marshes in Nova Scotia have been dyked for agriculture. Most of the salt-marsh habitats in Newfoundland have a high degree of domestic grazing, even though the marshes are small in size and rare in occurrence. The least disturbed in terms of domestic use are the Labrador salt marshes which, although grazed by migratory ducks and geese, have not yet been influenced by man's activities. In addition, the Labrador salt marshes are discussed and compared with the northern marshes of arctic Canada in terms of their ecology and formation.
Comparisons of phenology and growth of Michigan and western North American sources of Populus tremuloides
Authors: Brissette John C. , Barnes Burton V.
Published: November 2007

Populustremuloides Michaux progeny from 13 local clones and 12 clones from five locations in Alaska, Alberta, and Utah were grown in southeastern Michigan to compare phenology and early growth. The progeny of western clones broke bud as much as 2 weeks before, and stopped growth up to 2 months earlier than local clones. After 2 years the western progeny averaged only 26–38% the height of the Michigan progeny. Survival and growth of ramets from 49 clones collected from British Columbia to Colorado and planted in southeastern Michigan were studied after 7 years. Only 30% of the 116 ramets and 39% of the clones survived. The poor performance of western clones in both experiments is probably due to their adaptation to longer photoperiods and (or) lower growing season minimum temperatures than occur in southeastern Michigan.
Some insect associates of the pinewood nematode in eastern Virginia
Authors: Carling D. E.
Published: November 2007

"Dauerlarvae" of the pinewood nematode Bursaphelenchusxylophilus (Steiner and Buhrer) were extracted from captured insects that emerged from caged wood of Pinusthunbergii Parl., Pinussylvestris L., and Piceaglauca (Moench) Voss. Monochamustitilator F. carrying B. xylophilus emerged from all three tree species. Neocanthocinusobsoletus Oliv. carrying B. xylophilus emerged from only P. thunbergii although noncarriers emerged from all three tree species. Amniscuscollaris Hald. Neocanthocinusnodosus F., and Xylotrechussagittatussagittatus Germ, also emerged from caged wood, but none carried B. xylophilus. Monochamustitilator appears to be the primary insect associate of B. xylophilus in this area, and in all probability is a primary vector. Neocanthocinusobsoletus is also associated with B. xylophilus, but to a lesser degree than M. titilator. It is possible that N. obsoletus may, under certain circumstances, function as a vector for B. xylophilus, but its feeding and pupation habits suggest its vector role would be minor.
The effect of shade on flowering of Piceaglauca
Authors: Marquard Robert D. , Hanover James W.
Published: November 2007

Differences in fecundity and tree size of white spruce (Piceaglauca (Moench) Voss) were observed within a mixed Picea plantation differentially shaded by a hardwood stand. To relate environmental factors to tree height and fecundity, the plantation was divided into four regions based on the time of the day each region first received direct solar radiation. Thirty percent of the white spruce in the most shaded and 76% in the sunniest region flowered. Photon flux density, spectral quality, and ambient temperature were measured throughout the plantation. Trees in the most shaded region were significantly shorter and received 18% less photosynthetically active radiation than trees in the sunniest region. Photon flux density within the plantation best explained differences in fecundity and tree size.
Effects of irrigation, pulp mill sludge, and repeated coppicing on growth and yield of black cottonwood and red alder
Authors: Harrington Constance A. , DeBell Dean S.
Published: November 2007

Growth and yield of black cottonwood (Populustrichocarpa Torr. and Gray) and red alder (Alnusrubra Bong.) were measured at four successive 2-year coppice harvests. Three levels of amended pulp mill sludge (450, 225, and 0 t•ha−1) were applied before planting, and one-half of the plots were irrigated during the 2-year establishment period prior to the first coppice cycle. Yields of black cottonwood were generally much higher than yields of red alder; maximum ovendry yields obtained were 13.8 t•ha−1•year−1 for black cottonwood and 7.1 t•ha−1•year−1 for red alder. The species differed in their responses to treatment. Growth and yield of black cottonwood was increased by the initial sludge applications, but the reverse was true for red alder. The initial irrigation treatment had carryover effects on the yields of subsequent growth cycles for both species. For all treatments, the greatest yields were usually obtained at the first or second coppice harvest. On the average, red alder yields declined substantially between the third and fourth harvests; black cottonwood yields were generally more consistent between these two harvests. Both species sprouted after all four harvests; however, rootstock mortality generally increased with each harvest. Mortality was much higher for red alder than for black cottonwood; after four coppice harvests, mortality on red alder treatments averaged 55–79%. Average mortality on black cottonwood treatments ranged from 12 to 38%. The management implications of the results are discussed.
Carbon storage patterns in Douglas-fir ecosystems
Authors: Cropper Jr. Wendell P. , Ewel Katherine Carter
Published: November 2007

An ecosystem-level carbon cycling model, coupled with estimates of forested land area classified in 10-year age classes, was used to simulate regional net carbon storage in young Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) ecosystems in western Oregon and Washington. The age-specific net carbon storage patterns were similar in 1934 and 1980, but total carbon storage was 1268 × 103 Mg more in 1980 than in 1934. Net carbon release was predicted for the first 15–20 years of forest development, because of decomposition of detritus and soil organic matter following harvest. This may vary between 10 and 30 years at specific sites with higher or lower actual evapotranspiration (AET) rates, respectively, than the regional average. Calculations of annual carbon storage based on tree biomass alone exceeded estimates calculated from the simulation by 1–2 Mg C•year−1.
Alternative methods for determining edge effect on small sample plots
Authors: Meldahl R. S. , Nordheim E. V. , Ek A. R.
Published: November 2007

The effect of plot edge on tree growth on four uniformly spaced plots was assessed prior to using the data for development of growth simulation models. The plots were established with hybrid poplar (PopulusbalsamiferaL. × P. tristisFrisch.) cuttings at square spacings of 1, 2, 4, and 8 ft (0.30, 0.61, 1.22, and 2.44 m) with a larger open space to separate the plots. The survival, diameter, and height of individual trees were determined annually for 5 years. Data from the narrowest spacing (1 × 1 ft) (1 ft = 0.3048 m) and at the oldest age (5 years old) were used to describe attempts to determine the extent of any edge effect. The methodology involved the examination of diameter and survival trends across the plots. Regression analysis was also used to determine a uniform interior region with diameter at breast height as the dependent variable and location, number of live neighbors, and a measure of competition as possible independent variables. Each of the methods has limitations, but all of them provide some evidence as to the number of trees affected by the border.
Breeding implications of juvenile selection in a range-wide black spruce provenance test
Authors: Nienstaedt Hans
Published: November 2007

Using 3-year heights, the tallest 49 provenances were selected in a nursery test of 110 black spruce (Piceamariana (Mill.) B.S.P.) provenances. A field test of the selected provenances was planted in Wisconsin; two tests of 108 provenances, both in Minnesota. Characteristics evaluated in the nursery included heights after two, three, and five growing seasons, and growth initiation and cessation in the second and third growing season. Heights were measured in the field tests. Separate statistical analyses, ANOVA and simple correlation, were used for the full complement of provenances and for those that were selected. All nursery characteristics varied significantly; the correlations between latitude and height decreased with age, and were not significant after five season's growth. Differences among provenances in free growth may explain this. Selection at age 3 years was not effective; too many selection errors were evident in the test of the full complement of provenances. Early selection on the basis of heights and phenological characteristics is not an effective way of reducing large range-wide provenance tests to breeding populations.
Cambial electrical resistance related to the number of vascular cambial cells in balsam fir
Authors: Smith K. T. , Blanchard R. O. , Shortle W. C.
Published: November 2007

Cambial electrical resistance (CER) was related to the number of cells per radial file of vascular cambium in dominant and codominant balsam fir (Abiesbalsamea (L.) Mill.) trees sampled during the growing season. Scanning electron microscopy (SEM) was used to examine the vascular cambial zone (VCZ) of balsam fir during the growing and dormant seasons. Trees selected for SEM were categorized as having growing season CER < 10 kΩ or CER > 12 kΩ. The two growing trees with CER < 10 kΩ had a mean of seven cells per radial file of VCZ in contrast with four cells per radial file in the two trees of CER > 12 kΩ. Trees of either growing season category had dormant season CER > 12 kΩ and four cells per radial file of VCZ. The relationship between CER and the number of cells per radial file of VCZ supports the hypothesis relating CER to periodic growth rate in balsam fir.
Effects of urea and ammonium nitrate fertilizer on growth of a young thinned and unthinned Douglas-fir stand
Authors: Barclay H. J. , Brix H.
Published: November 2007

The effects of two sources of nitrogen fertilizer applied at rates of 224 and 448 kg N/ha on growth of a thinned and unthinned 24-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stand were studied. Ammonium nitrate yielded higher growth of diameter and volume than did urea over a 9-year period, particularly with thinning. Height growth was not affected by nitrogen source. The efficiency of nitrogen fertilization in terms of stem volume response per kilogram of nitrogen applied was greatest with ammonium nitrate in thinned plots. Tree mortality increased substantially with level of fertilization for both sources, and decreased markedly with thinning.
A method to culture immature embryos of Populusdeltoidesinvitro
Authors: Kouider Mohamed , Skirvin Robert M. , Saladin K. Paul , Dawson Jeffrey O. , Jokela Jalmer J.
Published: November 2007

Immature embryos were excised from capsules of Populusdeltoides Bartr. ex Marsh, resulting from the artificial pollination of female branches maintained in moist soil. Embryos excised 10–21 days postpollination produced multiple shoots (2–30) when cultured on a modified Murashige and Skoog medium. Embryos 28–35 days postpollination produced single or multiple shoots when cultured on the same medium. Embryos grown in reduced light produced more vigorous shoots than embryos grown at higher light intensities. The addition of glutamine to the medium in reduced light stimulated the embryos to thicken and increased the quality of the shoots produced. The methods described may be useful in rescuing embryos resulting from artificial hybridization in cases where they might otherwise be lost.
Biomass and leaf area in contrasting lodgepole pine forests
Authors: Pearson John A. , Fahey Timothy J. , Knight Dennis H.
Published: November 2007

not available
Propagation of Abiesfraseri by cuttings: orthotropic shoot production from hedged stock plants
Authors: Wise Farrell C. , Blazich Frank A. , Hinesley L. Eric
Published: November 2007

Fraser fir (Abiesfraseri (Pursh) Poir.) stock plants grown as transplants (4 years old) or sheared Christmas trees (14 years old) were subjected to independent combinations of hedging and chemical treatments to induce orthotropic shoot production. Decapitation treatments that removed the most top growth produced the greatest number of orthotropic shoots in each age-class after one growing season. Sprays of dikegulac at 1000 and 3000 ppm did not stimulate orthotropic shoot formation. Orthotropic shoots induced on maturing Christmas trees rooted in lower percentages than plagiotropic cuttings from similar nondecapitated trees. Since rooting and survival of the severed shoots were largely or totally unaffected by hedging treatments, decapitation treatments that produced the most shoots the 1st year continued to exhibit the most rooted cuttings at the end of the following season. At that time, superior treatments on 4- and 14-year-old plants had produced less than three and five rooted orthotropic shoots per stock plant, respectively. The stock plants received no additional hedging and were evaluated for shoot production after a second season. No treatment differences occurred within the older plants, but superior treatments from the 1st year tended to be retained within the transplants. In a separate study, orthotropic shoot production by severe decapitation was enhanced by maintaining low fertility.
Stein-rule estimation of coefficients for 18 eastern hardwood cubic volume equations
Authors: Green Edwin J. , Strawderman William E.
Published: November 2007

A Stein-rule estimator, which shrinks least squares estimates of regression parameters toward their weighted average, was employed to estimate the coefficient in the constant form factor volume equation for 18 species simultaneously. The Stein-rule procedure was applied to ordinary least squares estimates and weighted least squares estimates. Simulation tests on independent validation data sets revealed that the Stein-rule estimates were biased, but predicted better than the corresponding least squares estimates. The Stein-rule procedures also yielded lower estimated mean square errors for the volume equation coefficient than the corresponding least squares procedure. Different methods of withdrawing sample data from the total sample available for each species revealed that the superiority of Stein-rule procedures over least squares decreased as the sample size increased and that the Stein-rule procedures were robust to unequal sample sizes, at least on the scale studied here.
The choice between design-dependent and model-dependent sampling
Authors: Schreuder H. T. , Wood G.B.
Published: November 2007

Design-dependent and model-dependent sampling strategies are discussed. Model-dependent strategies can be very efficient in highly specialized sampling situations where an underlying model can reasonably be assumed, such as in sampling for timber sales, but can also be very unreliable if the wrong model is assumed. This is illustrated by the application of stratified sampling with probability proportional to size (a design-dependent sampling scheme) and stratified sampling from the cumulated values of an independent variable x (a model-dependent, purposive sampling scheme) to selected data sets with somewhat diverse characteristics.
Optimal harvest scheduling at the forest level in the presence of the risk of fire
Authors: Reed W. J. , Errico D.
Published: November 2007

The effect of fire on forest yields has been well documented in stand-level analyses; however, forest-level effects are less widely known. A set of dynamic equations can be constructed that describe the evolution of a forest under the impact of harvesting and random fire. When fire is treated in a deterministic fashion, these equations can be used to formulate an optimal harvest scheduling problem that can be solved using linear programming. Examples using white spruce data for the Fort Nelson Timber Supply Area of British Columbia show that even modest rates of fire can have a dramatic impact and that present harvest scheduling models may be considerably overestimating projected forest harvest levels. Results also show that the deterministic approach appears to be a reasonable approximation of the true stochastic fire problem.
Trend surface analysis of spatial patterns of tree size, microsite effects, and competitive stress
Authors: Thomson A. J.
Published: November 2007

Trend surface analysis was used to determine the spatial patterns of tree size, competitive stress, and effects of microsite on growth. A three-dimensional representation of the trend surface facilitated interpretation. Gradients of competitive stress depended on the competition index used. Microsite effects have a spatial trend and individual tree genetic effects are represented by the residuals from this trend.
Application of a geometrical volume equation to species with different bole forms
Authors: MacDonald G. B. , Forslund R. R.
Published: November 2007

Stem analysis of 20 Abiesbalsamea (L.) Mill., 68 Piceamariana (Mill.) B.S.P., 19 Piceaglauca (Moench) Voss, 31 Populustremuloides Michx., and 37 Betulapapyrifera Marsh. revealed form variation between species. A volume equation based on the paracone (a geometrical solid midway between a paraboloid and a cone) estimated individual tree volume within 10% of the true volume (at the 95% confidence level) for all species. The input variables required were total height and diameter at a relative height of 0.2 for Betulapapyrifera and 0.3 for the other four species. If breast-height diameter was used, the effect of form variation on the accuracy of volume prediction was more pronounced. In this case, the geometrical equation modified for each species according to the average centre of gravity provided more consistently accurate volume estimates than either the paracone equation or Honer's transformed variable equation. For all species, the diameter measurement position was more critical than the version of the geometrical equation selected.
Mass of downed wood in northern hardwood forests in New Hampshire: potential effects of forest management
Authors: Gore Jeffery A. , Patterson III William A.
Published: November 2007

Downed (i.e., fallen, dead) wood was sampled in 1-, 15-, 50-, and 100-year-old managed stands, an uneven-aged, managed stand, and an uncut stand of northern hardwoods in New Hampshire. Mass of downed wood ranged from a mean of 32 t/ha in the 15- and 50-year-old stands to 86 t/ha in the recently cut stand. Mean estimates varied significantly among stands, although most of the variation was due to the large amount of downed wood in the recently cut stand. The range of downed-stem diameters was greatest in the 100-year-old and uncut stands. Large (>38 cm) logs were notably absent from the uneven-aged, managed stand, indicating that selective cutting utilizes mature stems efficiently. Comparison of our data with other estimates shows that the amount of downed wood in northern hardwood stands declines to about 20 t/ha within 20–30 years after logging. Quantities remain relatively stable for up to an additional 30 years and then begin to increase. They stabilize at 35–40 t/ha after approximately 100 years. Large-diameter logs become an increasingly important component of downed wood as stands mature beyond 50 years of age. Rapid decomposition of even the largest logs precludes continued accumulation of downed wood in uncut, old-growth stands. The data suggest that less downed wood and fewer large-diameter logs are likely to accumulate under short-rotation (<50 years) harvest, whole-tree harvests, and selection cuts than under long rotations or in uncut forests.
Inland spruce cone rust (Chrysomyxapirolata) control: relation of ferbam application to basidiospore production, rainfall, and cone phenology
Authors: Summers D. , Sutherland Jack R. , Woods T. A. D.
Published: November 2007

Experiments were conducted over a 3-year period (1982–1984) at a white spruce (Piceaglauca (Moench) Voss) seed orchard near Salmon Arm, British Columbia, to relate the control of inland spruce cone rust (Chrysomyxapirolata Wint.) by ferbam to the number of fungicide applications, basidiospore production, rainfall, and cone phenology. Either multiple or single applications of ferbam during the period starting about 1 week before and through the pollination period reduced the incidence of the disease by 5- to 10-fold without any reduction in seed yield per cone, although seed germination was reduced slightly.
Nutrient and biomass removals from a red spruce – balsam fir whole-tree harvest
Authors: Smith Jr. C. T. , McCormack Jr. M. L. , Hornbeck J. W. , Martin C. W.
Published: November 2007

A mechanized whole-tree harvest was conducted on a watershed in central Maine dominated by Picearubens Sarg. and Abiesbalsamea (L.) Mill. The harvest removal and redistribution of biomass, nitrogen, phosphorus, calcium, magnesium, and potassium were estimated and evaluated with respect to estimates of site nutrient reserves. Regression equations were developed to estimate the nutrient contents and ovendry weight of the aboveground components of the Picearubens and Abiesbalsamea. Unit area estimates of nutrient and biomass removals were based on the application of the regression equations to a tally of all trees on twelve 0.04-ha square plots. Unit area estimates were made of exchangeable and total nutrients contained in the forest floor and glacial till above a hardpan. The harvest removed 90% of the biomass, 91 % of the nitrogen, phosphorus, potassium, and calcium, and 90% of the magnesium in the above-stump portions of the forest. These removals were from two to four times the amount of nutrients that would have been removed by a bole-only harvest, while increasing biomass removals by 1.4 times. The nutrients removed by the harvest were between 0.1 and 5% of the total soil reserves. Nutrient removals are evaluated in the context of three commonly used evaluation approaches: static comparisons of nutrient pools, nutrient input–output budgets, and computer simulation.
Comparison of gibberellins A3 and A4/7 for promoting strobili in western hemlock
Authors: Rottink Bruce A.
Published: November 2007

Weekly foliar sprays of either 150 mg•L−1 of gibberellin A3 with surfactant, 150 mg•L−1 of a mixture of gibberellins A4 and A7 (A4/7) with surfactant, or deionized water with surfactant were applied to potted western hemlock (Tsugaheterophylla (Raf.) Sarg.) during the growing season. Gibberellin A4/7 was effective in promoting strobili production, but gibberellin A3 was not.
A comparison of live and dead fine root weights in stands of Sitka spruce in contrasting soil water regimes
Authors: Nisbet Thomas R. , Mullins Christopher E.
Published: November 2007

The variation in live and dead fine root weights with soil water regime was studied on three sites supporting closed-canopy stands of Sitka spruce (Piceasitchensis (Bong.) Carr.). Soil types were a very poorly drained peaty gley, an imperfectly drained peaty gley, and a freely drained podzolized brown earth. Fine root material was extracted from replicate cores (0–10 cm) and categorized as live or dead. Live fine root weight, live to dead fine root ratio, and the number of live fine root tips all differed significantly between sites, decreasing with increasing dryness of the soil water regime.
Effects of acidity on invitro pollen germination and tube elongation in four hardwood species
Authors: Ryn D. M. Van , Jacobson J. S. , Lassoie J. P.
Published: November 2007

The effects of media acidity on pollen germination and tube elongation of four northeastern tree species, flowering dogwood (Cornusflorida L.), black birch (Betulalenta L.), yellow birch (Betulaalleghaniensis Britton), and sugar maple (Acersaccharum Marsh.), were investigated. Pollen was collected and germinated in growth media that were acidified to pH values ranging from 5.0 to 2.6. Pollen of all four species were affected by acidification of the germination medium to below pH 4.2. At pH 3.0 and 2.6 no pollen germinated in any species. Betwee pH values of 4.2 and 3.4, germination was reduced by more than 50% from that at pH 5.0. Mean tube length was reduced at the lowest pH at which germination occurred. The pH of the growth medium increased during pollen germination to at least 5.2 when initial pH values were 3.8 and above. These results suggest that media acidity can influence pollen germination and, consequently, acid rain, which now occurs in eastern North America, may affect reproductive processes in northern hardwood forests.
A method of counting chromosomes of hardwood trees using root tips and young leaves
Authors: Hömmö Leena M. , Särkilahti Eliisa M.
Published: November 2007

Double staining with Feulgen and Giemsa was used for root tips and young leaves and it allowed counts of the mitotic chromosomes of Betulapapyrifera Marsh, and Populustremula L. The following chromosome numbers were easily determined: B. papyrifera, 2n = 70, 2n = 84, and 2n = 140; P. tremula, 2n = 38 and 2n = 57.
Nondestructive estimation of the needle weight and stem weight of small loblolly pine trees (Pinustaeda)
Authors: Shear Theodore H. , Perry Thomas O.
Published: November 2007

A method for estimating needle weight of 4-year-old loblolly pine trees from branch numbers and measurements is described. Bole weights are estimated independently from diameter measurements at the root collar. Development of independent estimates of needle weight and bole weight allowed an analysis of the variation in bole weight that was attributable to needle weight (as an independent variable).
Black spruce outplant performance: effect of winter application of hexazinone on shear-bladed sites in boreal Ontario
Authors: Wood J. E. , Althen F. W. von , Campbell R. A.
Published: November 2007

Three field experiments were carried out to assess the performance of 1.5 + 1.5 black spruce (Piceamariana (Mill.) B.S.P.) transplants and FH508 Japanese paperpot seedlings in relation to various levels of chemical site preparation with Pronone® (granular hexazinone) applied during the winter to 4700 trees on shear-bladed, imperfectly drained stone-free clay and clay loam soils. Second- and 3rd-year assessments revealed that both stock types responded similarly to chemical site preparation. Growth data were fitted to linear and, where appropriate, quadratic response models. The response of planted seedlings was positive and generally linear over the range of dosages (0 to 6 kg active ingredient/ha) applied. Chemical site preparation had little or no effect on survival of either stock type. In comparison with the transplants, the paperpot seedlings were in better condition and were of a similar size at the end of the assessment period.