bluuebunny/crossref_metadata_2025 huggingface dataset:
Physiological quality of lodgepole pine and interior spruce seedlings: effects of lift date and duration of freezer storage
Authors: Ritchie Gary A. , Roden John R. , Kleyn Nick
Published: December 2007

Owing to frozen ground, nurseries in interior Oregon, Washington, and British Columbia are often unable to lift bare-root seedlings during midwinter when they are in peak physiological condition. Therefore, seedlings are normally lifted in the fall and planted either immediately or after overwinter storage, or lifted in the spring and planted either immediately or after brief storage. The objective of this study was to ascertain which of the above strategies produced planting stock with the highest physiological quality. The species evaluated were lodgepole pine (Pinuscontorta Dougl.) and interior spruce (Piceaglaucaengelmannii complex). Seedlings were grown in a Weyerhaeuser Canada nursery near Armstrong, B.C., and lifted on nine dates spanning early October 1982 to late March 1983. Seedling quality was evaluated at each lift date and following 2 and 6 months in freezer (−1 °C) storage. Evaluations consisted of measurements of dormancy release index, root growth potential (RGP), stress resistance (SR), and frost hardiness (FH). The main effects of lift date and storage duration were generally highly significant on all seedling-quality attributes. Lift date × storage duration interactions were also highly significant in most cases. Dormancy weakened throughout winter in the nursery, with accumulated chilling. Storage slowed the release of dormancy for most lift dates. RGP was very high in fall-lifted seedlings, but declined rapidly after storage. RGP again increased in late winter, but was not appreciably affected by storage except for March-lifted seedlings. SR was relatively high in fall-lifted seedlings and very low in spring-lifted seedlings. SR was also reduced by storage, especially after 6 months. However, SR did not fall as rapidly in stored seedlings as it did in seedlings left in the nursery bed. FH was −30 °C in early October; during midwinter FH was beyond the limit of measurement (−40 °C). Seedlings of both species appeared to deharden in storage, but at a relatively slow rate. The best operational strategy seems to be fall lifting, beginning November 1, with overwinter freezer storage. Spring-lifted seedlings tended to exhibit low RGP, low SR, low FH, and poor storability.
Transfer of elements to the atmosphere during low-intensity prescribed fires in three Australian subalpine eucalypt forests
Authors: Raison R. J. , Khanna P. K. , Woods P. V.
Published: December 2007

Measurements were made of the transfer of N,P,K, Ca, Mg, Mn, and B to the atmosphere during low-intensity (350–600 kWm−1) prescribed burns in three Australian subalpine eucalypt forests dominated by overstoreys of either Eucalyptuspauciflora (Sieb. ex Spreng), Eucalyptusdives (Schau.), or Eucalyptusdelegatensis (R. T. Baker). Elemental transfer was calculated as the difference between the quantity of an element in the fuel (litter plus understorey) before burning and that present in the postfire residues which were recovered quantitatively using small aluminium trays. Complete recovery of fine ash is essential for accurate budgeting for elements other than N. The mass ranges of elements transferred to the atmosphere (kilograms per hectare) were as follows: N, 74–109; P, 1.96–3.04; K, 12.1–21.0; Ca, 18.7–29.7; Mg, 4.5–9.7; Mn, 1.6–4.3; B, 0.08–0.12. These transfers represented, as a percentage of the element initially present in the fuel, the following: N, 54–75; P, 37–50, K, 43–66; Ca, 31–34; Mg, 25–49; Mn, 25–43; B, 35–54. The percentage loss of elements was positively linearly correlated with the percentage loss in fuel weight. High concentrations of P and cations occur in fine ash, especially grey (mineral) ash. In comparison with unburnt litter, concentrations of Ca, Mg, and P were increased by 10- to 50-fold, 10- to 35-fold, and 10-fold in fine (<1 mm) ash produced at the E. pauciflora site, respectively. Hence, transport of a relatively small mass of fine ash either during or after a fire may result in the removal of a significant quantity of nutrients. Prescribed fire rotations of about 10–12 years are required in the forests studied to permit natural inputs of N to approximately replace the amounts transferred to the atmosphere in a single fire. For P replacement, rotation length would need to exceed 20 years. The major impact of regular burning would appear to be on the N cycle because of the rapid reaccumulation of N in shrub biomass and surface litter, thus rendering it highly susceptible to volatilization in a subsequent burn.
Impact of dwarf mistletoe on the growth of western hemlock trees having different patterns of suppression and release
Authors: Thomson A. J. , Alfaro R. I. , Bloomberg W. J. , Smith R. B.
Published: December 2007

The impact of dwarf mistletoe on the volume growth of western hemlock was evaluated in trees from five locations on northeast Vancouver Island. Within each area, sampling was designed to minimize the effects of site variability. However, differences in age and in patterns of suppression and release between infection classes were observed in some stands. Growth was corrected for these differences by subtracting the suppression core and by making comparisons at equivalent ages. Volume losses associated with dwarf mistletoe infection were higher than reported in our previous studies in other areas, averaging 23 and 39% with moderate and severe infection levels, respectively.
Effects of high levels of fertilization with urea on growth of thinned and unthinned Douglas-fir stands
Authors: Barclay H. J. , Brix H.
Published: December 2007

The diameter and volume growth of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) were documented 9 years after thinning and fertilization. The treatments involved three levels of thinning (0, 1/3, and 2/3 of basal area removed) and six levels of fertilization (0–1344 kg N/ha) with urea. Increments for both diameter and gross volume increased with the rate of fertilization and responses were still apparent 9 years after treatment. For unthinned plots, the 9-year volume growth responses were 30, 50, and 80% with fertilizer rates of 224, 448, and 896 kg N/ha, respectively. The efficiency of fertilizer use, measured as stem volume response per unit of nitrogen applied, decreased with the rate of fertilization, but this picture may change over a longer response period. There was a positive interaction between fertilization and thinning such that high levels of both mutually enhanced growth. Mortality increased with fertilization, but only noticeably in unthinned plots.
A selective medium for Phellinusweirii
Authors: Hutchins Anita Stiebrs , Fay Harlan , Knutson Don
Published: December 2007

A selective medium developed for the isolation of Phellinusweirii consists of 45 g/L of malt agar, 80 ppm mycostatin, 100 ppm benomyl, 8 ppm claforan, and sufficient 1 N HCl to bring the pH to between 2.6 and 2.8. The fungus was recovered from wood chips with advanced decay and from small roots 5–10 mm in diameter, to the general exclusion of associated microorganisms.
Harvesting profitability as affected by classification of costs and assignment of the components of scheduled time
Authors: Howard Andrew F.
Published: December 2007

The principles of production economics were used in a study of the profitability of grapple yarding operations in coastal British Columbia. The effect of changes in the classification of costs and assignment of system scheduled time on the marginal piece size and net returns were quantified. Cruise data and site information from a tract of timber sold under the Ministry of Forest and Lands Small Business Enterprise Program were used in a case study. Estimates of production rates for grapple yarding were made using data available in the literature. Results from a detailed cost analysis were combined with the production rates to predict yarding costs. Labor and equipment costs charged to individual trees were varied to determine the effect on the marginal piece size and net returns. The various components of system scheduled time assigned to individual trees were also varied. The optimal level of fiber utilization, given economic theory, increased while profitability declined with reductions in system costs charged to individual trees. The size of the marginal piece and yarding profitability were less sensitive to changes in the manner in which the various components of system scheduled time were assigned to trees.
Biomass and nutrients in regenerating woody vegetation following whole-tree and conventional harvest in a northern mixed forest
Authors: Hendrickson O.Q.
Published: December 2007

Biomass and nutrient contents of regenerating woody plants and litter fall were measured after a northern mixed conifer–hardwood forest was harvested by conventional and whole-tree methods. Before harvest, the central Ontario study site was occupied by a 95-year-old pine (Pinusresinosa, P. strobus) and aspen (Populustremuloides, P. grandidentata) stand growing on gently rolling, gravel-free outwash sands. Four years after harvest, aspen abundance increased 100-fold in both harvested areas, with higher densities after whole-tree harvest (WTH) (4.1 stems/m2) than after conventional harvest (CH) (2.7 stems/m2). No self-thinning of aspen occurred between 2 and 4 years after harvest. Total aboveground woody biomass accumulated at 2.0 t•ha−1•year−1 in the WTH area and 1.5 t•ha−1•year−1 in the CH area; the preharvest rate was 2.0 t•ha−1•year−1. Peak autumn litter production occurred earlier in the harvested areas than in an adjacent uncut area. Cycling of N and K in litter fall returned to preharvest rates after 4 years. Cycling of Ca in litter fall was lower after WTH than after CH. Vegetation uptake of N and K (litter fall plus woody biomass) in the harvested areas in year 4 exceeded the preharvest value. Increased N accumulation in woody biomass (3.0 kg•ha−1•year−1 before harvest, 10.6 kg•ha−1•year−1 after WTH) would place a relatively greater demand on forest floor N pools in the WTH than in the CH area owing to lack of N input in logging slash. Although WTH did not reduce initial rates of biomass production, Populus spp. had lower concentrations of N, Ca, and Mg in the WTH area than in the CH area. There may be a danger that WTH on less fertile sites in the region will produce dense, unproductive aspen stands with low rates of self-thinning.
Initiation of roots on hypocotyl cuttings of Pinussylvestris, with emphasis on direct rooting, root elongation, and auxin uptake
Authors: Grönroos Roland , Arnold Sara von
Published: December 2007

Direct rooting of hypocotyl cuttings of Pinussylvestris L. is described and compared with rooting via wound tissue. The optimal 3-indolylbutyric acid treatment for direct rooting of Pinussylvestris hypocotyl cuttings under in vitro conditions was 1.23 mM for 24 h. This treatment resulted in 45% rooting within 3 weeks after cutting. During this period, only direct rooting was observed. Three to 4 weeks after cutting, roots developed either directly on the hypocotyl or via wound tissue. After the first month, rooting took place predominantly via wound tissue. The optimal 3-indolylbutyric acid treatment found for in vitro culture could successfully be used for hydroponic culture (under nonsterile conditions). In vitro culture inhibited root elongation. However, after transfer of rooted cuttings from in vitro to hydroponic culture, root elongation increased markedly. Uptake studies with 3-[5(n)-3H]indolylacetic acid mixed with the nutrient solution showed that auxin uptake by the cutting probably occurred mainly through uptake of the nutrient solution. After 24 h treatment with 1.43 mM 3-indolylacetic acid, the concentration taken up by the cuttings was 0.91 nmol/mg fresh weight. Differences between individual cuttings in auxin uptake could not explain the poor direct rooting of Pinussylvestris hypocotyl cuttings cultured in vitro.
The contrast in stand dynamics as revealed by comparing parameter estimates for a general stand growth model
Authors: Tait D. E. , Jahraus K. V.
Published: December 2007

A general stand model is fitted to and used to describe the pattern of stand dynamics for six different species of conifers. The species considered are Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), lodgepole pine (Pinuscontorta Dougl.), western hemlock (Tsugaheterophylla (Raf.) Sarg.), jack pine (Pinusbanksiana Lamb.), white spruce (Piceaglauca (Moench) Voss), and red pine (Pinusresinosa Ait.). The model, a causal process model, uses two difference equations and six species-specific parameters to generate changes in stand volume and density as a function of volume, density, and site quality. In a simulation framework, the model represents a variable-density, variable-site yield equation. The model's structural equations are invariant from species to species. The differences in species stand dynamics are thus reflected by differences in the species-specific parameter values. The variation in species dynamics is accounted for by variation in only three of the model's parameters. The first of these three parameters reflects the site-determined growth potential of the species, the second reflects the reduction in growth that results from stand crowding, and the third corresponds to a density-independent mortality rate.
Realized genetic gain for 2nd-year height in jack pine
Authors: Rudolph Thomas D. , Kang Hyun C. , Guries Raymond P.
Published: December 2007

A complete cycle of within-family selection for 2nd-year height in jack pine (Pinusbanksiana Lamb.) was accomplished. The expected absolute gain from a theoretical population is 9.3%. The expected gain calculated using actual selected parental group means was 6.5% for upper selection and −6.5% for lower selection; realized gains were 5.1% for upper selection and −3.7% for lower selection. Reasons for reductions in the realized gain compared with expected gain include (i) a finite base population size; (ii) biological constraints such as inconsistent seed production; (iii) non-normal distribution for the trait of interest; and (iv) non selected male parents in open pollination.
Foliar analysis and response of fertilized chlorotic western hemlock and western red cedar reproduction on salal-dominated cedar–hemlock cutovers on Vancouver Island
Authors: Weetman G. F. , Fournier R. , Barker J. , Schnorbus-Panozzo E.
Published: December 2007

Microplot and conventional plot trials were used to determine the nutritional status and required nutrient additions to bring young regenerations of western hemlock (Tsuga heterophylla (Raf.) Sarg.) and western red cedar (Thujaplicata Donn ex D. Don) out of "check." The trees were growing on deep mor-humus Podzols invaded by dense salal (Gaultheriashallon). Salal removal by grubbing and application of Garlon was also tested. Foliar vector analysis, used for hemlock, identified a response to N and P that was confirmed by subsequent 3-year height growth response. Salal removal resulted in increased N uptake only in cedar. Cedar also responded to N and P additions, but vector analysis was not feasible owing to indeterminate growth. Foliar analysis values are compared with published data. It is suggested that salal competition or allelopathy may be the primary cause of inadequate N and P nutrition.
Regional variability in nitrogen mineralization, nitrification, and overstory biomass in northern Lower Michigan
Authors: Zak Donald R. , Host George E. , Pregitzer Kurt S.
Published: December 2007

Potential net nitrogen (N) mineralization, potential net nitrification, and overstory (boles and branches) biomass were measured in nine forest ecosystems commonly found within the well-drained uplands of northern Lower Michigan. The ecosystem types ranged from oak-dominated forests on coarse-textured outwash sands to mesic northern hardwood forests on sandy glacial till. Overstory biomass was calculated using species-specific allometric equations developed for Lake States hardwood species. Potential net N mineralization and potential net nitrification were measured by a 30-day aerobic laboratory soil incubation. Analyses of (co)variance were used to determine differences in potential N mineralization, net nitrification, overstory biomass, and biomass increment among the nine ecosystem types. Linear and nonlinear regression analyses were used to predict overstory biomass and biomass increment using potential net N mineralization as the independent variable. Overstory biomass ranged from 92 t•ha−1 in a xeric oak ecosystem to 243 t•ha−1 in a northern hardwood ecosystem; annual biomass production ranged from 1.3 to 3.5 t•ha−1 year−1, respectively. Potential net N mineralization was lowest in the xeric oak ecosystem (52.0 μg N•g−1) and greatest in the mesic northern hardwood ecosystem (127.8 μg N•g−1). Potential net nitrification was 45.5 μg NO3−-N•g−1 in the northern hardwood ecosystem; 10 to 230 times greater than in other ecosystems. A saturating exponential model (y = a(1–e−kx) + c) produced the smallest residual mean squares in predicting overstory biomass (R2 = 0.822) and annual biomass increment (R2 = 0.847) from potential net N mineralization. Maximum overstory biomass and biomass increment predicted from this equation were 247 t•ha−1 and 3.7 t•ha−1, respectively. In addition, laboratory net N mineralization potentials were highly correlated with annual rates of N mineralization determined by insitu incubation (r2 = 0.849). Overstory biomass and woody biomass increment were poorly correlated with potential net nitrification. The exponential function used to predict biomass increment from N mineralization suggests that the productivity of some northern hardwood forests in northern Lower Michigan is not limited by N availability.
Distribution of the pinewood nematode in China and susceptibility of some Chinese and exotic pines to the nematode
Authors: Baojun Yang , Qouli Wang
Published: December 2007

From 1983 to 1987 a survey was made to determine the hosts and geographic distribution of the pinewood nematode Bursaphelenchusxylophilus (Steiner and Buhrer), the cause of pine wilt disease, in China. Samples (669) were obtained from dead and dying conifers in 18 provinces and in the federally administrated cities of Beijing and Shanghai. The nematode was only found in samples from Pinusthunbergii and P. massoniana in and around the cities of Nanjing and Zhenjiang (both in Jiansu Province). To determine the susceptibility of Chinese and exotic pines to the pinewood nematode, 15 pine species were inoculated with a Chinese isolate. The 2- to 5-year-old trees, growing at Qingdao (Shandong Province) and Hongjiang (Hunan Province), were inoculated in mid-August to mid-October 1985. The results showed that one pine (P. bungeana) was extremely susceptible to the pinewood nematode, seven were highly susceptible (P. yunnanensis, P. densiflora, P. armandii, P. kwangtungensis, P. elliottii, P. koraiensis, and P. thunbergii), four were moderately susceptible (P. taiwanensis, P. griffithii, P. fenzeliana, and P. sylvestris var. mongolica), and three were resistant (P. taeda, P. massoniana, and P. banksiana). The results are discussed in relation to the needs for quarantine and management of pine wilt disease in the People's Republic of China.
Red pine growth and chemical composition of foliage and forest floors across a precipitation-chemistry gradient in Wisconsin
Authors: Bockheim J. G. , Leide J. E. , Frelich L. E.
Published: December 2007

Three red pine (Pinusresinosa Ait.) plantations were located at each of five sites across the precipitation-chemistry gradient in Wisconsin (loadings of H ion, SO42−, and NO3− generally decrease from southeast to northwest). The plantations were selected to be as similar as possible in stand characteristics, including age, initial stocking, number of thinnings, site index, and basal area, and in soils (mixed frigid Typic Udipsamments or Entic Haplorthods). Despite the care exercised in selecting the plantations, analysis of variance incorporating a nested design showed that for the growth parameters, within-site variation generally was greater than among-site variation. The large within-site variation may have masked any differences attributable to variations in precipitation chemistry across the gradient. Site-related differences in radial increment (1982–1986 period) were attributed to time since thinning. There were significant site-related differences in mass, concentrations, and contents (mg/50 fascicles) of N, P, Ca, and S in current needles and in mass, concentrations, and contents (kg•ha−1) of N, P, and S in the forest floor. Differences in mass and chemical composition of needles among sites may be due to slight differences in soils. We attribute the differences in mass and chemical composition of the forest floor among sites to differences in preplanting site conditions and stand treatment.
Correcting for nonrandom errors in a fixed-effect model
Authors: Reich Robin M. , Arvanitis Loukas G.
Published: December 2007

In this article, a statistical method of estimating the microsite component (a nonrandom error) in a fixed-effect model is presented and discussed. The approach uses generalized least squares to partition the model variance into two components: one part due to microsite and the other one due to random errors. An iterative procedure is then used to solve for the maximum likelihood estimate of the microsite component. Application of the technique to a slash pine (Pinuselliottii Engelm. var. elliottii) spacing trial indicates that 30% of the variability in total tree height at age 6 years was due to microsite, whereas the remaining 70% was due to random errors.
Relation between the permeability and the anatomy of jack pine sapwood with stand development
Authors: Pothier David , Margolis Hank A. , Poliquin Jean , Waring Richard H.
Published: December 2007

The anatomical characteristics of sapwood from the base of the live crown of trees from 11 jack pine stands (Pinusbanksiana Lamb.) of different age and site quality were related to the patterns of change of longitudinal sapwood permeability (k) previously observed to occur among these stands. Tracheid length (Lt) increased rapidly from a minimum of 1.9 mm to a plateau of around 3.6 mm as stand age and site quality (productivity class) increased. Sapwood relative water content (Rs) measured before saturation ranged from 78 to 85% for the majority of trees. Samples taken from trees growing on poor sites, however, exhibited significantly lower values of Rs, which probably resulted in their remaining below saturation during the determination of sapwood permeability. The lower Rs values were assumed to be reflective of more adverse water balances during the growing season associated with rapidly drained and (or) shallow soils. Tracheid lumen diameter (Dl) was positively correlated with k within age-classes 15 and 35, but not thereafter. The initial relation between Dl, and k is thought to be associated with corresponding increases in the area of pit membranes, which determines the number of pores within a pit membrane. Values of k were never more than 60% of the values calculated by Poiseuille's law for ideal capillaries (kc) and were generally less than 40%. Values of k tended to approach kc with increasing Lt and decreasing Dl. Overall, Poiseuille's law by itself could not explain the changes in the hydraulic properties of jack pine sapwood with stand development. However, Lt and Rs could together account for 72% of the variation in k. Young stands that had different k depending on site quality generally had corresponding differences in Lt, Rs, and (or) Dl. Mature stands that had reached maximum k on all quality sites no longer showed differences in Lt, Rs, or Dl.
Postfire black spruce establishment in subarctic and boreal Quebec
Authors: Sirois Luc , Payette Serge
Published: December 2007

Forest regeneration in areas burned during the 1950s in northern Quebec was studied along topographic and climatic gradients, from the northern Boreal Forest to the northern Forest–Tundra. Regenerated plant communities are mostly dominated by Cladinamitis in well-drained uplands and by hygrophilous shrub species in moister lowlands. The age structure of 23 stands, as they were immediately before and about 30 years after the 1950s fires, was used to analyze the patterns of establishment and development of black spruce (Piceamariana (Mill.) B.S.P.) populations associated with fire disturbance. Postfire black spruce establishment was active during the first 20 years of vegetation recovery, then it decreased rapidly. Three older populations originating from 1936 and 1922 fires showed a rapid postfire tree establishment, whereas a long delay of recolonization was observed in the 1906 fire. Along the topographical gradient, postfire regeneration was more rapid in hill sites, whereas spruce recruitment was more abundant in lowland sites. Along a northward latitudinal gradient, prefire populations showed an increasing trend in age range, mean age, and mean age of youngest individuals. This gradient coincided also with an increasing fire rotation period from south to north. The proportion of stunted individuals in postfire populations was often more important than in prefire populations on the same sites, suggesting more rigorous growth conditions associated with forest removal. Because most black spruce seedling establishment is occurring during a short period in this area, it is suggested that stand density is determined by regeneration conditions, including seed input and seedbed quality, soon after the fire. Therefore, comparisons between prefire and 30-year-old postfire populations can be used as an index to evaluate fire impact on stand density.
Root growth potential and bud dormancy of 2 + 0 eastern white pine grown in a Virginia nursery
Authors: Johnsen Kurt H. , Feret Peter P. , Seiler John R.
Published: December 2007

Root growth potential and dormancy release index were examined over 2 years using 2 + 0 eastern white pine seedlings grown in a Virginia nursery. Root growth potential patterns were quite different between years. The relationship between dormancy release index and chilling sums (0–7 °C) was consistent between years. Approximately 2800 chilling hours were necessary to break terminal bud dormancy fully. There was a highly significant, positive linear relationship between root growth potential and dormancy release index above a dormancy release index of 0.20 when 2 years data were combined. For dormancy release index values <0.20, the relationship between root growth potential and dormancy release index was inconsistent between years.
Factor levels for density comparisons in the split-block spacing design
Authors: Riitters Kurt H. , Stanton Brian J. , Walkup Robert H.
Published: December 2007

The split-block spacing design is a compact test of the effects of within-row and between-row spacings. But the sometimes awkward analysis of density (i.e., trees/ha) effects may deter use of the design. The analysis is simpler if the row spacings are chosen to obtain a balanced set of equally spaced density and rectangularity treatments. A spacing study in poplar (Populus spp.) illustrates the approach.
An inventory of innovative technology use in North American processing of wood structural panels and softwood lumber
Authors: Cohen David H. , Sinclair Steven A.
Published: December 2007

During 1988, wood products firms responsible for over one-third of the structural panel production and two-thirds of the softwood lumber in Canada and the United States were surveyed to produce an inventory of new processing technologies adopted for each of these wood products segments. Included in structural panels were softwood plywood and nonveneered panels (oriented strand board and waferboard). Technology usage, for each segment, was evaluated by a use intensity index, which measured the proportion of 1987 production that used each surveyed technology. Use intensity ranged from less than 1% to more than 90% for different technologies surveyed. Multivariate statistical analysis was used to investigate which technologies were most compatible with each other and what underlying qualities linked different technologies together. Knowledge of these changes in wood processing can be advantageous in developing different directions for forest and wood science research. In addition, this inventory is a useful tool to explore areas for technological innovation in the processing of the forest resource.
Invitro plant regeneration via callus culture of mature Salixexigua
Authors: Stoehr Michael U. , Cai Mantang , Zsuffa Louis
Published: December 2007

Callus induction, callus growth, and plantlet regeneration were examined using leaf explants of three Salixexigua clones. Calli were initiated on three basal media supplemented with 0.1 mg/L (0.44 μM) or 0.5 mg/L (2.2 μM) of benzylaminopurine and 0.1 mg/L (0.45 μM) or 0.5 mg/L (2.3 μM) of 2,4-dichlorophenoxyacetic acid in a factorial fashion. After 7 weeks of growth, callus production was highest on woody plant medium. Developed calli were subsequently cultured on woody plant medium supplemented with either 0.1 or 0.5 mg/L of benzylaminopurine for shoot induction. Shoot primordia developed only at 0.1 mg/L (0.44 μM) benzylaminopurine in two clones, suggesting clonal variation in organogenic response. Shoots larger than 1.0 cm in length were successfully rooted in half-strength Murashige and Skoog medium without hormones.
Soil chemistry changes after 27 years under four tree species in southern Ontario
Authors: France Elizabeth Anne , Binkley Dan , Valentine David
Published: December 2007

After 27 years of stand development, the accumulated forest floor under replicated plots of white pine (Pinusstrobus L.), white spruce (Piceaglauca (Moench) Voss), paper birch (Betulapapyrifera Marsh.), and silver maple (Acersaccharinum L.) ranged from 240 g/m2 under maple to 3680 g/m2 under white pine. Forest floor pH ranged from a low under maple of 3.7 to a high under white spruce of 5.9. No significant differences were found in pH in 0–15 cm depth mineral soil; however, substantial differences in the acid neutralization capacities were evident among species, with soils under maple showing the lowest capacity to resist further acidification.
Sapwood and heartwood taper in Scots pine stems
Authors: Ojansuu Risto , Maltamo Matti
Published: December 2007

The heartwood and sapwood of Pinussylvestris L. were analysed using simultaneous taper models for stem without bark and for heartwood. Sapwood area tapered monotonically from the base to the top of the stem. Below crown base the stem tapered more slowly than in the crown. The proportion of heartwood in the tree stem was higher in dense sample plots than in sparse ones and also decreased significantly with increasing relative size of a tree in a plot. Height at crown base correlated significantly with the proportion of heartwood, stand density, and relative size. Height at crown base was the most effective additional independent variable for predicting sapwood basal area at crown base when diameter at breast height and tree height were measured. Connected with diameter at breast height and tree height measurements, width of the sapwood at breast height explained significantly better sapwood and heartwood volumes than height at crown base.
Impact of spruce budworm defoliation on the number of latewood tracheids in balsam fir and black spruce
Authors: Krause Cornelia , Morin Hubert
Published: December 2007

The influence of spruce budworrn (Choristoneurafumiferana (Clem.)) defoliation was analysed at different stem heights by counting the number of latewood tracheids and measuring tree-ring width. The total height of the tree was divided into three different equal parts: the lower, the middle, and the upper sections of the total stem length. However, only the results of the lower and the upper sections will be presented in this paper. The reduction of ring widths started in the upper part for the living crown and continued downwards to the stem base (0 m) with a delay of 1–2 years. The number of latewood tracheids generally showed a reduction 1 year earlier than the ring widths, particularly in the crown, but also in the other parts of the stem. Considering this, we think that the reduction of the number of latewood tracheids may date the beginning of spruce budworm defoliation more accurately and present a better characterization of the first impact of spruce budworm than the measuring of the ring widths. This parameter will be particularly helpful (when expensive equipment, such as a densitometer or an image analysis system cannot be used) in detecting past outbreaks in the tree-ring records, especially when defoliation records are missing and when the reduction of the ring widths is not very pronounced.
Midwinter dehardening of montane red spruce during a natural thaw
Authors: Strimbeck G.R. , DeHayes D.H. , Shane J.B. , Hawley G.J. , Schaberg P.G.
Published: December 2007

We documented 3 to 14 °C of dehardening in current-year foliage of 10 mature, montane red spruce (Picearubens Sarg.) trees during a natural thaw from 12 to 21 January 1995. Mean cold tolerance was about −47 °C before the onset of thaw conditions, and individuals ranged from −38 to −52 °C. After 3 days of thaw, mean cold tolerance dropped to −39 °C, with a range of −32 to −44 °C. Trees did not regain prethaw levels of cold tolerance until sometime between 31 January and 9 February, or 10 to 20 days after subfreezing temperatures resumed. The least cold tolerant tree was at risk of injury when temperature at the field site fell to an estimated −33.8 °C on 6 February, and this same tree developed noticeably more injury than other trees when injury symptoms developed in late March. No evidence of dehardening was found in balsam fir (Abiesbalsamea (L.) Mill.) trees from the same stand. All red spruce trees also showed the potential for net assimilation of carbon during the thaw, as determined by measurement of photosynthetic capacity under laboratory conditions. From the abrupt and substantial dehardening and persistence of the dehardened state, we conclude that dehardening during periods of warm weather may be a significant factor in freezing injury and decline of montane red spruce populations.
PROBING THE STANDARD MODEL WITH DILEPTON DECAYS OF TOP QUARK PAIRS AT CDF
Authors: WHITESON DANIEL
Published: December 2007

The dilepton decays of the top quark are a powerful laboratory for probing the Standard Model and searching for hints of a more fundamental theory. We present a detailed analysis of the production cross section and the kinematic qualities of top quark pair candidate events in [Formula: see text] collisions at [Formula: see text] = 1.96 TeV collected by the CDF detector which include two leptons in the final state, suggesting the decay [Formula: see text]. We describe the selection of candidate events to suppress major backgrounds and present the number of observed events over background. As a test of the top quark hypothesis, the kinematics of the events are analyzed via a measurement of M top with unprecedented precision.
THE UNIT OF ELECTRIC CHARGE AND THE MASS HIERARCHY OF HEAVY PARTICLES
Authors: LÓPEZ CASTRO G. , PESTIEAU J.
Published: December 2007

We propose some empirical formulas relating the masses of the heaviest particles in the standard model (the W, Z, H bosons and the t quark) to the charge of the positron e and the Higgs condensate v. The relations for the masses of gauge bosons mW = (1+e)v/4 and [Formula: see text] are in good agreement with experimental values. By requiring the electroweak standard model to be free from quadratic divergences at the one-loop level, we find: [Formula: see text] and [Formula: see text], or the very simple ratio (mt/mH)2 = e.
UNIFIED DARK MATTER IN SCALAR FIELD COSMOLOGIES
Authors: BERTACCA DANIELE , MATARRESE SABINO , PIETRONI MASSIMO
Published: December 2007

Considering the general Lagrangian of k-essence models, we study and classify them through variables connected to the fluid equation of state parameter wκ. This allows one to find solutions around which the scalar field describes a mixture of dark matter and cosmological constant-like dark energy, an example being the purely kinetic model proposed by Scherrer. Making the stronger assumption that the scalar field Lagrangian is exactly constant along solutions of the equation of motion, we find a general class of k-essence models whose classical trajectories directly describe a unified dark matter/dark energy (cosmological constant) fluid. While the simplest case of a scalar field with canonical kinetic term unavoidably leads to an effective sound speed cs = 1, thereby inhibiting the growth of matter inhomogeneities, more general non-canonical k-essence models allow for the possibility that cs≪1 whenever matter dominates.
FROM A HARMONIOUS UNIFYING HYBRID PREFERENTIAL MODEL TOWARD A LARGE UNIFYING HYBRID NETWORK MODEL
Authors: FANG JINQING , LI YONG , BI QIAO
Published: December 2007

The motivation of this work raises four challenging questions: (1) Why is it that so many generalized random network models exist but they cannot be completely consistent with real-world networks? (2) Are these complex networks fundamentally attached in a random preferential manner without any deterministic attachment for both un-weighted and weighted networks? To answer the first two questions, we propose a harmonious unifying hybrid preferential model (HUHPM) controlled by a total hybrid ratio. (3) Why are social networks mostly positive degree-degree correlation but biological and technological networks tend to possess negative degree-degree correlation? (4) Are there coherent physical ideas and a unification formation mechanism for studies of complex networks? To seek a better answer of all these questions, especially the last two above, we extend the HUHPM to a large unifying hybrid network model (LUHNM), based on introducing two new hybrid ratios. We study the two models above, both numerically and analytically. All findings of topological properties in the network models above can give a certain universally meaningful result, which reveals some nontrivial topological properties, new phenomena, and give a relatively satisfactory answer.
TRANSPORT PROPERTIES OF n-POLYANILINE/p-POROUS SILICON HETEROJUNCTIONS
Authors: FARAG A. A. M. , ASHERY A. , YAHIA ABED M. , SHENASHEN M. A. , HINDIA T. A.
Published: December 2007

The donor/acceptor heterojunction devices having configuration n-PANI/p-PSi were fabricated by in-situ chemical oxidative polymerization method of aniline on p-type porous silicon. The structure of n-PANI/p-PSi junctions was examined by scanning electron microscopy and X-ray diffraction spectroscopy. The dark current-voltage measurements were performed in the temperature range of 303–393 K to determine the electrical transport mechanisms of these devices. Rectifying properties were obtained and capacitance–voltage at 1 MHz behavior indicates an abrupt interface. At low forward bias, the current was found to be limited by thermionic emission of holes from p-PSi over the PANI/PSi barrier in the PANI thin film. For relatively higher voltage, the conduction was dominated by a space charge limited current mechanism, with an exponential distribution of traps. Also, various electrical parameters were determined from the I-V and C-V analysis.
STRUCTURE AND MAGNETIC PROPERTIES OF Co12X(X = Ni, Ag, Pt, Au) CLUSTERS
Authors: LU Q. L. , JIANG J. C. , WAN J. G. , WANG G. H.
Published: December 2007

The ground state structures of Co 12 X ( X = Ni , Ag , Pt , Au ) clusters are obtained by a genetic algorithm with a Gupta-like many-body potential, and further optimized using the density functional theory with generalized gradient approximation. The structures of Co 12 X have a slightly distorted icosahedral pattern. The X atom is on the surface for the most stable configuration. Their total magnetic moments are 0μ B , 3μ B , 21μ B , and 22μ B , respectively. The reasons for the reduction of magnetism of Co 12 X are discussed in detail.
EVALUATING INTONATIONAL FEATURES FOR EMOTION RECOGNITION FROM SPEECH
Authors: ZERVAS PANAGIOTIS , MPORAS IOSIF , FAKOTAKIS NIKOS , KOKKINAKIS GEORGE
Published: December 2007

This paper presents and discusses the problem of emotion recognition from speech signals with the utilization of features bearing intonational information. In particular parameters extracted from Fujisaki's model of intonation are presented and evaluated. Machine learning models were build with the utilization of C4.5 decision tree inducer, instance based learner and Bayesian learning. The datasets utilized for the purpose of training machine learning models were extracted from two emotional databases of acted speech. Experimental results showed the effectiveness of Fujisaki's model attributes since they enhanced the recognition process for most of the emotion categories and learning approaches helping to the segregation of emotion categories.
NAMED ENTITY RECOGNITION IN GREEK TEXTS WITH AN ENSEMBLE OF SVMS AND ACTIVE LEARNING
Authors: LUCARELLI GIORGIO , VASILAKOS XENOFON , ANDROUTSOPOULOS ION
Published: December 2007

We present a freely available named-entity recognizer for Greek texts that identifies temporal expressions, person, and organization names. For temporal expressions, it relies on semi-automatically produced patterns. For person and organization names, it employs an ensemble of Support Vector Machines that scan the input text in two passes. The ensemble is trained using active learning, whereby the system itself proposes candidate training instances to be annotated by a human during training. The recognizer was evaluated on both a general collection of newspaper articles and a more focussed, in terms of topics, collection of financial articles.
RELATIONSHIP OF IMPAIRMENT, DISABILITY AND WORKING STATUS AFTER RECONSTRUCTIVE SURGERY OF THE WRIST
Authors: De Smet Luc
Published: December 2007

The aim was to study the relationship between impairment (function) and disability (participation) in wrist surgery, according to the WHO definitions.

The outcome of 205 wrist operations were studied. The impairment was expressed as range of motion (ROM) and gripping force, the disability as the DASH score.

There was a significant correlation between DASH and gripping force (R = 0.47). The correlation between ROM and DASH was weaker (R = 0.24).

In manual workers, shorter temporary disability periods were significantly associated with lower DASH score.

In (reconstructive) wrist surgery, impairment, disability and working status are significantly correlated. Gripping force measurement is a reliable tool for evaluation and gives a good impression of the disability. Preservation of some mobility is important, however the amount of ROM is not essential for the disability.
A giant Late Triassic–Early Jurassic evaporitic basin on the Saharan Platform, North Africa
Authors: Turner P. , Sherif H.
Published: December 2007

This paper describes the Late Triassic and Early Jurassic evaporites of the Berkine/Ghadames Basin in eastern Algeria and western Libya, which is important because it forms the regional seal to a number of hydrocarbon reservoirs in the Triassic Argilo-Gréseux Inférieur. This evaporitic succession spans the time interval Norian to Late Liassic and is divided into three contrasting units (S1, S2 and S3). S1 consists of five evaporitic cycles dominated by mudstone and halite, which represent the main salt deposits of the Berkine Basin. At this time the Berkine/Ghadames basin was a restricted evaporitic basin with a barrier to the north (Medenine High) separating the basin from the developing peri-Tethys and North Atlantic. The succession thickens to the west, thins around the Hass Messouad Ridge and continues across the Maghreb into the western High Atlas of Morocco, a distance of some 1500 km. S2 is represented by the basin-wide development of a carbonate platform in Pliensbachian times. This is the product of a relative sealevel rise concomitant with the developing extension of the region and may reflect the opening of an Atlantic gateway. S3 comprises five cycles that are predominantly mudstones, fine-grained carbonates and anhydrites. Mounded structures, evident on seismic sections, may represent the development of patch reefs and the whole succession is interpreted as a shallow-marine carbonate–evaporite ramp. Similar thickness variations to those observed in Sequence 1 continue through Sequence 3 and reflect the on-going influence of differential subsidence along basement lineaments. A number of factors controlled the development of the evaporite basin. These include Late Triassic sealevel rise and flooding of a sub-sealevel basin, combined with globally warm climatic conditions and on-going extensional tectonics in the peri-Tethyan and Atlantic areas. Restricted circulation was caused by an east–west oriented sill to the north (Medenine High in central Tunisia) and the basin was episodically refilled as global sealevel rose during the Early Mesozoic and extensional tectonics continued.
Depositional environments of a salina-type evaporite basin recorded in the Badenian gypsum facies in the northern Carpathian Foredeep
Authors: Bąbel M.
Published: December 2007

An integrated group of conceptual models for evaporite deposition is presented for a shallow salina-type basin, supplied both with marine and non-marine water, and with a water level separated from and drawn down below world sea-level. Knowledge of, and terminology for, modern limnology is used in these models in order to build a new and more comprehensive link between the hydrography and hydrochemistry of brines and the depositional and stratigraphical record anticipated in such basins. In these modelled basins it is assumed that (as in saline lakes): (1) the evaporite deposition reflects the stratification-mixing cycles in the brine column; (2) the evaporative crystallization of salts culminates during the mixing periods; and (3) the evaporite facies are linked to the position of water zones separated by a horizontal pycnocline. The models are prepared especially for interpretation of subaqueous coarsely crystalline gypsum (selenite) deposition in perennial-to-ephemeral saline pans, and also for fine-grained gypsum deposition (clastic, microbialite and pedogenic) on specific, flat, semi-emerged shoals (majanna-type shoals), commonly flooded by wind-driven brine sheets, in between them. Coarse, crystalline selenites appear to form below the pycnocline and the crystallization of particular well-developed grass-like selenite beds is thought to be connected with the pycnocline highstands. Such beds are both marker beds and ideal datum surfaces. The models presented are used for sedimentological interpretation of the various gypsum facies of the Badenian (Middle Miocene) evaporite basin in the northern Carpathian Foredeep. The observed architecture of these facies suggests that the margin of the basin was occupied by a system of variable saline pans (dominated by selenite deposition) and evaporite shoals (dominated by gypsum microbialite deposition); some of these shoals were majanna-type. Many features of the studied facies can be clearly explained by the models presented, particularly by the rapid and variable fluctuations in water and pycnocline levels incomparable in time scale and size with any global sea-level changes. All these features together consistently suggest that the Badenian gypsum basin was a salina-type basin with a water level below global sea-level, although salts in the basin are/were basically marine in origin.