bluuebunny/crossref_metadata_2025 huggingface dataset:
Transgenic Populus hybrid expresses a wound-inducible potato proteinase inhibitor II - CAT gene fusion
Authors: Klopfenstein Ned B. , Shi Nian Qing , Kernan Andrea , McNabb Jr. Harold S. , Hall Richard B. , Hart Elwood R. , Thornburg Robert W.
Published: July 2007

A hybrid poplar clone has been transformed with a previously constructed wound-inducible potato proteinase inhibitor (pin2) – chloramphenicol acetyltransferase (CAT) chimeric gene linked to a nopaline synthase (nos) – neomycin phosphotransferase II (NPT II) selectable marker gene. The Populusalba × Populusgrandidentata Hansen clone was transformed by means of leaf cocultivation with Agrobacteriumtumefaciens strain A281 containing a binary vector. Shoots were regenerated and rooted on selective medium containing kanamycin sulfate. Subsequently, plants were established in soil for greenhouse and field growth. NPT II activity from the nos – NPT II selectable marker gene was observed in leaf extracts, thereby confirming expression of the transferred selectable marker gene in poplar. Southern hybridization confirmed the incorporation of a single copy of the pin2–CAT construction into the genome of the transformed hybrid poplars. Northern analysis of transgenic poplar leaves demonstrated that the potato pin2–CAT gene construction also was inducible in this woody dicotyledon. Thus, the wound-inducible promoter from an herbaceous dicot functions in a distinct family of woody dicots.
The effect of land classification and stratification on derivation of timber supply and allowable cut in harvest scheduling
Authors: Chong Se-Kyung , Beck Jr. James A.
Published: July 2007

The effects of boundary designations of timber management units on the allowable cuts were examined, and a new approach to derive marginal-cost curves for timber supply was developed. The maximum even-flow allowable cut from the whole forest as a unit was 1.33–2.13% larger than the sum of the five maximum even-flow allowable cuts from the five working circles. Maximum even-flow allowable cuts found with linear programming using stand aggregation were 1.31–2.10% larger than allowable cuts using area aggregation. Maximum per period cost constraints were found, on average, to increase predicted differences from unconstrained stand-based versus area-based analysis. Use of the maximum cost constraints led to the ability to develop curves for the marginal cost of allowable cut for both stand-based and area-based analyses. By incrementally examining increases in the allowable cuts generated on the independent management units at different cost constraints, a curve for the average marginal cost of allowable cut was derived. Careful use of this curve will allow woodland managers to select the least costly method of analysis for any particular desired allowable cut. As well, the selected curve can aid managers in determining the marginal cost of timber supply at any production level and to set upper limits on external wood purchase prices. While biological data were easier to derive for stand-based aggregation, area-based aggregation led to smaller linear programming models, which were thus cheaper to solve, and it was much easier to develop location-dependent economic data for these type models than for stand-based models.
Evaluating the effects of risk on the economics of juvenile spacing and commercial thinning
Authors: Reed William J. , Apaloo Joseph
Published: July 2007

The temporarily increased fire hazard that is believed to result from the process of thinning is included in a single-stand model for assessing the economic benefits of juvenile spacing. Formulas for the expected net present value and the land expectation value are given along with methods for determining the age of financial maturity and the optimal rotation age. A numerical example is given to illustrate the degree of loss due to the increased fire risk. The problem of commercial thinning when the risk of fire is present is addressed using continuous-time models. It is shown how, when the fire hazard is exogenous to the thinning activity, the problem reduces to one of deterministic optimal control with the discount rate adjusted upward by an amount equal to the fire hazard rate. In the case when the fire hazard increases whenever thinning is taking place, it is shown that in general the optimal thinning policy is qualitatively different from that which is optimal in the no-risk case and involves periods of thinning at the maximum rate interspersed with periods of no thinning activity.
Variance in response of pole-size trees and seedlings of Douglas-fir and western hemlock to nitrogen and phosphorus fertilizers
Authors: Radwan M. A. , Shumway J. S. , DeBell D. S. , Kraft J. M.
Published: July 2007

Three experiments were conducted to determine effects of N and P fertilizers on growth and levels of plant-tissue nutrients of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) and western hemlock (Tsugaheterophylla (Raf.) Sarg.). Both pole-size trees in closed-canopy stands and potted seedlings were used. Soil series were Bunker for Douglas-fir and Klone for western hemlock in experiments 1 and 3, and Vesta in experiment 2. For each species in experiments 1 and 2, P and N fertilizers were tested in six or eight treatments using factorial design. In experiment 3, N and P fertilizers were individually tested on seedlings, at one rate of application each. Nitrogen fertilizers used were urea in experiment 1 and ammonium nitrate in the other two experiments; P was applied as triple superphosphate in all three experiments. In general, fertilization changed levels of some plant-tissue nutrients of the pole-size trees and potted seedlings. Neither height nor basal-area growth of the trees was significantly affected by any of the fertilization treatments in the first two experiments. Seedling growth of both Douglas-fir and western hemlock was dramatically improved by the P fertilizer, but was negatively affected by the N fertilizer. Results clearly show differences between pole-size trees and seedlings in response to N and P fertilizers. They also suggest that N not be applied where soils are high in N and low in P and that P applications be confined to sites with low-P soils, when trees are young, before canopy closure.
A model of genetic variation for Pinus ponderosa in the Inland Northwest (U.S.A.): applications in gene resource management
Authors: Rehfeldt G. E.
Published: July 2007

Models were developed to describe genetic variation among 201 seedling populations ofPinusponderosa var. ponderosa in the Inland Northwest of the United States. Common-garden studies provided three variables that reflected growth and development in field environments and three principal components of six variables that reflected patterns of shoot elongation. Regression models were developed for describing genetic variation across the landscape. Using functions of latitude, longitude, and elevation as descriptors, these models produced values of R2 that were as large as 0.66, while averaging 0.39. The models described genetic variation as occurring along relatively steep elevational clines and gentle geographic (i.e., latitudinal and longitudinal) clines. An exercise at validating the models with independent data supported their veracity. Predictions made by the models are applied to limiting seed transfer, designing breeding zones, planning gene conservation programs, interpreting phenotypic variation, and predicting the effects of environmental change on the adaptedness of populations.
Genotype–nutrition interactions in field-planted loblolly pine
Authors: Crawford D. T. , Lockaby B. G. , Somers G. L.
Published: July 2007

Four families of loblolly pine (Pinustaeda L.), representing a productivity gradient, were compared to determine inherent differences in productivity and nutrient efficiency for two nutrient regimes. The nutrient regimes consisted of a nonfertilized treatment, representing a deficiency of N, P, and K, and a fertilized treatment, ensuring an adequate supply of N, P, and K. Nutrient efficiency was determined using the traditional measure of nutrient use efficiency and alternative measures, including biomass and nutrient accumulation over time, element ratios, specific absorption rate, internal translocation, and a graphical technique. Family and nutrient regime differences were found in biomass production, biomass allocation, and nutrient efficiency. Of the nutrient efficiency measures, biomass and nutrient accumulation, nutrient use efficiency, and specific absorption rate tended to mirror family productivity differences. Family variation in element ratios, internal translocation, and the graphical technique did not mirror biomass production and, thus, were able to provide additional information on specific nutrient use mechanisms of efficiency that is not provided by traditional nutrient use efficiency calculations, the latter being confounded by biomass production.
Stump diameter and DBH relationships for white oak and black oak in the Lower Peninsula of Michigan
Authors: Ojasvi Prabhat R. , Ramm Carl W. , Lantagne Douglas O. , Bruggink Jeffrey
Published: July 2007

Principal component analysis of white oak (Quercusalba L.) and black oak (Quercusnigra L.) revealed different stem profiles across four ecological land units in the Lower Peninsula of Michigan. Multivariate linear regression and geometric models were developed to predict DBH from stump diameter for both species. For the multivariate model, the prediction variables were stump diameters at 15 and 30 cm above the ground level. The geometric model uses stump diameter at any height. Both the multivariate and geometric models can be used to predict DBH; however, the geometric models have the advantage of using fewer variables and being more flexible than the multivariate models.
Somatic embryogenesis in American chestnut
Authors: Merkle S. A. , Wiecko A. T. , Watson-Pauley B. A.
Published: July 2007

Cultures were initiated from developing ovules and excised embryos of American chestnut (Castaneadentata (Marsh.) Borkh.), collected from five source trees on three dates during early and middle stages of fruit development. Explants were cultured initially on semisolid induction medium containing 0.25 mg/L benzyladenine and either 6 mg/L naphthaleneacetic acid or 4 mg/L 2,4-dichlorophenoxyacetic acid for 1 or 2 weeks. Then they were either transferred to hormone-free medium or medium with 0.25 mg/L benzyladenine or maintained on the original induction media. Ovules collected from three of the five trees 6 or 7 weeks postanthesis produced embryogenic cultures. Those pulsed for 1 or 2 weeks on auxin-containing medium prior to transfer to media without auxin produced multiple somatic embryos directly from the radicle end of the zygotic embryo. Cultures maintained on auxin-supplemented media initially produced proembryogenic masses, which formed globular and heart-stage embryos as they aged. Transfer of clusters of somatic embryos from auxin-supplemented media to hormone-free medium promoted maturation of embryos to the cotyledon stage.
The temporal and spatial analysis of tree age distributions
Authors: Duncan Richard P. , Stewart Glenn H.
Published: July 2007

The temporal and spatial patterns of tree establishment and stand disturbance history are often based on the interpretation of age-class frequency distributions. In particular, the presence of even-aged groups of trees is often used as compelling evidence of past disturbance. However, even-aged groups of trees may be indistinguishable in an age distribution if several different-aged patches occur, especially if their ages overlap. For two different types of forest we used spatial autocorrelation analysis to statistically test for the presence of even-aged patches in tree age data. Ordination and cluster analysis were subsequently applied to a matrix of association measures that reflected both spatial proximity and age similarity to identify even-aged groups of trees. Although the method worked well for our forests, which contained light-demanding tree species, it is likely to be less applicable to forests dominated by shade-tolerant species, because trees may be of many different ages if they were present as suppressed individuals prior to disturbance. However, in these instances the method could be usefully applied in other types of analysis, such as the distribution of growth release dates, tree-fall or fire-scar dates, and growth rates.
Gap-phase structure of a subalpine old-growth forest
Authors: Lertzman Kenneth P. , Krebs Charles J.
Published: July 2007

We examined four stands in a subalpine old-growth forest in the Coast Mountains of southwestern British Columbia for gap-phase structure. Though the stands varied in the proportions of each species, all had a similar distribution of area under closed canopy and in gaps (overall means: 29% closed canopy, 52% expanded gap, 18% canopy gap). Median areas of canopy gaps and expanded gaps were 41 and 203 m2, respectively. Most gaps (90%) had more than one gap maker, and gap makers within a gap were often from mortality events separated in time. Half of all gap makers died standing, and only 13% were windthrown. Pacific silver fir (Abiesamabilis (Dougl.) Forbes) was represented among gap makers in a much higher proportion than among canopy trees in general (64 vs. 45%). The estimated forest turnover time varied from 280–1000 years, depending on assumptions about the time taken for gaps to be filled. Distinctive features of gap-phase structure and dynamics in this forest are the high proportion of area in gap, small gap size, multiple gap makers of varying stages of decay, and long tenure of gaps before they are filled.
Geographic variation in the monoterpene composition of black spruce
Authors: Chang Jye , Hanover James W.
Published: July 2007

Monoterpene composition of the cortical oleoresin of black spruce (Piceamariana (Mill.) B.S.P.) was determined for 33 seed sources growing in a replicated plantation in southern Michigan. Four of the nine measured monoterpenes differed significantly among origins. 3-Carene and terpinolene were high, but α-pinene was low in the Manitoba and Saskatchewan seed sources. A cluster analysis of the data separated the populations into western and eastern groups. Black spruce is more similar to red spruce (Picearubens Sarg.) than to white spruce (Piceaglauca (Moench) Voss) in terpene composition. Significant correlations occurred between individual monoterpenes, but only the positive correlations among 3-carene, terpinolene and γ-terpinene are considered meaningful in regard to terpene biosynthesis.
Accroissement en volume de l'épinette noire: précision de sa détermination
Authors: Zarnovican Richard
Published: July 2007

The relationship between volume growth rate and diameter growth rate (diameter at breast height) was studied from growth data established by stem analysis for dominant black spruce trees (Piceamariana (Mill.) B.S.P.) of a black spruce – feather moss stand. The results indicate a very close relationship between the two variables, and a linear model was chosen to predict volume growth rate. Independent model validation, based upon analysis of residual errors, indicates a small positive bias (0.006%) with a relatively good precision (±9.9%) and a χ2 test anticipated accuracy of ±0.71% at the 0.05 probability level. The annual volume increment calculated with the prediction model and with the local volume equation for validation data was more precise (bias = −0.02 dm3/year, precision = ±11.8%) than the volume increment calculated with this model and the general volume equation (bias = −0.39 dm3/year, precision = ±26.4%). Finally, the χ2 test showed that the anticipated accuracy of the annual volume increment was ±0.54 dm3/year at the 0.05 probability level for the prediction model and the local volume equation, and ±0.90 dm3/year for the prediction model and the general volume equation for validation data.
Effects of maturation and gibberellin A4/7 on flowering and branching characteristics of Larixlaricina
Authors: Eysteinsson Throstur , Greenwood Michael S.
Published: July 2007

Flowering and the flowering response to the plant growth regulator gibberellin (GA4/7) were assessed on potted, greenhouse-grown tamarack (Larixlaricina (Du Roi) K. Koch) grafts made from ortets aged 1 to 74 years. Female flowering decreased with ortet age, whereas male flowering remained similar, resulting in an increased proportion of pollen cones with age. The decrease in total flowering with age was not adequately explained by smaller size or lower vigor of the older scions. Scions from the youngest ortets produced more, but shorter, second-order branches than scions from older ortets. GA4/7, applied in foliar sprays beginning at the start of long-shoot extension, resulted in increased flowering of both sexes, with a proportionately greater increase in female flowering by scions from younger ortets but a roughly equal increase in flowering of both sexes by scions from the oldest ortets. Furthermore, the overall flowering response to GA4/7 (proportionate to control) increased with ortet age. GA4/7 did not affect branch terminal increment, but did increase overall second-order lateral increment slightly.
Foliar response of red spruce saplings to fertilization with Ca and Mg in the Great Smoky Mountains National Park
Authors: Miegroet Helga Van , Johnson Dale W. , Todd Donald E.
Published: July 2007

The objective of this field study was to test whether Ca and (or) Mg was deficient in two red spruce (Picearubens Sarg.) sites located at 1720 and 1950 m in elevation in the Great Smoky Mountains National Park near Clingmans Dome, North Carolina. Initial current needle Ca and Mg concentrations were, respectively, 1700 and 620 μg/g at the upper site, and 1940 and 670 μg/g at the lower site, suggesting poorer nutrient conditions at the upper site. Twenty-eight saplings at each site stratified by height were involved in an individual-tree fertilization trial. Within each stratum four treatments were applied randomly: (i) no fertilization, (ii) 200 kg/ha Ca as CaCl2, (iii) 100 kg/ha Mg as MgCl2, and (iv) 200 kg/ha Ca as CaCl2 plus 100 kg/ha Mg as MgCl2. Fertilizer was applied in April 1989 and 1990, and needles that subsequently formed in the 1989 and 1990 growing seasons were sampled in November 1989 and 1990, respectively. Post-fertilization nutrient concentrations, needle weights, and nutrient contents were compared through analysis of covariance with the pre-treatment needle weight as covariate. Vector analysis suggested an improvement in Ca nutrition and potential growth response with Ca and Ca + Mg fertilization at the upper site in the 1st year but not at the lower site. Neither site appeared to be Mg deficient. Magnesium fertilization had an antagonistic effect on Ca uptake at both sites, whereas Ca addition seemed to improve Mg uptake. Our study suggests that foliar Mg concentrations of 600 μg/g are well within the sufficiency range, but that red spruce saplings may experience incipient Ca deficiency in the field when Ca concentrations in the current needles are <1700 μg/g.
Influence de l'intensité lumineuse, de la température nocturne de l'air et de la concentration en CO2 sur la croissance de semis d'épinette noire (Piceamariana) produits en récipients en serres
Authors: Lord Daniel , Morissette Sylvain , Allaire Jacques
Published: July 2007

Growth of containerized black spruce seedlings grown in greenhouses was studied in relation to factors known to influence plant growth. Artificial light intensity (3.80 and 72.04 μmol•m−2•s−1) and night air temperature (5, 10, 12.5, 15, and 20 °C) were considered in a first experiment and artificial light intensity (4.24 and 59.57 μmol•m−2•s−1) and CO2 air concentration (ambient and 1000 μL•L−1) in a second one. Higher light intensity and CO2 enrichment increased dry biomass of seedlings as well as growth in height and stem diameter. Both factors similarly enhanced the last two parameters since height/diameter ratios showed little variation among treatments. Reducing night air temperature down to 10 °C did not significantly influence height growth nor biomass increase when high intensity light was provided. Lower light intensity raised the threshold to 12.5 °C. Shoot height, diameter, and dry biomass as well as the number of branches and buds per millimeter were strongly reduced by a 5 °C night air temperature. High intensity light enhanced growth of containerized black spruce seedlings more than CO2 enrichment or a 5 °C night air temperature. When used simultaneously, these growth enhancing factors had a synergistic effect during most of the treatment period; thereafter, the effect became partially additive. The relative growth rate peaked at the onset of exponential shoot growth and decreased after this point. However, the enhancing factors were still efficient since absolute growth differences between seedlings grown under the most favorable conditions and controls kept increasing. The faster growing pace imposed by these growth enhancing conditions during the treatment period was maintained over the entire first growing season.
Response of tree growth to climatic variation in the mixed conifer and deciduous forests of the upper Great Lakes region
Authors: Graumlich Lisa J.
Published: July 2007

Tree-ring data were used to define regional tree-growth anomalies (i.e., recurring spatial patterns of growth that differ from long-term averages) for 11 species growing in a network of sites spanning the deciduous and mixed hardwood–conifer forest boundary in the upper Great Lakes region. Tree-ring samples were collected at 11 sites that are classified as mesic to dry–mesic based on species composition. At each stand at least 20 trees were sampled of each species dominant in the canopy, resulting in one to five species collections per stand and 31 chronologies in total. Principal component analysis was used to define the common variance among the chronologies. Three components explain 57.4% of the variation among the chronologies, indicating that common patterns of tree growth exist within the multispecies network. Component loadings indicate that (i) species to species variation is more important than site to site variation and (ii) species can be segregated into distinct groups based on their common patterns of growth through time. Correlations between the three-component-score time series and climatic data indicate that growth anomaly patterns are weakly, but significantly, correlated with growing-season temperature and precipitation variables. Extreme climatic events (i.e., greater than 1 SD above or below the mean) are very important in generating differential growth rates among the species sampled.
Stand, family, and rust-source effects on four attributes of lodgepole pine resistance to western gall rust
Authors: Blenis P.V. , Pinnell H.D. , John S.E.T.
Published: July 2007

Lodgepole pine (Pinuscontorta var. latifolia Engelm.) seedlings from 23 open-pollinated pine families from five stands in west-central Alberta were inoculated with western gall rust (Endocronartiumharknessii (J.P. Moore) Y. Hiratsuka) spores from four locations within 69 km of those stands. Six weeks after inoculation and at 3-week intervals for 21 weeks thereafter, seedlings were examined for symptoms of infection and galls. Eighteen months after inoculation, most trees in a sample of 1321 had either fully developed galls or no galls; partial gall formation was uncommon. Frequency of gall formation was highly correlated with the area under the disease progress curve (AUDPC) of symptom appearance and the AUDPC of gall appearance. It was also correlated, although less strongly, with the frequency of seedlings that had initially shown symptoms of infection but had no galls 21 weeks after inoculation. Regardless of whether AUDPC of gall appearance, frequency of gall formation, or failure to develop galls following infection was used as the criterion of resistance, the results were similar. Family effects were greater than stand effects, and rust-source effects were smaller than family effects and not always significant. There was no interaction between rust-source effects and either stand or family effects.
The chloroplast genome of Pinussylvestris; physical map and localization of chloroplast genes
Authors: Karpinska B. , Karpinski S.
Published: July 2007

A physical map of Pinussylvestris L. chloroplast DNA for three restriction endonucleases (PstI, SacI, and KpnI) has been prepared by hybridization of isolated or cloned restriction fragments. Pinussylvestris chloroplast DNA is about 120 kilobases. Ten chloroplast genes have been localized by hybridization with heterologous chloroplast DNA probes. The genome contains single copies of the 23S and 16S rRNA genes and lacks any large repeated sequences. The restriction site arrangement and gene order have been compared with other known chloroplast DNA genetic maps of pine species.
A time to ignition–temperature–moisture relationship for branches of three western conifers
Authors: Xanthopoulos Gavriil , Wakimoto Ronald H.
Published: July 2007

The effect of convection column air temperature and live needle moisture content on ignitability of tree branches was verified and quantified by exposing branches of three conifer species to a hot-air convection column, at temperatures between 400 and 640 °C, and measuring time to ignition. The three species were ponderosa pine (Pinusponderosa Laws.), Douglas-fir (Pseudotsugamenziesii var glauca (Beissn.) Franco), and lodgepole pine (Pinuscontorta Dougl.). The experiment was repeated monthly over the course of a year, taking advantage of the natural fluctuation of live needle moisture content. Three multiple regression equations for the prediction of time to ignition with air temperature and needle moisture as the independent variables were developed.
Microprojectile-mediated DNA delivery in haploid and diploid embryogenic cells of Larix spp.
Authors: Duchesne Luc C. , Lelu Marie-Anne , Aderkas Patrick von , Charest Pierre J.
Published: July 2007

A particle bombardment protocol using the Dupont Biolistic™ particle delivery system and the β-glucuronidase reporter gene was developed for embryogenic cell lines of Larix. Comparison of four sizes of tungsten microprojectiles showed the highest transient gene expression with 1.11 μm diameter particles. The highest β-glucuronidase transient gene activity was in cells bombarded 5 and 6 days after subculturing to fresh media. Comparison of 22 different cell lines of haploid and diploid Larixdecidua, Larixleptolepis, LarixXleptoeuropae, and LarixXeurolepis showed variation among the cell lines in β-glucuronidase gene activity, embryogenesis, and cell growth. In diploid lines, the levels of transient gene expression were higher with youngest lines; however, this trend was not distinguishable in haploid lines
Estimating leaf area index and light extinction coefficients in stands of Douglas-fir (Pseudotsugamenziesii)
Authors: Smith Nicholas J.
Published: July 2007

Both photosynthetically active radiation penetrating the overstory canopy and overstory leaf area index were determined in forty-three 12 × 12 m plots in even-aged Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stands. Stands were located on the east side of Vancouver Island, British Columbia, between 300 and 800 m on flat to south-facing slopes and were from a wide range of stem densities and stocking levels. In nine core plots total tree leaf area index was estimated using regression equations from individual-tree stem diameter and stand relative density. A single extinction coefficient did not govern the attenuation of photosynthetically active radiation with respect to leaf area index. For a given leaf area index, the extinction coefficient was smaller at low relative densities because of the presence of canopy gaps. Light attenuation models assuming a single extinction coefficient seriously underpredict stand leaf area index, especially at low stand densities. A modified Beer's Law model was used to predict light penetration, which implicitly accounted for foliage clumping.
Leaf nitrogen dynamics with particular reference to retranslocation in evergreen and deciduous tree species of Kumaun Himalaya
Authors: Negi G.C.S. , Singh S.P.
Published: July 2007

The concentration and mass of nitrogen (N) were followed seasonally in leaves of 26 trees species of Central Himalaya: 11 evergreen species with about 1-year leaf life-span and 15 deciduous species. Like the deciduous species, the leaves of these evergreen species start senescing and losing mass in the year of formation. Species with higher N status retranslocated a larger proportion of leaf N prior to leaf abscission than the species with less favourable N status. The percentage of N mass in the leaf that was retranslocated during senescence ranged from 32.7 to 75.3%, but none of the species with N concentration less than 2.5% in mature leaves retranslocated more than 60% of N. Compared with evergreen species, on average the deciduous species showed higher N concentration in mature leaves (3.2 vs. 2.5%), higher proportion of leaf mass loss during senescence (31.6 vs. 26.2%), and greater proportion of retranslocated N mass from leaves (57.1 vs. 51.8%). With regard to the N-use efficiency the two groups of species were not clearly different. The dependence of deciduous species on retranslocated N mass for leaf growth during the dry period of the premonsoon season was greater than that of the evergreen species, which showed partial dependence on the soil N pool for new leaf formation.
Interaction of Douglas-fir with red alder and salal foliage litter during decomposition
Authors: Fyles J.W. , Fyles I.H.
Published: July 2007

Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) foliage litter was incubated in the laboratory in 100/0, 75/25, 50/50, 25/75, and 0/100% mixtures with foliage litters from red alder (Alnusrubra Bong.), a nitrogen-fixing tree species, and salal (Gaultheriashallon Pursh) an ericaceous shrub. Mass loss and mineral nitrogen content were measured at eight dates during the 32-week incubation. The occurrence of interaction between litters, observed as deviation from a linear trend across mixtures at each date, was determined by polynomial contrasts. Douglas-fir–red alder mixtures decomposed faster than predicted by mass loss from pure litters throughout the study, apparently because of nitrogen mineralized by the red alder component. Douglas-fir–salal mixtures decomposed more slowly than predicted between 7 and 25 weeks. The study demonstrates the potential for litters to interact with positive or negative effects on decomposition rates and emphasizes the need to examine such interactions if litter decomposition in the field is to be understood.
Frost, canker, and dieback of Douglas-fir in the central interior of British Columbia
Authors: Reich Richard W. , Kamp Bart J. van der
Published: July 2007

The relationships between dieback severity of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), growing-season frosts, and invasion by canker pathogens in plantations >10 years old in central British Columbia are described. The coincidence of frosts and dieback events was determined by dissection and by mapping dieback damage in arid around frost pockets. Putative canker pathogens were isolated from bark and fruiting bodies. The timing of significant dieback events coincided with major growing-season frosts, as determined by the formation of frost rings. Damage was most severe in shallow depressions and valley bottoms. Early flushing trees were more severely affected than late flushing trees in two of three plantations. Seven weak canker parasites were isolated from dead Douglas-fir bark. Among these, Sclerophomasemenospora Funk was restricted to tissues killed by frost or other factors, while Leucocytosporakunzei (Fr.:Fr.) Munk and a Sirodothis sp. accounted for about 65% of isolates from recently killed bark. Outside frost prone areas, these fungi were common as small latent branch cankers, but caused no further discernable damage. Areas of high dieback hazard could be identified from topographic features seen on aerial photographs. Of the area of Douglas-fir plantations >10 years old, 4.7% was severely damaged by dieback. It is recommended that lodgepole pine (Pinusconforta Dougl.) be planted in frost-prone areas.
Dehydration tolerance of five bur oak (Quercusmacrocarpa) seed sources from Texas, Nebraska, Minnesota, and New York
Authors: Kuhns Michael R. , Stroup Walter W. , Gebre G. Michael
Published: July 2007

Dehydration tolerance was studied in saplings of five widely distributed sources of Quercusmacrocarpa Michx. growing together in an outdoor plot in Lincoln, Nebraska. Membrane electrolyte leakage, expressed as percent injury, was used as a measure of dehydration tolerance. Leaves were excised from several plants of each source on July 16 after a long dry period and on August 26 after a long moist period. Leaves were allowed to dry for various times in a laboratory, their water potential was measured, and membrane injury was determined. Regressions were calculated for percent injury versus leaf water potential, so sources could be compared at selected water potentials. All sources showed increased leakage at lower water potentials, with most leakage occurring below a water potential of −3 MPa. A source from Texas had the highest leakage, 23% at −6 MPa in August, while a source from a more xeric site in north central Nebraska generally had the lowest leakage. Stress preconditioning appeared to affect leakage, with leakage often significantly lower in July than in August.
Prediction of crown fire behavior in two stands of jack pine
Authors: Wagner C.E. Van
Published: July 2007

Published data on two sets of experimental fires in jack pine (Pinusbanksiana Lamb.) forest were subjected to two forms of analysis. The first was a classification into surface fires and two kinds of crown fire, passive and active. In the second, the data were used to develop a model to predict both the spread rate of fire and the degree of crown consumption. The model consists mainly of two limiting equations for spread rate, one for surface fires and the other for full crowning fires; the independent variable is the Canadian Initial Spread Index. A critical surface intensity is first used to distinguish surface fires from crowning fires. A further process then estimates the degree of crowning and places the calculated final spread rate somewhere in the space between the limiting equations. The model inputs include six physical stand properties plus a pre-estimate of surface fuel consumption. It is a blend of physical theory and empirical observation.
Cation and anion fluxes in northern hardwood throughfall along an acidic deposition gradient
Authors: Liechty Hal O. , Mroz Glenn D. , Reed David D.
Published: July 2007

Ionic concentrations and fluxes were measured for 2 years in five northern hardwood stands along an acidic deposition gradient that extends from northern Minnesota (lowest deposition) to southeastern Michigan (highest deposition). Precipitation fluxes of H+, SO42−, and NO3− were, respectively, 340, 69, and 83% greater at the site with the highest deposition than at the site with the lowest deposition. No significant differences among sites were evident for precipitation fluxes of cations along the gradient. Fluxes of H+, SO42−, NO3−, Ca2+, and Mg2+ in throughfall increased along the gradient and were positively correlated with increased atmospheric inputs of H+, SO42−, and NO3− measured at the sites. Fluxes of SO42− and NO3− in throughfall were greater than precipitation fluxes, indicating dry deposition in excess of any assimilation of these anions from precipitation. Dry deposition inputs of SO42− increased from the northwestern to southeastern sites and were estimated to range from 23 to 49% of precipitation inputs. Precipitation acidity was neutralized by the canopy in all stands, but the amount of H+ retained by the canopy was significantly greater at sites with the greatest precipitation acidity. Throughfall fluxes of Ca2+ and Mg2+ in excess of precipitation fluxes were positively correlated with the canopy retention and deposition of H+ along the gradient. Increased throughfall fluxes of these cations were consistent with hypothesized increases in canopy leaching of cations with increased acidic deposition. Increased canopy leaching of Ca2+ and Mg2+, resulting from elevated acidic deposition, was estimated to represent as much as 6.2 and 12.9% of foliar contents of these cations, respectively. Although HCO3− and organic anions were found to play an important role in maintaining electroneutrality in throughfall along the gradient, strong acid anions increasingly dominated anionic composition of throughfall with increasing acidic deposition.
Influence of cultural practices on the relationship between frost tolerance and water content of containerized black spruce, white spruce, and jack pine seedlings
Authors: Calmé Sophie , Margolis Hank A. , Bigras Francine J.
Published: July 2007

Two experiments were performed to study how cultural practices influenced the relationship between frost tolerance and water content of black spruce (Piceamariana (Mill.) B.S.P.), white spruce (Piceaglauca (Moench) Voss), and jack pine (Pinusbanksiana Lamb.) seedlings. In the first experiment, first-year black spruce seedlings were subjected to 14-d mid-August treatments of short days of 8 h or to natural day length, during which time seedlings were either irrigated or not. In the second experiment, first-year white spruce, black spruce, and jack pine seedlings were fertilized at two levels, normal or double, during the growing season. In the fall, we followed the evolution of frost tolerance, water content (dry weight to fresh weight ratio), height and diameter growth, bud formation, and mineral concentrations of shoots and roots. In the first experiment, short days accelerated frost acclimation, drop in water content, and bud formation. Short days with no irrigation triggered the cessation of height growth. In the second experiment, normal fertilization slightly improved frost tolerance in white spruce. Diameter growth (except for white spruce) and bud formation were enhanced by high nitrogen concentration, whereas no significant effect of fertilization could be found on height growth and water content. In both experiments, the relationship between frost tolerance and water content was independent of treatments and indicated that nontolerant seedlings (lethal temperature for 50% of the seedlings > −10 °C) had dry weight to fresh weight ratios of less than 30% for the three species. Thus, this rapid method of evaluating frost tolerance could be useful to seedling producers in eastern Canada and might be applicable to other species in other regions as well.
A mean-variance approach to short-term timber selling and forest taxation under multiple sources of uncertainty
Authors: Ollikainen Markku
Published: July 2007

The effects of forest taxation on timber supply under the double uncertainty of real interest rate and future timber price are analyzed in a mean-variance framework. If future timber price and interest rate are independent random variables, there exists an asymmetry between lenders and borrowers, as there is in the single interest rate uncertainty case. Borrowers cut more and lenders cut less as a response to double uncertainty relative to single price uncertainty. If timber price and interest rate are correlated, the sign of the covariance is crucial for the interpretation of the optimality conditions and for the comparative static analysis results. If covariance is negative, borrowers still tend to increase their cutting, but the behaviour of lenders depends on the relative magnitudes of risks associated with interest rate and timber price, which is indicated by variances and covariance. Finnish data are used to evaluate the size of various risks and the sign of covariance. The evidence suggests that a statistically insignificant negative correlation exists and that the covariance is zero.
Simulated fate of leaf litter and large woody debris at a riparian cutbank
Authors: Malanson George P. , Kupfer John A.
Published: July 2007

Leaf litter and woody debris are important sources of carbon for stream ecosystems, but the patterns of such inputs are variable. To clarify the processes that may lead to such variations, we modified a computer simulation model of forest dynamics to record the production, transport, and decomposition of leaf litter and woody debris given conditions found on a floodplain. The species chosen represent those of floodplains in the central Mississippi River valley, United States. We examined differences in model results when the conditions simulated were (i) a floodplain forest interior or a riparian cutbank edge, (ii) high or low flood regimes, and (iii) with or without the direct removal of material by flood flows. Projections of productivity of floodplain interior sites were similar to those observed in other studies in comparable areas. The inclusion of edge effects increased litter and debris production significantly. There were differences in how material produced was apportioned: there was a greater input to the river that had edge effects and, trivially, flood removal; there was greater on-site storage otherwise. Interaction effects were found because of the dependence on initial productivity. This simulation indicates that the particular local effects of hydrological and geomorphological processes will affect the fate of carbon on floodplains and reveals the importance of a spatially explicit conceptualization of forest dynamics.
Repeated measures in randomized block and split-plot experiments
Authors: Gumpertz M.L. , Brownie C.
Published: July 2007

Randomized block and split-plot designs are among the most commonly used experimental designs in forest research. Measurements for plots in a block (or subplots in a whole plot) are correlated with each other, and these correlations must be taken into account when analyzing repeated-measures data from blocked designs. The analysis is similar to repeated-measures analysis for a completely randomized design, but test statistics must allow for random block × time effects, and standard errors for treatment means must also incorporate block to block variation and variation among plots within a block. Two types of statistical analysis are often recommended for repeated-measures data: analysis of contrasts of the repeated factor and multivariate analysis of variance. A complete analysis of repeated measures should usually contain both of these components, just as in univariate analysis of variance it is often necessary to decompose the main effects into single degree of freedom contrasts to answer the research objectives. We demonstrate the multivariate analysis of variance and the analysis of contrasts in detail for two experiments. In addition, estimation of coefficients assuming a polynomial growth curve is discussed in detail for one of these experiments. The first experiment, a randomized complete block design, is a forest nutrition study of the long-term effects of midrotation nitrogen and phosphorus fertilization on loblolly pine (Pinustaeda L.); the second experiment, a split-plot design, is an air-pollution study of the effects of ozone and acid precipitation on loblolly pine growth.
Breeding objectives for pulp production of Eucalyptusglobulus under different industrial cost structures
Authors: Borralho N.M.G. , Cotterill P.P. , Kanowski P.J.
Published: July 2007

Breeding objectives were defined for pulp production of Eucalyptusglobulus Labill, using a simple profit equation relating the monetary cost savings per tonne of pulp produced with stem volume, wood density, and pulp yield. The economic importance of each trait was calculated for five different pulp and forestry industry scenarios with widely different cost structures. Selection indices integrating various combinations of volume growth, wood density, and pulp yield were compared for their ability to meet the different breeding objectives. There was surprising consistency in results across the range of breeding objectives and cost structures studied. It was clear that selection indices integrating volume, wood density, and pulp yield gave the most accurate selection and maximized genetic gain in breeding objectives. The cost savings from indices that included only volume were always much less than one-half, and sometimes as low as one-quarter, as much as those from indices integrating volume and wood traits. In the case study considered, E. globulus in Portugal, these cost savings had substantial implications for company profitability.
Survival rate and nuclear irregularity index of sapwood ray parenchyma cells in four tree species
Authors: Yang K.C.
Published: July 2007

Survival rate and the newly developed nuclear irregularity index (NII) of sapwood ray parenchyma cells were studied within single trees of four species: Pinusbanksiana Lamb., Piceamariana (Mill.) B.S.P., Abiesbalsamea (L.) Mill., and Populustremuloides Michx. The survival rate of ray parenchyma cells is defined as the number of living earlywood ray parenchyma cells in uniseriate rays, divided by the total number of dead and living ray parenchyma cells recorded, multiplied by 100. NII is defined as the ratio of the number of irregularly shaped nuclei of uniseriate ray parenchyma cells to the total number of the irregular and regular nuclei recorded in earlywood, multiplied by 100. The location where death of ray parenchyma cells was first seen in the sapwood varied with species from the second to the seventh growth ring, counted from the cambium. In general, the marginal cells in the outer sapwood died earlier in a given growth ring than the central cells. The survival rate of the sapwood ray parenchyma cells decreased curvilinearly from the outer or middle sapwood towards the boundary of sapwood and heartwood. Based on survival rate classification, Pinusbanksiana and Populustremuloides are type II species, in which some ray parenchyma cells die in the middle or inner sapwood and the number of dead cells increases from the middle sapwood towards the heartwood. Piceamariana and Abiesbalsamea are type III species, in which some ray parenchyma cells die in outer sapwood and the number of dead cells increases from the outer sapwood towards the heartwood. NII increased from the middle of the sapwood towards the sapwood–heartwood boundary and reached its maximum at the growth ring immediately adjacent to the heartwood. NII increased from May to a maximum in the middle of the growing season and then decreased sharply. The months of sharpest decline of the NII in Pinusbanksiana, Piceamariana, and Populustremuloides were August, July–August, and August–October, respectively. In Abiesbalsamea no sharp decline of NII was observed. The findings of this study are in agreement with those of other investigators who used different criteria to indicate the initiation time of heartwood formation. Thus it appears that NII can be added to the list of indicators that pinpoint the initiation time of heartwood formation.