bluuebunny/crossref_metadata_2025 huggingface dataset:
Interpreting foliar analyses from Douglas-fir as weight per unit of leaf area
Authors: Smith R. B. , Waring R. H. , Perry D. A.
Published: July 2007

To evaluate whether changes in leaf weight might affect the interpretation of foliar analyses, seasonal samples of current and older Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) needles were compared from contrasting environments in the Coast Range and Cascade Mountains of western Oregon, U.S.A. Foliage from trees grown in the climatically mild and moist Coast Range maintained nearly constant weight and nitrogen content per unit of leaf area throughout the year, regardless of whether stands were thinned or left unthinned. In contrast, foliage from trees growing in the harsher environment of the Cascade Mountains averaged only half the weight per unit of leaf area of samples from the Coast Range during the dormant season. During the summer, foliage weight and nitrogen content per unit of leaf area increased by more than 50% in the Cascades. These values were 20–40% less, respectively, than those observed in the foliage of Coast Range trees. In the Cascades, thinning significantly increased both foliage weight and nitrogen content. Implications of these findings are discussed in regard to interpreting foliar analyses.
À propos de l'estimation de l'accroissement annuel courant par l'accroissement périodique moyen
Authors: Zarnovican Richard
Published: July 2007

Evaluation of the relationship between current annual increment (CAI) and mean periodic increment (MPI) reveals that the latter is a valid estimator of the CAI. However, the accuracy of this estimation depends on length of period and phases of growth.
Optimisation du complexe récolte–pulvérisation dans la lutte contre la tordeuse des bourgeons de l'épinette
Authors: Ung Chhun-Huor , Boudoux Michel , Hardy Yvan J.
Published: July 2007

An optimization model was developed as an additional tool for the management of the forest – spruce budworm (Choristoneurafumiferana (Clem.)) complex. The management objectives being considered deal only with losses in wood and the direct benefits of wood production. The spruce budworm model developed by the Institute of Resource Ecology, University of British Columbia, was used to evaluate the results of various management strategies for the forest–budworm complex. Based on dynamic programming, the optimization model determines in a temporal frame the optimal rates of insecticide to be sprayed and the annual rhythm of forest harvesting.
Spread of Armillariaostoyae in juvenile lodgepole pine stands in west central Alberta
Authors: Klein-Gebbinck H. W. , Blenis P. V. , Hiratsuka Y.
Published: July 2007

Juvenile lodgepole pine (Pinuscontorta Dougl. var. latifolia Engelm.) were excavated at three sites near Hinton, Alberta. In all cases in which Armillariaostoyae (Romagn.) Herink had become established in the root collar or taproot, it was also able to colonize lateral roots. In cases in which only lateral roots were infected, subsequent colonization generally was primarily distal to the point of infection. Rhizomorphs were associated with 89% of 21 infected roots, whereas only 19% of 70 roots with no associated rhizomorphs were infected. Stumps, roots, and debris from the previous generation of trees were the inoculum sources for 78% of 36 infected juvenile trees, and infected regeneration served as the inoculum source for the remaining trees. Rhizomorphs occasionally were attached to the roots or rhizomes of plants other than pine, especially fireweed (Epilobiumangustifolium L.). There was no spatial relationship between stumps and symptomatic trees. Nearest neighbor analysis indicated that the likelihood of an individual tree developing symptoms was dependent on whether trees within 0.15 m were dead or dying but independent of the apparent health of trees at greater distances.
Estimating the effects of land-use change on global atmospheric CO2 concentrations
Authors: Dale Virginia H. , Houghton R. A. , Hall Charles A. S.
Published: July 2007

Determining how land-use change effects atmospheric CO2 concentrations requires new approaches to research because of the large area and the long period of time involved. This special issue of the CanadianJournalofForestResearch presents a series of papers that demonstrate one approach to the problem. Estimates of the flux of carbon to the atmosphere are based on site-specific information concerning the effects of land-use change on the carbon content of terrestrial vegetation. This spatially explicit approach combines historical and current information on land-use change for a specific area. South and southeast Asia was chosen for the study because the region is undergoing major land-use changes and makes a significant contribution to atmospheric CO2. The results of the study have assisted in reducing the uncertainty about the magnitude of carbon release while providing new constraints to the analysis.
The response of western juniper (Juniperusoccidentalis) to reductions in above-and below-ground tissue
Authors: Miller P. M. , Eddleman L. E. , Miller J. M.
Published: July 2007

Plants are balanced systems that integrate processes of carbon fixation and uptake of water and nutrients to optimize resource acquisition. Response of Juniperusoccidentalis Hook. to reductions in above- and below-ground tissue was measured to determine effects on carbon dioxide assimilation, leaf conductance, intercellular carbon dioxide, xylem water potential, foliage nutrient concentration, aboveground growth, water-use efficiency, and potential photosynthetic nitrogen-use efficiencies. Approximately 50% of the old foliage was removed and lateral roots were severed at the canopy edge in early April 1988; physiological processes were measured during three periods in the summer of 1988. Foliage removal increased rates of carbon dioxide assimilation and photosynthetic nitrogen-use efficiency, but neither increased growth nor improved water status or nitrogen concentration of remaining foliage. Cutting lateral roots reduced assimilation, leaf conductance, foliage nitrogen concentration, branchlet elongation, water-use efficiency, and photosynthetic nitrogen-use efficiency. By late August, juvenile and small-adult J. occidentalis in the cut-top treatment had compensated for foliage removal by reestablishing patterns of water-use efficiencies similar to those of control plants, which may indicate that an overall metabolic control was functioning to regulate the balance between carbon dioxide assimilation and water loss. Cutting lateral roots had a more lasting effect on efficiencies; by late August, juveniles and small adults still had significantly lower water-use efficiencies than controls.
Estimating components of propagated variance in growth simulation model projections
Authors: Mowrer H. Todd
Published: July 2007

First-order Taylor series variance estimation equations were embedded in a growth simulation model to estimate propagated variances during growth and yield projections. Variance equations estimated three error components: covariances propagated through predictor variables, covariances from estimated regressor coefficients, and covariances between regressor coefficients and variables. A separate Monte Carlo process was used to estimate the total variance in projected variables caused by simultaneous perturbations in values of initialization variables and in regressor coefficients. Variances estimated by these two procedures were compared over five consecutive projection periods for six variables in a forest growth simulation model. While results agreed closely for the variance in mean stand diameter, disparities increased for other variables later in the model estimation sequence. Disparities were attributed to differences between the populations used in both variance estimation procedures and to possible violations of Taylor series assumptions in the variance estimation equations.
A simple method for cross-dating increment cores from living trees
Authors: Yamaguchi David K.
Published: July 2007

For many types of forest studies, it is essential to identify the exact years of formation of annual rings in increment cores taken from living trees. To accomplish this, dendrochronologists employ cross dating, which involves both ring counting and ring-width pattern matching, to ensure against counting error, or errors, caused by missing or false rings. To date, published accounts of the cross-dating process generally describe a graphical method for achieving cross dating, known as skeleton plotting. However, when working with cores from living trees, skeleton plotting is seldom necessary. Such cores can commonly be cross-dated more quickly and easily by listing the narrow rings that are present in each core in a laboratory notebook and then comparing core notes for shared narrow rings. The latter approach permits faster recognition of ring-width patterns because calendar-year, rather than relative-year, dates are assigned to rings in cores. It also allows cross-dating records to be stored in a more concise manner.
Cutting, burning, and mulching to control Kalmia: results of a greenhouse experiment
Authors: Mallik A. U.
Published: July 2007

A greenhouse experiment was conducted to study the effect of cutting, cutting plus burning, and mulching treatments on Kalmia regrowth. Kalmia plants were transplanted into plastic buckets, and the treatments were applied in the greenhouse. After 8 months, the plants receiving cutting and cutting plus burning treatments showed no significant difference in the number and length of new sprouts compared with the control. However, the sprouts that developed after the cutting and cutting plus burning treatments were robust, with significantly higher dry weights compared with the control. Although there was no significant difference in the number of rhizomes between these treatments, rhizome lengths and dry weights were significantly smaller than those of the control. Mulching treatments dramatically reduced Kalmia regrowth in terms of both aboveground and belowground components. A field trial is recommended for Kalmia control in central Newfoundland using mulching equipment.
Explosive discharge of jack pine dwarf mistletoe (Arceuthobiumamericanum) seed in Manitoba
Authors: Punter David , Gilbert Jeannie
Published: July 2007

Seeds of the dwarf mistletoe, Arceuthobiumamericanum Nutt. ex Engelm., explosively discharged from plants parasitizing 40- to 60-year-old jack pine trees (Pinusbanksiana Lamb.), were collected on cheesecloth traps at two sites in Grand Beach Provincial Park at 2-h intervals during daylight hours. Microclimatic variables were continuously recorded during the discharge period. Seeds were recovered up to 18 m from the canopy margin. Seasonal fluctuations in numbers of seeds trapped were attributed in part to fungal hyperparasitism of fruits and high spring temperatures. The spatial distribution of seeds was strongly leptokurtic, with most landing within 12 m of the canopy margin. Neither the onset nor the distance of discharge could be ascribed to any single microclimatic parameter. With one apparent exception, no discharge occurred during the hours of darkness. The number of seeds trapped rose rapidly between sunrise and 11:00 central standard time, when temperature was increasing and relative humidity was falling. Stepwise regression analysis confirmed that change in relative humidity was predominantly responsible for the diurnal periodicity of seed discharge. Based on our observations, we recommend a minimum 20-m buffer zone to protect pine regeneration from A. americanum infected residual trees.
Timber quality classes from cruise data for lodgepole pine sawn at a board mill in British Columbia
Authors: Howard Andrew F.
Published: July 2007

Information on timber quality can play an important role in a wide range of planning activities at sawmills. A system for assessing timber quality does not exist for lodgepole pine (Pinuscontorta Dougl.), which is one of the most important commercial species in the interior of British Columbia. A classification system for lodgepole pine timber was developed from cruise data collected according to procedures prescribed by the British Columbia Ministry of Forests. A sawmill lumber yield study was made to obtain the data necessary to test the grading system. Regression analysis, likelihood ratio tests, and analysis of variance were used to test for significant differences in lumber grade yields and log values among six quality classes. The findings indicate that data collected during cruising can be used to separate timber into distinct quality classes. The quality classes showed appreciable variation in average log value when current lumber prices were applied.
Stimulation of flowering by grafted black spruce and white spruce: a comparative study of the effects of gibberellin A4/7, cultural treatments, and environment
Authors: Greenwood Michael S. , Adams Gregory W. , Gillespie Michele
Published: July 2007

not available
Weight and nutrient content of litter during secondary succession on well-drained uplands of the East Gulf Coastal Plain in Mississippi
Authors: Hlnesley L. E. , Nelson L. E. , Switzer G. L.
Published: July 2007

Production of forest litter was examined over 2 years in a chronosequence of stands representing four stages of secondary succession on well-drained uplands of the East Gulf Coastal Plain in Mississippi. Average age for these stands was from 22 to 207 years. Early succession was dominated by dense pine stands, whereas mature forests were about 75% hardwood. Litter mass was greatest early in succession, when productivity was highest, and decreased as stands matured. Foliage was approximately 70% of the litter throughout succession. The remaining 30% was mostly large woody material in young pine stands, but a heavy reproductive component in mature stands. Stands dominated by pines produced litter throughout the year, whereas hardwood stands were more cyclic. In young pine stands, the N and P content of litter was already 80–90% of the maximum value realized later in succession, whereas Ca and Mg accumulated in proportion to hardwood basal area. Nutrient concentrations in litter varied by season, component, and stage of succession. Foliar litter that fell in the spring and summer had higher N and P concentrations than that that fell in the fall. Seasonal patterns of litter production, as well as variations in nutrient concentration, made the monthly variation of nutrients returned to the forest floor less extreme than that of foliar litter fall weights.
Repeated measures experiments in forestry: focus on analysis of response curves
Authors: Meredith M. P. , Stehman S. V.
Published: July 2007

Treatment effects over time are frequently investigated using repeated measures designs, but analyses of these experiments frequently fail to address a primary objective of collecting data over time, namely description of the response curve. The analysis advocated in this paper utilizes the intrinsic continuity of the repeated measures factor by focusing on response curves. Treatments are compared by analyzing estimated coefficients of response curves proposed by the investigator. This approach provides more information on treatment effects than analyses that compare treatments separately at each time period. Analysis of estimated coefficients is easier to interpret than multivariate analyses of variance and does not require often biologically implausible assumptions of split-plot analyses currently in vogue. An example describing effects of aluminum on sugar maple (Acersaccharum Marsh.) seedling growth illustrates the method.
Effects of Hebeloma arenosa on growth and survival of container-grown red pine seedlings (Pinus resinosa)
Authors: MacFall J. S. , Slack S. A.
Published: July 2007

The ability of the ectomycorrhizal fungus Hebelomaarenosa Burdsall, MacFall & Albers to enhance growth and survival of container-grown red pine seedlings (Pinusresinosa Ait.) was investigated. Shoot height of H. arenosa inoculated seedlings was 28% greater than noninoculated seedlings when grown without fertilizer applications. Eight-week-old seedlings transplanted into a Ball mix (a mixture of peat, bark, and perlite) containing up to a 1:64 dilution of fungal inoculum had significantly greater root dry weights and root/shoot ratios than noninoculated seedlings when grown for an additional 14 weeks. Under experimental greenhouse conditions, root and shoot dry weights of container-grown red pine seedlings that had been directly seeded into Ball mix containing up to a 1:256 dilution of fungal inoculum were significantly greater than weights measured for noninoculated seedlings. Root and shoot dry weights of container-grown seedlings seeded directly into a 1:5 dilution of H. arenosa inoculum and Ball mix and then grown under commercial production conditions were greater than comparable weights of noninoculated seedlings. Hebelomaarenosa inoculation significantly increased seedling survival following outplanting, but did not increase seedling growth. Hebelomaarenosa did not colonize roots growing from the root plug into the surrounding soil.
A probability distribution model for age–age correlations and its application in early selection
Authors: Magnussen S.
Published: July 2007

Bootstrap-generated distributions of age–age correlations of stem volume in a red pine (Pinusresinosa Ait.) spacing trial supported the contention of the β distribution as a realistic model for age–age correlations in small populations where normal approximations are inappropriate. The model describes age–age correlations as a repeatability of tree performance. The orthonormal decomposition of the total variance into among- and within-tree variance components was derived from Fourier-transformed time series of the trait values. Applications for early selections include (i) finding the optimum selection age for various numbers of selections made and (ii) predictions of age–age correlations.
The effect of host variability on growth and performance of the introduced pine sawfly, Diprionsimilis
Authors: Codella Jr. Sylvio G. , Fogal Wlllard H. , Raffa Kenneth F.
Published: July 2007

Diprionsimilis (Htg.) (Hymenoptera: Diprionidae) was reared in the laboratory on Pinusbanksiana Lamb, and Pinusstrobus L. from the second stadium through adult emergence. Groups of larvae were fed current-year or previous years' foliage from specific trees. Host species had a significant, but limited, effect on D. similis growth and performance. Foliar age had a stronger and more consistent effect on development. In contrast with reports for other diprionid species, previous years' needles had a consistently greater adverse effect on D. similis performance than did new growth. This suggests that there is a conflict between the avoidance of host tissues with high allelochemical concentrations and the avoidance of those with reduced nutrient content. Larval survival did not vary between foliar treatments, which suggests that the detrimental effects of host diet are chronic rather than acute. Female fecundity was strongly associated with cocoon weight, but the relationship varied with host diet and diapause incidence, as did the relative reproductive potential. Substantial between-tree variability in insect performance indicates a potential for resistance breeding programs. Tree rankings for each performance variable were highly consistent, which would permit the development of an expeditious screening procedure.
Aerial tree volume functions for eucalypts in Western Australia
Authors: Biggs P. H.
Published: July 2007

Large-scale, fixed-base aerial photography is being used together with ground sampling in a major inventory of eucalypt forest in Western Australia. This paper describes the aerial tree volume functions derived for that inventory, covering species in the jarrah (Eucalyptusmarginata) forest. The equations, derived from ground measurements, predict gross bole volume from estimates of total height and vary with the site quality of the forest. They are used to predict volume from photomeasurements of total height that have been corrected for measurement error. The functions appear suitable for this forest type, although the volumes of veteran trees with severely damaged crowns are underestimated.
Capacity changes in the United States paper and paperboard industries: q theory and empirical models
Authors: Zhang Dali , Buongiorno Joseph
Published: July 2007

A parsimonious model of capacity expansion is proposed for the United States paper and paperboard industries. The work grows out of Tobin's q theory, which suggested that the ratio between market value and replacement cost of capital is crucial in investment decision making. The model assumes that firms in the two industries are price takers, with a marginal cost of production equal to the average cost. The q values for the paper and paperboard industries were calculated as the ratios of the shadow price of existing capacity to the cost of new capacity. Annual data from 1958 to 1988 were used for estimation, with static and dynamic models of capacity changes. The results showed that a single dynamic equation using the q ratios alone explained most of the gross changes in capacity in both the paper and paperboard industries of the United States during the period considered.
Post-fire regeneration of Pinusalbicaulis: height–age relationships, age structure, and microsite characteristics
Authors: Tomback Diana F. , Sund Sharren K. , Hoffmann Lyn A.
Published: July 2007

We studied post-fire Pinusalbicaulis Engelm. seedling establishment in the Sleeping Child and Saddle Mountain burns of western Montana 26 and 28 years, respectively, after fire. Pinusalbicaulis seeds are dispersed primarily by Clark's nutcracker (Nucifragacolumbiana Wilson) in caches of 1–15 or more seeds. Consequently, P. albicaulis seedlings and trees often occur in clusters. In the Sleeping Child burn we collected regeneration data from 63 quadrats along a 3.6-km transect and from 14 quadrats along a 20.6-km road transect; in the Saddle Mountain buhn we collected data from 41 quadrats along a 3.2-km transect. We determined regression models for height versus age and age versus height relationships for P. albicaulis and Abieslasiocarpa (Hook.) Nutt. and used the latter regression models to construct regeneration age structures for both bums. For both conifers a disproportionately high percentage of regeneration was established between 1977 and 1985, about 17–25 years after fire. Thus, major regeneration was episodic. A small increase in mean seasonal rainfall between 1977 and 1985 possibly contributed to this recruitment surge. Age differences of 1–8 years occurred among seedlings in 65–86% of the seedling and tree clusters sampled, suggesting delayed germination of some cached seeds. Pinusalbicaulis regeneration was more frequently associated with Vacciniumscoparium Leiberg and less frequently associated with Xerophyllumtenax (Pursh) Nutt. and Luzulahitchcockii Hamet-Ahti relative to the overall frequency of occurrence of these plants among quadrats.
Effet des sites et des traitements sylvicoles sur la croissance, l'allocation en biomasse et l'utilisation de l'azote de semis de quatre espèces feuillues en plantations dans le sud-ouest du Québec
Authors: Cogliastro Alain , Gagnon Daniel , Bouchard André
Published: July 2007

To identify conditions leading to the successful establishment of hardwoods in plantations, several parameters related to growth, biomass allocation, and nitrogen nutrition were analyzed in relation with variations in soil resources, among four plantation sites, and different weed control treatments. White ash (Fraxinusamericana L.), butternut (Juglanscinerea L.), bur oak (Quercusmacrocarpa Michx.), and red oak (Quercusrubra L.) seedlings were planted in 1988 on four sites typical of glacial tills, littoral sands, and marine clays found in southwestern Quebec. Weed control treatments consisted in the use of a low persistence herbicide (glyphosate) and that of an organic mulch composed of chipped hardwood branches. A control treatment was included in the design. Weed control was best with the herbicide, resulting in an increase in soil temperature, water content, and nitrate concentration. Seedlings from the herbicide treatment reached a greater height and their leaf biomass was 25% that of the total biomass, and twice as much that of the control. Their root biomass accounted for 35% as compared to 50% for the control. The total amount of leaf nitrogen was 10 times greater in the herbicide treatment. Mortality rates were highest for white ash, bur oak, and butternut on sites where water availability was lowest, as well as in the absence of weed control. Red oak mortality was lowest on the littoral sand site. Mortality was the same with either weed control treatments although clearly lower than that of the control. The relative growth rate and net assimilation rate, as well as nitrogen use efficiency, were lower on the marine clay site, a high agricultural potential site. Because of a reduction of weed competition in the herbicide treatment, white ash had similar height growth on all sites, whereas bur oak, butternut, and red oak, in particular, grew best on nonexposed sites with light-textured soils. Successful establishment of hardwood seedlings depends strongly on the control of competing herbaceous weeds during the first years of growth in plantation. In southwestern Quebec, on glacial tills where topography increases water supply through seepage, wind-sheltered sites show a high potential for valuable hardwood reforestation. Such sites have a low agricultural potential because of their very high stonyness.
Using limited dependent variable estimators for estimating percent decay
Authors: Lemay Valerie M. , Kozak Antal , Marshall Peter L.
Published: July 2007

The data used for the estimation of percent decay are bounded by zero and 100. Because a value of 100% indicates that the tree is completely decayed, this value is not observable in nature. However, a value of zero percent is often observed over a wide range of the independent variables. The distribution of percent decay is a combination of a truncated continuous distribution for percent decay greater than zero and a discrete component for the zero percents. The use of ordinary least squares with this type of data results in biased and inconsistent estimates of the coefficients of a percent decay equation. An alternative is the tobit estimator (a combined regression and probit estimator based on a maximum likelihood equation), which results in consistent estimates of the coefficients if the error terms of the model are independent and identically distributed as the truncated normal distribution. A Monte Carlo simulation using data for three species with different proportions of zero percents was performed to compare the ordinary least squares and tobit estimators. As expected, the tobit estimator resulted in quite different estimates of the coefficients of the equations than did ordinary least squares. An unexpected result was that the estimated expected percent decay was slightly more biased for the tobit estimator than for the ordinary least squares estimator, even with a large number of zero percents in the data set. Possible explanations for the Monte Carlo simulation results and recommendations for fitting percent decay equations are given in the paper.
Percent decay estimation using decayed wood area at breast or stump height
Authors: LeMay Valerie M.
Published: July 2007

The estimation of tree percent decay is important for estimating the quantity and quality of wood available for timber products. Several different independent variables have been used to estimate the percent decay of standing trees, but often the resulting percent decay predictions are poor. Other independent variables are required for more precise prediction of percent decay. The objective of this study was to examine the use of percent decay area measured at breast or stump height as a possible variable for estimating tree percent decay. Data used in testing included one species group, true fir (Abies spp.), and two species, western red cedar (Thujaplicata Donn) and trembling aspen (Populustremuloides Michx.), from several zones of the province of British Columbia. The use of percent decay area at either breast or stump height resulted in substantial improvements in the estimation of percent decay for all species in all zones. As an alternative to the expensive task of measuring percent decay area on all trees, a sampling design is suggested and one possible design is illustrated.
Cambial and internal electrical resistance of red spruce trees in eight diverse stands in the northeastern United States
Authors: Smith K.T. , Ostrofsky W.D.
Published: July 2007

Rating systems are being developed to determine the degree to which forests are at risk from pests, pathogens, and anthropogenic disturbances. Measurements of electrical resistance of living trees have been shown to be correlated with cambial growth and alterations of wood function in a wide range of species. A comparison was made of patterns of cambial electrical resistance and of stem internal electrical resistance for eight red spruce (Picearubens Sarg.) stands in the northeastern United States. Stands were compared by a new procedure using cambial electrical resistance profiles. The resulting groupings provided a refinement of vigor categories over other comparative methods, and the technique should prove useful for guiding management decisions. No direct relationship was found between the internal tree condition and the cambial electrical resistance, and implications of this with regard to monitoring forest stand health are discussed.
Variable-form taper functions for four Alberta tree species: Reply
Authors: Newnham R.M.
Published: July 2007

not available
Comparative restriction site maps of chloroplast DNA of Piceaabies, Piceaglauca, Piceamariana, and Piceasitchensis
Authors: White E.E. , Watkins R.F. , Fowler D.P.
Published: July 2007

Physical maps of chloroplast DNA of four species of Picea Diet, were compared. Restriction site differences occur between species. Four restriction site mutations were mapped, and between species differences in three more were inferred from restriction fragment patterns. Differences observed among species were not sufficient to allow phylogenetic interpretations. No differences in gene order among species were observed. Gene organization in the chloroplast genome of Picea is compared with that of Pinus L. and Pseudotsuga Carr. Gene order is colinear with that of Pseudotsuga with the exception of one inversion. Though the genomes of Picea and Pseudotsuga are colinear over a greater length than those of Picea and Pinus, this does not imply that Picea and Pseudotsuga are more closely related to each other than to Pinus, since these three patterns of gene organization could have evolved by inversion events that differed only in the order in which they occurred.
Price elasticities of substitution between species in the demand of U.S. softwood lumber imports from Canada
Authors: Hseu Jiing-Shyang , Buongiorno Joseph
Published: July 2007

The softwood lumber that Canada exports to the United States is a heterogeneous mix of spruce, fir, red cedar, pine, hemlock, and other species. The purpose of this study was to determine to what extent each species is a distinct economic good by using a characteristic demand equation. The theory consisted of a cost-minimizing aggregate U.S. demand for imports and of share equations for each species. Partial adjustment was introduced to accommodate out-of-equilibrium observations. The results showed that the demand for each species, except fir, was elastic with respect to the price of that species, with elasticities that differed substantially by species. Cross-price elasticities between individual species were generally small. It is shown how the effect of a price change of any single species consists of two parts: a market-expansion effect that is the same for all species and a substitution effect that is species specific.
The use of flavonoid glycosides for the identification of elm hybrids
Authors: Heimler Daniela , Pieroni Andrea , Mittempergher Lorenzo , Buzzini Pietro
Published: July 2007

The utilization of elm leaf flavonoids as biochemical markers for the identification of artificial and natural hybrids of elm species is discussed. Two to 11 individuals from controlled crosses of Ulmuscarpinifolia Gled., Ulmuspumila L., Ulmusparvifolia Jacq., and Ulmusjaponica (R.) Sarg. were examined. Five to seven individuals from each parental species, and a number of putative hybrids between U. carpinifolia and U. pumila that naturally occur in central and northern Italy, were also examined. Quantitative data on leaf flavonoid glycosides were obtained by means of high-performance thin layer chromatography and examined by multivariate discriminant analysis. The results show that it is possible to identify the hybrid obtained between these species even if the parents are unknown, provided a number of individuals of the parental species are examined; therefore, it is also possible to certify putative hybrids. The higher variability of the flavonoid glycoside data of U. carpinifolia and U. pumila and the probable presence of F2 generation individuals make the certification of natural hybrids between these two species in some cases difficult or even impossible.
Early selection of black spruce using physiological and morphological criteria
Authors: Sulzer A.M. , Greenwood M.S. , Livingston W.H. , Adams Greg
Published: July 2007

A retrospective test of 36 half-sib black spruce (Piceamariana (Mill.) B.S.P.) families was initiated using surplus seed from the same families growing in six 10-year-old test plantations in New Brunswick. Height, diameter, cold hardiness, gas exchange rates, chlorophyll content, and leaf weight/leaf area ratios of the 3-year-old greenhouse-grown seedlings were determined and related to 10-year field height. The variables that correlated most highly with height at age 10 were seedling height (r = 0.491) and diameter (r = 0.441). Seedling cold hardiness was significantly correlated with both 3-year (r = −0.508) and 10-year height (r = −0.337), the better growing families being more cold hardy. Although photosynthesis and the ratio of photosynthesis to transpiration (a measure of "instantaneous" water use efficiency) were correlated with seedling height, neither of these measures showed a significant relationship with height at age 10. The potential usefulness of both physiological and morphological parameters for early testing purposes is discussed.
Linkage of allozyme loci in Japanese red pine (Pinusdensiflora)
Authors: Na'iem Mohammad , Tsumura Yoshihiko , Uchida Kohji , Nakamura Toru , Ohba Kihachiro
Published: July 2007

Linkage relationships among 29 polymorphic loci were investigated in Japanese red pine, Pinusdensiflora Sieb. et Zucc. Haploid megagametophytes from 12 highly heterozygous plus-tree clones were used. A total of 217 pairs of two-locus combinations were available for the linkage study. Chi-square and Akaike Information Criterion analyses identified 19 pairs of linkages. Close linkages (r = 0–0.10) were seen for Est-2, 3–Aap-2, 3, Dia-1–Acp, and Shd-1–Got-1. Strong linkages (r = 0.10–0.20) were seen for Est-2, 3–Dia-1, Est-2, 3–Acp, Aap-2, 3–Dia-1, Got-2–Lap-1, and Pgm–Aap-1. Moderate linkages (r = 0.20–0.30) were seen for Adh–Sod, Adh–Pgi-1, 2, Adh–Lap-1, G2d–G6p, and Dia-2–Amy pair of linkages. The remaining six pair combinations, namely 6Pg-1–Est-2, 3, 6Pg-1–Acp, Est-1–Acp, Est-2, 3–Shd-1, Sod–Pgi-1, 2, and Adh–Got-2 were weakly linked (r = 0.30–0.40). In all, 22 loci were classified into five linkage groups by means of three-point mapping methods.
Some mathematical programming approaches for optimizing timber age-class distributions to meet multispecies wildlife population objectives
Authors: Hof John G. , Raphael Martin G.
Published: July 2007

We investigated three approaches for finding optimum allocations of forest age-classes to meet multispecies conservation objectives for a community of terrestrial vertebrate species. We illustrate our approaches using data on relative abundances of 92 species of amphibians, reptiles, birds, and mammals sampled from five habitat types (age-classes) of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) forests in northwestern California. Our three approaches involved maximizing (i) the expected number of viable species; (ii) the minimum probability of viability among all species; and (iii) the joint probability of viability across all species. Each approach was demonstrated using an assumption that viability is linearly related to abundance or that viability is logistically related to abundance. We discuss limitations of our approach focusing on assumptions of data quality, relative conservation priority among taxa, relationships between estimated abundance of a population and its probability of viability, interspecific interactions, and the need for evaluation of spatial distribution of habitats.
Calcium carbonate precipitation–dissolution along a forest primary successional sequence on the Tanana River floodplain, interior Alaska
Authors: Marion G.M. , Cleve K. Van , Dyrness C.T.
Published: July 2007

Calcareous (alkaline) soils exist along the river floodplains of interior Alaska. In calcareous soils, the balance of CaCO3 reflects net system acidification–alkalinization. The objectives of this study were to determine the origin of the CaCO3, quantify CaCO3 precipitation–dissolution, and quantify net system acidification–alkalinization along a forest primary successional sequence (250 years) on the Tanana River floodplain of interior Alaska. The CaCO3 concentrations in the initial soil profiles were positively correlated (R2 = 0.883) with silt concentrations. Differences in CaCO3 concentrations in the early soil profiles between sites of similar age, between forest successional stages, and among soil horizons within a profile are primarily due to differences in silt concentrations, which are controlled by the alluvial deposition process. There was a curvilinear decrease in CaCO3 content along the forest successional sequence, suggesting that the CaCO3 originated with the alluvial material and was not formed insitu. The loss of CaCO3 was equivalent to a loss of acid-neutralizing capacity of 10.0 kequiv•ha−1•year−1, which is a high rate of soil acidification. These forested, relatively pristine ecosystems are dominated by internal sources of acidity.
Denitrification and nitrogen fixation in floodplain successional soils along the Tanana River, interior Alaska
Authors: Klingensmith K.M. , Cleve K. Van
Published: July 2007

Forest floors and mineral soils from early (open willow), middle (poplar–alder), and late (white spruce) floodplain primary successional stages were examined for nitrogen fixation and denitrification. The acetylene-reduction and acetylene-inhibition techniques were used separately and in combination to measure nitrogenase and denitrification activities, both in laboratory and field studies. In situ N2O production was undetectable at all sites and during all sampling periods. Denitrifying activity measured in the field with acetylene amendments was low to undetectable, except after a brief flood in the open willow stand when N2O production ranged from undetectable to 34 ng N•cm−2•h−1 within the newly deposited alluvium–old mineral soil interface. Intact core assays also had low to undetectable denitrification activities; the highest activities (259 ng N•g−1 h−1) were measured in the poplar–alder forest floor in the fall. Laboratory studies showed that potential denitrification enzyme activity (DEA) was also greatest in the poplar–alder forest floor (4332 ng N•g−1•h−1), once again occurring in the fall. In early and midsuccessional stages, the interactive effects of temperature, carbon, and NO3− limited denitrification, yet even with the addition of the limiting amendments, low to undetectable DEA was observed in mineral soils. The later white spruce successional stage also had low to undetectable DEA, increasing only with the addition of the full DEA media and independent of temperature changes. Nonsymbiotic nitrogenase activities were highly variable, ranging from undetectable to 30 ng N•cm−2•h−1. Highest activities were seen in the open willow, newly deposited alluvium–old mineral soil interface immediately after a flood and approximately 1 month after the flood on the newly deposited silt surface. Only the white spruce forest floor had measurable nonsymbiotic nitrogenase activity at all sampling times. Alder root nodule nitrogenase activity showed no significant differences between sampling periods. The estimated annual nitrogen fixation rate of 164 kg N•ha−1 for alder root nodules is a substantial N contribution to the alder stand and to the floodplain ecosystem in general.
Canadian forest tenures and the silvicultural investment behavior of rational firms
Authors: Luckert Martin K. , Haley David
Published: July 2007

Discrepancies between the theoretical and actual investment behavior of firms in the Canadian forestry sector are described. It is demonstrated that these inconsistencies are, in reality, illusionary. They result from the failure of some analysts to account for the institutional framework within which private forest companies in Canada make decisions concerning the replacement and management of forest crops. When the constraints imposed on the private sector are considered, conduct of forestry firms does conform to "economic rationality". Thus, conventional economic theory can be used to predict firms' behaviors. It is suggested that Canadian forest policies encourage behavior in private firms which may significantly reduce the value of public forest resources. Specifically, firms have no incentives to efficiently allocate scarce capital resources to silvicultural activities.
Supplemental mass pollination success rate in a mature Douglas-fir seed orchard
Authors: El-Kassaby Yousry A. , Barnes S. , Cook C. , MacLeod D.A.
Published: July 2007

Supplemental mass pollination (SMP) success rate in a mature Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seed orchard was studied with the aid of a unique electrophoretically detectable allozyme marker. Operational applications, and branch applications that were carried out one, two, or three times, were conducted during the orchard's maximal pollen release (i.e., the height of pollination). No significant increase in seed-yield traits (total number of seeds per cone, number of filled seeds per cone, and seed efficiency) was observed between wind-pollinated and SMP-treated (operational and one and multiple branch visits) cones. However, multiple branch visits (18%) showed significant increase in SMP success rate when compared with the operational visit (8%) or the one branch visit (9%) results. No significant increase in SMP success rate was obtained when the number of branch visits was increased from two (17.8%) to three (17.9%). It was concluded that operational SMP had the potential to improve the genetic value of the treated Douglas-fir crops even under high pollen load. The degree of improvement is dependent directly on SMP fertilization success and indirectly on the genetic value differential between the supplemented and the orchard's ambient pollen, the frequency of application, and the quality of the pollen applied (i.e., viability).
Acceptability of thiram-treated conifers to snowshoe hares
Authors: Rangen Sheila A. , Hawley Alex W.L. , Hudson Robert J.
Published: July 2007

During March of the first winter and November of the subsequent fall following application of thiram to white spruce (Piceaglauca (Moench) Voss), treated twigs provided protection against snowshoe hare (Lepusamericanus Erxleben) depredation (P = 0.0001). Both experiments were conducted at Edmonton, Alta., with animals under restricted-feed conditions. In March, thiram-treated trees were more resistant to hare clipping of apical stems (P = 0.0001) and buds (P = 0.001), and barking of stem areas (P = 0.0001) compared with browsing of treated apical stems (P = 0.058) and buds (P = 0.026), and barking of stem areas (P = 0.013) in November once current annual growth had emerged and substantial weathering had occurred. Height of stems removed also differed between treatments during November (P = 0.0001). Overall, thiram treatments may help increase conifer survival in reforestation areas supporting snowshoe hares if used in concert with other deterrent means until more effective control measures are developed.
Photoperiod and night frost influence the frost hardiness of Chamaecyparisnootkatensis clones
Authors: Hawkins B.J.
Published: July 2007

Frost hardiness in yellow cypress (Chamaecyparisnootkatensis (D. Don) Spach) was studied over the winter to determine the relative influence of photoperiod and subzero temperatures on the hardening and dehardening processes. Stecklings (rooted cuttings) of five clones from each of three provenances were grown outdoors and in two controlled-environment chambers at 10:5 °C day:night temperatures and 12- or 6-h photoperiods. Half of the plants in each photoperiod treatment were subject to a 4-h night frost, three times per week from December through to March. Frost hardiness was assessed at intervals using the freeze-induced electrolyte leakage method. Variability in frost hardiness was greater among clones within provenances than among provenances. Significant differences in hardiness among clones existed throughout the experiment; however, the ranking of clones by hardiness was not consistent. Stecklings in the 6-h photoperiod were consistently more hardy than their counterparts subjected to 12-h photoperiods. Stecklings placed outdoors had equivalent hardiness to those in the 6-h photoperiod until the advent of natural frosts in January. At this time, the outdoor trees were the most hardy. Night frost also significantly increased frost hardiness in stecklings in controlled environments. Stecklings in all treatments began to deharden between January and March. The outdoor plants dehardened most rapidly. Stecklings in the controlled environments dehardened slowly until the night-frost treatment ended, whereupon previously frozen plants dehardened more rapidly than their unfrozen counterparts.
Sulfur inputs and outputs for two European beech forests growing on different soil substrates
Authors: Sah S.P. , Meiwes K.J.
Published: July 2007

Using a flux-balance approach, the S budget of two heavily polluted beech (Fagussylvatica L.) forest ecosystems growing on acid and calcareous soil substrates was investigated. Total S deposition (dry and wet fall) at both sites was large (2.3 and 3.2 kequiv.•ha−1•year−1 at the calcareous and acidic beech forest sites, respectively). The contribution of dry deposition to the total S deposition in both stands was significant; dry deposition of S exceeded the deposition of S even in bulk precipitation. The atmospheric input of S exceeded, at both sites, the forest S requirements by 6–7 times. Consequently, at the acidic beech forest site, phytotoxins like Al3+ (2 kequiv.•ha−1•year−1) were released with seepage water, neutralizing the acid input. At the calcareous beech forest site, leaching of huge amounts of Ca2+ (15 kequiv.•ha−1•year−1) and HCO3− (12 kequiv.•ha−1•year−1) was significant enough to offset the effects of acid precipitation. About 20% of the atmospheric S input in both beech stands accumulated in the vegetation. The S input–output balance in the acidic beech forest indicated a slight tendency towards S accumulation in the soil in the form of AlOHSO4. The S budget in the calcareous beech forest stand was more or less balanced.