bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Ozone and Acidic Deposition on Carbon Allocation and Mycorrhizal Colonization of Pinus taeda L. Seedlings
Authors: Adams M. B. , O'Neill E. G. 
Published: April 2024

Abstract
Patterns of carbon allocation and mycorrhizal colonization were examined in loblolly pine seedlings from two half-sib families exposed to three ozone treatments (charcoal-filtered air, ambient air + 80 ppb O3, and ambient air + 160 ppb O3) and three rain pH levels (5.2, 4.5, and 3.3) for 12 weeks in open-topped chambers in a field setting. No statistically significant effects of ozone or rain pH were detected on biomass, root:shoot ratios, or carbon allocation; some consistent patterns were observed, however. Coarse root starch concentrations and mycorrhizal infection varied significantly with ozone levels. No significant interactions of ozone, rain pH, or genotype were detected. For. Sci. 37(1):5-16.
The Establishment of Boreal and Sub-boreal Conifer Plantations: An Integrated Analysis of Environmental Conditions and Seedling Growth
Authors: Brand David G. 
Published: April 2024

Abstract
Data from similar field experiments located in the Great Lakes-St. Lawrence, Boreal, and Sub-boreal spruce regions of Canada were used to study relationships among factors such as environmental conditions, seedling growth and survival, and growth analytical yield components. The growth analysis includes both a conventional growth analysis and an integrated analysis of growth and environmental conditions. Survival was best after soil surface modification or weed control. Growth responses were positively related to increases in soil temperature and nutrient availability, and a decrease in vegetative competition. Yield component analysis indicated that Net Assimilation Rate (NAR) was positively related to improved growth. Changes in Specific Leaf Area tended to buffer the effects of changes in NAR on growth, however, and Relative Growth Rate (RGR) responded less to the treatments than did NAR. RGR was related to the availability of light, nitrogen, and soil energy or the efficiency of light, nitrogen, and soil energy use by seedlings on the three sites. As availability of a particular resource improved, growth allocation shifted away from tissues that are used to acquire that resource. Seedlings grew fastest where treatments caused both the availability of a resource and the efficiency (growth/unit resource) of its use to increase. The analytical framework proposed has application in studying the responses of trees to environmental changes and in determining factors that limit tree growth. For. Sci 37(1):68-100.
Analysis of Yield-Density Relationships in Experimental Stands of Douglas-Fir and Red Alder Seedlings
Authors: Shainsky Lauri J. , Radosevich Steven R. 
Published: April 2024

Abstract
Seedlings of red alder (Alnus rubra Bong.) and Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) were planted into a two-species density matrix composed of five monoculture densities and mixed stands with all possible pairwise combinations of the monoculture densities. Regression equations were fit to the response of mean tree stem volume to the two species' densities generated in this matrix. Regression coefficients quantifying the intensity of competition indicated that alder density had approximately twice the effect of Douglas-fir density on individual tree stem volume of both species. The densities of the two species had a multiplicative effect on mean tree stem volume. In addition, the effects of alder and Douglas-fir densities on tree size were interdependent. The effects of alder density on stem volume varied with Douglas-fir density and declined as Douglas-fir density increased. Similarly, the effects of Douglas-fir density on stem volume varied with alder density. The interdependency between the two species' densities resulted in an unusual pattern in which Douglas-fir individual stem volume increased as Douglas-fir density increased at high densities of alder. For. Sci. 37(2):574-592.
An Evaluation of Public Research in Three Forest Products Industries
Authors: Seldon Barry J. , Hyde William F. 
Published: April 2024

Abstract
This paper follows an earlier assessment of softwood plywood research by evaluating public research in the sawmill, woodpulp, and wood preservatives industries. Together, these are a sufficiently broad group of forest product industries to enable generalizations about the merit of public forest products research. The general econometric results for the three additional industries are at least as satisfying as those in the broader research evaluation literature. Public research in each of the four industries returned a net social gain for the 1950-1980 period of our examination. Large consumer gains and producer gains that are either negative (sawmills, woodpulp, wood preservatives), or divided among too many firms to enable private profitability (sawmills, SWPW), or nonmarket and environmental (wood preservatives, perhaps woodpulp), justify the public role in each industry. There is some suggestion, however, that politically encouraged research activities have not paid off. Our summary policy statement is that public research managers, particularly at the Forest Products Laboratory, when allowed their own judgment, have made socially beneficial decisions. For. Sci. 37(2):669-687.
Effects of Foliar Spray and Prill Applications of Nitrogen Fertilizer on Four Mixed-Conifer Stands
Authors: Miller Richard E. , Hazard John W. , Young Donald C. 
Published: April 2024

Abstract
Concentrated urea-ammonium nitrate solution (32% N) and urea prill (46% N) were applied by helicopter at dosages of 56, 112, 224, and 448 kg N/ha before and during the growing season to four 40- to 70-year-old mixed stands of Pseudotsuga menziesii and Tsuga heterophylla. Stand growth was measured repeatedly in the next 10 years. Applying 112 kg N/ha or more to these poor-site stands increased gross and net volume growth; volume growth was related linearly to N dosage of both prill and spray. Gains from prill apparently exceeded those from spray, but a subsampling of plots indicated that actual dosages, especially of spray, were less than target dosages. At the target dosage of 224 kg N/ha, 10-year gains in gross growth averaged 34.0 m3/ha (30%) and 8.0 m3/ha (7%) after prill and spray, respectively. Although fertilization accelerated tree losses, cumulative volume of dead trees was less than 15% of gross volume growth. Season of fertilization seemed to have no effect on efficiency of either prill or spray, but suspected differences between actual and target dosages may have influenced this comparison. This concentrated N solution at dosages up to about 224 kg N/ha caused little or no increase in foliar or tip damage. Doubling this conventional dosage and applying in the growing season, however, increased visible damage and may have decreased gains in volume growth. Helicopter application of both fertilizers made this investigation resemble operational fertilization, but this increased application error and uncertainty about interpretation of results. For. Sci. 37(3):741-754.
Calibration of Height and Volume Equations with Random Parameters
Authors: Lappi Juha 
Published: April 2024

Abstract
A new method for using sample tree heights and diameters to calibrate (localize) height/diameter and volume/diameter equations for a given stand is presented and illustrated with Scots pine data. The height/diameter and volume/diameter equations are assumed to contain random parameters that vary from stand to stand. The means, variances and both within-equation and between-equation covariances of the random parameters are estimated using data where volumes of trees from several stands are accurately measured. In applications, the random parameters of the height and volume equations of a new stand are predicted from sample tree heights and diameters using the covariance structure of parameters and linear prediction theory. When the number of sample trees was small, the new method predicted volumes of tallied trees better than a traditional method. For. Sci. 37(3):781-801.
Internal Redistribution of N in Sitka Spruce Seedlings with Partly Droughted Root Systems
Authors: Ferrier Robert C. , Alexander Ian J. 
Published: April 2024

Abstract
Split pots were used to allow measurement of the potential N retranslocation from roots of Sitka spruce subject to drought. Withholding water from one part of the root system had no effect upon increases in total weight and N content of the whole trees, or of the shoot and roots separately. However, the distribution of root weight and N content between the split parts of the root system did change.
The results indicate that the droughted roots of these spruce seedlings retranslocated 23% of the nitrogen initially present in them before experimental conditions were imposed. This retranslocation is considerably less than that reported elsewhere for senescing needles, but fine-root nitrogen retranslocation may be a potentially significant flux in forest systems where fine-root turnover is high. There was some evidence of N movement from needles to sustain compensatory growth of roots in response to nutrient and/or water stress. For. Sci. 37(3):860-870.
Optimum Plantation Planting Density and Rotation Age Based on Financial Risk and Return
Authors: Taylor Randy G. , Fortson James C. 
Published: April 2024

Abstract
A stochastic simulation model was developed to estimate the impacts of site index, planting density, and rotation age on the return and risk of unthinned loblolly pine plantations. Return was estimated as the average present value of an infinite series of rotations for each site, density, and age combination. Risk was approximated as the standard deviation of the present value for each combination. Sources of risk were stumpage rate risk, survival risk, and yield risk. Variability in yield estimates (i.e., yield risk), was the major source of financial risk associated with investments in loblolly pine plantations. Volatility in stumpage rates (i.e., stumpage rate risk), had the least impact on the risk of the investment. For average sites (site index 60 base age 25 years), short rotations are less risky than long rotations. But, as expected, short rotations also tend to have lower returns. Risk averse investors should prefer high planting densities and short rotations. Investors who wish to maximize return alone should select high planting densities with longer rotation ages. Low planting densities (less than 600 stems/ac) are not efficient for sites with site index 50 base 25. For. Sci. 37(3):886-902.
Physiological and Growth Responses of Eight-Year-Old Loblolly Pine Stands to Thinning
Authors: Ginn Shannon E. , Seiler John R. , Cazell Ben H. , Kreh Richard E. 
Published: April 2024

Abstract
The influence of thinning at age 8 on the photosynthetic rate, needle conductance, xylem water potential, foliar nutrient content, and growth of loblolly pine trees was studied during their ninth and tenth growing seasons. At the end of the second post-thinning growing season, trees in thinned stands had 51% greater stem diameter growth, and 29% greater basal area growth than trees in unthinned stands. Two years after thinning, trees in thinned stands also had crown diameters over 78 cm larger than unthinned trees. Although not statistically significant, live crown ratios were beginning to decrease more rapidly in unthinned stands.
Significant physiological changes due to thinning were generally observed only in the lower crowns where needle physiology was found to resemble that of upper crown needles. In thinned stands, lower and upper crown photosynthesis (3.98 vs. 4.07 μmol m-2 s-1, respectively) and needle conductance (94.2 vs. 95.3 mmol m-2 s-1, respectively) did not differ significantly. This is in contrast to the unthinned stands where both light saturated photosynthesis (3.22 vs. 4.17 μmol m-2; s-1, lower and upper crown respectively) and needle conductance (74.3 vs. 100.8 mmol m-2 s-1, lower and upper crown respectively) were substantially decreased in the lower crown. The increase in crown size and the ability (physiologically) of lower crown foliage to take advantage of the increased light following thinning are likely the major factors resulting in the increased growth of loblolly pine following thinning. For. Sci. 37(4):1030-1040.
Economic Relationships Between Parcel Characteristics and Price in the Market for Vermont Forestland
Authors: Turner Robert , Newton Carlton M. , Dennis Donald F. 
Published: April 2024

Abstract
An implicit price model is used to analyze the market for forestland in Vermont. Data were collected on physical and locational characteristics associated with a sample of recent sales (100-500 ac tracts). Least squares regression was used to identify marginal implicit prices of the characteristics. More than 46% of the variation in price per acre was explained by the set of characteristics and all significant characteristics influenced the price in the expected direction. Parcel size had little effect on price per acre; however, the presence of road frontage, the presence of open land, increases in population, proximity to major roads and ski areas, and lower taxes all contributed to higher prices. For. Sci. 37(4):1150-1162.
A Method for Estimation of Fractal Dimension of Tree Crowns
Authors: Zeide Boris , Pfeifer Peter 
Published: April 2024

Abstract
A method is proposed for estimating fractal dimension of tree crowns from measurements of foliage mass and crown volume. Because fractal dimensions for each of the ten investigated species were greater than two, crown surface and volume depend on the unit of measurement. The power relationship between foliage mass and crown volume reflects self-similarity of tree crowns. In all studied cases, fractal dimensions of dominant trees were greater than those of intermediate trees of the same species. Fractal dimension can be used as an indicator of tolerance, crown class, and foliage distribution within a crown. For. Sci. 37(5):1253-1265.
Competition Indices for Mixed Species Northern Hardwoods
Authors: Holmes Michael J. , Reed David D. 
Published: April 2024

Abstract
Several competition indices are evaluated to determine their relationship with annual diameter growth in mixed species northern hardwood stands in upper Michigan. Indices are evaluated on four species with different shade tolerance. A new index which incorporates factors representing both root and crown competition is formulated and tested. Simple size ratio indices perform as well or better in their correlation with annual diameter growth than growing space, area overlap, and root/crown indices. Hegyi's index and several forms of the new root/crown index show the most consistent performance across study species. For. Sci. 37(5):1338-1349.
Trend Monitoring with Varying Coefficient Models
Authors: Deusen Paul C. Van 
Published: April 2024

Abstract
Some statistical procedures are presented for monitoring time trends. An F-statistic is given for testing the hypothesis that a particular state-space model fits two time intervals equally. This is useful when a specific time is believed to be the beginning of a structural change. The likelihood-ratio criterion can be used to test the hypothesis of no trend-change by testing that parameter values in the second interval stay constant at the end value of the first interval. When a transition time is not known in advance, cusum procedures can be employed (Brown et al. 1975, Harvey and Durbin 1986) as exploratory tools. An example application is made to some slash pine (Pinus elliottii Engelm.) tree-ring data from the southern United States that shows evidence of a 20-year recurring blight. For. Sci. 37(5):1365-1375.
Analysis of Spatial Patterns of Lodgepole Pine Attacked by Outbreak Populations of the Mountain Pine Beetle
Authors: Mitchell Russel G. , Preisler Haiganoush K. 
Published: April 2024

Abstract
Five years of mountain pine beetle, Dendroctonus ponderosae Hopkins, attacks on lodge-pole pine, Pinus contorta Dougl., were analyzed in an early outbreak situation using generalized linear models to shed light on patterns in the colonization process. The chosen logit model indicated three covariates as significant factors in the probability of trees being colonized by the mountain pine beetle. The first covariate related to tree size and spatial relationships among trees colonized the same year; its effect was most obvious for trees in the smaller diameter classes. The other two covariates correlated with tree diameters and vigor, and they indicated a greater probability of attack for larger trees and trees with low vigor. The model showed that the probability of trees being colonized in this stand increased significantly as the outbreak gained momentum, but only as long as the food supply (trees with dbh ≥ 23 cm) was abundant. It also showed that the pattern of selection of large and small trees did not change significantly as beetle pressure increased over time. Findings suggested that big trees were important to outbreaks beyond simply generating beetles, and that many trees were colonized only because they were dose to other trees under attack. For. Sci. 37(5):1390-1408.
A Neural Network to Predict Particleboard Manufacturing Process Parameters
Authors: Cook Deborah F. , Massey Joseph G. , Shannon Robert E. 
Published: April 2024

Abstract
A methodology to predict the occurrence of out of control conditions, based on current operating conditions, in a particleboard manufacturing facility was developed using neural network theory. Multivariable linear regression and time series analysis techniques were applied to analyze the data set for informational purposes. Back-propagation neural networks were successfully trained to represent bonding treatment process parameters. The inputs to the network included data representing the current process condition, including moisture contents, bulk densities, and dryer temperatures, along with historical values of these same parameters. Neither the regression nor the time series analysis resulted in the development of a valid statistical model. The best trained neural networks were able to successfully predict the development of out of control conditions in the manufacturing process for 70% of the test cases, having been trained using only a relatively small training data set. Thus the potential for the utilization of neural networks in manufacturing process analysis was demonstrated. For. Sci. 37(5):1463-1478.
Substitution Between Tropical and Temperate Sawlogs
Authors: Vincent Jeffrey R. , Brooks David J. , Gandapur Alamgir K. 
Published: April 2024

Abstract
Japan is the world's most important log importer. This paper develops a multi-output profit function framework to quantify the impacts of economic factors on Japan's imports of sawlogs from two temperate regions, North America and the Soviet Union, and one tropical region, the South Seas. Econometric results indicate that sawlogs from the three regions were substitutes for each other during 1970-87. Imports from each region were significantly affected by relative net prices (lumber price minus log input cost per unit of lumber), with cross-net-price elasticities between temperate and tropical categories increasing over time. Technical change (the residual trend after controlling for price effects) was significant and biased against imports from the South Seas. These findings suggest that scarcity of tropical hardwood sawlogs induced by deforestation or restrictive trade policies will lead to increased demand for temperate softwood sawlogs. Current forest-sector models, which do not treat hardwoods as substitutes for softwoods, fail to capture this emerging feature of global trade in forest products. For. Sci. 37(5):1484-1491.
A Kalman Filter Approach to Localizing Height-Age Equations
Authors: Walters David K. , Burkhart Harold E. , Reynolds Marion R. , Gregoire Timothy G. 
Published: April 2024

Abstract
Equations for modeling the height-age pattern of forest trees or stands are typically developed on a regional basis. Due to variation in growth patterns within regions, these equations may be polymorphic and quite complex. As an alternative to increasing the complexity of an equation, this study presents procedures for the evaluation of height-age relationships through the use of simple, regional equations combined with local stand data.
The base model in this study was Schumacher's (1939) logarithm of height-reciprocal of age model. An average regional guide curve was developed using data from a wide range of loblolly pine plantations. A Kalman filter procedure was used to localize this regional equation to a specific stand. This procedure employs the general concept of feedback (local stand data combined with a simple regional model) in localizing the simple equation. By using information on a particular stand's height growth development, the original equation is modified to better model that stand. The modification is made by feeding local information into an estimation procedure that combines it with the regional information (equation) and modified parameter estimates are calculated.
Three loblolly pine data sets were used to compare the localization strategy with the simple, regional model, as well as a more complex polymorphic equation. The results indicate that the Kalman filter method can result in improved prediction for specific stands. For. Sci. 37(6):1526-1537.
Comparison of Expressions for Crown Size of Woody Competitors in Herbicide Efficacy Studies
Authors: Knowe Steven A. 
Published: April 2024

Abstract
Control of woody species based on one-, two-, and three-dimensional expressions of crown size was evaluated in relation to sensitivity to statistical comparison of treatment means and correlation with crop tree growth. The overall mean and coefficient of variation for percent control based on regression-adjusted post-treatment crown height, crown diameter, crown profile, crown area, and crown volume were compared for five common hardwood species in a site-preparation study located in the Georgia piedmont. Estimates of overall mean control were similar among the expressions of crown size, but the estimate was lowest when based on crown diameter and largest when based on crown volume. The coefficient of variation in control was smallest when calculated from crown height and highest when calculated from either crown area or crown volume. Based on orthogonal contrasts, control calculated from crown height and crown diameter tended to be more sensitive to treatment differences than other expressions of crown size. Control calculated from crown volume tended to be the least sensitive to treatment differences, resulting in more conservative orthogonal contrasts. The one- and two-dimensional expressions of crown size had consistently higher correlations with mean size of the crop trees at age 4 than the three-dimensional expression of crown size (crown volume). For. Sci. 37(6):1664-1670.
Comparison of Leaf Area Index Estimates from Tree Allometrics and Measured Light Interception
Authors: Smith Frederick W. , Sampson D. Arthur , Long James N. 
Published: April 2024

Abstract
We compared estimates of leaf area index (LAI) based on tree allometrics and light interception in 15 lodgepole pine (Pinus contorta var. latifolia) stands in southeastern Wyoming. LAI from stem allometrics was estimated with a local equation demonstrated to produce accurate and unbiased leaf area estimates for the stand conditions in this study. LAI from measured light interception, estimated with a species-average light extinction coefficient using the Beer-Lambert Law, was not correlated with LAI determined from tree allometrics. Light extinction coefficients varied from 0.29 to 0.67 when determined from allometric estimates of LAI and measured light interception. The derived light extinction coefficients were inversely correlated with LAI (r² = 0.79). High LAI may be associated with canopy architectures where foliage distribution results in reduced light capture effectiveness. Variation in light capture by lodgepole pine canopies may preclude the use of a species average light extinction coefficient for estimating LAI. For. Sci. 37(6):1682-1688.