bluuebunny/crossref_metadata_2025 huggingface dataset:
The Influence of Herbaceous Weed Control and Seedling Diameter on Six Years of Loblolly Pine Growth—A Classical Growth Analysis Approach
Authors: Britt J. R. , Mitchell R. J. , Zutter B. R. , South D. B. , Gjerstad D. H. , Dickson J. F.
Published: April 2024

Classical growth analysis equations were applied to three loblolly pine (Pinus taeda L.) seedling ideotypes (determined by groundline diameter) that were subjected to either 2 years of complete herbaceous weed control (low weed abundance: LWA) or no herbaceous weed control (high weed abundance: HWA). For the first 2 growing seasons, seedlings of the LWA treatment had greater mean relative growth rate (RGR) and mean net assimilation rate (NAR) values. However, during years four through five, RGR and NAR were significantly lower in the LWA treatment than in the HWA treatment. The reduction in herbaceous weed interference appeared to reduce mean leaf area ratio (LAR) throughout the study period.

Several trends in this data set suggest that growth analysis parameters may be confounded with size. The largest ideotype generally exhibited the smallest RGR, and RGR declined as trees increased in biomass. To remove the potential confounding of size, the basis of comparison was changed from trees of equal age to trees of equal biomass (total aboveground dry weight at the beginning of each growing season). This method resulted in a different interpretation of the results. For a given biomass, trees in the LWA treatment had greater RGR and LAR than those in the HWA treatment throughout the study period. Growth of seedling ideotypes within a given weed abundance treatment all fell along a single curve, suggesting that there was no apparent interaction between initial seedling diameter and herbaceous weed control.

After the trees reached six kg biomass, the direct benefits from reduced herbaceous interference had apparently ceased. Initially, large differences in NAR were observed between treatments, but these differences diminished as trees approached 5 kg. In contrast, differences in LAR were initially small but increased as tree biomass increased. As trees increased in biomass, the partitioning of carbon into leaf area seems to be more responsible for the productivity gains associated with weed control. For. Sci. 37(2): 655-668.
Allozyme and Leaf Morphological Variation of Eastern Cottonwood at the Northern Limits of Its Range in Ontario
Authors: Rajora O. P. , Zsuffa L. , Dancik B. P.
Published: April 2024

Allozyme variation of 84 trees of eastern cottonwood (Populus deltoides Bartr. ex. Marsh. var. deltoides) from 9 populations in Ontario was studied at 33 loci coding for 11 enzyme systems in root tips. Morphological variation of 7 leaf characters was studied for 57 trees. On average, 42.4% of the loci per population was polymorphic, the number of alleles per locus was 1.7, and the observed heterozygosity was 0.063. The overall mean for genetic distances among populations was 0.007. Principal component analysis (PCA) of allozyme data separated the populations into five groups with a slight separation of eastern and western populations. Leaf characters showed significant variation among (P ≤ 0.003) and with one exception within (P ≤ 0.027) populations. Vein numbers showed significant correlation with longitude (r = 0.81, P < 0.009) and latitude (r = -0.69, P < 0.05). None of the other leaf characters was related to latitude and longitude. PCA of leaf characters separated the Long Point population from the others. Significant (P < 0.01) Mahalanobis distances for leaf characters were observed among populations. There was no concordance between the patterns of variation and differentiation based on allozymes and morphological parameters. The results suggest moderate allozyme and high leaf morphological variation in eastern cottonwood in Ontario. For. Sci. 37(2):688-702.
Using a Parallel Distributed Processing System to Model Individual Tree Mortality
Authors: Guan Biing T. , Gertner George
Published: April 2024

Parallel distributed processing (PDP, also known as artificial neural network) was introduced as an alternative for modeling regular noncatastrophic individual tree mortality. A two hidden-layered PDP system was created using back-propagation as the learning procedure and the sigmoid function as the transfer function. An empirical data set was used to test the performance of the system. Using the performance of a logistic regression as a benchmark, the new system had a better fit to the data than that of the logistic regression. It was also found that, though the system was not instructed to fit the data with logistic curves, the response surface of the model closely followed a logistic response surface. This finding suggests that, based on the goodness-of-fit measure employed, the best function to model individual tree mortality may indeed be the logistic function. A PDP system can be regarded as a procedure which attacks the problems of parameter estimation and model selection simultaneously. Topics regarding the potential use of a PDP system as an alternative to modeling individual tree mortality were also discussed. For. Sci. 37(3):871-885.
A Self-Contained Freezing Chamber for Tree Ecophysiological Studies in the Field
Authors: Dang Q. L. , Lieffers V. J. , Rothwell R. L.
Published: April 2024

A self-contained freezing chamber was constructed for use in tree ecophysiological studies in the field. The chamber has two layers, an outer layer of polystyrene board to provide both physical support and insulation, and an inner chamber of plastic to protect the twig and foliage from mechanical damage from the packs of freezing medium. The freezing medium is a NaCl:ice mixture which can provide chamber temperatures as low as -20.3°C. The mean temperature at seven locations within the chamber was -4.1°C with a standard deviation of ±0.3°C when a NaCl:ice mixture of 16(gm):1.65(l) was used. In field trials, it took two people about 3 minutes to set up the apparatus on a twig. The technique was found to be both practical and economical for field freezing experiments, especially in handling large sample sizes. For. Sci. 37(3):924-930.
Pass-Through of Exchange Rates on Prices of Forest Product Exports from the United States to Europe and Japan
Authors: Uusivuori Jussi , Buongiorno Joseph
Published: April 2024

Western Europe and Japan are major importers of forest products from the United States. Foreign exchange policies can influence the volume of trade mostly to the extent that devaluations or appreciations of the dollar are passed through to importers in the form of lower or higher prices in their currency. This paper reports measures of the pass-through for 6 European countries and Japan, for 11 commodities. The pass-through was obtained from a bivariate time-series model of export price and exchange rate. The data were from January 1978 to December 1988, a period of wide fluctuations in the value of the dollar. The results showed that the pass-through was often incomplete. In addition, the pass-through was asymmetric: appreciations of the dollar tended to increase foreign prices more than devaluations decreased them. Together the two findings suggest, first that dollar devaluations might not be effective in increasing exports of forest products, and second that global forest product markets are susceptible to inflation spread by currency realignments. The pass-through varied considerably by region, commodity, and over time: while the short-term pass-through could be complete, the effect could decay to a small fraction of the initial value, or disappear completely within 1 year. This result is consistent with previous findings of weak or inexistent effects of exchange rate changes on quantities traded. For. Sci. 37(3):931-948.
Tree-Ring Growth of Interior Douglas-Fir After One Year's Defoliation by Douglas-Fir Tussock Moth
Authors: Alfaro René I. , Shepherd Roy F.
Published: April 2024

Reductions in ring width of Douglas-fir, Pseudotsuga menziesii [Mirb.] Franco, trees defoliated for 1 year by the Douglas-fir tussock moth, Orgyia pseudotsugata (McDunnough), are reported. Trees were treated with a nuclear polyhedrosis virus, but the resultant epizootic which killed larvae and reduced defoliation took several weeks to develop and trees sustained varying degrees of damage. No negative effects of defoliation were noted in the year when feeding took place; on the contrary, a growth stimulation occurred. Defoliation levels above 50% resulted in growth reduction for 2 years following defoliation relative to nondefoliated trees. The implications of these growth changes for cost/benefit analysis of control options are discussed. For. Sci. 37(3):959-964.
Timber Supply and Life Cycle Harvest of Nonindustrial Private Forest Owners: An Empirical Analysis of the Finnish Case
Authors: Kuuluvainen Jari , Salo Jorma
Published: April 2024

The timber supply and life cycle harvest of nonindustrial private forest owners is studied. Given a perfect capital market, optimal harvesting decisions depend on timber prices, the interest rate, and the merchantable timber stock. Under effective credit rationing, timber supply and the life cycle harvest become dependent on forest owners' preferences, i.e., timber supply and consumption decisions must be made simultaneously. Thus, the effect of the price of timber on short-term supply becomes ambiguous, and the interest rate only has a negative income effect. Further, because the harvest and consumption are decided simultaneously, supply is also affected by owner characteristics. The optimal life cycle harvest rate need not be constant, and the age of the owner is a relevant explanatory variable. The timber supply function is estimated using Finnish micro data from 1982 to 1985, and the Tobit model. The hypothesis of an imperfect capital market cannot be rejected as the owner characteristics, including the owner's age, have highly significant coefficients, although the estimated coefficient of the interest rate is positive. The positive effect of the interest rate may be due to the fact that the loans of the credit-rationed forest owners in the sample are relatively small, and the positive effect of the nonrationed forest owners dominates. However, the effects of other capital (or, e.g., amenities) market imperfections cannot be ruled out. For. Sci. 37(4):1011-1029.
The Effect of Forest Productivity Taxes on Timber Stand Investment and Rotation Length
Authors: Amacher Gregory S. , Brazee Richard J. , Thomson Thomas A.
Published: April 2024

The qualitative and quantitative effects of productivity taxes are modeled. Previous analyses are extended in three directions. First, we correctly derive the qualitative effects of the forest increment tax on initial stand investment and rotation length. Second, we incorporate the harvest income tax into the Faustmann model, derive the qualitative effects of the harvest income tax on initial stand investment and rotation length. The qualitative effects from imposing productivity taxes on rotation length and initial stand investment cannot be predicted a priori. Whether rotation length and initial stand investment increase or decrease depends on whether rotation length and initial stand investment are complementary or competitive inputs in the stumpage volume function. Third, we simulate the effects of productivity taxes for Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) and loblolly pine (Pinus taeda) stumpage volume functions. Two general conclusions emerge from the simulations. First, similar to the qualitative effects, the quantitative impacts from imposing productivity taxes on rotation length and initial stand investment are impossible to predict a priori. Rotation length and initial stand investment may increase or decrease depending on the form of the volume function, the tax rate, and the interest rate. Second, the impacts of imposing productivity taxes on rotation length and initial stand investment range from quite modest to very large. For. Sci. 37(4):1099-1118.
Growth Patterns of Deerbrush and Snowbrush as Functions of Age and Shrub Vigor
Authors: Minore Don , Means Joseph E. , Cunningham Patrick G. , Weatherly Howard G.
Published: April 2024

To describe the growth of deerbrush (Ceanothus integerrimus Hook & Arn) and snowbrush (C. velutinus var. velutinus Dougl. ex Hook.) by age and shrub vigor, stem-analysis techniques were applied to 61 open-grown shrubs of each species in southwestern Oregon. Present crown dimensions were measured, and past stem lengths for each year of growth were determined by dissecting the longest stem. Models were fit to describe stem length as a function of plant age and stem length at age 10 (L10) for each species. Shrub height and crown area were then related to length of the longest stem, and curves were constructed to illustrate crown development by age and L10. The results can be used to estimate the growing space that will be occupied by open-grown shrubs of either species at any time from ages 4 through 20. For. Sci. 37(4):1140-1149.
Effects of Seed Weight and Rate of Emergence on Early Growth of Open-Pollinated Douglas-Fir Families
Authors: St. Clair J. B. , Adams W. T.
Published: April 2024

Seed weight, time of emergence, and three measures of seedling size were recorded for 39 open-pollinated Douglas-fir (Pseudotsuga menziesii vat. menziesii [Mirb.] Franco) families in order to assess family variation in seed weight and emergence, and the influence of these seed traits on early growth. Families were planted both as ungerminated seed and as recent germinants to test whether using germinants minimized seed effects on early growth. To evaluate the effect of competition on the relationships of seed weight and rate of emergence to seedling size, individuals of families were planted in mixed-family blocks at close spacing, in single (pure) family blocks at close spacing, and at a wide, noncompetitive spacing. Families differed significantly in seed weight, total percent emergence, and rate of emergence. Nevertheless, correlations of seed weight to rate of emergence, and seed weight and rate of emergence to seedling size were not strong. Using germinants was ineffective in diminishing seed effects, and interfamily competition had only a minor influence on magnifying seed effects. For. Sci. 37(4):987-997.
Stochastic Log Price, Land Value, and Adaptive Stand Management: Numerical Results for California White Fir
Authors: Haight Robert G.
Published: April 2024

This paper presents an adaptive management formulation for determining the timing and intensity of thinning and the time of clearcut for stands with any age structure and with stochastic log prices. In contrast to previous timber management studies with stochastic prices, the formulation allows the determination of the best time to switch from forestry to another land use or from selection harvesting to plantation forestry. Harvests are determined with a piecewise linear function that relates harvest intensity and stand value. The parameters of the function include its slope, location, and length. Optimal parameter values are determined using stochastic simulation. Delivered log price is a stationary process that is the sum of a deterministic constant and a normally distributed random error. Numerical results are presented for young and mature stands of California white fir [Abies concolor (Gord. & Glend.) Lindl. (Iowiana [Gord.])]. The results include when to terminate forestry and switch land use. The expected time of clearcut is inversely related to the bare land value. The effect of price variation on the time of clearcut depends on land value. For low land values, increasing price variation decreases the expected time of clearcut; for high land values, the effect of price variation is reversed. The results include estimates of the relative economic efficiency of plantation versus uneven-age forestry. The size of trees in the initial stand rather than price variation phys the critical role in determining the relative economic returns. Because the results are dependent on the assumption that the price process is stationary, caution should be used in extending the results beyond the case presented here. For. Sci. 37(5):1224-1238.
The Acceleration of Fire from Point Source to Equilibrium Spread
Authors: McAlpine R. S. , Wakimoto R. H.
Published: April 2024

The acceleration phase of a forest fire, from ignition to the equilibrium rate of spread, is perhaps the most important phase of fire behavior because often it represents the only time period in which suppression efforts could be effective. A series of experimental fires in a wind tunnel were conducted to evaluate this acceleration phase. Two types of fuel and a total of three fuel loadings and four wind speeds were tested. The results were analyzed as distance/time data, and a predictive equation produced of the form: Distance = β0 X Timeβ1 The derivative of this equation relating rate of spread at a specific elapsed time since ignition compares favorably with theoretical acceleration model curve forms. The elapsed time required to achieve an equilibrium rate of spread was constant for each fuel type over the range of conditions tested. For. Sci. 37(5):1314-1337.
The Incorporation of Risk in Optimal Selection Age Determination
Authors: Newman David H. , Williams Claire G.
Published: April 2024

This paper explores the effect of decision-making criteria on optimal selection age determination in a loblolly pine (Pinus taeda L.) tree breeding program. Three different selection ages, 2, 4, and 6 years, are compared using biological, economic, and risk-adjusted simulation methods. The 4-year selection option is found to be superior to the other options by virtually all criteria used in this analysis. This choice of 4 years is also quite robust regarding the assumptions used in the analysis such as prices, costs, gain estimates, and breeding strategy. For. Sci. 37(5):1350-1364.
Genetic Structure and Mating System of Northern Red Oak (Quercus rubra L.) in Pennsylvania
Authors: Schwarzmann John F. , Gerhold Henry D.
Published: April 2024

Horizontal starch gel electrophoresis was used to estimate isozyme allele frequencies at 13 enzyme loci for each of 1048 northern red oak embryos representing 8 populations in Pennsylvania. The average expected heterozygosity over all loci and populations, HT;, was 0.233. Red oak populations were in Hardy Weinberg equilibrium (FIS = -0.008) and very weakly differentiated (GST = 0.009). In two populations the maximum likelihood multilocus estimates of outcrossing were 1.002 and 1.015. Neither estimate was significantly different from complete outcrossing (t = 1.0). Although 28 of 32 single-tree outcrossing estimates were not significantly different from t = 1.0, an analysis of singletree outcrossing rates indicated significant tree-to-tree variation in both stands. Only 2 of 24 heterogeneity G-tests were significant, indicating that pollen pool allele frequencies showed little spatial variability and/or outcrossing was independent of maternal genotype. These results suggest that (i) family clustering is weak in red oak populations, and (ii) most members of open-pollinated families are half-sibs probably derived from a large number of pollen parents. Thus, results of open-pollination progeny tests are likely to reflect real differences in mean breeding values of most families. In addition, estimates of additive genetic variances and heritabilities are not likely to be biased sharply upwards by an increased genetic correlation among family members. Furthermore, acorns derived from seed production areas are likely to be outcrossed and contain a high level of genetic variation. For. Sci. 37(5):1376-1389.
Modeling the Effect of Winter Climate on High-Elevation Red Spruce Shoot Water Contents
Authors: Boyce Richard L. , Friedland Andrew J. , Webb Elizabeth T. , Herrick Graham T.
Published: April 2024

During the winter of 1989-90, meteorological towers were erected at two sites (880 and 1010 m elevation) within the spruce-fir zone on Mt. Moosilauke, New Hampshire. Hourly means of temperature, wind velocity, relative humidity, and solar radiation were collected and stored on data loggers. Previous-year shoots were collected from four spruce trees at each site on a weekly basis, and their relative water contents (RWC) were determined.

Measured meteorological parameters were used to simulate changes in the RWC of previous-year spruce shoots through the winter. Our model suggests that shoot water is replenished throughout the winter, presumably from water stored in older woody structures or by root uptake. Recharge was defined to be directly dependent on shoot water saturation deficit (WSD = 100% - RWC), with a temperature cutoff of -4°C. The predicted output of the model generally followed measured RWC. According to our model, periods of high transpiration were associated with low relative humidities, sometimes accompanied by high temperatures and high levels of radiation. Our results suggest that winter water relations in spruce are governed by a balance between transpirational losses, which are primarily dependent upon meteorological conditions, and the rate of recharge, which is dependent on shoot water potential, temperature and perhaps soil water availability. For. Sci. 37(6):1567-1580.
Stand and Stock Tables from Double-Point Samples
Authors: Matney Thomas G. , Parker Robert C.
Published: April 2024

Double- or two-phase point sampling with a regression estimator is a common forest inventory procedure. When the first-phase sample consists of basal area points only, a diameter distribution based on the first-phase sample cannot be estimated. Thus there is no basis for adjusting the volume distribution of the second-phase sample by regression or ratio estimators within each diameter class. A weighted constrained least squares procedure to align the second-phase stand and stock tables with the first-phase volume and basal area may be applied to obtain a suitably adjusted size class volume distribution. The least squares method described in this paper produces an adjusted stand and stock table with total basal area equal to the first-phase sample total basal area and total volume equal to the regression volume estimate. Because adjustment magnitude can be made inversely proportional to class variance, this method provides better results than adjusting classes by the ratio of second- to first-phase basal area estimates. For. Sci. 37(6):1605-1613.
Using a Geographic Information System to Study a Regional Wood Procurement Problem
Authors: Brinker Richard W. , Jackson Ben D.
Published: April 2024

A geographic information system was used to develop a spatial pulpwood procurement modeling technique with northwestern Louisiana as an example. Overlays of spatial features were created from public information or were developed from questionnaires, regression analysis, and simulation. Manipulation of these layers provided inferences about resource location and availability. This information aided in determining current competition for stumpage and in relocating wood concentration yards to areas of less competition. The overlay structure portrayed the current total pulpwood demand and supply picture for the study region and was adjusted to forecast future market scenarios.

Three demand levels were differentiated. The effect of moving three selected woodyards within the study region was evaluated. A heuristic evaluation of key wood procurement factors included area of low demand, percentage of removals to growth, parish ranking of total growing stock per ha, and percentage of NIPF ownership. New woodyard locations were selected based on wood procurement factors, highway network, urban area location, and location of nontraversable water bodies that would impede truck movement.

Simulated relocations reduced the total area of high demand by 6.4% and increased the low demand areas by 44.0%. The relocation of these woodyards could reduce wood procurement costs for those woodyards remaining in what was originally the high demand area in the central portion of the study region. Also, the potential problem of overcutting in two parishes may be reduced while increasing removals from four northwestern parishes that had approximately 50% or less of removals to growth. Limitations of the approach are discussed as are the difficulties encountered in gathering spatial data for the analysis. For. Sci. 36(6):1614-1631.
Growth Model Predictions as Affected by Alternative Sampling-Unit Designs
Authors: Hann David W. , Zumrawi Abdel Azim
Published: April 2024

This study analyzed the effect on growth-model predictions of introducing differential design error to predictor variables that are influenced by the sampling-unit design, such as basal area per acre. Computer simulations of five forest stands were generated from random spatial distributions and field data coveting a range of stand conditions. Two variable-radius cluster designs and four sizes of fixed-radius circular plots were used to sample the generated stands. Sample data were used to predict single-period gross basal area growth rates in both a single-tree and a whole-stand growth model. The sampling-unit design used to develop each model was defined as the standard error-free method of measuring the predictor variables.

For both models, the average of gross basal-area growth rate predictions from 50 samples of each alternative sampling-unit design were not significantly different from the standard design. However, using a different sampling-unit design may produce large differences in individual predictions, particularly when small sampling units are used for application of models developed using relatively large sampling units. Such differences may affect decisions about treatment of a stand and could complicate the validation of a growth-and-yield model. For. Sci. 37(6):1641-1655.
Compatible Deterministic and Stochastic Predictions by Probabilistic Modeling of Individual Trees
Authors: Vanclay Jerome K.
Published: April 2024

A single growth model can provide both deterministic and stochastic predictions which are compatible. Change may be expressed using probabilistic functions which can represent proportions of populations or probabilities for individuals. The former represents determinism while the latter enables the stochastic implementation. The same functional relationships may thus be used to generate compatible deterministic and stochastic predictions. All components of forest growth and change, including diameter increment, can be expressed as probabilistic functions, enabling construction of a single model which provides compatible stochastic and deterministic outcomes. Users may specify the minimum expansion factor corresponding to the simulated plot size and thus control the granularity of predictions. Such a model may facilitate numerical estimation of confidence intervals about yield forecasts and sustained yield estimates. For. Sci. 37(6):1656-1663.
Technical Change in the North American Forestry Sector: A Review
Authors: Stier Jeffrey C. , Bengston David N.
Published: April 2024

Economists have examined the impact of technical change on the forest products sector using the historical, index number, and econometric approaches. This paper reviews econometric analyses of the rate and bias of technical change, examining functional form, factors included, and empirical results. Studies are classified as first- second-, or third-generation approaches. First-generation studies are based on simple value-added measures of output, usually employ simple functional forms to represent the production technology, and incorporate only capital and labor inputs. Second-generation studies are characterized by estimation of more complex, flexible dual cost or profit functions and typically include resource and often energy inputs. Third-generation studies also rely upon dual formulations of the production structure and include multiple factors; however, in addition they specify the dynamics of adjustment of quasi-fixed factors over time. The studies reveal a tradeoff between the richness of the theoretical structure of the production technology and the consistency of the empirical results. Most studies have reported a labor-saving and energy-using bias to technical change, but little or no wood-saving bias, and many report a wood-using bias. Since technical advances occur in spurts, the use of a simple linear time trend to represent the state of technology is a major limitation of virtually all models. Alternative measures, such as the power ratings or throughput measures, might better capture the characteristics of a technology. Use of such measures might also be combined with a cross-sectional approach in an attempt to avoid some of the statistical problems, such as serial correlation, that characterize time series data. Finally, if the goal of the analysis is to forecast factor demand and cost implications of technical change, simulation models may offer a more promising alternative. For. Sci. 38(1):134-159.
Empirical Bayes Development of Honduran Pine Yield Models
Authors: Green Edwin J. , Strawderman William E. , Thomas Charles E.
Published: April 2024

Occasionally it is of interest to calibrate a given growth or yield model to data from several regions. If it is expected that the parameters from different regions can somehow be regarded as similar, then a Bayesian approach suggests itself. A cursory examination of the literature reveals that most of the theoretical work on empirical Bayes estimation for the linear model has focused on simultaneously estimating the coefficients in one model. In these methods the usual least squares estimates of the model parameters are shrunk toward their mean. One set of parameter estimates results. In contrast we desire a method whereby multiple sets of parameter estimates are produced. We report the results of using such a method to calibrate yield models for unthinned Honduran pine plantations to data from 21 soil-site groups. The models compare favorably to those developed via traditional methods and allow estimation of regression coefficients even for soil-site groups for which the design matrix is not of full rank. For. Sci. 38(1):21-33.
Indirect Prediction of Breeding Values for Fusiform Rust Resistance of Slash Pine Parents Using Greenhouse Tests
Authors: de Souza S. M. , Hodge G. R. , White T. L.
Published: April 2024

Six-week-old greenhouse-grown seedlings of 100 open-pollinated slash pine families were artificially inoculated with fusiform rust fungus at the USDA Forest Service Resistance Screening Center (RSC). All families had been tested for rust resistance in four or more field tests. Selection indices were developed to use symptoms of rust infection observed in the greenhouse to predict parental breeding values for field resistance to fusiform rust. Of the 100 families, 75 represented an unimproved population, while 25 represented a population improved for rust resistance. A large number (56,688) of indirect selection indices were considered in an attempt to identify efficient indices which use a small number of traits. Indices were developed using three different sets of variance and covariance estimates: (1) from the unimproved population, (2) from the improved population, and (3) from the combined population. Separate indices were necessary for the two distinct populations. The new indices were more correlated with field resistance and result in more efficient indirect selection for field resistance than the equation currently in use by the RSC. However, the greenhouse test to indirectly assess field rust resistance (using the new indices) is somewhat less efficient than a single field progeny test on average. For. Sci. 38(1):45-60.
Simulation of the Collapse of Bent-Over Vortex Pairs Observed in Wildland Fires
Authors: Haines Donald A. , Smith Mahlon C.
Published: April 2024

During intense wildland fires a transient vortex pair sometimes occurs that may form with a near vertical axis but then bends over and becomes horizontal. Collapsing limbs of these vortex pairs threaten fire fighters. Therefore, this study simulated vortex collapse in a wind tunnel. Collapse was produced by cross air flow upstream of the heat source. Using an upstream, wing-shaped obstacle to create cross air flow, the wind tunnel experiments showed that small changes in wing angle, and thus cross air flow, could cause major changes in the structure of the vortex pair. For. Sci. 38(1):68-79.
Shoot Selection and the Rooting and Field Performance of Tropical Pine Cuttings
Authors: Haines R. J. , Copley T. R. , Huth J. R. , Nester M. R.
Published: April 2024

Several morphological features were significantly related to the rooting response, and subsequent field performance as rooted cuttings, of shoots collected from hedged stool plants of an F1 hybrid between Pinus caribaea var. hondurensis and P. tecunumanii. Results indicate that it will be possible to manipulate rooting and field performance by shoot selection at the time of harvest of cuttings. The cutting which best meets the objective of maximum rooting without loss of field performance is the terminal segment from a shoot over 30 cm in length, with an actively growing juvenile bud, primary needles in excess of 25 mm, secondary needles present but less than 10 mm in length, and basal diameter over 2 mm. The use of second and third segments of shoots, where these have the appropriate features, would permit greater utilization of material with only a minor decrease in rooting. Primary needle length was the best morphological predictor of both rooting and field height growth. Significant positive genetic correlations suggest that within-family selection for primary needle length will involve selection for clones which root well and which display good height growth in the field, perhaps as a result of slower stool plant aging. For. Sci. 38(1):95-101.
Thinning and Nitrogen Fertilization in a Grand Fir Stand Infested with Western Spruce Budworm. Part I: Insect Response
Authors: Mason Richard R. , Wickman Boyd E. , Beckwith Roy C. , Paul H. Gene
Published: April 2024

Thinning and nitrogen fertilization of a grand fir (Abies grandis [Dougl. ex D. Don] Lindl.) stand were tested as possible alternative techniques for managing outbreaks of the western spruce budworm (Choristoneura occidentalis Freeman). Treatment effects on an infestation of budworm and associated defoliating insects were evaluated over 5 years by a replicated split-plot experiment. Mean densities of budworm egg masses and larvae tended to be higher on fertilized plots than on control plots, but differences were not significant during the course of the experiment. Total herbivore biomass was, however, 40-60% greater and individual larvae were 32-38% heavier for 2-4 years after fertilization. Thinning alone produced a significantly greater dry mass of budworms in one year although the difference was relatively small. Fertilization also significantly increased the weight of male and female pupae by 6-23% for 4 years whereas thinning had no effect on pupal weight. Parasitization of late larvae and pupae was significantly reduced in one year by fertilization but was not affected by thinning. In general, defoliating insects seemed to benefit from the applied treatments, especially fertilization; however, overall budworm survival and prevailing trends of the outbreak were unaffected by the treatments and seemed to be determined mostly by other environmental factors, probably natural enemies. The ultimate value of thinning and fertilizing infested forests as a method of pest management must be viewed in the larger context of the total effect on tree and stand productivity. For. Sci. 38(2):235-251.
Spruce Budworm Defoliation and Growth Loss in Young Balsam Fir: Period Models of Needle Survivorship for Spaced Trees
Authors: Fleming Richard A. , Piene Harald
Published: April 2024

The age-dependent Weibull model described detailed observations of needle survivorship taken in two protected plots of young, spaced, balsam fir (Abies balsamea [L.] Mill.) on the Cape Breton Highlands, Nova Scotia, Canada. Throughout the midcrown, the rates of age-specific needlefall increased with needle age, indicating a Type I survivorship curve typical of foliage. It was shown that the needle populations experienced distinct stages of needlefall as they aged. Few needles surviving a period of "infant mortality" in their first year fell in their second. There was a low, but steady, increase in the rates up to age 4-5, with a further increase in the rates for older needles. The mean longevity of the needle populations ranged from 4.1 to 6.1 years and generally increased with tree age. Differences between trees of the same age and differences between crown levels explained little more of the variation in needle fall than that already explained by needle age alone. For. Sci. 38(2):287-304.
Chance Constraints and Chance Maximization with Random Yield Coefficients in Renewable Resource Optimization
Authors: Hof John G. , Kent Brian M. , Pickens James B.
Published: April 2024

This paper treats a variety of approaches to account for random yield coefficients with known means and variances in renewable resource optimization models. General formulations are discussed first, followed by a forestry case example that demonstrates the formulations and resulting optimal solutions in a renewable resource application. Different approaches to approximating the normal cumulative density function are evaluated using simulation. For. Sci. 38(2):305-323.
Geometric Errors in Natural Resource GIS Data: Tilt and Terrain Effects in Aerial Photographs
Authors: Bolstad Paul V.
Published: April 2024

Simulation studies were performed to estimate geometric errors in spatial data from monoscopic interpretation of large format aerial photographs. Positional and area error were simulated for a range of photo scales (1:10,000 to 1:40,000), camera tilts (0° to 4.2°), and relief (vertical range from 0 m to 750 m). Average positional errors were observed between 4 m and 104 m and varied positively with tilt and terrain range and inversely with scale. Area errors were observed over a range of polygon sizes, from 40 to 600 ha. Average area error ranged from 0.0 to 10.7% and was positively related to tilt and terrain range and not related to scale or polygon size. The magnitude of these errors and the availability and low cost of requisite correction technologies suggest analytical methods for removing relief and tilt distortion should be employed under most circumstances. For. Sci. 38(2):367-380.
Measuring Forest Site Quality Using the Parameters of a Dimensionally Compatible Height Growth Function
Authors: McDill Marc E. , Amateis Ralph L.
Published: April 2024

This article presents a new approach to modeling forest site quality which centers on interpreting as measures of site quality the parameters of a stand height growth model. It is argued that site index, which relies on a single height at a particular age, is not capable of reflecting important differences in the shapes of height growth trajectories. In the proposed approach, the parameters of the height growth function and the function itself completely describe the projected dominant height growth curve. In order to make the approach applicable in a wide variety of modeling situations, a method of allowing the number of site quality parameters to vary is proposed. The most flexible model configuration allows the estimation of all parameters separately for each stand and requires remeasurement or stem analysis data that span a relatively long period of time. Less flexible model configurations involve the simultaneous estimation of parameters that are different for each stand (stand-level parameters) with parameters that are the same for all stands (global parameters). Stand-level parameters measure different aspects of site quality that are unique for each stand and global parameters measure different aspects of site quality that are unique for each stand. These less flexible model configurations may be useful when modeling objectives warrant combining stand-level and global parameters or in situations where the mixture of longitudinal and cross-sectional data precludes fitting the most flexible model form. The approach works best with a growth function that offers maximum flexibility with a minimum of parameters and when the parameters of the growth function have intuitive biological interpretations. A new growth function with these properties is presented in this paper. The new growth function is dimensionally compatible and has two biologically meaningful parameters: a rate parameter and a maximum size parameter. The integrated form of the growth function also includes initial conditions which can be specified with data or as an additional parameter to be estimated. Two applications of the approach to modeling dominant height growth of loblolly pine (Pinus taeda L.) are described: one where sufficient longitudinal data allowed fitting several model forms and another where data limitations required the use of less flexible models. For. Sci. 38(2):409-429.
A Scenario Approach to Stochastic Anticipatory Optimization in Stand Management
Authors: Valsta Lauri T.
Published: April 2024

A flexible model for stochastic optimization is developed that can be used with forest stand simulation models. Stochasticity is represented by a large set of scenarios, each of which is an outcome of stochastic processes. A stochastic environment is described by random yearly growth rate levels and catastrophes, such as wild fire or windthrow. The optimization model is defined in control variable space and includes the timing, intensity, and type of thinning, and rotation length for an even-aged stand. Single-tree growth and mortality models are used. Numerical results in a risk-neutral case show that the optimum rotation is shortened with an increasing probability of a catastrophe. Further, an increasing growth rate variation has mixed and weak effects that depend, in particular, on the tree mortality model. If a stand cannot be thinned, increasing risk-taking shortens the optimum rotation, given the model set used. For. Sci. 38(2):430-447.
Variation in the Constitutive Defensive System of Loblolly Pine in Relation to Bark Beetle Attack
Authors: Nebeker T. Evan , Hodges John D. , Blanche Catalino A. , Honea C. Ronald , Tisdale Robert A.
Published: April 2024

Total flow over a 4-hr period, rate of flow, and relative viscosity were measured on 13 full-sib families in 1987. Significant differences between families were detected for all parameters measured. These parameters have been suggested as being useful in predicting relative host susceptibility to bark beetle attack. Certain families are suggested to be potentially more resistant to bark beetle attack than other families based on these parameters of interest. During 1988, 1989, and 1900 trees of unknown parentage (woods run) were wounded at different times during the day and total resin flow measured hourly for 24 hr. Rate of flow was calculated. Significant differences in flow were found at the beginning of the 24-hr period for all years. Nineteen eighty-eight was the only year that these differences continued for the entire 24 hr. Patterns of flow were similar for all years with 70% to 87% of flow occurring within the first 8 hr after wounding. Findings presented here, although preliminary, are encouraging in that it may be possible to incorporate potential bark beetle resistance information into tree improvement programs. For. Sci. 38(2):457-466.
A Measure of Innovativeness for a Sample of Firms in the Wood Household Furniture Industry
Authors: West Cynthia D. , Sinclar Steven A.
Published: April 2024

Characterizing innovators and early adopters of technological innovations can benefit promoters of new technologies. Marketing researchers have found correlates between characteristics of adopters and the time of adoption which have been helpful in identifying those firms most likely to adopt and targeting them with the appropriate marketing mix. Firms in the wood household furniture industry were segmented based on their adoption of 13 processing technologies into an innovator group and a noninnovator group. These groups were contrasted on a variety of characteristics. Innovators were found to differ significantly from noninnovators in firm size, technological expertise, technological progressiveness, opinion leadership, information sources, and cosmopolitanism of the decision-making group. This information can be used by equipment suppliers, government agencies, and the furniture industry itself to encourage adoption of new processing technologies. For. Sci. 38(3):509-524.
An Assessment of Some Nonsampling Errors in a National Survey Using an Error Budget
Authors: Gertner G. , Köhl M.
Published: April 2024

Different error budgets are approximated for the First Swiss National Forest Inventory. An error budget displays the effects of individual errors and groups of errors on the accuracy of estimates. The goal of developing the error budgets was to account for the significant sources of errors that can be expected in the national survey. Sources of error included measurement error of quantitative and qualitative attributes, regression error, and sampling error. It was found in general that the national survey system was not very sensitive to unbiased random errors but was sensitive to systematic measurement errors. For. Sci. 38(3):525-538.
Optimal Harvesting with Stand Density Targets: Managing Rocky Mountain Conifer Stands for Multiple Forest Outputs
Authors: Haight Robert G. , Monserud Robert A. , Chew Jimmie D.
Published: April 2024

A solution is presented for the stand management problem of optimizing timber yields (expressed as either present value or volume production) while satisfying constraints intended to meet nontimber management objectives such as deer habitat or visual quality. The constraints are stand density targets formulated exogenously by the forest management staff and are expressed as a simple function relating both the minimum and maximum numbers of trees per acre to quadratic mean diameter. The goal is to find the sequence of diameter-class thinnings that maximizes yield while staying between the trees per acre bounds for each quadratic mean diameter. The solution method is a derivative-free coordinate-search process that incorporates penalty functions for the constraints. Examples focus on mixed-conifer stands in the Northern Rocky Mountains with three different land use designations: timber production, timber production in visually sensitive areas, and timber production in whitetailed deer winter habitat. Growth and yield is forecast dynamically with the Stand Prognosis Model. Results show that significant reductions in present value and volume production may result from meeting stand density targets. In addition, the solution algorithm quickly finds infeasible targets (all of the wildlife management constraints proved to be infeasible). Because the solution algorithm also provides near-feasible solutions, it is easy to identify specific targets that need to be relaxed to obtain feasibility. Thus, the results from the solution algorithm can be used to quantify the costs associated with meeting the nontimber management goals. Furthermore, results from such analyses should greatly assist in determining efficient levels of production for multiple forest outputs. For. Sci. 38(3):554-574.
Effects of Supply and Demand Determinants on Pulpwood Stumpage Quantity and Price in Texas
Authors: Carter Douglas R.
Published: April 2024

This paper presents a dynamic model of the Texas pine pulpwood stumpage market. The analysis incorporates profit maximization of the demand side with utility maximization on the supply side to analyze short-run market behavior. The model is estimated using a ridge regression form of three-stage least squares to redress the problems associated with degrading collinearity. Multipliers are then constructed to predict the short- and long-run equilibrium impacts of supply and demand determinants on pulpwood quantity and price. For. Sci. 38(3):652-660.