bluuebunny/crossref_metadata_2025 huggingface dataset:
Analytical Estimates of Loblolly Pine Tree Center of Mass and Mass Moment of Inertia
Authors: Fridley J. L. , Tufts R. A.
Published: April 2024

Center of mass and mass moment of inertia of a solid can be calculated by appropriate integration over the volume of the object. Taper functions estimate tree stem diameter as a function of stem height and dbh. Center of mass and mass moment of inertia about two axes were estimated for 21 loblolly pine (Pinus taeda) trees using nine different taper functions to estimate the volume of integration. Laboratory measurements (from a previous study) of the same 21 trees served as a basis for evaluating and comparing the estimates. The center of mass values determined via the taper equations are similar among taper functions. However, significant differences were found, most importantly between measured values and estimates using six of the taper functions. Few significant differences were found in the mass moment of inertia values estimated via taper equations. For. Sci. 35(1):126-136.
Use of Sensitivity Analysis to Guide Primary Data Collection Efforts in the Construction of "Mongrel" Input-Output Models
Authors: Jamnick Mark S. , Gilless J. Keith
Published: April 2024

A formula is presented for estimating the sensitivity of an input-output model's predictions of sectoral total gross outputs to errors in its technical coefficients without recalculating the inverse matrix. When building a "mongrel" input-ouput model (i.e., one based partly on primary data and partly on secondary data), the formula can be used to identify "significant" technical coefficients (those meriting estimation with primary data). Data from models of Humboldt County, California, and the state of Alabama are used to illustrate the use of the formula. Given plausible, albeit arbitrary, significance thresholds for errors in these models, relatively few technical coefficients in either appeared to merit estimation with primary data—indicating that the incremental costs associated with enhancing purely secondary data models may be quite low relative to the resulting gains in model reliability. For. Sci. 35(1):pp. 237-244.
Using N2-Fixing Albizia to Increase Growth of Eucalyptus Plantations in Hawaii
Authors: DeBell Dean S. , Whitesell Craig D. , Schubert Thomas H.
Published: April 2024

Plantations of Eucalpytus saligna Sm. grow rapidly in Hawaii, but supplemental nitrogen (N) is required on many sites. Because of the high cost of synthetic N fertilizer, mixed species plantings in which N is added by Albizia falcataria (L.) Fosb., an N2-fixing tree, are being tested on the island of Hawaii. Five combinations of Eucalyptus and Albizia were compared with each other, with pure Albizia, and with pure Eucalyptus fertilized periodically with nitrogen. The test is a randomized block design with four replications on the wet, Hamakua coast. At 48 months, Eucalyptus trees in the mixed plantings containing 34% or more Albizia were equal to or larger than those in the pure, fertilized stands. Total dry yields ranged from 109 ton/ha in pure Albizia plantings to 67 ton/ha in mixed species plantings with only 11% Albizia. Yields in the mixed plantings with 34 to 66% Albizia were 103 to 105 ton/ha, whereas yield in the pure, fertilized Eucalyptus stand was 94 ton/ha. Nitrogen concentration of Eucalyptus foliage increased as the amount of Albizia increased in the stand; and in mixed plantings with 34% or more Albizia, foliar N concentration exceeded that of the pure, fertilized, Eucalyptus treatment. Phosphorus levels in Eucalyptus foliage similarly increased as amounts of Albizia increased in the stand. At 48 months, total N was higher in soils of mixed species and pure Albizia plantings than in soils of the pure, fertilized Eucalyptus treatment. Albizia can provide the N needed by Eucalyptus in high-yielding bioenergy plantations along the Hamakua coast. For. Sci. 35(1):64-75.
Developing Growth and Yield Models Using Dimensional Analysis
Authors: Amateis Ralph L. , McDill Marc E.
Published: April 2024

The concept of dimensional compatibility where the dimensions of expressions on both sides of an equation are consistent is presented as a useful principle for growth and yield models. A procedure for obtaining dimensional compatibility, called dimensional analysis, is presented as a tool for developing growth and yield models and is demonstrated in the context of two growth and yield modeling problems. For. Sci. 35(2):329-337.
Forest Planning and Decision Making under Fuzzy Environments: An Overview and Illustration
Authors: Mendoza Guillermo A. , Sprouse William
Published: April 2024

Forest systems are inherently complex and therefore lend themselves naturally to fuzzy approaches in planning and decision making. In recognition of this, a two-stage approach to forest planning is proposed. This paper describes two modeling approaches or methods representing the two critical stages in planning: (1) generation of alternatives, and (2) evaluation and prioritization of these alternatives. The method for generating alternative solutions adopts a fuzzy approach, which allows for a more robust and flexible generation of alternatives. The second method enables the decision maker to examine the generated alternatives, elicit his or her perceptions and judgments, and use these judgments to synthesize a set of prioritized alternatives. A multiple-use planning problem adopted from the Shawnee National Forest is used to illustrate the methods. For. Sci. 35(2):481-502.
Systems of Equations in Forest Stand Modeling
Authors: Borders Bruce E.
Published: April 2024

Growth and yield models are often composed of systems of related equations. Parameter estimation techniques such as two-stage and three-stage least squares have been suggested for fitting such systems. An alternative theoretically sound parameter estimation procedure that can be used for any number of sequentially related equations, linear and nonlinear, is presented and discussed. Implementation of this procedure is illustrated for two systems of equations. For. Sci 35(2):548-556.
Optimal Tariffs on Intermediate and Final Goods: The Case of Tropical Forest Products
Authors: Vincent Jeffrey R.
Published: April 2024

Products made from tropical timber are subject to a variety of tariff and nontariff barriers. This paper considers the potential welfare gains from the imposition of optimal (welfare-maximizing) tariffs on these products. Optimal tariffs and associated welfare gains are determined by applying nonlinear programming to a static (single-period), three-region, three-product, partial equilibrium simulation model of the tropical forest products sector. Optimal tariffs are determined for each region both with and without retaliation by other regions. In the case of retaliation, two- and three-region Cournot-Nash equilibria are described. Principal findings are that modest welfare gains are possible in the absence of retaliation, but large losses may result if other regions retaliate. Since tariff revenue is the critical component of the welfare increase, the redistribution of this revenue has important equity implications. For. Sci. 35(3):720-731.
Price Indexes for Deflating Public Forestry Research Expenditures
Authors: Bengston David N.
Published: April 2024

The extent to which inflation has eroded the real purchasing power of forestry research budgets is poorly understood. No widely accepted and satisfactory price index exists for assessing the impact of inflation on forestry research. Official government research statistics use the GNP deflator to express research expenditures in constant dollars, despite the serious shortcomings of such a broad indicator of inflation for deflating research expenditures. Two forestry research price indexes are calculated in this paper, one for USDA Forest Service research and the other for university forestry research. The GNP deflator has adequately represented the inflationary trend in Forest Service research, but it has substantially underestimated the rate of inflation in university forestry research in recent years due mainly to real growth in faculty compensation during the 1980s. The divergence between the university forestry research price index calculated in this study and the GNP deflator indicates that the purchasing power of university forestry research is significantly less than estimates based on the GNP deflator would suggest. For. Sci. 35(3):756-774.
Regression Estimators for Late-Instar Gypsy Moth Larvae at Low Population Densities
Authors: Wallner W. E. , Devito A. S. , Zarnoch S. J.
Published: April 2024

Two regression estimators were developed for determining densities of late-instar gypsy moth, Lymantria dispar (Lepidoptera: Lymantriidae), larvae from burlap band and pyrethrin spray counts on oak trees in Vermont, Massachusetts, Connecticut, and New York. Studies were conducted by marking larvae on individual burlap-banded trees within 15-m diameter plots and recapturing them with pyrethrin sprays to tree crowns at night. Both estimators are based on data that are relatively easy and inexpensive to gather in the field. The estimator for individual trees may be useful in determining relative densities, but the plot estimator, which had an R² of 0.99, can be used with a high degree of confidence for determining absolute densities in plots containing several oak trees. Validation of the plot density estimator at five sites in Maryland demonstrated its utility for sampling late-instar gypsy moth. Both estimators were valid only when previous years' egg-mass densities were ≤75/ha and decreased in efficiency when prior year egg masses were ≥495/ha. These estimates are best suited for density estimates in sparse or building gypsy moth populations in which other procedures are especially difficult to use or evaluate. For. Sci. 35(3):789-800.
Genetic Variance in Growth of Balsam Poplar Under 16- and 8-Hour Photosynthetic Periods
Authors: Schnekenburger Frank , Farmer Robert E.
Published: April 2024

Six to seven balsam poplar (Populus balsamifera L.) clones from each of four provenances on a latitudinal transect (45° to 53° at 89° to 91°W) were grown for 78 days under 16- and 8-hour photosynthetic periods. Analysis of variance and functional growth analysis were used to evaluate genetic variation in growth and development under the two regimes. Relative Growth Rate and Unit Leaf Rate of plants growing under the 8-hour regime were, respectively, 85 and 60% of those of plants under 16-hour photosynthetic periods, while final dry weight under long periods was over twice that under short ones. Leaf Area Ratio, Specific Leaf Area, and the Leaf Area Partitioning Coefficient were all larger under 8-hour periods. During the initial 30 days of the experiment, shoot-root ratio was greater under the 8-hour regime, but there was no difference between regimes by final harvest. Provenance effects were generally small and statistically nonsignificant, while clonal variation within provenances was large. The ratio of the relative growth rate of the shoot to that of roots (i.e., the allometric constant) was negatively correlated with latitude of provenance. For. Sci. 35(4):903-919.
Movement of Chloropicrin or Methylisothiocyanate through the Boles of Douglas-Fir Trees
Authors: Morrell J. J. , Newbill M. A.
Published: April 2024

Movement of the wood fumigants chloropicrin and methylisothiocyanate (MITC) through living Douglas-fir trees was evaluated at selected heights above treatment holes 18 and 42 months after treatment. Wood-sample extracts were analyzed by gas chromatography. After 18 months, concentrations of MITC were 10 to 30 times higher than those of chloropicrin. Concentrations of both chemicals were higher in heartwood than in the wetter sapwood. After 42 months, concentrations of both chemicals were much higher and apparent at greater distances from the point of application. MITC concentrations were again higher than those of chloropicrin, which has a lower water solubility that may limit diffusion. Both chemicals moved through Douglas-fir heartwood as far as 4 m from the application point over the 42 months. For. Sci. (36):192-195.
Soil pH and Nitrogen Influence Pisolithus Ectomycorrhizal Development and Growth of Loblolly Pine Seedlings
Authors: Marx Donald H.
Published: April 2024

Five families of loblolly pine were grown from April to February in fumigated soil at pH 4.8, 5.8, and 6.8. All microplots received vegetative inoculum of Pisolithus tinctorius (Pt) and three, six, or nine applications of NH4NO3 at 50 kg N/ha/application through August, which totaled 150, 300, or 450 kg N/ha. Vegetative inoculum of Pt buried in soil lost significant viability after 54 days at soil pH 6.8. Inoculum viability declined in all treatments after 81 days, but it was only a little over a third as viable at pH 6.8 as at lower pH levels. Up to three applications of NH4NO3 at 50 kg N/ha each did not affect inoculum viability.

The five test families of loblolly pine reacted similarly to soil treatments. Seedling heights, root-collar diameters, and top dry weights were more affected by soil pH than by application of N. As soil pH increased, seedling growth decreased. Dry weight of roots, total length of lateral roots, and number of short roots were not significantly influenced by either soil treatment. Total Pt ectomycorrhizal ratings (combining number of mycorrhizae and proportion of different morphological types) were about one-fourth as much at pH 6.8 as in more acid soil conditions. Applications of NH4NO3 resulting in soil concentrations of NO3-N ranging from 60 to 120 kg/ha and NH4-N ranging from 90 to 130 kg/ha at pH 4.8 and 5.8 were associated with the most abundant Pt ectomycorrhizal development. Increased N applications increased Pt development at pH 5.8 and 6.8. Calcium equivalent treatments, using CaSO4 at similar Ca concentrations, suggested seedling response was due to soil pH and not Ca concentrations. For. Sci. 36(2):224-245.
A Quantitative Description of a Deciduous Forest Canopy Using a Photographic Technique
Authors: McIntyre Blodwyn M. , Scholl Martha A. , Sigmon John T.
Published: April 2024

Three features of a deciduous forest canopy were measured using nondestructive techniques. Vertical distribution of leaf area was measured using an established technique (MacArthur and Horn 1969). A technique was developed and used to quantify seasonal variation in the canopy. Leaf area index (LAI) was calculated with several techniques, which were compared to litter trap LAI values to determine their accuracy. A new technique for LAI calculation was developed, which accurately estimated LAI at our site and may be applied to other eastern hardwood forests.

These three techniques are proposed to quantitatively describe a deciduous forest canopy. These measurements can be made nondestructively, with minimal equipment and labor costs, and with a high degree of accuracy. For. Sci. 36(2):381-393.
Glyphosate Translocation and Efficacy Relationships in Red Maple, Sweetgum, and Loblolly Pine Seedlings
Authors: D'Anieri Peter , Zedaker Shepard M. , Seiler John R. , Kreh Richard E.
Published: April 2024

Glyphosate herbicide was applied to red maple, sweetgum, and loblolly pine seedlings at the end of the second growing season to evaluate the effects of application timing and water stress on glyphosate absorption, translocation, and efficacy. Although there was no difference in 14C-glyphosate absorption among species, sweetgum translocated significantly more herbicide to the roots and stem below the treated leaf than red maple and loblolly pine. These differences may explain, in part, the variability among species in susceptibility to glyphosate. Application timing and water stress had an interacting effect on red maple and loblolly pine efficacy. Increasing water stress resulted in decreased efficacy in August, but had no consistent effect in September and October, possibly due to physiological changes associated with the development of fall dormancy. Glyphosate was most phytotoxic to sweetgum, followed by loblolly pine and red maple, which corresponds to results observed in commercial pine release applications. For. Sci. 36(2):438-447.
Monoterpene Composition and Fusiform Rust Resistance in Slash Pine
Authors: Michelozzi M. , Squillace A. E. , White T. L.
Published: April 2024

Cortical monoterpene composition was determined for 43 relatively resistant and 42 relatively susceptible slash pine clones selected on the basis of their fusiform rust resistance breeding values. Fifty-seven percent of the clones having high proportions of β-phellandrene were relatively resistant, while only 15% of the low β-phellandrene clones were relatively resistant. Reasons for the relationship are not clear, but presence of the high β-phellandrene gene may be linked with other traits more directly involved with resistance. Certain combinations of monoterpenes, including particular minor constituents, may be more indicative of resistance than β-phellandrene alone, but further work is needed. For the present, tree improvement workers should consider determining monoterpene composition of candidate trees prior to progeny testing, and culling trees with low β-phellandrene content. For. Sci. 36(2):470-475.
Shoot Elongation Patterns of Loblolly Pine Families Selected for Contrasting Growth Potential
Authors: Bridgwater Floyd E.
Published: April 2024

Ten half-sib families of loblolly pine chosen to represent a wide range of size in 8-year-old field trials, exhibited different shoot elongation patterns during their second year in retrospective seedling trials. In all but two families, the different patterns of annual shoot elongation were consistent in irrigated and nonirrigated treatments. Two families that ranked high for growth rate in the 8-year-old field trials also had greater annual shoot growth in the seedling trial without irrigation, but performed poorer than expected when well watered. The different patterns in annual height increment arose as a consequence of changes in the relative contributions of numbers of stem units, the average shoot length per stem unit, and the percentage of trees elongating. However, total annual height increment produced during the second year was a better predictor of the size of half-siblings after 8 years in field trials than any of the components of shoot growth. Families with greater size after 8 years in field trials had longer annual leaders in the seedling trial, but for varying reasons. Some were longer primarily because they had more stem units, while others had average numbers of stem units but greater-than-average stem unit lengths. The percentage of trees elongating near the end of the season was of little or no importance in determining the relative ranks of families within each of two geographic populations studied, but contributed to the differences between the two populations. For. Sci. 36(3):641-656.
The Declining Even Flow Effect and the Process of National Forest Planning
Authors: Pickens James B. , Kent Brian M. , Ashton Peter G.
Published: April 2024

Recent literature (McQuillan 1986) has identified what may be a serious flaw in the planning process used by the USDA Forest Service. The problem, which McQuillan called the declining even flow effect (DEFE), can occur during repeated iterations of a planning process in cases where a timber harvest scheduling model whose objective is wealth maximization subject to nondeclining yield constraints is utilized. The DEFE creates a situation in a sequence of plans over time in which the first period harvest level declines below that attained for previous planning iterations. This paper addresses the relationship between the process used by the Forest Service to develop FORPLAN models and the DEFE. An example using Kootenai National Forest planning documents is presented to illustrate the highly constrained nature of Forest Service planning models. The effect of these constraints and other characteristics of FORPLAN models on the DEFE is examined. Two items common to nearly all forest planning models, a land base which is not entirely old-growth and constraints to assure that the 40-ac clearcut limit is not violated, caused a large reduction in the DEFE observed in a FORPLAN version of McQuillan's case study model. However, one characteristic of Forest Service planning models, the use of intermediate harvest options, which plausibly could have reduced the DEFE, did not. The major conclusion of the study is that the regulations, initial conditions, and formulation of the FORPLAN model all tend to reduce the likelihood and magnitude of the DEFE. For. Sci. 36(3):665-679.
Combining Inventory Estimates with Possibly Biased Auxiliary Information
Authors: Green Edwin J. , Strawderman William E.
Published: April 2024

The usual method of combining sample data with auxiliary information is the familiar precision-weighted composite estimator. However, application of this estimator is straightforward only when the auxiliary information is unbiased. If this is not the case, and the bias is unaccounted for, then the risk of the usual composite estimator can be greater than that of the sample mean. We conjecture that investigators are often unsure of the possible bias in their auxiliary information. Accordingly, we develop an estimator which mimics the usual composite estimator when the auxiliary information is unbiased, yet dominates the sample mean even as the bias becomes large. In addition, unlike the usual composite estimator, the new estimator does not require one to specify the variance of the auxiliary information. The performance of both estimators, and the sample mean, is examined based on results of a simulation trial on actual sample data. For. Sci 36(3):693-704.
Sprouting Shrub Response to Different Seasons and Fuel Consumption Levels of Prescribed Fire in Sierra Nevada Mixed Conifer Ecosystems
Authors: Kauffman J. B. , Martin R. E.
Published: April 2024

Virtually all shrub species present in mixed conifer forests of the Sierra Nevada have evolved specialized adaptations to survive the frequent low intensity surface fires that characterized the fire regime of this ecosystem. In this study we examined the variable sprouting response of broad-leaved shrubs and hardwoods following prescribed fires burned under a wide range of environmental and fuel conditions. Shrub survival was often dramatically different between treatments (i.e., fuel consumption level and season of burn), species, and size classes within plant species. Of the four different burn treatments, survival of the shrubs and hardwoods was as low as 12% after early fall burns (high levels of fuel consumption) and as high as 79% after early spring burn treatments (moderate levels of fuel consumption). As much as 95% of the smallest size of the small classes of shrubs (i.e., those ≤50 g dry weight biomass) were killed by prescribed fires. In contrast, the majority of larger individuals survived fires of low-moderate consumption, but rates of survival declined with increasing levels of fuel consumption.

Post-fire shrub physiognomy was significantly lower in crown volume, crown area, height, and aboveground biomass. The number of individual shrub stems per individual significantly increased after fire. Postfire biomass partitioning was different among sprouting species; in the deciduous-leaved Quercus kelloggii, the percentage of aboveground biomass composed of leaves was lower, and the percentage composed of woody tissues was higher than that of the evergreen-leaved Lithocarpus densiflorus. For. Sci. 36(3):748-764.
Critical Height Versus Importance Sampling for Log Volume: Does Critical Height Prevail?
Authors: Deusen Paul C. Van
Published: April 2024

The estimator developed in Van Deusen (1987) is generalized to allow for unbiased estimation of log or tree volume using the critical height method. Comparisons are made with importance sampling (Gregoire et al. 1986) that suggest that the critical height method is more efficient and robust. The critical height method also requires fewer computations in the field. For. Sci. 36(4):930-938.
Individual Choice and Regional Acreage Response to Cost-Sharing in the South, 1971-1981
Authors: Hardie Ian W. , Parks Peter J.
Published: April 2024

Total acreage responding to a given economic incentive is a key measure of the effectiveness of many government forest land-use programs. Examples are the FIP and America the Beautiful programs. Acreage response depends both on landowner behavior and on land characteristics. Prediction of this response for new or untried government incentives consequently requires simultaneous estimation of landowner land-use decisions and of the number of acres affected by the decisions. A method to predict aggregate acreage response to proposed land-use programs is described in the paper. This method is illustrated by an analysis of how cost-sharing could have affected NIPF owner investment in pine regeneration on harvested lands in the South in 1971-1981. Results show that cost-sharing may have encouraged 70% of the regeneration investment observed during the period, and that changes in the cost-share incentive would have been an effective way to change the amount of pine acreage planted or seeded in the South during this period. Application of the method to proposed future programs would require a new area frame sample survey. For. Sci. 37(1):175-190.
Principal Components Regression to Mitigate the Effects of Multicollinearity
Authors: Morzuch Bernard J. , Ruark Gregory A.
Published: April 2024

One consequence of multicollinearity among the structural independent variables of a regression model is that variables are frequently deleted as a means of proceeding with sensible hypothesis tests. Principal components regression has the advantage of avoiding model specification error due to variable deletion. The technique works as follows: the independent variables are orthogonalized into their principal components; components with low information content are deleted; the model is estimated by ordinary least squares; then the principal component estimators are converted into coefficients in the original parameter space, where a judgement about their contribution is made via an F-test. An example using tree growth data is presented to demonstrate the merits of principal components regression over variable deletion. Results indicate that "correct" structural specification does not have to be compromised through variable deletion when collinearity is present. This obviously has implications for large-scaled regression models, in which an increased number of independent variables in the specification may promote a level of collinearity that is not conducive to making statistical inferences. Analytical methods like principal components, that adjust for the effects of collinearity on the variable selection process, are merited. For. Sci. 37(1):191-199.
Distributive Effects of Forest Service Attempts to Maintain Community Stability
Authors: Daniels Steven E. , Hyde William F. , Wear David N.
Published: April 2024

Community stability is an objective of USDA Forest Service timber sales. This paper examines that objective, and the success the Forest Service can have in attaining it, through its intended maintenance of a constant volume timber harvest schedule. We apply a three-factor, two-sector modified general equilibrium model with empirical evidence from the timber-based counties of western Montana. Departure from a market responsive timber policy can have positive impacts on the wood products sector, but the net effects on the local community are very small. The costs to the public treasury of pursuing such a policy dwarf these small community benefits. For. Sci. 37(1):245-260.
Nitrogen and Family Effects on Biomass Allocation of Loblolly Pine Seedlings
Authors: Li Bailian , Allen H. L. , McKeand S. E.
Published: April 2024

Biomass of stem, needles, and roots were determined for seedlings of 23 open-pollinated loblolly pine families alter 20 weeks' growth in a greenhouse under two nitrogen (N) levels (5 and 50 ppm). Allometric analysis was used to determine the N and family effects on the biomass allocation. Nitrogen had significant effects on seedling growth and biomass allocation to stem, needles, and roots. Low N resulted in smaller seedling size, but relatively more biomass was allocated to roots than under the high N condition. N stress generally favored biomass allocation to roots at the expense of needles or both needles and stem. Relative allocation of biomass to roots was significantly different among families with low N but not with high N. Larger seedlings exhibited greater allocation to roots possibly as a result of greater N stress. Different patterns of biomass allocation among loblolly pine families were related to their stem weight and height. Families with superior stem weight and height in both N environments had the largest root biomass proportional to seedling size in low N and had the smallest under the high N treatment. For. Sci. 37(1):271-283.
Relationship Between Total Nonstructural Carbohydrate Concentration and Root Diameter in Sugar Maple
Authors: Kolb T. E. , McCormick L. H.
Published: April 2024

Total nonstructural carbohydrate (TNC) concentration, an estimate of the carbohydrate energy readily available to the plant, was measured by chemical extraction (enzymatic hydrolysis) in dormant season roots of sugar maple (Acer saccharum Marsh.). In all sample trees, TNC concentration increased as root diameter decreased. On the average, root diameter explained 60% of the variation in TNC concentration within an individual tree. Linear regressions of TNC concentration on root diameter did not differ significantly among trees. Bias on TNC concentration introduced by differences in root size can be minimized by sampling similar root diameter classes among trees, or by adjusting TNC concentration to a common root size. For. Sci. 37(1):343-346.
Factors Affecting Nitrogen Concentration of Fine Roots in Forest Communities: Regression Analysis of Literature Data
Authors: Yin Xiwei , Perry James A.
Published: April 2024

Literature data on nitrogen concentration of live fine roots (≤10 mm in diameter) in forest communities were analyzed by multiple linear regression. After appropriate transformations, root diameter, minimum monthly mean temperature, forest origin, and forest type together accounted for 93.2% of variation in N concentration. We suggest the following possible ecological bases: fine-root N concentration (1) was negatively related to root diameter because of increased percent old tissue and structural material with root size, (2) was negatively related to minimum monthly mean temperature because of a combined effect of soil available N, root absorption capacity, and carbon production, and/or because of selection pressure of cold winter on the genetic trait of higher N in fine roots, (3) was higher in plantations than in natural stands because of species and site selections and management history, and (4) was higher in broad-leaved than needle-leaved forests because of different N cycling rates. For. Sci. 37(1):374-382.
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

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

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

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

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

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

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

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

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

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

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

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

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

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

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.