bluuebunny/crossref_metadata_2025_split huggingface dataset:
Efficient Combinations of Timber and Financial Market Investments in Single-Period and Multiperiod Portfolios
Authors: Thomson Thomas A. 
Published: April 2024

Abstract
This paper presents single-period and multiperiod portfolio expected returns and standard deviations for portfolios constructed from eight sawtimber investments and four financial market investments. Four of the timber investments are from growing timber crops in the South (southern pine, ash, gum, oaks) and four are from growing timber crops in the Midwest (white pine, red pine, aspen, and red oak). The financial market investments are common stocks, corporate bonds, U.S. Government bonds, and U.S. Government Treasury bills. Portfolios are computed two ways: (1) maximizing a quadratic utility function, which is inherently a single-period approach, and (2) maximizing a power utility function, which has been shown to be a suitable multiperiod optimization. The two models provide similar results showing that portfolio diversification across timber species and financial market investments is often appropriate. Risk-tolerant investors may choose only timber investments, while more risk-averse investors will hold both timber and financial market investments. The highest risk-highest return portfolio consists of red pine, while the lowest risk-lowest return portfolio is primarily made up of Treasury bills. This paper shows that as the investment horizon lengthens, the expected compound long-run portfolio return decreases, the standard deviation falls, and the most risky, efficient single-period portfolios are dominated by some less risky multiperiod portfolios. For. Sci. 37(2):461-480.
Analysis of Early Mortality of Douglas-Fir Seedlings in Postharvest Plantings in Northwestern California
Authors: Waters William E. , DeMars Clarence J. , Cobb Fields W. 
Published: April 2024

Abstract
A life table study was conducted of injury and mortality of Douglas-fir seedlings in 44 plantations on public and private lands in Humboldt and Del Norte Counties, CA. Field examinations were made three times each year for the first 3 years following planting. Apparent and real mortalities were compiled in life table format for nine time intervals.
Seedling mortality per time interval in the different ownerships varied from 0 to 35.0% in real percentage terms, and totalled 14.0 to 70.7%. Highest mean mortality occurred in intervals 2 and 3 (late spring to fall, first year). Trend analyses, using a curvilinear regression model, showed significant differences in rates of mortality among ownerships. The performance of containerized and bareroot seedlings was very similar.
Primary conclusions from the life table analyses, using a two-step modeling process, were (1) variations and covariations in mortality associated with intervals 2 and 3 were most important in determining total variation in survival in the 3-year period; intervals 1, 4, 7, and 9 also were critical in some instances; (2) planting- and weather-related factors were most important in intervals 1-4; disease, insects, and animals, alone and jointly, were more important in the second and third years; (3) substantial covariations in mortality among the time intervals indicated carryover effects; covariations among certain categories of causal factors indicated strong positive or negative interactions that either added to or dampened the direct effects of these factors. For. Sci. 37(3):802-826.
The Relation Between Reproductive Phenology and Reproductive Output in Determining the Gametic Pool Profile in a Douglas-Fir Seed Orchard
Authors: El-Kassaby Y. A. , Askew G. R. 
Published: April 2024

Abstract
A 15-year-old, Douglas-fir, full-sib seed orchard with 97 families was studied to establish the relation between reproductive phenology and reproductive output. Both male and female strobili development was monitored throughout the flowering season, and seed-cone counts and male strobili productions were determined. The overall potential gametic contributions of each family were estimated in terms of proportional contributions to the seed crop and parental balance.
Families varied greatly in both seed-cone and pollen contributions. The top 5 contributors of cones were different from the top 5 pollen contributors. Assessing seed-cone and pollen contributions prior to cone induction or supplemental mass pollination will be valuable for increasing the genetic value of orchard seed. Estimates of the genetic value of the orchard crop should be calculated after completion of a parental balance study focused on both seed and pollen contributions and their reproductive phenology timing. For. Sci. 37(3):827-835.
Further Assessment of the Price Competitiveness of Malaysian Lauan Lumber Imports in the United States
Authors: Haji-Othman Mohd Shahwahid 
Published: April 2024

Abstract
The market share approach is used to assess the degree of price competitiveness of Malaysian rough and dressed Lauan lumber in the United States' import market. The partial adjustment and adaptive expectation (PAAE) model used reduces to a static model for rough Lauan lumber and an adaptive expectation (AE) model for dressed Lauan lumber. The results obtained suggest that these types of Malaysian lumber are price competitive. For. Sci. 37(3):849-859.
Seed Chemistry of the Tropical Tree Vochysia hondurensis Sprague
Authors: Blanche C. A. , Hodges J. D. , Gomez A. E. , Gonzalez E. 
Published: April 2024

Abstract
This investigation was conducted as part of a continuing effort to develop a database on the chemistry of tree seeds. Seeds of Vochysia hondurensis Sprague were collected from three mature trees vigorously growing in a wet site, 400 m above sea level in San Ramon de la Virgen, Sarapiqui, Costa Rica. These were analyzed for starch, reducing and nonreducing sugars, total N (protein), amino N, total lipid, and fatty acids. The seeds contained high concentrations of lipids (28.6%) and protein (34%), but extremely low concentrations of carbohydrates (4.21%). Although 11 fatty acids were detected, three (oleic, arachidic, and cis-11-eicosenoic) comprised 80% of the total fatty acid weight. Based on these chemical contents, V. hondurensis seeds appear to exhibit orthodox behavior. For. Sci. 37(3):949-952.
Leaf Area and Foliar Biomass Relationships in Northern Hardwood Forests Located Along an 800 km Acid Deposition Gradient
Authors: Burton Andrew J. , Pregitzer Kurt S. , Reed David D. 
Published: April 2024

Abstract
The canopies of northern hardwood forests dominated by sugar maple (Acer saccharum Marsh.) were examined at five locations spanning 800 km along an add deposition and climatic gradient in the Great Lakes region. Leaf area index (LAI) calculated from litterfall ranged from 6.0 to 8.0 in 1988, from 4.9 to 7.9 in 1989, and from 5.3 to 7.8 in 1990. The data suggest that maximum LAI for the sites is between 7 and 8. Insect defoliation and the allocation of assimilates to reproductive parts in large seed years reduced LAI by up to 34%. Allometric equations for leaf area and foliar biomass were not significantly different among sites. They predicted higher LAI values than were estimated from litterfall and could not account for the influences of defoliation and seed production. Canopy transmittance was a viable alternative for estimating LAI. Extinction coeffidents (K) of 0.49 to 0.65 were appropriate for solar elevations of 63° to 41°. Patterns of specific leaf area (SLA) were similar for the sites. Average sugar maple SLA increased from 147 cm² g-1 in the upper 5 m of the canopy to 389 cm² g-1 in the seedling layer. Litterfall SLA averaged 196 cm² g-1 for all spedes and 192 cm² g-1 for sugar maple. Similarity among the sites in allometric relationships, maximum LAI, canopy transmittance, and patterns of SLA suggests these characteristics were controlled primarily by the similar nutrient and moisture availability at the sites. A general increasing trend in litter production along the gradient could not be attributed to N deposition or length of growing season due to year to year variability resulting from insect defoliation and seed production. For. Sci. 37(4):1041-1059.
Allozyme Variation of Port-Orford-Cedar (Chamaecyparis lawsoniana): Implications for Genetic Conservation
Authors: Millar Constance I. , Marshall Kimberly A. 
Published: April 2024

Abstract
Variation at 32 allozyme loci in nine disjunct populations of Port-Orford-cedar (POC) from the California floristic region was measured to estimate the amount and pattern of genetic variability in natural stands. Variation in electrophoretically detectable loci was moderately high, with mean number of alleles per locus = 1.9, 64.9% polymorphic loci, and observed heterozygosity = 0.13. Diversity was highest in the seven populations from the coastal mountains and lowest in the two populations from the inland portion of POC's distribution. The Sacramento River population in the inland group had only 44% polymorphic loci, and observed heterozygosity equaled 0.05. Populations in the inland region were allozymically distinct from those in the coastal region as well as from each other. Mean genetic distances among the coastal populations were 0.005 compared to 0.016 between the inland and coastal groups and 0.013 between inland populations. Population variation accounted for 5% of the total allozyme diversity. Genetic conservation efforts for POC in California are evaluated. In situ areas are already being established in some genetically important localities, although many gaps remain; ex situ coverage is inadequate. For. Sci. 37(4):1060-1077.
Association of an Insect-Fungal Complex with Red Pine Decline in Wisconsin
Authors: Klepzig K. D. , Raffa K. F. , Smalley E. B. 
Published: April 2024

Abstract
Red pine decline, characterized by an expanding circular area of dead and declining trees, is becoming increasingly prevalent in Lake States plantations. A 3-year study was conducted to determine whether any insects, fungi, and/or soil parameters were associated with this syndrome. The root collar weevil—Hylobius radicis, the pales weevil—Hylobius pales, the pitch—eating weevil Pachylobius picivorus, the red turpentine beetle—Dendroctonus valens and Hylastes porculus were significantly more abundant in declining stands than in healthy Pinus resinosa stands. These root— and lower stem—infesting insects consistently carried Leptographium terebrantis and Leptographium procerum. Higher soil organic matter, pH and K levels were also associated with areas of mortality. Intensive root sampling revealed high levels of root mortality, staining, infestation with Leptographium species and extensively grafted root systems in declining red pine stands. This advancing belowgound mortality precedes the aboveground symptoms of reduced radial growth, thin crown structure, and infestation by the pine engraver, Ips pini, and its fungal associate Ophiostoma ips. Colonization by the latter two species is always associated with and/or responsible for ultimate tree death. A sequence of interactions among this complex of organisms and abiotic factors is proposed as the cause of red pine decline. For. Sci. 37(4):1119-1139.
Diagnosis and Recommendation Integrated System (DRIS) Nutrient Norms for Fraser Fir Christmas Trees
Authors: Rathfon R. A. , Burger J. A. 
Published: April 2024

Abstract
Fraser fir (Abies fraseri [Pursh] Poir.) is an important Christmas tree species in Virginia and North Carolina. Because it is responsive to fertilization, and because most Fraser fir growers fertilize their crop, a scientifically based nutrient diagnosis and fertilizer recommendation system is needed. The objective of this study was to develop and test Diagnosis and Recommendation Integrated System (DRIS) norms for Fraser fir Christmas trees for the ultimate purpose of establishing a nutrition diagnosis and fertilizer prescription system. A total of 107 Fraser fir plantations were sampled for foliage, soil, and diameter measurements. These plantations represented the range in site conditions and management practices for Fraser fir Christmas trees grown in Virginia. Foliage and soil were analyzed for macro- and micronutrients. DRIS norms were developed from these data using standard DRIS procedures. A total of 42 nutrient ratios were significant discriminators of tree performance as measured by variation in groundline diameter. The norms were tested using sixth-year data from a factorial fertilizer trial. Nutrient limitations due to both deficiencies and imbalance were detected and correctly diagnosed using the newly derived norms. A more thorough validation will be made with time, but this preliminary test showed that these norms are a reasonable first approximation. For. Sci. 37(4):998-1010.
Harvesting Loblolly Pine Plantations with Hardwood Competition and Stochastic Prices
Authors: Haight Robert G. , Smith William D. 
Published: April 2024

Abstract
This paper presents numerical results of the effects of stochastic stumpage prices on economic optimal thinnings and rotation ages for loblolly pine (Pinus taeda L.) plantations in the Piedmont region of North Carolina. The numerical results are obtained with a dynamic programming model that provides optimal harvest levels as a function of price, stand density, and age. For numerical tractability the network is relatively coarse with a 5-year decision cycle and 50 trees/ac intervals for the harvest control variable. Sawtimber and pulpwood stumpage price probabilities are assumed to be independent and stationary and are based on the means and variances of past price observations. Optimal full-rotation management strategies for both pure and mixed-species plantations show that sawtimber and pulpwood price variation do not affect the timing and intensity of early commercial thinning. Stumpage price variation does affect the timing of dearcutting. Gains in present value are made by timing the clearcut to a period with high sawtimber stumpage price. Results on the effects of hardwood competition show that the opportunity cost of hardwood competition that persists through one rotation is higher than the cost of eliminating the hardwoods early on. The effects of restrictions in the size of the dynamic programming network and the stationarity assumptions in the stochastic price processes are discussed. For. Sci. 37(5):1266-1282.
Formulating Adjacency Constraints in Linear Optimization Models for Scheduling Projects in Tactical Planning
Authors: Jones J. Greg , Meneghin Bruce J. , Kirby Malcolm W. 
Published: April 2024

Abstract
Models for scheduling projects in tactical planning often must contain relationships that restrict activities on adjacent lands. Conventional formulations of these relationships require large numbers of constraints. Minimizing the number of constraints permits modeling larger areas when faced with software and hardware limitations on number of constraints. This paper presents an approach for efficiently formulating adjacency relationships in mixed-integer programming models. The approach typically results in one-half to one-quarter of the number of equations required by formulations used in the past. For. Sci. 37(5):1283-1297.
Modeling Red Pine Tree Survival with an Artificial Neural Network
Authors: Guan Biing T. , Gertner George 
Published: April 2024

Abstract
A model based on an Artificial Neural Network (ANN) was developed for modeling and predicting red pine survival. The new model uses diameter at breast height and estimated annual diameter growth as its predictors. For training neural networks, a proportional coding scheme based on Gaussian distributions was used to transform the data into patterns of activities. Four model performance criteria--sum of square errors (SSE), χ² statistic, final predicted error (FPE), and predicted squared error (PSE)—were used to determine the adequacy of the new model. Based on the four criteria, the ANN-based new red pine survival model not only fits the data better than a statistical model; it is also expected to perform better on future data, provided that the training data are representative. The response surface of the ANN model shows it has the required flexibility to model red pine survival, especially in modeling both small and large but slow growing trees. This study also shows that a proportionally coded training data set may indeed be an effective form of input data representation for developing red pine survival models based on artificial neural networks. For. Sci. 37(5):1429-1440.
Effect of Canadian Forest Tenures on Rent Distributions and Resource Allocations: A British Columbia Case Study
Authors: Luckert Martin K. 
Published: April 2024

Abstract
Forestry firms in Canada are regulated by restrictions which define various types of forest tenures. In regulating the behavior of forestry firms, tenures affect rent distributions and resource allocations. A survey method is developed to assess the relative costs of restrictions to tenure holders and to identify regulations which are of potential importance in affecting distributions and allocations. The method is applied in a case study in British Columbia. Results identify those tenure requirements which are most costly to tenure holders and show all regulations surveyed to be of potential importance in influencing rent distributions and resource allocations. For. Sci. 37(5):1441-1462.
Establishing Cause-Effect Relationships Using Forest Survey Data
Authors: Schreuder H. T. , Thomas C. E. 
Published: April 2024

Abstract
The issue of whether Forest Survey data can be used to establish cause-effect relationships is addressed. We discuss analogous situations in other fields of science, where survey data has been useful in establishing cause-effect, as well as some of the statistical theory developed expressly to deal with cause-effect. We conclude that cause-effect may be established, if both the potential cause and effect variables are measured in the Survey provided the variables are measured accurately, estimated properly, and are based on a large enough sample. Otherwise, Forest Survey data can be used, however, to establish growth trends for large areas, suggest and identify potential cause-effect hypotheses, and identify supplemental data sets to be collected to bolster or reject potential hypotheses.
Tilted Tree Hypsometry
Authors: Grosenberg L. R. 
Published: April 2024

Abstract
State-of-the-art technique for measuring height of leaning, forked, crooked, or curved trees is briefly reviewed. The most efficient method employs an expensive tiltable range- finding dendrometer which can measure various types of leaning or nonlinear trees. However, a much less expensive tiltable nonranging hypsometer can be employed on straight leaning trees. This recently developed technique uses spherical triangulation observation points to eliminate bias attributable to lean in the slant plane toward or away from the observer. Necessary formulae and many numeric examples are given to aid in understanding the computational process. For. Sci. 37(6):1581-1590. 12
Singular Path Solutions and Optimal Rates for Thinning Even-Aged Forest Stands
Authors: Betters David R. , Steinkamp Eric A. , Turner Matthew T. 
Published: April 2024

Abstract
Optimal control singular path solutions for determining economically efficient thinning schedules have been found to have both concave and convex shapes. This study examines the characteristics of such paths and shows that the shape of the singular path does not necessarily determine whether the rate of thinning should increase or decrease with time. Empirical tests show the optimal thinning solution to be dependent on the parameters used in the growth equation, specifically the aging function used in ensuring the aging and dying processes are accurately represented in the model. Most applications have derived parameters resulting in decreasing rates of thinning and primarily convex singular paths. For. Sci. 37(6):1632-1640.
A Generalized Approach to Stand Table Projection
Authors: Nepal Sunil K. , Somers Greg L. 
Published: April 2024

Abstract
A new algorithm for stand table projection based on existing estimates of future basal area and survival is derived and demonstrated. An observed stand table is first projected by applying either an existing diameter growth equation or a growth equation derived from appropriate diameter distributional assumptions. The stand table is adjusted by an algorithm that equates the future stand table to existing estimate of basal area and survival. The algorithm does not use any species-specific parameters and can therefore be applied to any species for which future estimates of basal area and survival are available. This algorithm provides comparable estimates when the initial diameter distribution is close to the unimodal distribution assumed by parameter recovery procedures in diameter distribution growth and yield models. In fact, the algorithm reduces to the same future stand table when the initial stand table is actually generated by the diameter distribution derived by the parameter recovery procedure. However, if the observed stand table is multimodal, the prediction by this algorithm is better than predictions from the parameter recovery method alone. Favorable comparisons are also made with the stand table projection method introduced by Pienaar and Harrison (1988), for natural even-aged longleaf pine stands. For. Sci. 38(1):120-133.
An Evaluation of Sampling Methods and Model Forms for Estimating Height-Diameter Relationships in Loblolly Pine Plantations
Authors: Arabatzis Alexandros A. , Burkhart Harold E. 
Published: April 2024

Abstract
The prediction performance of eight height-diameter regression models was compared for estimating mean stand height when fitted to data selected from 175 loblolly pine (Pinus taeda) sample plots by (i) simple random sampling without replacement, and (ii) stratified random sampling with dbh classes acting as strata. Among the models tested, the nonlinear model of the form H = aeb/D performed best especially when fitted to data selected by simple random sampling. A small gain in precision obtained by stratification into dbh classes was outweighed by a substantial increase in bias due to the arbitrary allocation of numbers of sample trees to the strata. To update existing height-diameter models, it is recommended that new trees be selected and measured on every occasion instead of retaining the same sample trees used previously for model fitting. For. Sci. 38(1):192-198.
Genetic Parameters and Gains Expected from Selection for Dry Weight in Eucalyptus globulus ssp. globulus in Portugal
Authors: Borralho N. M. G. , Cotterill P. P. , Kanowski P. J. 
Published: April 2024

Abstract
Genetic and phenotypic parameters of growth and wood density were calculated for two open-pollinated progeny trials of Tasmanian Blue Gum (Eucalyptus globulus ssp. globulus) in Portugal. These parameters are used to develop selection indices and predict genetic responses for different strategies. Mean individual heritabilities (averaged across the two trials) of height and wood density were high (h2 = 0.34 ± 0.10 and 0.65 ± 0.12, respectively) and those of sectional area and dry weight were intermediate (h2 = 0.18 ± 0.06 and 0.21 ± 0.11). Mean genetic correlations (across trials) were strongly positive (0.94 ± 0.05 to 0.99 ± 0.03) between dry weight and height or sectional area, and moderate (0.17 ± 0.20) between dry weight and wood density. Sectional area and height were slightly negatively correlated (-0.08 ± 0.25 to -0.09 ± 0.17) with density.
Selection indices constructed to maximize genetic gain in dry weight gave results which clearly favored indirect selection on height. A genetic gain of around 47% in dry weight may be expected from second-generation selection of 1 tree in 200 for E. globulus in Portugal. Marginal deterioration can occur in wood density unless family means for either dry weight or density are included in the index with height. A strong response in wood density from index selection requires a substantial sacrifice of gains in dry weight. For. Sci. 38(1):80-94.