bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic Gains in Growth and Simulated Yield of Pinus monticola
Authors: Rehfeldt G. E. , Wykoff W. R. , Hoff R. J. , Steinhoff R. J.
Published: April 2024

Between years 7 and 25, genetic variances for height and diameter have increased in 29 full-sib western white pine (Pinus monticola Dougl.) families planted on two sites. Family differences in height were statistically significant throughout most of the period, while differences in breast-high diameter were detected after year 13. Estimated heritabilities for height were relatively constant, averaging 0.11 and 0.33 for individuals and families, respectively; those for diameter have generally increased throughout the period and by year 25 had reached 0.14 for individuals and 0.43 for families. These heritabilities coupled with relatively large phenotypic variances suggest that programs of forward selection should provide genetic gains of about 7% in the height or 9% in the diameter of individual trees in year 25. Genetic correlations of height at various ages with stem volume in year 25 were high (>0.85), as were the correlations involving diameter and 25-yr volume after year 13. Correlated responses to selection suggested that year 7 would be the most efficient time to select, providing 85% of the maximum gain available in 25-yr volume. A stand simulation model was used to project the yields (volume per acre) expected from the progenies of selections made in year 7. Results of the simulations suggested that the amount of increase in yield depended on the density, rotation length, and manner by which genetic gains accrue beyond year 25. The results implied that relatively small gains in the attributes of 25-yr-old trees can result in either increased volumes per acre for a given rotation or decreases in the rotation to achieve a given volume. For. Sci. 37(1):326-342.
Soil Nitrogen Changes Associated with Slash Pile Burning in Pinyon-Juniper Woodlands
Authors: Covington W. Wallace , DeBano Leonard F. , Huntsberger Thomas G.
Published: April 2024

A combination of a time sequence and an experimental approach, both with repeated measurements, was used to determine the effects of slash pile burning in a pinyon-juniper woodland. Results showed that burning caused mediate increases (approximately 50-fold) in soil ammonium concentrations. Nitrate concentrations were not immediately affected; however, by one year after burning, nitrate concentrations were approximately 20 times higher where piles had been burned than in unburned controls. These increases in inorganic nitrogen disappeared by year 5 after burning. Such a combination of repeated measures with both a time sequence approach and an experimental approach offer a procedure for rapidly estimating long-term response functions in forest research. For. Sci. 37(1):347-355.
Radial Enlargement of Mortality Centers Caused By Arceuthobium pusillum Peck in Black Spruce Stands
Authors: Baker F. A. , French D. W.
Published: April 2024

Sequential aerial photography of dwarf mistletoe (Arceuthobium pusillum infested black spruce stands (Picea mariana [Mill.] BSP.) was used to measure the radial enlargement of circular mortality centers. Site index and stand density had no effect on the average 4.7 ± 3.3 ft/yr expansion rate. Methods for determining spread rates are discussed. For. Sci. 37(1):364-367.
Efficient Combinations of Timber and Financial Market Investments in Single-Period and Multiperiod Portfolios
Authors: Thomson Thomas A.
Published: April 2024

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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.
Stem and Foliage Elongation of Young Loblolly Pine as Affected by Ozone
Authors: Mudano J. E. , Allen H. L. , Kress L. W.
Published: April 2024

The rate, timing, and pattern of shoot and foliage elongation on the main stem of 3-year-old loblolly pine exposed to two levels of ozone were examined in the Piedmont of North Carolina. Shoot growth rates were generally greater in plots which received charcoal-filtered air (CF) than in plots which were exposed to ozone at three times ambient levels (3X). The pattern and duration of height growth were unaffected by ozone. Main stem elongation occurred continuously from late March to September and was 90% complete by mid-August in both treatments. Foliage elongated continuously from early April to early November. First and second flush foliage elongation rates were significantly greater in CF plots. Foliage elongation rates for subsequent flushes were similar for the two treatments. Except for the fifth flush, the number of fascicles produced was consistently greater in CF plots. As with shoot growth, the pattern and duration of foliage elongation on the main stem did not appear to be affected by ozone. For. Sci. 38(2):324-335.
Impacts of Pear Thrips Damage on Root Carbohydrate, Sap, and Crown Characteristics of Sugar Maples in a Pennsylvania Sugarbush
Authors: Kolb T. E. , McCormick L. H. , Simons E. E. , Jeffery D. J.
Published: April 2024

Fall root total nonstructural carbohydrate concentration (TNC), spring sap sugar concentration and volume, and summer crown condition were compared for 2 years among sugar maples (Acer saccharum Marsh.) that exhibited different degrees of crown damage following a 1989 attack of pear thrips (Taeniothrips inconsequens Uzel) in a Pennsylvania sugarbush. Trees with heavy damage had lower root TNC the fall following attack and greater crown transparency in both years following attack compared with trees with less damage. In the first year following attack, sap sugar concentration and volume were greater for trees with light damage than trees with moderate or heavy damage. In the second year following attack, sap volume was still greatest for trees with light damage while trees with heavy damage had the highest sugar concentration of all damage classes. Calculated syrup production based on sap sugar concentration and volume was greatest for trees with light damage and lowest for trees with heavy damage in both years. Trees with heavy damage in 1989 had earlier 1991 spring budburst than trees with light damage, and early budburst was associated with greater 1991 thrips infestation. The results indicate that pear thrips damage had a detrimental impact on tree health and syrup production for the next 2 years. For. Sci. 38(2):381-392.
Age-Age Correlations and Early Selection for Wood Density in Young Coastal Douglas-Fir
Authors: Vargas-Hernandez Jesus , Adams W. T.
Published: April 2024

Age-age correlations and age-associated changes in the genetic control of wood density and its components (earlywood density, latewood density, and latewood proportion) were investigated in 15-yr-old trees of 60 open-pollinated families of coastal Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco). The possibility of using wood density components as secondary traits to increase the efficiency of early selection for overall wood density was also explored. Heritability estimates for overall density and its components increased with age, mainly because of a decrease in the error variance as the number of rings in the core sample increased. Overall density and its components at age 15 had strong genetic correlations with their respective traits at all younger ages analyzed. Moreover, with few exceptions, age-age genetic correlations were greater than phenotypic correlations. Early selection to improve overall density at age 15 was quite efficient (relative efficiency above 79%), even when selection was based on core density at the youngest age (age 7). Using wood density components as secondary traits produced a slight increase in the efficiency of early selection only at the youngest ages, presumably because age-age correlations for overall core density were already strong, limiting the possibility of additional improvement. For. Sci. 38(2):467-478.
A Note on the Welfare Gains from Genetic Progress in Forestry: What Can the Market Tell Us?
Authors: Löfgren Karl-Gustaf
Published: April 2024

In this note we pinpoint what the market can tell us ex-post about a previously unanticipated genetic breakthrough in tree breeding. The approach is, however, perfectly general and can be used in ex-post evaluations of new drugs in the pharmaceutical industry. The fundamental idea, which is accredited to Weitzman (1976), is that a flow concept like net income in a dynamic economy contains precise information about a stock concept like wealth. For. Sci. 38(2):479-483.
The Law of One Price in the Trade of Forest Products: Co-Integration Tests for U.S. Exports of Pulp and Paper
Authors: Buongiorno Joseph , Uusivuori Jussi
Published: April 2024

According to the law of one price, the export price of a well-defined commodity should be the same, regardless of destination, and the import price should be independent of the country of origin. This law has been used as a maintained hypothesis in several models of the international trade of forest products. Here, the law was tested with data on United States exports of pulp and paper, which represented 54% of the value of all forest product exports in 1988. The test was done with co-integration methods and with data from January 1978 to December 1988, for six European countries and Japan. The law of one price could not be rejected in 52 of the 56 pairs of price series analyzed. Thus, markets for United States pulp and paper exports were generally competitive, so that prices tended to converge in the long run. Consequently, spatial equilibrium models that do not distinguish between exports to different countries could be used in this context. Furthermore, the 1992 European unification should not affect markedly the prices obtained by United States exporters in different countries. Finally, the incomplete pass-through of exchange rates to export prices found in previous studies is likely to be due to demand and supply shifts induced by exchange rate realignments, and not to monopolistic forces. For. Sci. 38(3):539-553.
Optimizing the Management of Uneven-Aged Forest Stands: A Stochastic Approach
Authors: Gove Jeffrey H. , Fairweather Stephen E.
Published: April 2024

Mathematical programs used for management and policy decisions in natural resources normally contain at least one underlying component which is stochastic. A technique is presented that allows marginal, conditional, and empirical confidence regions to be calculated for a widely known model of optimal uneven-aged stand structure. The technique uses the nonparametric bootstrap to approximate the joint sampling distribution for the decision variables of the nonlinear programming model. Subsequently, multivariate normal theory is used to obtain 95% confidence statements on the decision variables and functions thereof. Results show that the optimal steady-state investment-efficient diameter distribution for uneven-aged northern hardwood stands is an imprecise estimate given the data used for growth model calibration and the assumptions of the mathematical model. However, confidence statements found using this methodology are only approximate as they rely on an estimate of the sampling distribution for the optimal diameter distribution, not on classical statistical theory. These findings suggest a very real need for modelers, managers, and policy makers to begin considering the role of stochastic model components in mathematical programming models in natural resources. For. Sci. 38(3):623-640.
Early Selection in Pinus ponderosa: Compromises Between Growth Potential and Growth Rhythm in Developing Breeding Strategies
Authors: Rehfeldt G. E.
Published: April 2024

Shoot elongation of seedlings from 13 wind-pollinated families in each of 3 natural populations was described in years 2 and 5 by a function that allowed calculation of the start, rate, duration, and cessation of elongation. Additive genetic variances for these variables and for height in year 5 were pronounced, heritabilities were high, and expected responses to selection were large. The age-age genetic correlation for each trait was strong, as were the genetic correlations for 5-year height with all traits except the start of shoot elongation. Expected responses to selection suggested that (1) genetic gains in growth can be pronounced; (2) strong selection for increased growth is accompanied by a change in growth rhythm to that typical of unselected populations from much milder environments; (3) selecting for the rate of shoot elongation tends to control the correlated responses in growth rhythm while providing about 70% of gains expected from direct selection on height; and (4) selecting in the greenhouse in year 2 is nearly as effective as selecting the field in year 5. While breeders might choose among strategies that either control correlated responses or optimize gains in growth potential, developing a program that is capable of realizing the expected gains requires an understanding of the system of genetic variability. For. Sci 38(3):661-677.
The Strategic Management Paradigm and the Wood Building Products Industry: A Model of Strategies and Firm Profitability
Authors: Cohen David H. , Sinclair Steven A.
Published: April 2024

A model of strategies and firm profitability was developed and tested for the North American wood building products industry. Five strategic variables (adoption of process technology, grade sector focus, investment intensity, forward integration, relative market share) were used to predict firm profitability as measured by return on sales for the largest producers of wood building products in North America. Adoption of process technologies, grade sector focus (i.e., product quality), and investment intensity all had significant positive impacts on return on sales. From a managerial perspective, this research shows no advantage in larger market share beyond a minimal efficient scale. However, superior firm profitability was linked to the application of new process technologies, investment intensity, and the production of higher grade products. For. Sci. 38(4):786-805.
Marked Point Processes in Forest Statistics
Authors: Penttinen Antti , Stoyan Dietrich , Henttonen Helena M.
Published: April 2024

Trees in a forest interact and therefore have to be considered as a system of dependent random variates from an unknown stochastic process. One such mathematical model which considers the spatial dependence among trees in a forest and their characteristics is a marked point process. The "points" are the tree positions and the "marks" are tree characteristics such as stem diameters or tree species. Statistical methods for marked point processes can give valuable information on the spatial interaction of trees. They are applied in this paper to describe spatial dependence of stem diameters in a spruce forest, of heights of trees in a stand of pine saplings, and of heights, stem diameters, and crown lengths in a mixed birch-pine forest area. For. Sci. 38(4):806-824.
Spatial Variability of Canopy Foliage in an Oak Forest Estimated with Fisheye Sensors
Authors: Wang Y. S. , Miller D. R. , Welles J. M. , Heisler G. M.
Published: April 2024

The vertical distribution of forest canopy elements is an important factor in canopy-atmosphere exchange processes and knowledge of the shape of the average vertical profile of leaf area density is a critical input to models of these processes. This study was conducted to determine the spatial variability of Leaf Area Index (LAI) in an oak forest when estimated with indirect fisheye techniques. A 35 mm camera with a 180° hemispherical lens and a LI-COR LAI-2000 Plant Canopy Analyzer (wavelengths < 490 nm) were used simultaneously to estimate vertical leaf area profiles and the horizontal variability in an oak forest in central Pennsylvania. Measurements were made at eight different heights in the canopy and repeated at nine different locations. The two sensors were in reasonable agreement. The photographic technique estimated the total leaf area index (LAI) to be 3.58, and the light sensor estimates resulted in an estimate of 3.40. The average precision was 8% for the LAI-2000 and 17% for the photographic technique. The point-to-point spatial variability of the LAI estimates was low when the whole canopy was measured from the ground and quite high when measuring the upper canopy. Ground level estimates of LAI using these fisheye techniques spatially average the canopy to the point where only four replications were necessary to sample the total LAI with 90% confidence. For. Sci 38(4):854-865.
Spatial Reduction Factors for Strata-Based Harvest Schedules
Authors: Daust David K. , Nelson John D.
Published: April 2024

The impact of block size and exclusion period on sustained yield predictions is examined for 27 hypothetical forests; forests are delineated by species, site and rotation age. Long-range harvest schedules are developed for the forests using (1) aspatial, strata-based formulations solved with linear programming, and (2) spatial, block scheduling formulations solved with Monte Carlo Integer Programming. The sustained yields estimated by the spatial formulations are in all cases lower (range: 2% to 29%) than those estimated by the aspatial formulations. The magnitude of the reduction in sustained yield increases as the exclusion period increases and the block size decreases. The magnitude of the reduction does not vary with species or site but is influenced by rotation age. Forests which are managed under longer rotation ages are less affected by exclusion period and block size constraints. Exclusion period reduction factors are developed which allow strata-based sustained yield estimates to be reduced to account for exclusion period constraints. FOR. SCI. 39(1):152-165.
Evaluation of the Size-Density Relationships for Pure Red Alder and Douglas-Fir Stands
Authors: Puettmann Klaus J. , Hann David W. , Hibbs David E.
Published: April 2024

Size-density trajectories were developed for pure red alder (Alnus rubra Bong) and Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) stands with quadratic mean diameter of the stand as the tree-size variable. The resulting self-thinning or maximum size-density line for red alder had a steeper slope (-0.64) than that for Douglas-fir (-0.52). The assumption of a common slope for all species is therefore not supported by our study. For red alder, the shape of the size-density trajectory and the elevation of the maximum line were not influenced by initial density or stand origin. Red alder and Douglas-fir mortality started at a relative density of 44% and 58%, respectively. FOR. SCI. 39(1):7-27.
Starch Content in Douglas-Fir: Diurnal and Seasonal Dynamics
Authors: Webb Warren L. , Kilpatrick Kran J.
Published: April 2024

Diurnal and seasonal starch dynamics in the crowns of young-growth Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco), and seasonal starch dynamics in various tissues of field-grown Douglas-fir seedlings, were determined in coastal mountains and valley sites in Oregon. The accumulation of photoassimilated carbon in the starch pools of seedlings also was investigated with steady-state 14C labeling. The pattern of starch buildup in twigs and attached needles of the young-growth Douglas-fir in spring and subsequent decline to nondetectable levels in fall was found to be correlated with budburst--later budburst at higher elevation signaled later increases in starch content. Starch content in the needles, stems, and roots of the Douglas-fir seedlings also was highest just after budburst and lowest in fall and winter. The daily starch pattern, which fluctuated considerably over 24 hr, was similar at all crown locations, and for needles and twigs. These data, and those from the 14C labeling, indicate that starch buildup in spring is from current photosynthesis. However, total starch content is too small to directly affect growth rates during the growing season--indeed, starch may be a buffer between rapidly fluctuating photosynthesis rates and ensuing translocation or growth processes. FOR. SCI. 39(2):359-367.
Estimation with Different Stratification at Two Occasions
Authors: Schreuder H. T. , Li J. , Scott C. T.
Published: April 2024

Since forest surveys may use different strata over time, permanent plots may be remeasured and new plots may be selected with different probabilities. The inclusion probabilities and joint probabilities of selecting both remeasured and new plots, considering both occasions, are derived. The Horvitz-Thompson estimator using two approximations to actual probabilities of selection and a stratified sampling estimator ignoring initial probabilities of selection are compared for bias and efficiency. The Yates-Grundy, probability proportional to size with replacement, jackknife, and stratified sampling variance estimators are evaluated in terms of bias in estimating the true variance of the estimators. Three populations are constructed with different rates of movement between strata from time 1 to time 2 to evaluate the estimators. The stratified sampling estimator performed poorly. The jackknife variance estimator is recommended. FOR. SCI. 39(2):368-382.
Regulating Competition on Conifer Plantations with Prescribed Cattle Grazing
Authors: Karl Michael G. , Doescher Paul S.
Published: April 2024

On conifer plantations, competitive understory vegetation often retards growth and establishment of tree seedlings. Livestock grazing exemplifies a method of controlling the understory vegetation and increasing the availability of site resources to tree seedlings. We hypothesized that prescribed cattle grazing ameliorates water stress of young tree seedlings by reducing root growth of competing understory species. On a Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) and ponderosa pine (Pinus ponderosa Dougl.) plantation in southwest Oregon planted in 1986, seedling water stress was evaluated with the pressure chamber technique and supplemented with gravimetric soil water determinations in 1986-1989. Root growth of orchardgrass (Dactylis glomerata L.), the major understory competing species, was quantified in 1988 and 1989 with the root periscope/mini-rhizotron technique. Seedling water stress levels during spring and summer were similar in a cattle-grazed vs. ungrazed area in 1986 through 1988, but in summer 1989, water stress was reduced significantly in the grazed area. Soil water content was higher in the grazed area in 1989, especially at the 10-20 cm soil depth. End of season (July) orchardgrass root growth was reduced 18% and 15% with grazing in 1988 and 1989, respectively. We conclude that repeated cattle grazing of orchardgrass reduced transpirational surface area and root growth sufficiently to increase soil water availability to seedlings. Thus, prescribed cattle grazing on conifer plantations can enhance seedling physiological status by acting as a regulator of above- and belowground competition. For. Sci. 39(3):405-418.
Patterns of Occurrence and New Sampling Implications for Instar IV Western Spruce Budworm (Lepidoptera: Tortricidae)
Authors: Torgersen Torolf R. , Colbert J. J. , Hosman Kevin P.
Published: April 2024

This study examines relations of western spruce budworm (Choristoneura occidentalis Free.) larval distribution on terminal tips, whole branches, among crown strata (vertical crown thirds), and within and among whole trees. Study sites were in Washington, Oregon, Idaho, Montana, and New Mexico and represented 63 plot-yr of data. A range of densities from <1.0 to >600 larvae per m² of foliage on midcrown terminal tips were observed. We validated and expanded on earlier published descriptions of intratree and intertree distribution of larvae as they influenced sampling schemes. Larval density on nominal 45 cm terminal tips in the lower crown-third were slightly better predictors of whole-tree density than were midcrown tips. Therefore, we propose the use of a two-tip sample from the middle of the lower crown-third of each sample tree. Equations are given to determine the number of trees to sample for desired precisions and confidence levels. We provide equations describing relations between larval densities on branch tips and whole branches in vertical crown-thirds, and their relation to whole-tree density. For. Sci. 39(3):573-593.