bluuebunny/crossref_metadata_2025 huggingface dataset:
A Neural Network to Predict Particleboard Manufacturing Process Parameters
Authors: Cook Deborah F. , Massey Joseph G. , Shannon Robert E.
Published: April 2024

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

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

Equations for modeling the height-age pattern of forest trees or stands are typically developed on a regional basis. Due to variation in growth patterns within regions, these equations may be polymorphic and quite complex. As an alternative to increasing the complexity of an equation, this study presents procedures for the evaluation of height-age relationships through the use of simple, regional equations combined with local stand data.

The base model in this study was Schumacher's (1939) logarithm of height-reciprocal of age model. An average regional guide curve was developed using data from a wide range of loblolly pine plantations. A Kalman filter procedure was used to localize this regional equation to a specific stand. This procedure employs the general concept of feedback (local stand data combined with a simple regional model) in localizing the simple equation. By using information on a particular stand's height growth development, the original equation is modified to better model that stand. The modification is made by feeding local information into an estimation procedure that combines it with the regional information (equation) and modified parameter estimates are calculated.

Three loblolly pine data sets were used to compare the localization strategy with the simple, regional model, as well as a more complex polymorphic equation. The results indicate that the Kalman filter method can result in improved prediction for specific stands. For. Sci. 37(6):1526-1537.
Comparison of Expressions for Crown Size of Woody Competitors in Herbicide Efficacy Studies
Authors: Knowe Steven A.
Published: April 2024

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

We compared estimates of leaf area index (LAI) based on tree allometrics and light interception in 15 lodgepole pine (Pinus contorta var. latifolia) stands in southeastern Wyoming. LAI from stem allometrics was estimated with a local equation demonstrated to produce accurate and unbiased leaf area estimates for the stand conditions in this study. LAI from measured light interception, estimated with a species-average light extinction coefficient using the Beer-Lambert Law, was not correlated with LAI determined from tree allometrics. Light extinction coefficients varied from 0.29 to 0.67 when determined from allometric estimates of LAI and measured light interception. The derived light extinction coefficients were inversely correlated with LAI (r² = 0.79). High LAI may be associated with canopy architectures where foliage distribution results in reduced light capture effectiveness. Variation in light capture by lodgepole pine canopies may preclude the use of a species average light extinction coefficient for estimating LAI. For. Sci. 37(6):1682-1688.
Evaluating Scots Pine for Resistance to Endocronartium harknessii
Authors: Burnes T. A. , Blanchette R. A.
Published: April 2024

Seedlings of eight different varieties of scots pine (Pinus sylvestris L.) were evaluated for resistance to pine-pine gall rust Endocronartium harknessii [J.P. Moore] Y. Hiratsuka using a concentrated aeciospore suspension (CAS). The presence or absence of galls on seedlings was recorded 24 wk after inoculation. Seedlings of variety Mongolica were the most resistant with 16% of the seedlings with galls, and Guadalajara and Alpine were the least resistant among the eight with 58% and 56% of the seedlings with galls, respectively. The remaining varieties were intermediately resistant. For. Sci. 37(6):1689-1691.
Ozone Impacts on Seasonal Foliage Dynamics of Young Loblolly Pine
Authors: Stow Tara K. , Allen H. Lee , Kress Lance W.
Published: April 2024

Effects of above- and below-ambient levels of ozone (O3) on the production, abscission, and duration of foliage of young loblolly pine (Pinus taeda L.) grown in open-top chambers were examined in the Piedmont of North Carolina. Assessments of fascicle elongation and number were made at frequent intervals during 1988, 1989, and 1990 for all 1988 primary flushes on the stem and at a branch position. Ozone treatment had little effect on overall foliage production; however, all elevated O3 levels reduced foliage retention. Foliage abscission for most flushes was initiated when cumulative O3 dose exceeded 130 to 220 ppm-hr regardless of crown position for trees exposed to ambient and above-ambient O3 levels. Reductions in leaf area duration of the 1988 cohort were observed at ambient and higher O3 levels. Total leaf area duration was 22 and 25% greater for the stem and branch positions in the charcoal-filtered as compared to nonfiltered treatments. The greater duration in charcoal-filtered chambers resulted from significantly greater retention into the third growing season. Foliage development and ozone responses at the branch position were more representative of the whole crown than those at the stem position. For. Sci. 38(1):102-119.
Comparing Vertical and Horizontal Modes of Importance and Control-Variate Sampling for Bole Volume
Authors: Valentine Harry T. , Bealle Catherine , Gregoire Timothy G.
Published: April 2024

Vertical and horizontal modes of both importance and control-variate sampling for estimating merchantable and total volumes of boles are described and compared. In the horizontal mode, heights are selected at random, and cross-sectional areas are measured. In the vertical mode, cross-sectional areas are selected at random and heights are measured. Estimates obtained by horizontal and vertical control-variate sampling (also known as the critical height method) were equally precise in tests using a proxy taper equation that was linear in cross-sectional area versus height. Both methods gave more precise estimates than did horizontal importance sampling, though the advantage was small for merchantable volume. The performance of vertical importance sampling varied with bole shape. It was the most precise method for some shapes, the least for others. For Sci. 38(1):160-172.
Rate and Depth of Sapwood Occlusion Following Inoculation of Pines with Bluestain Fungi
Authors: Parmeter J. R. , Slaughter G. W. , Chen M. , Wood D. L.
Published: April 2024

Length of sapwood lesions, depth of sapwood occlusion, and proportion of sapwood occluded increased generally but irregularly through the first 9 weeks following inoculation of small (17-32 cm dbh) Pinus ponderosa with Ophiostoma minus or Leptographium terebrantis. No significant increases were detected between 9 and 64 weeks. The average proportion of sapwood depth occluded at 4 weeks ranged from 0.1-0.15 for O. minus and 0.2-0.4 for L. terebrantis. This rate of occlusion was judged inadequate per se to account for development of crown symptoms in trees following mass attack by bark beetles. For. Sci. 38(1):34-44.
Improved Classification of Forest Vegetation in Northern Wisconsin Through a Rule-Based Combination of Soils, Terrain, and Landsat Thematic Mapper Data
Authors: Bolstad Paul V. , Lillesand T. M.
Published: April 2024

Landcover classifications which use evidential and hierarchical decision rules to combine satellite image, soils, and terrain data were compared to standard Landsat Thematic Mapper (TM) based maximum likelihood classifications (MLC) under northern Wisconsin forest conditions. Maximum likelihood classifications employed a visible, near-infrared, and mid-infrared band of TM image data, while a rule-based (combined) approach was used to integrate these data with soil texture information, terrain position, and soil-plant relationships for landcover classification. Comparisons were made for classifications by two analysts for each of two 300 km2 study areas. Accuracies from the combined data method were higher than the MLC method for all classifications. Accuracies averaged 89% for the combined method and 73% for the standard method when areas were classified into 13 landcover classes corresponding to Anderson levels II and III. Pairwise differences of Cohen's Kappa values for the two classification approaches were significantly different (P < 0.10) for all combinations of study area and analyst. For. Sci. 38(1):5-20.
Thinning and Nitrogen Fertilization in a Grand Fir Stand Infested with Western Spruce Budworm. Part II: Tree Growth Response
Authors: Wickman Boyd E. , Mason Richard R. , Paul H. Gene
Published: April 2024

The effects of thinning and nitrogen fertilization on tree growth in a grand fir (Abies grandis [Dougl.] Forbes) stand infested with western spruce budworm (Choristoneura occidentalis Freeman) were evaluated over 5 years by a replicated split-plot experiment. Fertilization treatments resulted in significantly reduced defoliation and significantly heavier biomass of shoots and foliage for the last 3 years of the study. There were, however, 30% fewer buds on fertilized grand fir midcrown branches at the end of the study. Height growth of fertilized trees was significantly greater than unfertilized trees 3 to 5 years after treatment and was almost double that of controls. Radial growth measured at breast height and base of live crown was significantly greater for fertilized trees 3 to 5 years after treatment; 5 years after treatment, radial growth of thinned trees also was significantly greater than the controls. Trees thinned and fertilized had almost double the growth of controls 2 to 5 years after treatment. Fertilized trees apparently produced fewer buds m-2 of foliage but more foliage per shoot than budworm larvae could destroy, and this resulted in significantly increased tree growth. The results of the study have implications for using fertilization as a management option for some budworm outbreaks. For. Sci 38(2):252-264.
Effects of Fall Fertilizer Applications on Mitotic Index and Bud Dormancy of Loblolly Pine Seedlings
Authors: Williams Hans M. , South David B.
Published: April 2024

A series of studies examined the effects of fall fertilization with diammonium phosphate (DAP) on mitotic index and bud dormancy [as measured by mean days to budbreak (DBB)] of two half-sib seed sources of loblolly pine. The first study tested different rates of DAP (0, 67, and 202 kg N/ha), the second study compared DAP with ammonium nitrate, and the third study examined the effect of different application dates (September 28, October 19, and November 9). An increase in mitotic index of unfertilized seedlings was observed during October and was due to developmental activity which follows initial budset. Differences in mitotic index were observed between families in all three studies. Overall, the Georgia family has a higher mitotic index, but in one study, the Virginia family had higher values in the spring. Both families tended to reach a minimum level of mitotic index at the same time (mid- to late December). However, the Virginia family reached maximum rest (as measured by days to budbreak) about 1 to 2 weeks prior to the Georgia family. Fertilization with DAP in the fall (after budset in September) did not delay the progression of the bud dormancy cycle as measured by days to budbreak in a greenhouse. The overall effect of fall fertilization on increasing the mitotic index was temporary and only lasted for about three weeks after fertilization. These findings indicated that a direct relationship may not exist between the bud dormancy cycle and mitotic index. For. Sci. 38(2):336-349.
Root Growth Potential and Starch Differences in Seedlings of Six Families of Genetically Improved Loblolly Pine
Authors: Rose Robin
Published: April 2024

The relationships among root growth potential, total fresh weight, and starch levels of six genetically improved families of loblolly pine (Pinus taeda L.) were examined during a test of root growth potential, with special focus on clarifying changes in starch concentrations as determined by destructive analysis. Seedlings were operationally grown and root-wrenched in a nursery, lifted in January and subjected to 14 days of cold storage at 3°C (38°F), then placed in a tank system in a greenhouse under extended 16-hr days and 30°-16°C (85°-60°F) day-night temperatures. Measurements taken over a 30-day period showed that (1) the percentage of starch initially in the roots was not related to root growth potential expression after 30 days, (2) the starch in new white lateral roots after 30 days was not related to root growth potential, and (3) seedlings that produced new roots tended to have more total starch in all plant parts than those that did not. For. Sci. 38(2):448-456.
A Comparison of Distance-Dependent Competition Measures for Height and Basal Area Growth of Individual Conifer Trees
Authors: Biging Greg S. , Dobbertin Matthias
Published: April 2024

The effect of competition on height and diameter² growth of individual conifer trees was examined. In this paper we modeled growth of individual trees as a product of potential growth reduced by competition. We investigated a number of competition indices that incorporate tree sizes and distances from neighbors, evaluated over varying competition zones. For these indices the reduction in mean square error relative to no competition index was used to judge performance. The performance of these indices varies by species and growth component (height or diameter² growth), but performance was generally better for tolerant white fir than for intolerant ponderosa pine. Additional competition measures that incorporate estimated crown parameters were developed and shown to improve on many of the traditional competition measures especially for ponderosa pine and Douglas-fir. For white fir, basal area performed well, but not as well as the individual tree competition indices that incorporate estimated crown parameters. We found that expanding the search zone did not improve our ability to estimate competitive effects. Choosing competitors with a height angle gauge was generally superior to selecting them with a DBH angle gauge. Results are summarized by species, type of competition index, and competition evaluation zone. For. Sci. 38(3):695-720.
Air Pollution Stress in the Bavarian Forest?
Authors: Visser Hans , Molenaar Jaap
Published: April 2024

Two objections expressed by Kandler (1992) to our results in a recent article (Visser and Molenaar 1992) are discussed. We argue that, although we did not use all data available from the fir stands under consideration, inclusion of the other measurements would not have changed our conclusions. We also point out that, contrary to Kandler's remark, deposition of pollutants (wet rather than dry deposition) may not be ignored as a potential stress factor in the Bavarian Forest. For. Sci. 38(4):870-872
Modeling Soil Temperature Effects on In Situ Decomposition Rates for Fine Roots of Loblolly Pine
Authors: Ruark Gregory A.
Published: April 2024

A study was conducted to quantify the relationship between soil temperature and fine root decomposition. Undisturbed soil cores containing root systems of loblolly pine seedlings were incubated in the lab under field capacity moisture conditions at constant soil temperatures of 15° and 25°C. Some seedling root systems were allowed to decompose in situ outside, where soil moisture and temperature were recorded. Laboratory and outside in situ results were compared to decomposition rates for seedling roots that were washed, air-dried, and reburied outside in mesh bags. Laboratory decomposition rates of the seedling root system, which contained fine laterals and a small taproot, averaged 31% and 44% weight loss annually, while annual rates of only the fine lateral root component averaged 57% and 66% loss of total weight at 15° and 25°, respectively. Average annual Q-10s of 1.4 and 1.2 were calculated between 15° and 25° for whole root systems and lateral roots alone. Lab incubation results were used to construct a regression model for fine root decomposition as a function of cumulative average monthly temperature. The model was validated against data on the root systems that were allowed to decompose in situ outside. Decomposition of this material after 1 yr was 43% complete for the whole root system and 60% complete for laterals. The observed remaining weight at various time intervals was accurately predicted from the regression model. After 1 yr, roots in the buried bags displayed a weight loss similar to the outdoor in situ samples. However, their decomposition rate was linear, whereas both outdoor and incubator in situ samples followed a curvilinear decay path. FOR. SCI. 39(1):118-129.
Genetic Variation Among Lake States Balsam Poplar Populations Is Associated with Geographic Origin
Authors: Riemenschneider Don E. , McMahon Bernard G.
Published: April 2024

Variation among populations of balsam poplar from Minnesota, Wisconsin, and Michigan (the Lake States) in tree height, phenology, and sylleptic branching was associated with geographic origin based on bivariate correlation, canonical correlation, principal component, and cluster analyses. Ninety percent of the joint variation in five traits was explained by two principal components, the first associated with late season growth and tree height, the second associated with number of sylleptic branches. Populations were delineated into northwestern, central, and southeastern clusters based on principal component one and two coordinates using Ward's minimum variance method. Populations from the south-eastern cluster grew taller, produced more late season leaves, and set bud later than populations from the northwestern and central dusters. FOR. SCI. 39(1):130-136.
Frequency Domain Tree-Ring Standardization
Authors: Van Deusen Paul C. , Reams Gregory A.
Published: April 2024

Prior to modeling tree-ring variation from climatic variables, an effort is made to standardize the tree-ring series by removing nonclimatic variance. A number of methods for standardizing tree-ting series in the frequency domain are presented along with a method for reducing end-fit problems. A technique for controlling the stiffness of a smoothing spline using frequency domain considerations is derived using matrix theory, and the spline is shown to be similar to other frequency domain methods. The results presented here elucidate earlier developments and allow for a more general application of frequency domain smoothing procedures. FOR. SCI. 39(1):55-65.
Retrospective Early Tests of Pinus sylvestris L. Seedlings Grown Under Five Nutrient Regimes
Authors: Eriksson Gösta , Jonsson Alena , Dormling Ingegerd , Norell Lennart , Stener Lars-Göran
Published: April 2024

Seedlings belonging to 36 families from a partial diallel mating between 11 parents of Scots pine (Pinus sylvestris L.) were cultivated for three growth periods in growth chambers at five nutrient levels in the range 5-45 mg N/liter. The ratios between N:K:P were always 100:65:13. Several growth and growth component characters were assessed, mainly during the third growth period. Additive genetic correlations between these characters and growth of other full-sibs from the same parents assessed at ages 10-28 in two adjacent field trials in southeastern Sweden were estimated. Estimates of the additive genetic correlations were obtained by calculating Pearson product moments of phenotypic values adjusted for nongenetic effects. Tests of independence between the genetic values in the phytotron and in the field trials were performed using rank correlation of the estimated GCA values. The lowest nutrient level gave low or negative genetic correlation coefficients with field data. For the four higher nutrient levels the genetic correlation coefficients between growth chamber data and field data increased with age of the field material. The strongest correlations were obtained with growth increments between years 13-23 and 23-28 (0.8-1.0). The standard errors of the estimates of the genetic correlation coefficients mostly varied between 0.2-0.5. FOR. SCI. 39(1):95-117.
Effect of Partial Defoliation on Growth and Carbon Exchange of Two Clones of Young Populus trichocarpa Torr. & Gray
Authors: Bassman John H. , Zwier John C.
Published: April 2024

A controlled environment study was performed to test the effect of two levels of a single partial defoliation on growth, dry weight partitioning, and gas exchange of two contrasting clones of Populus trichocarpa Torr. & Gray. One clone was from a moist habitat in western Washington and the other from a dry habitat in eastern Washington. Trees were partially defoliated (40% or 80% of leaf area removed) at the 25-leaf stage. Height, diameter, leaf area, and rates of net photosynthesis, dark respiration, transpiration, and leaf conductance were determined at the time of defoliation and 3 wk, and 5 wk after defoliation. Biomass distribution was determined following harvest 5 wk after defoliation. Defoliation caused reductions in height, diameter, and biomass in both clones compared to control plants. However, reductions were not proportional to level of defoliation, suggesting compensatory growth was occurring. Total biomass was reduced by 30% and 27% in the western and eastern Washington clones respectively by a 40% defoliation, and 43% and 35% following an 80% defoliation. A 40% defoliation caused an increase in the proportion of biomass in lateral branches of trees of the western Washington clone. An 80% defoliation caused an increase in the proportion of biomass in lateral branches of both clones. Both defoliation treatments reduced leaf area on the main stem but increased leaf area on lateral branches. Both levels of defoliation reduced root biomass of both clones. Specific leaf weight of leaves produced after defoliation in both clones increased. Partial defoliations of 40% and 80% had no effect on net photosynthesis of either clone. Rates of dark respiration in both clones were either unaffected by defoliation or slightly reduced. For. Sci. 39(3):419-431.
The Effects of GA3 and Organic Solvents on Acclimatization of Tissue Culture Propagated Black Cherry (Prunus serotina Ehrh.) Plantlets
Authors: Kavanagh Kathleen L. , Lee Dong-Hun , Drew Allan P. , Maynard Charles A.
Published: April 2024

Both gibberellic acid (GA3) and chilling were effective in inducing stem elongation of black cherry plantlets during acclimatization. At the rate of 100 mg/l, a foliar spray of GA3 was effective in stimulating stem elongation, but the effect was temporary. Most plantlets elongated to approximately 9 cm, but then set a resting bud. At rates above 200 mg/l, GA3 severely stunted root growth. An organic solvent solution enhanced the stem elongation response to GA3. When plantlets were treated with 100 mg/l GA3 in 0.2% DMSO and 54% ethanol, reinitiation of stem elongation was quicker, and bud set was delayed. Although the combination of GA3 and organic solvents induced stem elongation, it did not fully substitute for a chilling period. The minimum chilling period required to induce terminal bud break was 6 wk, and an additional 4 to 6 wk induced more rapid terminal bud break and stem elongation. For. Sci. 39(4): 644-654.
U.S. Policy and Canadian Lumber: Effects of the 1986 Memorandum of Understanding
Authors: Wear David N. , Lee Karen J.
Published: April 2024

A 1986 Memorandum of Understanding on softwood lumber imports (MOU) between Canada and the United States required that provincial governments levy export taxes on softwood lumber shipped to the United States. This agreement, with subsequent amendments, influenced trade from 1987 until it was abandoned by Canada in October of 1991. This paper investigates the market impact of the MOU, first by estimating an aggregate impact model of the Canadian share of the U.S. softwood lumber market and then by examining the implied price, quantity, and welfare effects. While the study shows the anticipated gains to U.S. producers of softwood lumber and losses to Canadian producers, U.S. consumer and efficiency costs were high, and the net of Canadian profit loss and export tax revenue was strongly positive. In addition, the net impact on market share appears to have persisted through 1990, in spite of considerable change in the policy's structure. These and other results should provide information for ongoing policy debate. For. Sci. 39(4):799-815.
A Mixed Integer Linear Programming Approach for Spatially Optimizing Wildlife and Timber in Managed Forest Ecosystems
Authors: Hof John G. , Joyce Linda A.
Published: April 2024

This paper presents mixed integer linear programming formulations for land allocation that optimize spatial layout for a single time period and that have the property that the number of integer variables is a linear function of the level of spatial resolution. The formulations focus on timber, edge-dependent wildlife, and area-dependent wildlife. They account for the amount of edge, the fragmentation of habitat area, and a habitat area threshold for minimum viable population size. Habitat area connectivity is modeled as a probabilistic condition. A case example demonstrates the approaches and includes landscape characteristics such as terrain, hiking trails, campgrounds, and rivers, which result in different productivities over the landscape and obstacles to wildlife habitat area connectivity. For. Sci. 39(4):816-834.
Notes: A Continuous-Time Markov Chain for Early Selections
Authors: Magnussen Steen
Published: April 2024

A discrete stepwise Markov chain for predicting relative performance of early selections at time of harvest is transformed into a continuous-time Markov chain by a simple transformation to a canonical form. Asymptotic predictions for t → ∞ are made possible. Prediction errors are derived from an autoregressive scheme and assumptions of multinominal one-step ahead errors. For. Sci. 39(4):845-850.
Simulation of Leaf Conductance and Transpiration in Juniperus occidentalis
Authors: Angell Raymond F. , Miller Richard F.
Published: April 2024

Western juniper (Juniperus occidentalis Hook.) is a conifer species well adapted to semiarid rangelands in portions of the western United States. Over a 2-yr period (1983-1984), water relations of mature western juniper trees were observed and soil temperature, soil water, air temperature, vapor density deficit (Da), and solar radiation were recorded. Data from 1983 were used to develop and calibrate a leaf conductance model for western juniper. The model was then tested against 1984 data. A daily soil water budget was maintained by coupling the conductance model with the hydrology component of the model SPUR (Simulation of Production and Utilization of Rangelands). Results indicate that the model successfully simulated seasonal conductance trends. Conductance was strongly affected by soil temperature and Da in spring, while soil water pressure and Da were important during summer. Simulated western juniper conductance rose to maximum in spring and was usually within one standard deviation of observed values. In the 1984 simulation, western juniper transpired 141 mm of water, 47% of the total evapo-transpiration for the site, and 44% of 1984 precipitation. Simulated western juniper conductance increased whenever environmental conditions moderated in late winter and spring. Juniper withdrew 37 mm of water between January and May 1984, suggesting it has potential to significantly alter watershed value and site productivity. For. Sci. 40(1):5-17.
Notes: Spatial Autocorrelation of Diameter and Height Increment Predictions from Two Stand Simulators for Loblolly Pine
Authors: Liu Jiping , Burkhart Harold E.
Published: April 2024

Using Moran indices, the spatial autocorrelation properties of diameter and height increment prediction from two loblolly pine stand simulators, TRULOB and PTAEDA2, were examined. Preliminary results indicated that the distance-dependent stand simulator (PTAEDA2) generated more desirable error structures, i.e., less spatially dependent, than the distance independent stand simulator (TRULOB) did both for total height and for dbh (diameter at breast height). The distribution of autocorrelation test statistics was positively shifted and positively skewed, possibly due to the lack of ability to account for microsite variation with both simulators. The dbh projection residuals were less desirable than the total height projection residuals, which might be explained by the modeling approach of these two models. The increments of total height were clearly spatially correlated, while those of dbh were mostly uncorrelated, except in a few cases. For. Sci. 40(2): 349-356.
A New Heuristic To Solve Spatially Constrained Long-Term Harvest Scheduling Problems
Authors: Yoshimoto Atsushi , Brodie J. Douglas , Sessions John
Published: April 2024

Because of capability limitations of the integer programming solution technique, a new heuristic algorithm was developed to solve spatially constrained long-term harvest scheduling problems. The proposed algorithm can handle multiple harvesting for each harvest unit over a long time horizon. The heuristic utilizes random ordering heuristic optimization and the PATH algorithm adapted from stand level optimization. Employing the proposed algorithm, a harvest scheduling system was constructed. The performance of the proposed algorithm is presented compared to the branch-and-bound algorithm in terms of the computational time as well as the objective value. Using two example forests, solutions by the proposed algorithm are stable in terms of the objective value and have harvest flow fluctuation much less than 3%. For short-term problems, solutions by the proposed algorithm tend to be optimal. For those problems, for which an optimal solution is found by the branch-and-bound algorithm, the solution can produce an objective value with deviation less than 2% from the optimum. The proposed algorithm yields better solutions for long-term problems than the branch-and-bound algorithm with the 1,000,000 limited number of iterations, and the lower bound derived by the proposed algorithm. Computational results reveal that as the time horizon increases, the proposed algorithm significantly and increasingly outperforms the "limited" branch-and-bound algorithm in terms of required computational time. The advantage of the proposed algorithm results from partitioning the problem into subproblems period by period using the PATH algorithm, and defining the objective function of the subproblem by minimizing absolute infeasibility on harvest flow constraints at each period under a two-period sequential feasibility condition. For. Sci. 40(3):365-396.
Selection Efficiency in a Nonselected Population of Loblolly Pine
Authors: Balocchi C. E. , Bridgwater F. E. , Bryant R.
Published: April 2024

Estimated selection-age efficiencies (present values of estimated correlated response) for family and within-family selection, based on both the additive and total genetic component for tree height of loblolly pine (Pinus taeda L.) at age 26, are reported for a study established near Bainbridge, Georgia, during 1963, 1964, and 1965. When correlated response was discounted at the rate of 8% per year, optimum selection ages for full-sib families, based on total genetic and on additive components alone, were 7 and 10 yr, respectively. Optimum selection ages were 6 and 7 yr for simultaneous selection of family and within-family for full-sib and half-sib families respectively, when based on the total genetic component. The optimum selection age for family plus within-family selection based on the additive component alone was 10 yr for both full-sib and half-sib families. Where production systems capture all, or part, of the nonadditive genetic variation, selection can be made 3 to 4 yr earlier than where systems capitalize only on additive genetic variance. Mass-controlled or supplemental pollination, "bulking-up" full-sib families by means of vegetative propagation, and vegetatively propagating selected individual genotypes, promise both greater genetic gains and earlier realization of those gains. For. Sci. 40(3):452-473.
The Value of Information Services in a Market for Factors of Production with Multiple Attributes: The Role of Consultants in Private Timber Sales
Authors: Munn Ian A. , Rucker Randal R.
Published: April 2024

The value of information services is incorporated into a hedonic pricing model in the context of private timber sales, where forestry consultants are often hired by landowners selling their timber. A data set containing detailed information on a sample of private sales is used to estimate the effects on bid prices of hiring a consultant. The estimated effects, using an estimation procedure that corrects for the statistical shortcomings of a simple OLS model, indicate that on average the increased price on consultant sales is approximately equal to the prices consultants charge for their services. For. Sci. 40(3):474-496.
Evaluating the Performance of Weight Functions with No Constraints on Function Types
Authors: Williams Michael S.
Published: April 2024

In weighted linear regression, the variance of the error terms is estimated by a weight function. Methods for testing two competing weight functions exist provided one of the functions is a special case of another weight function. A method based on an index of fit and bootstrap sampling, which allows two unrelated weight functions to be compared, is given. This method is tested on six artificial data sets of different sizes. For data sets of size 100 and larger, the proposed method could detect the difference between the weight functions σ²f1(xi) = σ²e1xi and σ²f2(xi) = σ²xi2 at the 95% level. For. Sci. 40(4):787-793.
Analysis of Uncertainty of Future Timber Yields in Forest Management
Authors: Weintraub Andrés , Abramovich Alejandra
Published: April 2024

We consider the effect that the uncertainty of future yields has on forest management. One way of modeling this problem is through chance constrained linear programming, where constraints are represented as probabilistic statements. Under normality conditions, an equivalent deterministic nonlinear program can be solved in an efficient way using a cutting plane algorithm, which takes advantage of the characteristics of the problem. To deal with uncertainty, we propose a forest planning approach, based on chance constrained linear programming. We also analyze the importance of including the consideration of uncertainty in the planning process. For this purpose, we simulate two scenarios, a deterministic one and another where uncertainty is included in the models. Results of a test case show that not considering uncertainty in the models when production demand constraints have small slack can lead to management situations with infeasible solutions. For. Sci. 41(2):217-234.
Interactive Effects of Atmospheric CO2 Enrichment and Soil N on Growth and Ectomycorrhizal Colonization of Ponderosa Pine Seedlings
Authors: Walker R. F. , Geisinger D. R. , Johnson D. W. , Ball J. T.
Published: April 2024

Interactive effects of elevated atmospheric CO2 and soil N fertility on above- and below-ground development of juvenile ponderosa pine (Pinus ponderosa Dougl. ex Laws.) were examined. Seedlings were grown from seed in atmospheres containing 700 μl l-1, 525 μl l-1, or ambient CO2. Medium and high soil N treatments were created by adding sufficient (NH4)2SO4 to the potting mix to increase total N by 100 μg g-1 and 200 μg g-1, respectively, while unamended mix, which had a total N concentration of approximately 300, μg g-1, served as the low N treatment. Three whole-seedling harvests at 4-month intervals permitted assessment of shoot and root growth and ectomycorrhizal formation resulting from inoculation with Pisolithus tinctorius (Pers.) Coker and Couch. After 4 months, CO2 enrichment increased shoot volume and dry weight of seedlings grown in high soil N, but this result was not evident in the other N treatments and did not persist to the second harvest. Root weight, however, increased, and shoot/root ratio decreased as the CO2 concentration increased within all three N treatments at the first harvest. At the second harvest, root weights within the high and intermediate N treatments were lowest in seedlings grown in ambient CO2 and shoot/root ratios decreased as CO2 increased in these two N treatments as well. Although the ectomycorrhizal infection percentage of seedlings grown in 700 μl l-1 CO2 was highest among the seedlings grown in high N after 4 months, mycorrhizal colonization was variable overall at the first and second harvests. After 1 yr, the 525 μl l-1 CO2 concentration stimulated above- and belowground growth more than the high CO2 atmosphere in both high and medium soil N. These seedlings also had relatively extensive ectomycorrhizal formation, but colonization was again variable. Results presented here suggest the response of juvenile ponderosa pine to CO2 enrichment is ephemeral, with the effects on roots more pronounced and persistent overall than those on shoots, and that the response is dependent on N availability. For Sci. 41(3):491-500.
Pragmatic Approaches to Optimization with Random Yield Coefficients
Authors: Hof John , Bevers Michael , Pickens James
Published: April 2024

This paper discusses practical methods for handling normally distributed random technical (yield) coefficients in linear programs that optimize natural resource allocation and scheduling. These methods are practical in the sense that they are applicable to large-scale real world models and do not require nonlinear solution methods. The paper begins with a description and demonstration of postoptimization approaches that are applicable to large, linear problems, and then explores methods for reducing overall risk through land allocation diversification. A central theme of the paper is the importance of providing some sort of allowance for uncertainty when presenting optimization results, which promotes a more realistic view of the problem by analysts and decision makers alike. For. Sci. 41(3):501-512.
Evaluation of the Competitive Environment for White Pine (Pinus strobus L.) Seedlings Planted on Prescribed Burn Sites in the Southern Appalachians
Authors: Elliott Katherine J. , Vose James M.
Published: April 2024

We evaluated the competitive environment around planted white pine (Pinus strobus L.) seedlings and monitored the response of seedling growth to competition from naturally regenerating herbaceous and woody species for 2 yr after prescribed burning. We evaluated the ability of distance-independent and distance-dependent competition indices to predict resource availability, determined if white pine seedlings responded to resource reduction by competitors, and identified species-specific contributions to the competitive environment through canonical correspondence analysis (CCA). Distance-independent measures of competition were not as well correlated with pine seedling growth as were distance-dependent measures. In 1991, competition was less important in 1991 than in 1992, and ordinating the species with CCA failed to improve the predictability of the competitive environment. By 1992, competition became more important, and individual species had differing effects on pine growth; we found that light was the most important resource limiting diameter growth and that the tall tree species were responsible for reduced light availability to pine seedlings. For. Sci. 41(3):513-530.
Genetic Parameter Estimates for Seedling Dry Weight Traits and Their Relationship with Parental Breeding Values in Slash Pine
Authors: Surles Scott E. , White Timothy L. , Hodge Gary R.
Published: April 2024

Seedlings from 64 open-pollinated families of slash pine were grown in low and high nitrogen (N) treatments (5 ppm and 50 ppm) in raised outdoor boxes. Destructive harvests were conducted 3, 6, and 10 mo after sowing to measure dry weights of needles, stems, tap roots, and lateral roots. Genetic parameters (i.e., family-mean heritabilities, Type A genetic correlations, and Type B genetic correlations) were estimated for dry weight traits at each destructive harvest. Family-mean heritability estimates were high for traits in all harvests (most exceeded 0.60). Type A genetic correlation estimates, measuring the commonality of gene effects between two traits measured in the same individuals (i.e., in the same N treatment), were not significantly different from + 1 for most dry weight traits at each harvest. Type B genetic correlation estimates, measuring the commonality of gene effects between two traits measured in different individuals of the same families (i.e., across the two N treatments), were also near + 1 for most traits. Genophenotypic correlations (a single-trait prediction index) between family means of seedling dry weight traits and parental additive genetic breeding values for 15-yr field volume growth were relatively high at the 3-mo measurement (mostly higher than 0.40), but the values were lower for the 6- and 10-mo measurements. Because most pairs of dry weight traits from the same harvest were highly genetically correlated with each other, correlations between field breeding values and those predicted from two-trait indices were only slightly higher than single-trait indices. However, when traits were combined across the three harvest dates, correlations between field breeding values and predictions from two-trait indices increased to over 0.50. The best early selection indices were more effective at identifying the bottom-ranked families than the top-ranked families. An early selection technique using these traits would not be efficient enough to supplant long-term field testing, but could be used to reduce the size of field tests via early culling of poor-performing families or to screen infusion candidates for minimal breeding value requirements. For. Sci. 41(3):546-563.
Uptake and Distribution of Nitrogen from Acidic Fog within a Ponderosa Pine (Pinus ponderosa Laws.)/Litter/Soil System
Authors: Fenn Mark E. , Leininger Theodor D.
Published: April 2024

The magnitude and importance of wet deposition of N in forests of the South Coast (Los Angeles) Air Basin have not been well characterized. We exposed 3-yr-old ponderosa pine (Pinus ponderosa Laws.) seedlings growing in native forest soil to acidic fog treatments (pH 3.1) simulating fog chemistry from a pine forest near Los Angeles, California. Fog solutions contained either 15NH+4, 15NO-3, or unlabeled N. The fog treatments were applied in open-top chambers in six 5-hr exposures. Soil treatments within each of the fog exposures were bare soil, soil overlain with L- and F-litter, and soil covered with plastic during the fog events to prevent fogwater from contacting soil. Seedlings were harvested and samples were collected 15 wk after the fog treatments. Uptake of 15N by roots was by far the dominant pathway for plant assimilation of fog-deposited 15N. Deposition of N in fog supplied 9.4% and 8.7% of the total N in current-year crown biomass in the litter-overlay and bare-soil treatments, respectively. Total N concentrations in every plant fraction except current-year stems were significantly higher in the bare-soil treatment than in the plastic-covered soil treatment. Less than 5% of the 15N deposited directly to the seedling crowns was retained by the plants in the covered-soil treatment, whereas 57% of the 15N deposited to the seedling/litter/soil systems was incorporated into plant biomass. The litter layers retained 15NH+4 more effectively than 15NO3. Data from this study suggest that N deposited from fog may be an important source of N for plant growth in forests of the SCAB where fog occurrence and pollution exposure coincide. For. Sci. 41(4):645-663.