bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simulation of Leaf Conductance and Transpiration in Juniperus occidentalis
Authors: Angell Raymond F. , Miller Richard F. 
Published: April 2024

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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.
Wood Relative Density Development in Red Pine (Pinus resinosa Ait.) Stands as Affected by Different Initial Spacings
Authors: Larocque Guy R. , Marshall Peter L. 
Published: April 2024

Abstract
The relationship between wood relative density and growth rate in red pine (Pinus resinosa Ait.) trees originating from different initial spacings was examined. Wood relative density was also related to crown development, as affected by competition. At young ages, the relative densities of entire rings and of the earlywood and latewood zones and the percentages of earlywood within the rings did not differ much among the spacings. As stands grew older, however, ring relative density and earlywood and latewood relative densities increased while the percentage of earlywood decreased. The closer the spacing, the faster relative density increased and the percentage of earlywood decreased. These changes closely followed changes in crown ratio. A good fit was obtained for an equation relating ring relative density to age and percentage of latewood for trees of various ages originating from a wide range of initial spacings. Ring width, ring relative density, and percentage of earlywood were regressed against (1) crown width and distance between the base of the crown and breast height and (2) crown volume and crown ratio. These equations did not fit well at young ages. However, the strength of the relationships improved with age, which indicated the increasing influence of crown development on wood density. For. Sci. 41(4):709-728.
Long-Term Structural Change in Uneven-Aged Northern Hardwoods
Authors: Leak William B. 
Published: April 2024

Abstract
The diameter distributions of 10 previously unmanaged northern hardwood stands on the Bartlett Experimental Forest in New Hampshire were analyzed to determine changes over a 35 yr period since a single cutting by the diameter-limit or single-tree selection methods. The diameter distribution of an uncut old-growth stand (the Bowl) provided a comparison. The cuttings left residual basal areas of 25 to 96 ft² of basal area per acre (5.7 to 22.0 m²/ha), as well as a wide range in diameter distribution. Basal area of the old-growth stand was 123 ft²/ac (28.2 m²/ha), and the diameter distribution was reverse J-shaped (negative exponential) as evidenced by a close fit (adjusted r² = 0.97) of log (no. of trees) over dbh class; the q (ratio between numbers of trees in successive 2 in. dbh classes) equaled 1.39. Under all cutting methods, the diameter distributions after 35 yr fit the reverse J-shaped form only moderately well with adjusted r²'s of 0.81 to 0.95. An equal or better fit in most cases (adjusted r²'s of 0.91 to 0.98) was provided by log (no. of trees) over dbh², which reflects the tendency of the quotients between numbers of trees per dbh class to increase with dbh. None of the initial diameter distributions of the cut stands had rotated sigmoid characteristics, but five of the final diameter distributions had significant rotated sigmoid characteristics, and at least two others showed graphical sigmoid tendencies. Apparently, rotated sigmoid characteristics are caused by disturbance, perhaps coupled with successional trends toward increased tolerant softwoods. For. Sci. 42(2):160-165.
An Analysis of the Impacts of Public Timber Harvest Policies on Private Forest Management in the United States
Authors: Adams Darius M. , Alig Ralph J. , McCarl Bruce A. , Callaway J. M. , Winnett Steven M. 
Published: April 2024

Abstract
Past studies of the impacts of changes in public timber harvest have commonly assumed that the extent and intensity of private forest management would remain unchanged in the face of shifting log prices and demand. This study reexamines the issue of public harvest impacts using a model of intertemporal log markets in which prices, private harvests, and timber management investment are endogenous. The model considers two classes of private owners in nine regions and subdivides the basic timber inventory into a large number of classes that influence yields and costs, including, site quality, species group, and past management. Six product groups are recognized with opportunities for substitution. Given the perfect market and foresight structure of the model, simulation results suggest a far more elastic market response to changes in public cut than found in past studies. Shifts in intertemporal patterns of private investment act to reduce the price and aggregate harvest impacts of public cut changes over time. Underlying these moderated market impacts, however, are larger interregional shifts in harvest and private owner welfare than suggested in earlier analyses. Through changing management investment, including conversion of lands from hardwood to softwood species types, some of the largest economic and biological/ecological impacts may be realized outside of the regions in which public forestlands are concentrated. For. Sci. 42(3):343-358.
Prediction of Gross Tree Volume Using Regression Models with Non-Normal Error Distributions
Authors: Williams Michael S. , Schreuder Hans T. 
Published: April 2024

Abstract
In developing new clones of forest trees, the first main goal is to propagate enough plantable plants for clonal field trials and a clonal archive. Models of clonal multiplication rates in Eucalyptus globulus indicate that this takes a similar time (about 56 wk) from the sowing of seed, whether multiplication is by axillary shoot culture in vitro or by stem cuttings propagation. Multiplication of unrooted shoots is relatively rapid in vitro but is largely offset by the greater time required for weaning, pricking out, and growth in the nursery. For. Sci. 42(4):415-418.