bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multilevel Nonlinear Mixed-Effects Models for the Modeling of Earlywood and Latewood Microfibril Angle
Authors: Jordan Lewis , Daniels Richard F. , Clark Alexander , He Rechun 
Published: April 2024

Abstract
Earlywood and latewood microfibril angle (MFA) was determined at 1-millimeter intervals from disks at 1.4 meters, then at 3-meter intervals to a height of 13.7 meters, from 18 loblolly pine (Pinus taeda L.) trees grown in southeastern Texas. A modified three-parameter logistic function with mixed effects is used for modeling earlywood and latewood MFA. By making the parameters of the logistic function linear functions of height, a three-dimensional model was developed that describes the changes of earlywood and latewood MFA within the tree. A first-order autoregressive correlation structure and a variance model corresponding to a variance covariate given by the fitted values for each wood type, but in which the proportionality constant differs according to the level of wood type, was identified as the within-group correlation and variance structures. Cross-validation was used to determine model accuracy and precision. The methods of model development including determination of the height structure, which parameters should be considered random or fixed, determination of an appropriate variance-covariance structure, and prediction are addressed. Model performance was evaluated utilizing informative statistics including likelihood ratio tests (LRTs), Akaike information criterion (AIC), and Bayesian information criterion (BIC). FOR. SCI. 51(4):357–371.
Forest and Pasture Carbon Pools and Soil Respiration in the Southern Appalachian Mountains
Authors: Bolstad Paul V. , Vose James M. 
Published: April 2024

Abstract
Our ability to estimate the changes in carbon (C) pools and fluxes due to forest conversion is hampered by a lack of comparative studies. We measured above- and belowground C pools and soil respiration flux at four forested and four pasture sites in the southern Appalachian Mountains. Above- and belowground C pools were significantly larger (P &lt; 0.01, t-test) at forested sites relative to pasture sites. The largest differences were in aboveground live biomass, which averaged 152 Mg ha−1 C at the forested sites and 1.9 Mg ha−1 at the pasture sites. Coarse root and stump C and surface detritus were also substantially different, averaging 41.3 and 32.6 Mg ha−1 C, respectively, at the forested sites, and less than 1 Mg ha−1 at the pasture sites. Fine root C was higher and mineral soil C lower at pasture sites relative to comparable forested sites, but neither difference was statistically significant. Soil respiration at a given temperature was generally lower at pasture sites relative to forest sites. However, soil temperatures at pastures were consistently higher than at forest sites. Estimated annual soil respiration flux averaged 10.9 Mg C ha−1 at the pasture sites and 12.6 Mg C ha−1 at the forested sites. FOR. SCI. 51(4):372–383.
An Alternative Incentive Structure for Wildfire Management on National Forest Land
Authors: Donovan Geoffrey H. , Brown Thomas C. 
Published: April 2024

Abstract
Wildfire suppression expenditures on national forest land have increased over the last 35 years, exceeding US$1 billion in 2000 and 2002. These increases in expenditure have been attributed, in part, to a century of aggressive wildfire suppression, resulting in a buildup of fuel on the nation's forests. The efficiency of the current incentive structure faced by Forest Service fire managers is analyzed. An alternative incentive structure is presented that encourages fire managers, as they work to limit wildfire damages, to contain costs and consider the beneficial effects of wildfire. FOR. SCI. 51(5):387–395.
Changes in Snag Populations in Northern Arizona Mixed-Conifer and Ponderosa Pine Forests, 1997–2002
Authors: Ganey Joseph L. , Vojta Scott C. 
Published: April 2024

Abstract
Snags (standing dead trees) are important components of forests that contribute to ecological processes and provide habitat for many life forms. We monitored dynamics of snag populations on 1-ha plots in southwestern mixed-conifer (n = 53 plots) and ponderosa pine (Pinus ponderosa, n = 60 plots) forests in north-central Arizona from 1997 to 2002. Of 2,240 snags marked in 1997, at least 76% remained standing in 2002, 17% had fallen and were relocated as logs, 0.5% were cut down, and the remainder (6%) were unaccounted for. Snag density increased significantly in mixed-conifer forest but not in ponderosa pine forest. Snag density increased mainly in the smaller size classes in both forest types. Density of large snags (≥46 cm in diameter and 9 m in height) increased slightly but nonsignificantly from 1997 levels in both forest types, and fell below current targets for retention. Species composition of snags differed between 1997 and 2002 in ponderosa pine forest, but not in mixed-conifer forest, and decay-class distributions differed among years in both forest types. A classification-tree analysis indicated that a ratio of height to diameter, species, and diameter were key variables in predicting whether a snag survived from 1997 to 2002. These results provide empirical data on snag populations and dynamics in this area and establish a basis for longer-term monitoring of snag populations and dynamics. FOR. SCI. 51(5):396–405.
A New Simulator for the Spread of Forest Root Diseases by Individual Root Contacts
Authors: Peet F. G. , Hunt R. S. 
Published: April 2024

Abstract
A new simulator for the spread of forest root diseases, and the testing of it, is presented. It differs from earlier models in that it represents a first step to incorporate the basic processes of spread by individual root contact. It therefore has a generality that allows its use in different host–pathogen and geographic situations. It stochastically grows individual roots longitudinally outward from the stem. They are tapered, turn, and contact other roots as they grow. The simulator transfers fungus stochastically at points of contact between healthy roots and infected stump or tree roots and moves the fungus along infected tree roots stochastically. The fungus can girdle the rootcollar, move out into other roots, and eventually kill the tree. Growth of roots and fungus movement along infected roots is on an annual basis for up to 200 years. Root growth, fungus growth along roots, disease spread, and stand openings are displayed dynamically in color on the computer screen as the simulation proceeds. Estimates for numbers of infected trees and mortality are provided in tabular and graphical form. Results from the simulator were close to the field data it was tested against. FOR. SCI. 51(5):425–437.
Effects of Fertilization and Vegetation Control on Microbial Biomass Carbon and Dehydrogenase Activity in a Juvenile Loblolly Pine Plantation
Authors: Blazier Michael A. , Hennessey Thomas C. , Deng Shiping 
Published: April 2024

Abstract
To characterize the influences of fertilization and understory vegetation suppression on microbial biomass and activity in a juvenile loblolly pine plantation, we measured microbial biomass C (Cmic) and dehydrogenase activity in soil monthly in response to (1) untreated control (CONT), (2) understory suppression with glyphosate (BC), (3) pine removal (NP), (4) pine removal with understory suppression (NPBC), (5) urea + diammonium phosphate with understory suppression (UDBC), and (5) slow-release urea with understory suppression (CUFBC). Cmic and dehydrogenase activity were significantly decreased relative to the CONT treatment by the NP, NPBC, UDBC, and CUFBC treatments. These reductions likely indicate a dependence of soil microbes on labile C sources derived from living vegetation. Fertilization + brush control decreased Cmic and dehydrogenase activity to a greater extent than brush control alone, suggesting that the availability of labile C sources was adversely affected by fertilization. Short-term reductions in Cmic were correlated with increases in soil NO3−. Results of this study demonstrate that, in this young, intensively managed pine plantation, labile C substrates from vegetation may be a predominant determinant of soil N availability through its influence on microbial biomass and activity. FOR. SCI. 51(5):449–459.
Airtanker Flight Distance between Fires: Random Fire Starts on Line Segments
Authors: Greulich Francis E. 
Published: April 2024

Abstract
Under high initial attack fire loads, dispatchers sometimes redirect airtankers that are working on other fires. The inherent variability of flight distance between random fire locations is a potentially important aspect of any model that would reallocate the airtanker resource between fires. Requisite formulas are derived, and computational procedures are provided in this article for the stochastic description of airtanker flight distances between fire-start locations randomly located along straight-line segments. Numerical approximations and comparisons with prior work confirm the results of detailed examples that establish a blueprint for application and continued model development. FOR. SCI. 51(5):460–471.
Variation in Wood Density and Shrinkage and Their Relationship to Growth of Selected Young Poplar Hybrid Crosses
Authors: Pliura Alfas , Yu Qibin , Zhang S. Y. , MacKay John , Périnet Pierre , Bousquet Jean 
Published: April 2024

Abstract
Wood density, various shrinkages and several growth traits were measured in two 10-year-old clonal trials at sites of contrasting growth potential. The material studied consisted of 12 clones of three poplar hybrid crosses, Populus deltoides × P. nigra, P. trichocarpa × P. deltoides, and P. maximowiczii × P. balsamifera, as well as P. deltoides. Wood density and longitudinal and radial wood shrinkages were significantly lower at the St-Ours than at the Windsor site, by 6.7, 46.7, and 14.9%, respectively, while growth rate was increased. The differences among hybrid crosses were significant for all growth traits and wood properties except for radial and tangential shrinkages of juvenile wood. P. deltoides had the highest wood density of 363.2 kg/m3, whereas P. maximowiczii × P. balsamifera wood had the lowest density of 299.8 kg/m3. The differences among hybrid crosses were significant for growth traits, primarily due to the fast growth of P. trichocarpa × P. deltoides and slow growth of P. deltoides. Among the wood properties measured, only tangential wood shrinkage exhibited clear radial intertree changes with cambial age. The tangential wood shrinkage increased from pith to mid-diameter and then started to decrease outward, with each hybrid showing a different pattern of variation. Phenotypic clonal mean correlations among growth traits and wood density were weakly negative. Correlations among growth traits and radial wood shrinkage ranged from weakly to strongly negative. Longitudinal shrinkage displayed strong negative correlations with radial and tangential shrinkages. Negative correlations found between wood density and longitudinal shrinkage and positive correlations between density and both radial and tangential shrinkages suggest that selection for high wood density may lead to increased transverse wood shrinkage but decreased longitudinal shrinkage. FOR. SCI. 51(5):472–482.
Acacia mangium, a Nurse Tree Candidate for Reforestation on Degraded Sandy Soils in the Malay Peninsula
Authors: Norisada M. , Hitsuma G. , Kuroda K. , Yamanoshita T. , Masumori M. , Tange T. , Yagi H. , Nuyim T. , Sasaki S. , Kojima K. 
Published: April 2024

Abstract
We investigated the suitability of Acacia mangium Willd., a fast-growing tropical leguminous tree, as a nurse tree for reforestation with indigenous species on severely degraded sandy soils in southern Thailand. Planting A. mangium yielded a survival rate of 91% and satisfactory growth (7.7 m height, 56 mm dbh, 59 Mg dry weight ha−1 aboveground biomass) 45 months after planting, indicating the species' suitability for reforestation. Three dipterocarp species (Dipterocarpus alatus Roxb. ex G. Don, Hopea odorata Roxb., and Shorea roxburghii G. Don.) planted simultaneously with A. mangium showed better growth than when planted alone. Seedlings of all three dipterocarp species that survived transplanting showed better survival when planted with A. mangium. The findings suggest A. mangium is an effective nurse tree for dipterocarp seedlings. The carbon and nitrogen contents of surface soil did not increase in the A. mangium stands. Microclimate measurements showed moderated air temperature, relative humidity, and soil temperature in the mixed planting. The moderated microclimate under the A. mangium canopy is thought to be responsible for the improved growth of the dipterocarp seedlings. If dipterocarp seedlings are planted after A. mangium grows enough to provide shade, initial survival rates should improve. FOR. SCI. 51(5):498–510.
Rhizobacteria Isolated from Loblolly Pine Seedlings Mediate Growth-Promotion of Greenhouse-Grown Loblolly, Slash, and Longleaf Pine Seedlings
Authors: Enebak S. A. 
Published: April 2024

Abstract
Loblolly (Pinus taeda L.), slash (Pinus elliottii Engelm.), and longleaf pine (Pinus palustris Mill.) seeds were inoculated in the greenhouse with rhizobacteria recovered from 4-month-old bareroot loblolly pine seedlings. Emergence and seedling densities were determined at 3- and 8-week intervals after sowing, respectively, with root and shoot biomass measured at 12 weeks. All bacterial strains significantly increased the speed of seedling emergence relative to untreated loblolly and slash pine seeds, while five strains significantly slowed longleaf germination. For loblolly and slash pine, there were no differences in percentage germination when comparing treated and untreated seed. However, all bacterial strains significantly reduced longleaf germination over nontreated seed. Treatment with rhizobacteria had significant positive and negative effects on seedling growth and biomass, depending on the tree species and bacteria isolate used. Five of the eight bacterial isolates tested increased shoot length of loblolly pine seedlings, whereas one strain increased above- and belowground biomass. Slash pine seedlings experienced growth increases with three bacterial strains. However, two bacterial strains, ALA-41G and ALA-54G, resulted in shorter slash pine shoots. Only strain ALA-3G increased shoot biomass of longleaf pine over nontreated longleaf seed. Increased seedling emergence and growth promotion by rhizobacteria collected from Pinus sp. is a potential useful tool for management of these forest species. The effect may be species-specific and the use of bacteria in forest nurseries for growth promotion will need to take this into account. FOR. SCI. 51(6):541–545.
Foliar δ13C and δ15N Response of Lodgepole Pine and Douglas-Fir Seedlings to Soil Compaction and Forest Floor Removal
Authors: Choi Woo-Jung , Chang Scott X. , Curran Michael P. , Ro Hee-Myong , Kamaluddin Mohammed , Zwiazek Janusz J. 
Published: April 2024

Abstract
The effects of soil compaction, forest floor (FF) removal, and rehabilitation treatments on foliar δ13C and δ15N of lodgepole pine (Pinus contorta) and Douglas-fir (Pseudotsuga menziesii) were studied on a calcareous soil. Regardless of soil compaction, FF removal (which reduces soil water potential) resulted in less negative foliar δ13C values of lodgepole pine (from −25.9 to −23.4‰), whereas soil compaction effects on foliar δ13C were observed only within the FF intact treatment. This result and the more negative foliar δ13C with increasing seedling growth most likely reflected limitation on CO2 diffusion due to water stress caused by those treatments. However, foliar δ13C of Douglas-fir (range −25.0 ∼ −24.5‰) were not affected by the treatments, indicating less susceptibility to water stress. Soil compaction reduced NH4+-N concentrations in the FF (from 48.5 to 28.0) and NO3−-N concentrations in the FF (from 13.8 to 6.4) and mineral soil (from 4.3 to 2.1 mg kg−1), and FF removal tended to decrease NH4+-N concentrations in the mineral soil. Foliar δ15N of both species were not affected by soil compaction but were increased by the FF removal and rehabilitation treatments, indicating that the latter two treatments dramatically altered soil N dynamics. FOR. SCI. 51(6):546–555.
Production Efficiency and Radiation Use Efficiency of Four Tree Species Receiving Irrigation and Fertilization
Authors: Allen Christopher B. , Will Rodney E. , Jacobson Marshall A. 
Published: April 2024

Abstract
To determine the effect of resource availability on efficiency of stemwood production, we calculated radiation use efficiency (Εstem = stem production/photosynthetically active radiation [PAR] interception) and production efficiency (PEstem = stem production/leaf area index [LAI]) from measurements of LAI, intercepted photosynthetically active radiation (IPAR), and stem production on stands of Pinus taeda, Pinus elliottii, Liquidambar styraciflua, and Platanus occidentalis during the sixth growing season. Treatments were control, irrigation only, and irrigation plus 57, 85, or 114 kg N ha−1 y−1. Compared to the control, irrigation plus 85 kg N ha−1 increased stem production: 8.7–15.0 Mg ha−1 y−1 (loblolly), 6.0–10.7 Mg ha−1 y−1 (slash), 1.2–12.8 Mg ha−1 y−1 (sweetgum), and 0.5–9.6 Mg ha−1 y−1 (sycamore). Annual PAR capture and LAI were correlated with stem production (r2 = 0.80, r2 = 0.66, respectively, average of 4 species). Fertilization and irrigation increased Εstem and PEstem for sycamore, whereas only fertilization increased efficiencies for sweetgum. Irrigation increased PEstem for the pines. Foliar [N], often a surrogate for photosynthetic efficiency, was positively correlated with both efficiency variables for the hardwoods (r2 from 0.65 to 0.79). For the pines, canopy size was the primary growth determinant. FOR. SCI. 51(6):556–569.
Estimating Supply Elasticity for Disaggregated Paper Products: A Primal Approach
Authors: Brown Roger , Zhang Daowei 
Published: April 2024

Abstract
Most existing elasticity estimates for the pulp and paper industry are based on aggregate products (e.g., total paper, paperboard, or paper except newsprint). Using United States data, we present and evaluate econometric output supply models for four relatively disaggregated paper products: newsprint paper (NP), printing/writing paper (PWP), tissue paper (TP), and packaging paper (PP). Sample periods vary from 14 years for PP (1987–2001) to 20 years for NP and PWP (1981–2001). Each paper type is specified using a two-stage least squares geometric distributed lag model in log–log form using monthly data. Estimated long-run (short-run) output price elasticities are 2.75 (0.69) for NP, 2.45 (1.07) for PWP, 1.77 (1.77) for TP, and 0.41 (0.24) for PP. Input demand elasticities for capital, wood fiber, labor, electricity, and wastepaper are also estimated for each paper type. FOR. SCI. 51(6):570–577.
Parsimonious and Completely Compatible Taper, Total, and Merchantable Volume Models
Authors: Jordan Lewis , Berenhaut Kenneth , Souter Ray , Daniels Richard F. 
Published: April 2024

Abstract
A parsimonious and compatible system of taper, total, and merchantable volume equations sharing a common vector of three parameter estimates was derived from Clark and Saucier's (1990) volume ratio model. Clark and Saucier's model expresses volume inside bark as a function of outside bark diameter and is itself not compatible with the derived taper equation. To ensure compatibility, models were fit to express volume outside bark as functions of diameter outside bark. By constraining the limits of integration of the taper function to go from the tip to groundline diameter, a completely compatible system of taper, total, and merchantable volume equations were developed. Systems of equations were fit using nonlinear seemingly unrelated regressions with nonlinear cross-equation constraints to account for contemporaneous correlations in the data. The system fit was found to account for at least 96% of the variation in diameter outside bark, total, and merchantable outside bark volume. FOR. SCI. 51(6):578–584.
Tropical Forest Measurement by Interferometric Height Modeling and P-Band Radar Backscatter
Authors: Neeff Till , Dutra Luciano Vieira , dos Santos João Roberto , Freitas Corina da Costa , Araujo Luciana Spinelli 
Published: April 2024

Abstract
A new approach to tropical forest biomass monitoring with airborne interferometric X and P-band synthetic aperture radar (SAR) data is presented. Forest height, basal area, and aboveground biomass are modeled from remote sensing data for a study site in the Brazilian Amazon. Radar data quality has improved: A novel digital model of vegetation height from X- and P-band interferometry is available along with the usual P-band backscatter information. The digital vegetation height model is derived from the interferometric surface models of the ground (from P-band) and the forest canopy (from X-band). The difference between the surface models is called “interferometric height,” and is used as a measure of vegetation height. Interferometric height is shown to relate to a subset of the forest trees that changes according to the forest successional stages. The suitability of radar backscatter and interferometric height as a means for forest and biomass monitoring was explored by relating forest parameters as measured in the field to remote sensing data. Basal area and biomass were related to radar backscatter with limited precision of r2 = 0.19 and r2 = 0.34, respectively. Mean forest height is shown to relate to interferometric height with good precision (r2 = 0.83, RMSE = 4.1 m). A statistical model for forest biomass as a function of both P-band backscatter and interferometric height information not only arrives at high values of precision (with r2 = 0.89 and a RMSE from cross-validation of only 46.1 t/ha), but also overcomes the well-known issue of backscatter saturation. This research shows that tropical forest biomass can be quantified and mapped over large areas for a range of forest structures with reasonably tight and similar errors. FOR. SCI. 51(6):585–594.
Comparison of Experimental Designs for Clonal Forestry Using Simulated Data
Authors: Gezan Salvador A. , White Timothy L. , Huber Dudley A. 
Published: April 2024

Abstract
Various alternatives for the design of clonal field trials in forestry were studied using simulated data to identify “optimal𠇍 or “near-optimal𠇍 scenarios for the estimation of genetic parameters. The simulated field site consisted of a rectangular grid on which 256 clones with 8 ramets each were installed. Estimates of genetic parameters were compared for (1) single-tree and four-tree row plots; (2) several experimental designs (completely randomized, randomized complete block, incomplete blocks of various sizes, and row–column); (3) no mortality versus 257% mortality; and (4) different patterns of environmental variability (only patches, only gradients, and both patches and gradients). Use of single-tree plots, on average, increased the correlations between true and predicted clonal values by 57% over four-tree row plots and increased genetic gain from selection. Starting with a parametric broad-sense heritability (H B 2) of 0.25 for a completely randomized design, the experimental designs resulting in the highest H B 2 were row–column designs for single-tree plots and incomplete blocks with 32 blocks per replication when four-tree row plots were used. These designs increased average heritability 107% and 147% over a randomized complete block design, respectively. The only effect of 257% mortality was an increase in the variability of some variance component estimates.