bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimating Log Volume Using the Centroid Position
Authors: Wiant H. V. , Wood G. B. , Furnival G. M. 
Published: April 2024

Abstract
In 8 of 15 comparisons by tree species (6 Australian and 9 American), log volumes were estimated with more precision when the interlog position for measuring cross-sectional area was located at the midvolume (centroid) position rather than the midlength (Newton) position. It is concluded that the centroid of a tree or log defines a position of special significance for estimating volume. A formula is developed for estimating log volume based on measurements of log length and diameter at both ends of the log and at any intermediate position. For. Sci. 38(1):187-191.
Growth in Relation to Canopy Light Interception in a Red Pine (Pinus resinosa) Thinning Study
Authors: Law Beverly E. , Riitters Kurt H. , Ohmann Lewis F. 
Published: April 2024

Abstract
Growth data from the most recent 5 years of a 40-year thinning study in an even-aged red pine (Pinus resinosa) forest in Cutfoot Sioux Experimental Forest, Minnesota, were used with intercepted photosynthetically active radiation (IPAR) data to determine the relationship between light interception and growth for a range of stand densities. Stand basal area (BA) growth was proportional to the amount of light intercepted within the stand (P = 0.06, r² = 0.73), and individual tree growth was inversely related to the amount of light intercepted by the canopy (P = 0.08, r² = 0.69). Stand growth efficiency (SGE = ratio of 5-year plot BA growth to plot median %IPAR) was only weakly correlated with stand density (P » 0.10, r = 0.31). The rate of change in stand growth efficiency may be a good indicator of change in forest condition over a range of stand densities. For. Sci. 38(1):199-202.
Leaf Area Estimation of Mature Foliage of Juniperus
Authors: Cregg Bert M. 
Published: April 2024

Abstract
The ratio of total surface area to projected leaf area was determined for mature foliage samples collected at three canopy heights from Juniperus virginiana and J. scopulorum from four seed sources grown in southeastern Nebraska. The relation of projected leaf area to leaf dry weight and volume was also determined. Total surface area was estimated to be 3.2 times the projected surface area. This relationship was independent of seed source or crown position. Projected leaf area can be satisfactorily estimated from weight or volume. However, these relationships differed by crown position or seed source. These results indicate that leaf area of mature juniper foliage may be rapidly estimated through measurement of projected surface area. Further, the leaf area of large samples may be estimated by determining the appropriate specific leaf area or surface-to-volume ratios. For. Sci. 38(1):61-67.
A Comparison of Hierarchical Bayes and Empirical Bayes Methods with a Forestry Application
Authors: Green Edwin J. , Strawderman William E. 
Published: April 2024

Abstract
Gibbs sampling for generating marginal posterior distributions in Bayesian analysis is introduced to the forestry literature. Hierarchical Bayes and (parametric) empirical Bayes methods are compared theoretically and with a practical example. It is shown that in the latter procedures, the error due to estimating the hyperparameters from the marginal distribution of the data is ignored. This results in underestimating the scale of the marginal posterior distributions. For. Sci. 38(2):350-366.
The Efficiency of Half-Sib, Half-Diallel and Circular Mating Designs in the Estimation of Genetic Parameters in Forestry: A Simulation
Authors: Huber Dudley A. , White Timothy L. , Hodge Gary R. 
Published: April 2024

Abstract
A technique based on MIVQUE (minimum variance quadratic unbiased estimation) and the first approximation of the variance of a ratio was used to compare efficiency per unit observation in lowering the variance of estimation of three genetic ratios (single tree heritability, Type B correlation, and dominance-to-additive variance ratio). The efficiency comparisons were made over eight levels of genetic control for three mating designs (half-sib, half-diallel, and circular with four crosses per parent) with variable numbers of parents at two or five locations. The field design was held constant within a location as four randomized complete blocks with a six-tree row-plot per cross (full-sib designs) or per half-sib family (half-sib design). For heritability estimation the half-sib mating design is the most efficient over numbers of location and parents in seven of the eight levels of genetic control, and the circular design is more efficient over all levels examined than the half-diallel design. For estimation of Type B correlation the circular design is superior under five of the eight genetic control levels and superior for every case examined to the half-diallel design. In the remaining 3 Type B correlation estimation cases, the half-sib design is superior. For dominance-to-additive variance ratio estimation, the half-diallel design offers little, if any, advantages over the circular design. Optimal numbers of parents (highest efficiency) for a mating design exist only for the half-diallel design and optima are extant for all three genetic ratios. Optimal numbers of locations exist for all three mating designs and vary with mating design and level of genetic control. For. Sci. 38(4):757-776.
Population Differentiation in Seedling Root Size Between Adjacent Stands of Jack Pine
Authors: Wright Robert A. , Wein Ross W. , Dancik Bruce P. 
Published: April 2024

Abstract
Seeds from adjacent wet-site and dry-site jack pine stands were planted in a common growth chamber, and seedlings were grown with and without drought. Population differentiation in root and shoot growth traits was assessed 14 and 35 days after seedling emergence. Seedlings originating from the wet site had significantly more tertiary roots than those originating from the dry site. Differences between wet- and dry-site populations in secondary root length and shoot biomass disappeared when adjusted for the effects of higher mean seed weight in the dry-site population. The strength of correlations between seedling size parameters and seed weight varied with seedling age and exposure to drought. Droughty conditions inhibited secondary and tertiary but not primary root growth. For. Sci: 38(4):777-785.
Modeling Rubber Tree Root Disease Epidemics with a Markov Spatial Process
Authors: Chadoeuf J. , Pierrat J. C. , Nandris D. , Geiger J. P. , Nicole M. 
Published: April 2024

Abstract
Root diseases of the rubber tree (Hevea Brasiliensis) due to Rigidoporus lignosus (Klotzsch) Imaz. and Phellinus noxius (Corner) G.H. Cunn spread along planting lines and cause serious damage. Various control methods exist. A mathematical model was developed which allows the influence of their various parameters on the dynamics of an epidemic to be evaluated. The health status of the trees on a planting line was considered as a Markov process. The model parameters were given a biological interpretation and estimated using the results of an epidemiological survey carried out in Côte d'Ivoire from 1977 to 1984. Hypotheses of influence of dead trees before the survey, stationarity of secondary infection, and development of initial infection were tested. By simulation of the main model, the parameters were linked to percentages of infected trees on each inspection and of healthy trees at the end of the epidemic, thereby allowing the effects of the control methods to be evaluated according to their nature, efficiency, and mode of application. FOR. SCI. 39(1):41-54.
Control Variate Estimators of Survivor Growth from Point Samples
Authors: Roesch F. A. , Van Deusen P. C. 
Published: April 2024

Abstract
Two estimators of the control variate type for survivor growth from remeasured point samples are proposed and compared with more familiar estimators. The large reductions in variance, observed in many cases for estimators constructed with control variates, are also realized in this application. A simulation study yielded consistent reductions in variance which were often 50% and occasionally over 70%. FOR. SCI. 39(1):66-77.
Douglas-fir Nutrients and Terpenes: Potential Resistance Factors to Western Spruce Budworm Defoliation
Authors: Clancy Karen M. , Itami Joanne K. , Huebner Daniel P. 
Published: April 2024

Abstract
Differences in the nutritional quality of Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) foliage may explain why some individual trees are more resistant or susceptiable than others to damage from the western spruce budworm, Choristoneura occidentalis Freeman. We compared levels of foliar nutrients (nitrogen, sugars, phosphorus, potassium, calcium, magnesium, copper, manganese, zinc, iron, sodium, and sulfur) and allelochemicals (mono- and sesquiterpenes) between "resistant" (light defoliation history) and "susceptible" (history of heavy defoliation) Douglas-fir trees in 1989 and 1990. Phenology of bud burst and the radial growth rate of the trees were also examined. Susceptible trees had lower levels of N and sugars than resistant trees. These results agreed with published predictions from artificial diet bioassays. Moreover, susceptible trees had mineral/N ratios (for P, K, Ca, Mg, Cu, and Zn) which were closer to the optimum levels previously established in diet bioassays. There were no detectable differences in foliar concentrations of terpenes. However, susceptible trees had a greater proportion of total terpenes that were monoterpenes, whereas resistant trees had a greater percentage of oxygenated monoterpenes. Resistant trees also had delayed bud burst and shoot expansion compared to susceptible trees, and they had accumulated more radial growth over the past 25 yr, implying they were more vigorous than susceptible trees. FOR. SCI. 39(1):78-94.
The Maximum Density Concept Applied to Uneven-Aged Mixed-Species Stands
Authors: Sterba Hubert , Monserud Robert A. 
Published: April 2024

Abstract
In even-aged pure stands, the relationship between density and quadratic mean diameter of different stands can be described by a hyperbola, the coefficients of which depend allometrically on dominant height (Sterba's modified Competition Density Rule). From the equations describing these relationships the slope of Reineke's maximum density line can be calculated and (for a given data set) tested against the hypothesis that this slope is - 1.605. Data from 134 even- and uneven-aged mixed species stands in northern Idaho and northwestern Montana showed that this slope depended on the skewness of the dbh1.5 distribution, which in turn was correlated with structural stand characteristics like "unevenagedness" and species mixture. The parameters of the extended Competition Density Rule were simultaneously estimated by nonlinear regression under an assumption relating asymptotic dominant height and maximum basal area by habitat type. Results demonstrated that both the maximum basal area at a given dominant height are higher in even-aged pure stands (with smaller skewness of the dbh1.5 distribution) than in uneven-aged mixed stands. Furthermore, the differences in maximum stem number and maximum basal area resulting from differing skewness decrease with increasing dominant height. Large differences in maximum basal area can be shown between different habitat types and any given site index, thus demonstrating that habitat types can be used to distinguish yield levels sensu Assmann. For. Sci. 39(3):432-452.
Use of TREGRO to Simulate the Effects of Ozone on the Growth of Red Spruce Seedlings
Authors: Laurence J. A. , Kohut R. J. , Amundson R. G. 
Published: April 2024

Abstract
TREGRO, a model developed to simulate the growth of sapling red spruce (Picea rubens Sarg.), was parameterized to grow 2- to 3-yr-old seedlings. Results of the simulation compared favorably to actual growth of seedlings used in a field study of the effects of ozone and acidic precipitation on tree physiology and development. Furthermore, a 10-yr simulation produced a modeled tree that corresponded to saplings used in another field experiment. Additional simulations were conducted to compare predicted effects of ozone on seedling growth to those measured in controlled experiments. Based on the performance of the model, we believe TREGRO can be used effectively to simulate both seedling and sapling red spruce growth, and the potential effects of ozone on the development of the trees. For. Sci. 39(3):453-464.
Fitting Discrete-Time Dynamic Models Having Any Time Interval
Authors: McDill Marc E. , Amateis Ralph L. 
Published: April 2024

Abstract
When the desired time interval of a difference equation is not the same as the interval at which the data used to fit the equation were collected (the measurement interval), some kind of interpolation method is necessary before fitting. Linear growth assumptions, which are often used for such interpolations, are almost always inconsistent with the growth function that is estimated and can lead to biased growth projections. A more logical approach is to use the hypothesized functional form of the difference equation as the basis for interpolation. Two interpolation methods based on this approach are presented. With one method, both the interpolation and the parameter estimation steps are implemented simultaneously. The second method implements the interpolation and parameter estimation steps separately and requires repeated model fittings until consistency is obtained between both steps. The procedures are demonstrated using a tree height growth example. Results are compared with an integrated, continuous-time version of the growth model that can be fitted without interpolation. Growth projections obtained with the proposed interpolation methods are closer to the projections obtained with the integrated, continuous-time model than projections obtained with other commonly used interpolation methods. A simple Monte Carlo analysis showed that two common interpolation methods based on linear assumptions produce biased parameter estimates but failed to show any bias in the parameter estimates obtained with the proposed methods. Parameter estimates obtained with the new interpolation methods converge to limiting values as the time interval of the difference equation is shortened. These limiting values can be used as estimates of the parameters of continuous-time versions of the growth model. For. Sci. 39(3):499-519.
Early Successional Pathways Following Wildfire and Subsequent Silvicultural Treatment in Douglas-Fir/Hardwood Forests, NW California
Authors: Stuart John D. , Grifantini Michael C. , Fox III Lawrence 
Published: April 2024

Abstract
Early successional sites were contrasted with old-growth Douglas-fir/hardwood forests to detect community-level, life form, and species diversity differences due to postwildfire silvicultural treatments. Treatments included: (1) salvage logged after wildfire; (2) not salvage logged after wildfire; and (3) previously established plantations. These silvicultural treatments were compared 2 yr after a 1987 wildfire and 12 yr after a 1977 wildfire. There was more forb and shrub cover on 1987 unsalvaged sites than on salvaged. Sites salvaged following the 1977 fire had more hardwood cover but less shrub cover than unsalvaged sites. Old-growth sites had more conifer and hardwood cover than the early successional sites. There was no difference in species diversity among the successional treatments; old-growth sites, however, were less diverse than all treatment sites combined. Based on these and results from other studies, tanoak and other hardwoods inhibited the establishment and growth of Douglas-fir on salvaged sites, while deerbrush and other shrubs inhibited Douglas-fir on unsalvaged sites. For. Sci. 39(3):561-572.
Fuel Loading, Bulk Density, and Depth of Forest Floor in Coast Redwood Stands
Authors: Finney Mark A. , Martin Robert E. 
Published: April 2024

Abstract
The relationship between forest floor depth and bulk density was examined for purposes of estimating fuel loading and consumption in forests dominated by the coast redwood (Sequoia sempervirens [D. Don] Endl.). Data were obtained from 47 samples at 2 sites. Samples of forest floor varied from 2 to 10 cm deep. For each sample, organic material was excavated in 1 cm strata within a 20 x 20 cm frame. Multiple regression analysis indicated that bulk density increased with strata depth, although a given stratum had lower bulk density in deeper profiles (P = 0.05). In practical terms, these variations have a small effect on the accuracy of estimates of forest floor consumption derived using the constant mean bulk density. For. Sci. 39(3): 617-622.
Adaptive Cluster Sampling for Forest Inventories
Authors: Roesch Francis A. 
Published: April 2024

Abstract
Adaptive cluster sampling is shown to be a viable alternative for sampling forests when there are rare characteristics of the forest trees which are of interest and occur on clustered trees. The ideas of recent work in Thompson (1990) have been extended to the case in which the initial sample is selected with unequal probabilities. An example is given in which the initial sample of trees is selected with probability proportional to tree basal area. If a characteristic of interest is observed on a sample tree, additional trees within a fixed distance of the sample tree are also included in the sample. For. Sci. 39(4):655-669.
Calibrating a Model of Stochastic Effects on Diameter Increment for Individual-Tree Simulations of Stand Dynamics
Authors: Stage Albert R. , Wykoff William R. 
Published: April 2024

Abstract
Stand dynamics is the expression of variation in tree and site attributes within the stand operating through the physiologic processes of establishment, accretion, and mortality. Because stand dynamics is the consequence of deviation-amplifying processes, models of stand dynamics should include both variation in processes attributable to known causes as well as to causes that can only be included by stochastic representation of the unexplainable residuum. When the magnitude and serial correlation of unexplained sources of variation in diameter increment are modeled by addition of a random variable, simulated development of both stand volume and spread of diameters are affected. In this report, we develop a model of the tree-to-tree component of unexplained variation that affects stand dynamics. This model is intended for use in individual-tree models of stand development in which time advances in intervals of unequal length. Our model combines results from published time-series analyses with original analyses of residuals from increment models and of measurement variation for diameter increment within individual trees. This eclectic approach is required because extensive data sets do not exist that include adequate samples of the factors known to affect increment and also include information required to model the error structure as well. For. Sci. 39(4):692-705.
The Relationship Between Timber Production, Local Historical Events, and Community Social Change: A Quantitative Case Study
Authors: Force Jo Ellen , Machlis Gary E. , Zhang Lianjun , Kearney Anne 
Published: April 2024

Abstract
This paper reports on a case study examining the relationship between timber production, local history, and community social change in a timber-dependent community over a 60-yr period. We hypothesize that community social change is associated with changes in the production level of the local resource system and/or local historical events. Regression models were developed for four community social change variables: size (number of employees), structure (number of churches), cohesion (number of marriages), and anomie (number of arrests). Indicators of timber production and local historical events were treated as independent variables influencing community social change. Local history events were divided into four categories: (1) nontimber related economic development, (2) timber-related development, (3) natural disasters, and (4) social unrest. The arrests model has a coefficient of determination (R²) of 0.86. This model included four independent variables: (1) mill production, (2) natural disasters, (3) national forest harvest, and (4) nontimber development. The model for the number of employees in timber-related jobs, with an R² of 0.58, includes both timber production and local history independent variables. The paper concludes with a discussion of the implications of these findings for the development of theory concerning timber-dependent communities. For. Sci. 39(4): 722-742.
Family Differences in Equations for Predicting Biomass and Leaf Area in Douglas-Fir (Pseudotsuga menziesii var. menziesii)
Authors: St. Clair J. B. 
Published: April 2024

Abstract
Logarithmic regression equations were developed to predict component biomass and leaf area for an 18-yr-old genetic test of Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco var. menziesii) based on stem diameter or cross-sectional sapwood area. Equations did not differ among open-pollinated families in slope, but intercepts assuming equal slopes did differ for equations predicting leaf, branch, or bark biomass, or leaf area. These results may be explained by family differences in partitioning between stemwood and bark and between stem and crown. Predictions of biomass and leaf area based on equations developed in this study differed from predictions based on equations from other studies by as much as a factor of two, suggesting that discretion is needed when applying equations to other sites at other stages of stand development and with other ranges of tree sizes. For. Sci. 39(4): 743-755.
Characterizing Spatial Patterns of Trees Using Stem-Mapped Data
Authors: Moeur Melinda 
Published: April 2024

Abstract
Procedures for stem-mapping trees on fixed area plots are described. Two statistical procedures for analyzing spatial patterns of the completely mapped tree data are presented. These procedures, known as nearest neighbor analysis and Ripley's K(d) function, consider the cumulative distributions of distances between trees, compared to a distance distribution for a point pattern generated by a random process. Nearest neighbor uses tree-to-nearest-tree distances, and Ripley's K(d) considers distances between all pairs of trees. Both procedures include edge correction schemes for trees near plot boundaries. The two analyses were applied to stem-mapped data from several old-growth study plots to investigate spatial interactions within and between groups of canopy trees. Patterns for trees in different mortality, size, and competitive classes were analyzed separately. Results showed that between-tree competitive interactions drive forest patterns from clustering toward regularity. There was also evidence that canopy gaps are an important mechanism in the regeneration process. The examples illustrate how spatial pattern analysis can be useful in describing and interpreting complicated development processes that result from competitive interactions between individual trees. For. Sci. 39(4):756-775.
Estimating the Historic Probability of Stand-Replacement Fire Using the Age-Class Distribution of Undisturbed Forest
Authors: Reed William J. 
Published: April 2024

Abstract
A simple probabilistic model for the destruction of forest stands by fire is used to determine a likelihood function for the problem of estimating the per annum probability of stand-replacement fire using data in the form of areas in various age classes of undisturbed old-growth forest. This enables the estimation of either an age-independent fire probability or of the parameters of a parametrically defined age-dependent probability. The model includes contagion effects (the probability of a stand burning being increased by other stands burning). Maximum likelihood is used to obtain estimates of the age-independent per annum probability of stand-replacement fire (or the parameters of an age-dependent model), along with a contagion parameter. Confidence intervals for the fire probability are also obtained. For. Sci. 40(1):104-119.