bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic and Environmental Components of Variation of Site Index in Inland Douglas-Fir
Authors: Monserud Robert A. , Rehfeldt Gerald E. 
Published: April 2024

Abstract
Results from two disparate and independent studies of inland Douglas-fir (Pseudotsuga menziesii [Mirb] Franco var. glauca) were combined to answer the following questions: First, how much variation in site index is associated with genetic variation? Second, what is the relative importance of the genetic and environmental components of phenotypic variation in explaining differences in mean height among stands of mature trees? Third, what is the magnitude of the interaction? An index to genetic variation, based on 3-year seedling height in provenance tests, accounted for approximately 40% of the variation in both 50-year and 100-year dominant height (i.e., site index) among 135 natural stands in northern Idaho and western Montana. Combining the genetic index and simple environmental variables (elevation, habitat series, latitude, longitude) accounted for nearly half the variation in site index. Path analyses estimated a strong correlation (0.76) between genotype and environment, reflecting the steep adaptive clines that are well known for this species. The analysis also indicated that the genotype is about a third more important than the contemporary environment in determining phenotypic variation in dominant height of natural stands. The results suggest that a combined genetic/mensuration model has potential to improve both tree breeding efforts and stand management. For. Sci. 36(1):1-9.
Stability Parameter Estimates for Stem Volume for Loblolly Pine Families Growing in Different Regions in the Southeastern United States
Authors: McKeand S. E. , Li Bailian , Hatcher A. V. , Weir R. J. 
Published: April 2024

Abstract
Stability analyses to evaluate genotype x environment (G x E) interaction for individual stem volume at 8 years of age were conducted in trials of open-pollinated loblolly pine (Pinus taeda L.) families established along an East-West (E-W) transect in coastal Mississippi, Alabama, Georgia, and Florida and along a North-South (N-S) transect from Virginia to Florida. The E-W analysis included 21 sites, and the N-S anlaysis included 20 sites. The stability analyses regressed the family-site means against site means. A family had average stabilty if the slope of the regression line (b) did not differ from the expected value of b = 1.0 and if the coefficient of determination (R²) of the regression was high. The family was unstable but responsive to site changes if the slope was b &gt; 1.0. The family was very stable across sites (i.e., did not respond to site changes) when the slope was b &lt; 1.0 across sites.
The vast majority of the families tested had average stability for volume at age 8. In the E-W tests, 35/43 families had b ≈ 1.0 with high R² values. In the N-S tests, 32/43 had b ≈ 1.0 with high R² values. Although significant G x E interaction was found for the other families in the tests, the biological and economic importance of the interaction was minimal, since there was a relatively strong positive relationship between family stability value (b) and family mean volume performance (r = 0.75 in E-W tests, r = 0.62 in N-S tests). The convergence of the heterogeneous family slopes across sites to a common point indicated that very little family rank change occurred. The stability values in the E-W and the N-S tests were highly correlated (r = 0.94) to each other. With such high repeatability among the 34 common families, the inheritance of stability values appears strong. For. Sci. 36(1):10-17.
Effects of Phosphorus and Ectomycorrhizas on the Carbon Balance of Loblolly Pine Seedlings
Authors: Rousseau J. V. D. , Reid C. P. P. 
Published: April 2024

Abstract
The influence of phosphorus fertilization and mycorrhizal development on net photosynthesis, dry matter, shoot-root partitioning, and shoot dark respiration was examined in loblolly pine. Seedlings, initially grown for 10 weeks under low phosphorus (P) conditions, were either fertilized with 0.1, 1.0, 4.0, 8.0, or 12.0 μg g-1 p and left nonmycorrhizal, or inoculated with three different concentrations of a mycelial slurry of Pisolithus tinctorius and fertilized with only 0.1 μg g-1 p. After an additional 7 weeks, net photosynthetic rate of all seedlings was measured followed by harvesting and determination of P content of foliage, and dry matter of foliage, stem, and roots. Both phosphorus fertilization and mycorrhizal development caused a substantial increase in the net rate of photosynthesis and dry matter accumulation, but neither treatment resulted in significant changes in shoot-root allocation of dry matter or shoot dark respiration. At low and medium levels of mycorrhizal development, the net photosynthetic response to mycorrhizal formation appeared to be due to enhanced P nutrition. However, at high levels of mycorrhizal development, as much as 17% of the total increase in the net photosynthetic rate that resulted from mycorrhizal development, may be attributed to mechanisms other than enhanced phosphorus nutrition. For. Sci. 36(1):101-112.
Improved Chestnut Tree Condition Maintained in Two Connecticut Plots after Treatments with Hypovirulent Strains of the Chestnut Blight Fungus
Authors: Anagnostakis Sandra L. 
Published: April 2024

Abstract
In two forest plots, competing trees were killed or cut around stump sprouts of American chestnut trees. Chestnut blight cankers were treated with hypovirulent (dsRNA-containing) strains at least once a year for 4 years to control the blight disease. Nine years after the first treatment, abnormal cankers were found as far as 75 and 55 meters from the edges of the treatment areas, and strains isolated from these cankers contained dsRNA molecules. The dsRNA was found in strains with vegetative compatibility types different from those of the treatment strains, indicating that dsRNA had spread to other strains and had been maintained in the pathogen population. Trees in areas with abnormal cankers had more live stems per sprout clump and more cankers per live stem than trees in a comparison area with a similar harvest history, and more than trees in an undisturbed forest area. For. Sci. 36(1):113-124.
Nematode-Induced Pine Wilt Disease: Factors Influencing Its Occurrence and Distribution
Authors: Rutherford T. A. , Mamiya Y. , Webster J. M. 
Published: April 2024

Abstract
Bursaphelenchus xylophilus, pinewood nematode, and B. mucronatus are members of the pinewood nematode species complex (PWNSC) from forested areas of the northern hemisphere. In the presence of suitable vectors, pathogenic forms of the PWNSC cause pine wilt disease in susceptible tree species in very warm climates. Pine wilt disease is expressed rarely in the northern hemisphere outside of Japan and south China. The disease is expressed only where susceptible pines have been introduced into environments warmer than their natural climatic range, or where pathogenic isolates of the PWNSC have been introduced into warm climates containing susceptible tree species. It is probable that the pine wilt epidemic in Japan is a result of a pathogenic form of the PWNSC being introduced around the turn of the century. Pine wilt disease has not been recorded for any part of North America, Europe, or Asia where mean daily summer temperatures are 20°C or below regardless of the presence of susceptible trees or pathogenic PWNSC isolates. Some PWNSC isolates from northern regions of Europe and North America move and reproduce more rapidly at lower temperatures than do PWNSC isolates from warmer climates. These characteristics may be factors that contribute to the differences in pathogenicity of different isolates of the PWNSC to different pine species. For. Sci. 36(1):145-155.
Value of Production Orchards Based on Two Cycles of Breeding and Testing
Authors: Williams Claire G. , de Steiguer J. Edward 
Published: April 2024

Abstract
As breeding cycles become increasingly shorter, it may not be profitable to install a production seed orchard at the completion of each cycle. Using a case study approach, we compare two mutually exclusive orchard strategies: skipping a third-generation seed orchard (while upgrading an existing second-generation orchard) versus establishing a third-generation orchard. Using net present value as a decision-making criterion, skipping a third-generation loblolly pine orchard is the better strategy when (a) genetic gain in height from third-generation parents is less than or equal to 7% over first generation parents, (b) annual demand for seedlings is less than 4000 ac annually, and (c) harvest in a third-generation orchard begins at least 11 years before it becomes obsolete. Foregoing a third-generation orchard saves establishment capital but carries a stringent commitment to accelerated breeding and testing. Acceptance of the risk associated with genetic gain projection is critical to the third-generation orchard decision. For. Sci. 36(1):156-168.
The Long-Run Timber Supply Function
Authors: Williams Jeremy S. , Nautiyal J. C. 
Published: April 2024

Abstract
The long-run equivalent annual timber supply functions resulting from two increasingly complicated versions of the Faustmann model were derived and examined. In both cases, the expression for the equivalent annual quantity of timber supplied was identical. A second main result was the mathematical proof that the slope of the long-run timber supply curve is positive along its entire length when establishment costs are fixed and variable. Some calculations were made using a well-established yield function for jack pine in Ontario, and these supported the theoretical conclusions. In contrast, the use of V*/t* as the equivalent annual output incorporates the implicit assumption that the discount rate is zero. For. Sci. 36(1):77-86.
Estimating Trends in Tree-Ring Data
Authors: Visser Hans , Molenaar Jaap 
Published: April 2024

Abstract
Two methods from econometrics are introduced to estimate growth trends in time series of ring widths or basal-area increments. First, a trend model is described with a stochastic level and slope. The second model combines a doubly differenced trend and an ARMA model additively. Both models are put into a state-space form and are estimated using the discrete Kalman filter. Unknown noise variances, which control the flexibility of the trends, can be estimated by maximum-likelihood optimization or chosen by hand. It is concluded that the trend plus AR (1) model in combination with ML estimation performs very well. This model is attractive, because the ML-estimation procedure enables an objective choice for unknown parameters. Examples are given of two special features: the prediction of future growth, and the weighing of missing or unreliable data. Finally, both models are compared with spline interpolation and are validated by means of simulated time series. For. Sci. 36(1):87-100.
Response of Optimal Stand Rotation and Management Intensity to One-Time Changes in Stumpage Price, Management Cost, and Discount Rate
Authors: Nautiyal J. C. , Williams Jeremy S. 
Published: April 2024

Abstract
A two-decision-variable, single-stand timber production model is presented, designed along lines suggested by classical economic production theory and standard biological growth theory. Management was interpreted as being comprised of a number of productive activities, which makes the model more general than that used by previous authors. Departing from work by Chang (1983), the sign of the second-order cross-partial derivative of volume with respect to rotation age and management intensity was found to be positive in a typical forest management scenario. The analogous partial derivative of soil expectation value was negative. It was then possible to show algebraically that a one-time increase in stumpage value induced a higher optimal management intensity and a lower rotation age. A one-time decrease in the cost of management caused changes of the same nature. Other methods were used to determine a one-time increase in the discount rate reduced both the optimal management intensity and rotation length, although the cost structure may be unusual enough to have the opposite effect on the optimal rotation. An inconsistency in the form of the production function used by Chang (1983) was found to account for the discrepancy between the comparative statics results reached in his empirical analysis and those found here. For. Sci. 36(2):212-223.
A Dynamic Model of Timber Markets
Authors: Brazee Richard , Mendelsohn Robert 
Published: April 2024

Abstract
A theoretical model of the dynamics of timber markets is developed. The adjustment process over time which a competitive timber market should undergo as a result of unanticipated demand shifts is analyzed. The adjustment process is characterized by an initial price shock and then a relatively long period of gradually changing prices, harvest ages, and harvest levels. This adjustment leads to a new steady state characterized by a fully regulated forest managed with Faustmann rotations. For. Sci. 36(2):255-264.
Classification of Forest Vegetation in North-Central Minnesota Using Landsat Multispectral Scanner and Thematic Mapper Data
Authors: Moore Margaret M. , Bauer Marvin E. 
Published: April 2024

Abstract
Computer classifications of Landsat-5 Thematic Mapper (TM) and Multispectral Scanner (MSS) data were evaluated to determine how forest and sensor characteristics affect the classification accuracy of Minnesota forest cover types. The test area was Itasca State Park in north central Minnesota. The experiments involved comparisons of sensors differing in spectral and spatial resolution.
To evaluate classification performance the Landsat classification maps were compared on a pixel by pixel basis with a digitized reference map of the Park. Classification results were compared for statistically significant differences using discrete multivariate statistics. Classification accuracies ranged from 26 to 86%, depending upon the sensor, number of classes, and performance measure used.
The most significant result was that the increased spectral/radiometric resolution of the TM data resulted in 7-15% absolute increase in forest cover classification accuracy over MSS data using conventional methods. The best spectral band combination was one band each from the visible, near infrared, and middle infrared. For. Sci. 36(2):330-342.
An Appraisal of the IIASA Model of the Global Forest Sector: Advances, Shortcomings, and Implications for Future Research
Authors: Cardellichio Peter A. , Adams Darius M. 
Published: April 2024

Abstract
The IIASA Global Forest Sector Trade Model is placed in the broader context of other forest sector models. Based on theoretical considerations and sensitivity analysis of the model, its strengths and weaknesses are discussed. The model provides a versatile and sophisticated system for analyzing forest sector policies, and incorporates many critical interregional and interproduct linkages that lie outside the sphere of previous modeling work. However, the model is a first-generation effort and requires further development to realize its potential as an analytical system. While the general structure of the model is well suited for policy analysis, individual sectors need to be designed with more careful attention to how their specification affects the overall simulation properties of the model. Extant data bases are not used optimally: data are used too intensively in some areas, while there are opportunities for expanded data use in others. Due to the complexity of the model and need for additional development, a substantial resource commitment must be made to understand, modify, and use it effectively. For those who make the investment, the Global Forest Sector Trade Model should prove useful for forest policy and forest industry research. For. Sci. 36(2):343-357.
Phosphorus Uptake Capacity of 14-Year-Old Loblolly Pine as Indicated by a 32P Root Bioassay
Authors: Pennell Kurt D. , Allen H. Lee , Jackson William A. 
Published: April 2024

Abstract
Excised loblolly pine roots were exposed to a 32p-labelled solution for 20 minutes to measure their capacity for P uptake. On five dates from March 1985 to March 1986, root samples were collected from 14-year-old loblolly pine which had received 101 kg P · ha-1 and 0 kg P · ha-1 when they were planted. Phosphorus uptake by roots of nonfertilized loblolly pine (1.10 μmol P · g-1 · hr-1) was significantly greater than that by roots of fertilized loblolly pine (0.72 μmol P · g-1 · hr-1) when sampled between June and October, but no difference was detected when sampled in March. Phosphorus uptake was decreased by approximately 50% at 7°C compared to 25°C, and in the presence of metabolic inhibitors. Phosphorus concentrations, measured after the bioassay, of roots from fertilized trees (0.93 g P · kg-1) were significantly greater than those of roots from nonfertilized trees (0.45 g P · kg-1) on all five sampling dates. Capacity for root P uptake did not have an advantage over root or foliar P concentrations as an indicator of P stress, and does not appear to be a practical diagnostic tool for semimature loblolly pine. For. Sci. 36(2):358-366.
A Comparison of the Pattern Search Algorithm and the Modified PATH Algorithm for Optimizing an Individual Tree Model
Authors: Yoshimoto Atsushi , Haight Robert G. , Brodie J. Douglas 
Published: April 2024

Abstract
A new stand-level dynamic programming algorithm was developed for determining the optimal residual diameter distribution for multiple stand entries. The proposed algorithm consists of the PATH algorithm and the concept of region-limiting strategies and iterated dynamic programming. Employing the proposed algorithm, a dynamic programming model was constructed with the Stand Prognosis Model, a single-tree/distance-independent growth model for forest types in the northern Rocky Mountains. Convergence, accuracy, and efficiency of the algorithm are discussed in comparison with a nonlinear programming algorithm, the Hooke and Jeeves method. For problems with three or more thinnings, the proposed algorithm yielded superior solutions with less computation time than did the Hooke and Jeeves method. For one and two thinning problems, the Hooke and Jeeves method provided better solutions. The advantage of the proposed algorithm stems from the ability of dynamic programming approaches to avoid including multiple partial local optima in the solution, and a clearer relationship to established principles of concave optimization. For. Sci. 36(2):394-412.
Projecting Stand Tables: A Comparison of the Weibull Diameter Distribution Method, a Percentile-Based Projection Method, and a Basal Area Growth Projection Method
Authors: Borders Bruce E. , Patterson William D. 
Published: April 2024

Abstract
Three yield projection models are compared and contrasted. All three models project yield implicitly by first projecting stand tables. The first model uses the Weibull probability density function, the second a percentile-based algorithm, and last a modification of an individual tree distance independent basal area projection model. It is shown that, for most criteria evaluated, the model which makes use of the distance-independent basal area projection algorithm is superior. For. Sci. 36(2):413-424.
Adoption Behavior of Technical Assistance Foresters in the Southern Pine Region
Authors: Hodges Donald G. , Cubbage Frederick W. 
Published: April 2024

Abstract
Evaluating the economic returns of forestry research has become a major concern of researchers and policy makers in the past decade. Before an accurate estimate of such returns can be estimated, however, information on the factors influencing individual adoption decisions and the timing of adoption needs to be understood. This paper presents the results of an analysis of the factors affecting assistance foresters' choices of management technology in the South. We surveyed public and private foresters assisting nonindustrial private forest landowners to determine what personal and external variables influence the adoption decisions of foresters. Specifically, we examined the variables related to the foresters' decisions to modify current management practices or use new technology. Using logit regression, we found that the forester's employer, information sources, professional membership, and perceptions of the management requirements in their region of responsibility can affect their adoption decisions. The research emphasis of even-aged management over the last 2 decades may be an additional factor in the foresters' decisions to change forest management decisions. For. Sci. 36(3):516-530.
Factors Influencing Forest Service Fire Managers' Risk Behavior
Authors: Cortner Hanna J. , Taylor Jonathan G. , Carpenter Edwin H. , Cleaves David A. 
Published: April 2024

Abstract
Fire managers from five western regions of the USDA Forest Service were surveyed to determine which decision factors most strongly influenced their fire-risk behavior. Three fire-decision contexts were tested: Escaped Wildfire, Prescribed Burning, and Long-Range Fire Budget Planning. Managers first responded to scenarios constructed for each decision-making context. Various types of risk were manipulated in each context to determine what factors could influence a shift in risk behavior. Following the presentation of scenarios, managers rated and ranked decision factors that might influence their decision-making on fire. Results show that safety, the resources at risk, public opinion, and the reliability of information were important influences on manager decisions. Local or regional policy changes and personal considerations had less influence. Manager ratings and ranking of what factors are important in fire decision-making were consistent with fire-risk decisions taken in each of the three decision contexts. Fire-risk behavior also varied from one geographic region to another and from one fire-decision context to another. Depending on the kinds of risks managers perceived, their decisions shifted along the risk-avoidance/risk-taking continuum. For. Sci. 36(3):531-548.
Active Potassium Uptake by Slash Pine Roots From O2-depleted Solutions
Authors: Fisher H. M. , Stone E. L. 
Published: April 2024

Abstract
Slash pine saplings were grown with their taproots divided between an upper chamber containing a well-drained peat-perlite mixture, and a lower solution-filled chamber. Roots developed in the lower chamber despite limited O2 availability, and exhibited active uptake of K from N2-sparged, hypoxic solutions. Treatments which altered the atmosphere composition (air to N2) surrounding the lower stems and basal taproots produced immediate large effluxes of K from the lower chamber root systems. This response was reversible and showed that submersed roots in hypoxic solutions depended on internal O2 transport from the basal taproot and stem to maintain normal metabolic functions. For. Sci. 36(3):582-598.
Alternate Expressions for the Economic Theory of Forest Fire Management
Authors: Rideout Douglas B. , Omi Philip N. 
Published: April 2024

Abstract
Two traditional economic efficiency criteria, minimization of cost plus net value change versus profit maximization, are compared in terms of the insights provided into fire management decisions. The historic rationale for favoring minimization over maximization is examined and questioned. Advantages of formulating the problem in terms of profit maximization include explicit attention to production relations obscured by previous graphical representations of the minimization criterion. The maximization formulation also facilitates more explicit treatment of revenue and objective functions. For illustration, we show the correspondence between fire management decisions and the firm with two inputs (presuppression, suppression) and two outputs (reductions in fire intensity and area burned). For. Sci. 36(3):614-624.