bluuebunny/crossref_metadata_2025 huggingface dataset:
Value of Production Orchards Based on Two Cycles of Breeding and Testing
Authors: Williams Claire G. , de Steiguer J. Edward
Published: April 2024

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

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

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

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

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

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

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

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

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

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

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

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

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

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.
Regional Variation in Growth Response of Coastal Douglas-Fir to Nitrogen Fertilizer in the Pacific Northwest
Authors: Peterson C. E. , Hazard J. W.
Published: April 2024

Hypothesis-testing for differences in growth responses among physiographic strata, thinning levels, and fertilizer dosage levels resulted in a set of empirical models for predicting volume increment response of even-aged coastal Douglas-fir to nitrogen fertilizer. Absolute and percent responses are estimated for stands both thinned and unthinned, as a function of dosage levels and physiographic provinces. Although not "highly" significant, the physiographic factor was retained in the models for purposes of refinement. For. Sci. 36(3):625-640.
Predicting Mortality in Mixed Oak Stands Following Spring Insect Defoliation
Authors: Crow Gerald R. , Hicks Ray R.
Published: April 2024

Data from 141 tenth-acre plots defoliated by a complex of looper species were summarized and analyzed using discriminant analysis. We found certain variables consistently associated with the status of trees as being live or dead (species, site quality, and aspect). Mortality was more likely among species in insect-preferred food classes, on better sites, and on north or northeast aspects. Classification of dead trees was more effective than for live trees. For. Sci. 36(3):831-441.
Feedback Thinning Policies for Uneven-Aged Stand Management with Stochastic Prices
Authors: Haight Robert G.
Published: April 2024

This paper presents an optimization model and a numerical method for determining feedback thinning rules for uneven-aged stand management when the stumpage price forecast is a stochastic process. Periodic thinning takes place over a finite time horizon, and the objective is to maximize expected present value. The thinning rules are based on a continuous function that maps the relationship between harvest intensity and observed stand value. The parameters of the function include its slope, location, and shape. The location parameter is defined as the stand reservation value, which is the minimum stand value required for harvest. Optimal parameter values are determined using stochastic simulation. Numerical results are presented using a stage-structured model for uneven-aged stands of California white fir (Abies concolor [Gord. & Glend.] Lindl. (Iowiana [Gord.])). Stumpage price is the sum of a deterministic constant and a normally distributed random error. With these assumptions, optimal feedback thinning policies have significantly higher expected present values than do thinning policies that ignore price fluctuations. However, feedback policies have greater volatility in harvest revenue over time. Sensitivity analysis shows that the expected present value of optimal feedback management increases as the level of price risk increases. For. Sci. 36(4):1015-1031.
Growth-Competition Relationships in Young Hardwood Stands on Two Contrasting Sites in Southwestern Wisconsin
Authors: Hix David M. , Lorimer Craig G.
Published: April 2024

Crown-based competition measures were used to assess the relationships between growth and competition for trees in young mixed-hardwood stands on two ecosystems with contrasting site conditions. The two southwestern Wisconsin ecosystems compared were gently sloping summits with deep loessal soils and steeply sloping southwesterly backslopes with loam soils. Individual trees were sampled from variable-radius plots located in 15 stands of 4 to 42 years old. The two best predictors of height growth are the height of a tree relative to the average height of dominants and codominants, and the cross-sectional area of the exposed portion of the crown at its widest point. The data confirmed theoretical relationships between growth and light intensity for species of differing shade tolerance. However, growth rates as a function of relative height did not approach an asymptote for any species, while growth response to increasing exposed crown area was asymptotic for the tolerant species. Species' relationships differed between the two ecosystems, with maximum height growth rates being lower on the drier site. Acer saccharum was the most efficient species (highest basal area growth rate) at the higher values of exposed crown area, but larger total crown size for sugar maple was a contributing factor in such cases. For. Sci. 36(4):1032-1049.
Pathogenic Variability Among Populations of the Pinewood Nematode, Bursaphelenchus Xylophilus
Authors: Kiyohara Tomoya , Bolla R. I.
Published: April 2024

Virulence of populations of Bursaphelenchus spp. associated with conifers varies throughout the range of this nematode in the United States and Japan. Populations of B. xylophilus (pinewood nematode, PWN) from Japanese black and red pine in the same and distantly separated pine stands in Japan range in virulence from 0-100% and there is a tendency for the most virulent populations to be in the northernmost part of the nematode's range where establishment has been relatively recent. Virulence of PWN populations, however, does not vary within a single pine or vector insect. Isozyme patterns are similar between virulent and avirulent populations and therefore cannot be used to differentiate them. Aspartate transaminase isozyme patterns can be used to differentiate between B. xylophilus and B. mucronatus. Pathogenicity of PWN in the United States depends on the interaction of the pine species with different PWN populations, the physiological status of the infected pine, and environmental conditions. Mating and reproductive potential, virulence, DNA sequence differences determined by restriction fragment length polymorphisms, and isozyme differences are useful criteria for studying population biology and genetics of PWN, and when used together, for describing speciation of Bursaphelenchus associated with conifers. For. Sci. 36(4):1061-1076.
Pine Tip Moth, Rhyacionia spp., Response to Herbaceous Vegetation Control in an Intensively Site-Prepared Loblolly Pine Plantation
Authors: Ross Darrell W. , Berisford C. Wayne , Godbee John F.
Published: April 2024

Herbicide release treatments were applied to an operationally regenerated loblolly pine (Pinus taeda L.) plantation to assess the effects of vegetation control on pine tip moth (Rhyacionia spp.) damage. Treatments included banded herbicide applications (1.5-m wide bands centered over rows of seedlings) for 1 or 2 years after planting, broadcast herbicide applications (total area covered) for 1 or 2 years after planting, and an untreated check. All of the herbicide treatments significantly reduced the mount of herbaceous vegetation and improved the survival and growth of planted pines. By the end of the third growing season, pine survival in the check plots (67%) was significantly less than survival in all of the herbicide-treated plots (≥92%). Trees in herbicide-treated plots suffered more tip moth damage than trees in the check plots during the first two growing seasons after planting, but by the third growing season, damage to trees in the check plots was equal to that in the herbidde-treated plots. The method or number of herbicide applications did not have a substantial effect on tip moth infestations. Pine growth gains resulting from reduced vegetative competition were more than enough to compensate for higher tip moth damage following herbicide treatments. However, increased tip moth damage still reduced potential growth gains. Two herbicide applications did not significantly improve pine survival or growth compared to one application, but the broadcast treatments produced slightly larger trees than the banded treatments by the end of the third growing season. For. Sci. 36(4):1105-1118.
Growth and Photosynthetic Responses to a Range of Light Environments in Chinese Tallowtree and Carolina Ash Seedlings
Authors: Jones Robert H. , McLeod Kenneth W.
Published: April 2024

Potted seedlings of Chinese tallowtree (Sapium sebiferum [L.] Roxb.) and Carolina ash (Fraxinus caroliniana Mill.) were grown in 5%, 20%, 53%, and 100% of full sunlight. Growth and dry mass partitioning at all light levels, differences between leaf photosynthetic systems developed at 20% and 100% light, and crown profiles of net photosynthesis (PN) in 53% of full sunlight were measured. Tallowtree dry mass peaked at 100%, light while ash dry mass peaked at 53% light. Expressed as a proportion of peak dry mass within species, growth of tallowtree exceeded that of ash at all light levels except 53% of full sunlight. In all but 100% light, tallowtree partitioned more dry mass to leaves than did Carolina ash. For plants grown in 100% light, PN was highly variable with low values in some tallowtree and most ash leaves, although highest PN occurred in ash. For plants grown in 20% light, PN was closely related to photosynthetic photon flux density (PPFD), and both species had similar PN Values at any given PPFD. For plants in 53% light, maximum PN occurred at the top of the crown in tallowtree and in the middle of the crown in Carolina ash. Tallowtree seedlings are shade tolerant and yet grow rapidly in full sun. For. Sci. 36(4):851-862.
A Shelterwood Method for Regenerating Red Oak in the Southern Appalachians
Authors: Loftis David L.
Published: April 2024

A shelterwood method is described that provides stand conditions that enhance the growth of established red oak advance reproduction, thereby improving the chances of maintaining an oak component in the next stand. Stocking of a mature, fully stocked stand is reduced to 60%, 65%, and 70% of initial stand basal area where oak site index is 70, 80, and 90 ft, respectively. The basal area reduction is accomplished from below using herbicides, leaving the main canopy essentially intact. This level and method of treatment prevents yellow-poplar, a primary competitor of red oak, from becoming established and growing prior to the final removal cut, and it eliminates most sprout competition from shade-tolerant subcanopy species after the final removal cut. The final removal cut can be made approximately 10 years after the initial treatment. For. Sci. 36(4):917-929.
Loblolly Pine Provenance Variation in Age of Transition from Juvenile to Mature Wood Specific Gravity
Authors: Szymanski Marcella B. , Tauer C. G.
Published: April 2024

Regional and seed source variation were examined for the age of transition from juvenile to mature wood specific gravity in loblolly pine (Pinus taeda L.) grown in Arkansas. No regional or seed source differences were found for the age of transition or rate of change from juvenile to mature wood specific gravity with an analysis of variance "F" test. However, contrasts for groups of provenance regions defined on the basis of broad geographic characteristics showed transition ages were earlier for regions west of the Mississippi (12.0-12.3 yr) when compared to eastern regions (12.6-13.0 yr). Variation in whole core specific gravity and juvenile and mature wood core specific gravity was significant on a source and regional basis. No regional or source differences were found for percent summerwood. Specific gravity was highest in the lost pines source, followed by sources from the northwest and northeast portions of the loblolly pine range, and lowest for sources from the gulf coast and interior portions of the loblolly range. Contrasts for groups of provenance regions reflect similar results for all specific gravity traits. Percent summerwood, whole core specific gravity, and juvenile and mature wood core specific gravity had negative phenotypic correlations with transition age. Whole tree specific gravity, basal area, and percent summerwood had positive phenotypic correlations with estimated core specific gravity. For. Sci. 37(1):160-174.
Integrated Forest Planning Across Multiple Ownerships and Decision Makers
Authors: Davis Lawrence S. , Liu Gao
Published: April 2024

Social evaluation of public and private land-use planning of forests and rangelands is increasingly integrated across multiple land ownerships and resolved in a politicized forum of multiple decision makers. Multicriterial optimization models have limited utility for decision analysis in this environment as they must be formulated from the perspective of a single decision maker. A flexible integer programming model is demonstrated as a useful and appropriate tool to simulate and explore the collective options in a multiple ownership integrated planning (MOIP) problem. Multiple budget constraints are featured in this model as a vehicle by which resource contributions from both landowners and nonlandowners can be explicitly recognized. The hypothesis that MOIP problems define a positive sum game is supported by analyzing the data set of published national forest plan Draft Environmental Impact Statements (DEIS) for California data set. For. Sci. 37(1):200-226.
Probit Analysis of Oak Wilt Transmission Through Root Grafts in Red Oak Stands
Authors: Bruhn Johann N. , Pickens James B. , Stanfield David B.
Published: April 2024

In pure stands of red oak species (subgenus Erythrobalanus) in Michigan's Upper Peninsula, individual oak wilt epicenters appear to expand virtually exclusively by movement of the pathogen through root grafts between diseased and healthy trees. Containment of individual disease epicenters can be accomplished by a combination of timely separation of grafted root systems and sanitation (to prevent overland establishment of new epicenters). Disease spread models were developed by probit analysis of field data. These models predict the probability that the oak wilt fungus will spread across root grafts to a healthy (target) tree during the year alter symptoms occur in a neighboring diseased (source) tree. Movement of the fungus was best predicted by a logarithmic transformation of the quotient obtained by dividing the sum of the diameters for the potential source and target trees by the distance between these trees. Multiple-stemmed source or target trees were accurately represented by the sum of the diameters of their component stems. Soil type was found to influence the relationship, presumably through its effect on rooting habit. Oak root systems appear to extend over greater distances through soils of the deeper and more uniformly sandy Grayling series than through those of the loamier Pemene series. The specific models developed depend on site-related data, and therefore should not be applied in other areas. However, the modeling approach is of general applicability and can be used to predict root graft spread of oak wilt in other areas. For. Sci. 37(1):28-44.
Chance-Constrained and Chance-Maximizing Mathematical Programs in Renewable Resource Management
Authors: Hof John G. , Pickens James B.
Published: April 2024

This paper discusses a broad range of approaches to optimizing natural resource allocation in the situation where amounts of available input(s) and/or amounts of desired output(s) are random. The paper begins by reviewing, the classic approach to this class of problems, "chance-constrained programming," followed by a discussion of "joint probability chance-constrained programming," and a new alternative "total probability chance-constrained programming." The paper then develops three "chance-maximizing" counterparts. Specific formulations for executing these approaches in natural resource management problems are developed that explicitly include the cumulative probability density functions. A forestry case example demonstrates .solution procedures and shows that the different approaches can yield substantially different results. Results from different solution procedures are also compared. For. Sci. 37(1):308-325.
A Note on Carmean's Estimate of Height from Stem Analysis Data
Authors: Newberry James D.
Published: April 2024

Carmean (1972) presented a method for adjusting height/age data from stem analysis. This adjustment is not correct when applied to that portion of a tree bole above the highest section point. In this part of a tree bole the adjustment always underestimates tree height for a given age. A simple modification is made to Carmean's method so that it is applicable to the top section of a tree. For. Sci. 37(1):368-369.
Confidence Intervals from Single Observations in Forest Research
Authors: Valentine Harry T. , Furnival George M. , Gregoire Timothy G.
Published: April 2024

A procedure for constructing confidence intervals and testing hypotheses from a single trial or observation is reviewed. The procedure requires a prior, fixed estimate or guess of the outcome of an experiment or sampling. Two examples of applications are described: a confidence interval is constructed for the expected outcome of a systematic sampling of a forested tract, and a hypothesis is tested in connection with a watershed experiment. Potential misuses of the procedure also are discussed. For. Sci. 37(1):370-373.
Topographic Influences on Nitrogen Cycling within an Upland Pin Oak Ecosystem
Authors: Zak Donald R. , Hairston Anne , Grigal David F.
Published: April 2024

Nitrogen mineralization and nitrification were studied within an upland pin oak (Quercus ellipsoidalis E.J. Hill) forest to determine if topography could be used to understand the spatial variability of N transformations within and among individual stands. Four upland pin oak stands were used for the study, and within each stand, transects were established on northeast (45° azimuth), southeast (135° azimuth), southwest (225° azimuth), and northwest (315° azimuth) facing aspects. Nitrogen mineralization and nitrification were measured at 5-wk intervals for 1 year at top, middle, and bottom slope position along each transect using an in situ soil incubation technique. Annual rates of mineralization among the four stands ranged from 3.0 to 6.7 g N m-2 yr-1, but were not significantly influenced by aspect or slope position. Although aspect had no effect on nitrification, bottom slope positions had significantly lower (0.3 g N m-2 yr-1) nitrification rates compared to middle (1.3 g N m-2 yr-1) and top (1.4 g N m-2 yr-1 slope positions. Annual N mineralization and nitrification increased with stand age. Slope position and aspect had little influence on N cycling rates within the subtle topography of east central Minnesota; time since disturbance seems to be the most important factor influencing the variability in N dynamics among upland pin oak stands. For. Sci. 37(1):45-53.
Western Hemlock and Douglas-Fir Seedling Development with Exponential Rates of Nutrient Addition
Authors: Burgess D.
Published: April 2024

Ingestad's concept of controlling relative addition rate was used in growing western hemlock (Tsuga heterphylla [Raf.] Sarg.) and Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) seedlings in styroblock containers under greenhouse conditions. Seedlings were fertilized for 14 weeks at different exponential rates following a 1 month pretreatment period. Based on their initial nitrogen contents, seedlings were fertilized with a complete Ingestad solution, twice weekly, at either a 1, 2, 4, or 6% per day exponentially increasing dosage, or with a constant amount each feeding (control treatment) of 0.991 mg N/seedling. Western hemlock and Douglas-fir seedlings grew fastest at the highest (6%) relative addition rate. Douglas-fir was more efficient than western hemlock at nitrogen uptake and succeeded in taking up the most nitrogen (55% of the nitrogen added) in the control treatment. Western hemlock was most efficient at nitrogen uptake in the 4% relative addition rate treatment, but still captured only 29.7% of the nitrogen added. Biomass allocation and nitrogen concentrations in seedlings of both species varied significantly with treatment, suggesting that different seedling types acclimated to different levels of nutrient stress could be produced using the concept of relative addition rate. The nitrogen concentrations of seedlings generally declined with time in the control and lowest relative addition rate treatments. For. Sci. 37(1):54-67.
A Simulation Model of the Role of Belowground Dynamics in a Florida Pine Plantation
Authors: Ewel Katherine C. , Gholz Henry L.
Published: April 2024

A model of a 29-yr-old slash pine (Pinus elliottii) plantation on a typical flatwoods site in north Florida evaluates the importance and magnitude of belowground processes in a forest. The model, which comprised 22 differential equations, most of them nonlinear, was parameterized with three sets of climate data and validated with measurements of soil moisture, soil CO2 evolution, root production, and root biomass.

Simulated gross primary productivity (GPP) in a year with normal rainfall was 29.5 Mg ha-1 yr-1 (C), which is consistent with measurements of GPP in a variety of north Florida sites. In the model, one-third of GPP was translocated to the roots, where more than 75% was spent on respiration. Root respiration varied little among the three simulations. Root turnover times were more variable. In the low rainfall simulation, root turnover time was 21% longer than in the other two simulations, which were nearly the same. Simulated P concentration in the soil and plant had much less effect on plant processes than soil moisture did. General agreement of transpiration rates with other studies indicated that evapotranspiration is the only major water loss in slash pine flatwoods. Simulated water-borne P losses from the site were therefore insignificant. Simulated foliage biomass varied considerably during the year, decreasing to less than haft its maximum biomass during an annual cycle in one of the simulations.

Comparison of the few sites with comparable estimates of C fixation and allocation suggests that 22%-43% of C fixed is used by roots, and that the proportion allocated to roots may be higher on nutrient-poor sites and sites with low temperatures. For. Sci. 37(1):397-438.
A Multivariate Model and Analysis of Competitive Strategy in the U.S. Hardwood Lumber Industry
Authors: Bush Robert J. , Sinclair Steven A.
Published: April 2024

Business-level competitive strategy in the hardwood lumber industry was modeled through the identification of strategic groups among large U.S. hardwood lumber producers. Strategy was operationalized using a measure based on the variables developed by Dess and Davis (1984). Factor and duster analyses were used to define strategic groups along the dimensions of cost leadership, focus, and differentiation. A five strategic group model was identified and examined for strategic orientation and intragroup homogeneity. Two groups had no distinctive strategic orientation that suggested a competitive advantage; one group exhibited an overall cost leadership strategy; one exhibited a differentiation strategy; and one group exhibited a dual overall cost leadership/differentiation strategy. Strategic change in the industry was predicted to be primarily toward increased differentiation. Three strategic groups indicated significant change in this direction, and one group indicated an increase along both the focus and differentiation dimensions. For. Sci. 37(2):481-499.
Price and Welfare Effects of Catastrophic Forest Damage From Southern Pine Beetle Epidemics
Authors: Holmes Thomas P.
Published: April 2024

Southern pine beetle (Dendroctonus frontalis) epidemics are periodically responsible for catastrophic levels of mortality to southern yellow pine forests. Traditional forest damage appraisal techniques developed for site specific economic analysis are theoretically weak since they do not consider aggregate impacts across ecosystems and related markets. Because the traditional model estimates losses only to producers with damaged forests, it provides misleading information from a distributional standpoint by ignoring impacts on producers with undamaged forests and timber consumers. An economic model of timber supply and demand is introduced and used to develop a new technique for estimating short-run market level impacts of catastrophic forest damages. The null hypothesis that catastrophic disruption of forest ecosystem production has no effect on timber markets is tested using intervention analysis and data on the recent Texas-Louisiana epidemic. Parameter estimates are used to compute short-run changes in economic welfare for producers on damaged forests, producers on undamaged forests, and timber consumers. Principal findings are: (1) changes in social welfare resulting from catastrophic damage to standing timber across forest ecosystems requires market-level analysis, and (2) the net change in economic welfare resulting from insect epidemics is unambiguously negative. For. Sci. 37(2):500-516.
Self-Thinning and Stand Density
Authors: Zeide Boris
Published: April 2024

Does the actual line of serf-thinning converge with the upper boundary of stand biomass in the course of stand development? This question is the source of continuing arguments about serf-thinning of forest stands. The relationship between average crown length and crown width can provide a solution to this question. If the lines diverge and horizontal canopy closure diminishes, then crown length would increase faster than crown width. Empirical data show that, indeed, the growth rate of crown length exceeds that of crown width. This fact indicates that the upper boundary of stand biomass is not the asymptote of self-thinning. Although the limiting line cannot be observed, it can be determined analytically. The notion of limiting density might be helpful in quantifying self-thinning, degree of disturbance, and stand density. For. Sci. 37(2):517-523.
The Structure of Forestry Production: Short-Run and Long-Run Results
Authors: Wear David N. , Newman David H.
Published: April 2024

This paper extends the study of regional forestry production to address long-run production possibilities using a restricted profit function approach. The model consists of two outputs, sawtimber and pulpwood; one variable input, regeneration effort; and two quasi-fixed inputs, land and growing stock. Estimation is performed using cross-sectional data of industrial timber production in the southeastern United States. Estimated values include own- and cross-price elasticities between inputs and outputs, Hicksian elasticities of substitution, shadow prices of the quasi-fixed factors, and long-run Marshallian elasticities. While short-run supply elasticities are consistent with earlier studies, long-run results show much greater supply responses as land and management inputs are given time to adjust. These results also suggest that ambiguous results regarding pulpwood and sawtimber substitutability found in previous studies can be explained by a shift from complementarity in the short run to substitutability in the long run. For. Sci. 37(2):540-551.
Relationships Between the Diameter Distributions Before and After Thinning
Authors: Murray D. M. , von Gadow K.
Published: April 2024

Specific equations to predict the change in diameter with thinning are derived from the statistical consistency conditions that ensure that the thinned and the remaining distributions add up exactly to the before thinning distribution. These equations contain two parameters, the location separation parameter and the scale separation parameter, that quantify the degree of selectivity of a thinning operation. For. Sci. 37(2):552-559.
Efficiency of Early Selections for Stem Volume and Predictions of Size Distributions of Selections in a Red Pine Spacing Trial
Authors: Magnussen Steen
Published: April 2024

Simulated phenotypic selections for superior stem volume at age 34 were carried out in a red pine spacing trial between age 10 and age 34. The efficiency of selections increased exponentially with selection age and with diminishing initial spacing. Interactions between spacing, age, and the intensity of selection modified the overall efficiency of early selections. The probability that a tree would remain in a given relative size class during a 2-or 4-year-period increased with age when the initial spacing was less than 2.1 m. Wider spacings induced a decline in these probabilities. Realistic predictions of future size class distributions of trees selected for superior size at age 10 were generated from a maximum of 4 years growth information with the help of Markov chains (transition probability matrices). Age 34 standardized means of early selections could be estimated within 2% from a quadratic response surface with age, spacing, and selection intensity (%-select) as independent variables. For breeding purposes, selections at age 10 appeared more attractive than later selections. Predictions of age 10 to age 34 years correlations of stem volume based on these Markov chains produced realistic results for plantations planted at a 3.0 m square spacing and closer. For. Sci. 37(2):593-612.
Genetic Variation in Nitrogen Use Efficiency of Loblolly Pine Seedlings
Authors: Li Bailian , McKeand S. E. , Allen H. L.
Published: April 2024

Seedlings of 23 open-pollinated loblolly pine (Pinus taeda L.) families were grown in a greenhouse at two nitrogen (N) levels (5 and 50 ppm). Differences among families for components of N use efficiency (NUE) were evaluated from measurements of biomass and N accumulation in different parts of seedlings. NUE, defined as stem biomass produced per unit of N applied, was partitioned into two major components: uptake and utilization efficiencies. Family differences were detected for NUE and its two components at low N and for utilization efficiency at high N. Heritability estimates indicated that NUE traits were under a moderate to high degree of genetic control. NUE and its components were generally positively correlated with root and shoot growth of seedlings. Families with more nitrogen (high uptake efficiency) had greater root length and stem height at low N but not at high N. Strong correlation of seedling root and shoot traits with NUE components indicated that genetic differences in N use may reflect differences in seedling growth. The relative contribution of uptake or utilization efficiency to the variation in NUE was different at the two N levels. At the high N level, differences among families for NUE were due largely to variation in utilization of absorbed N, while uptake and utilization efficiencies contributed equally to the variation in NUE at the low N level. Furthermore, some families with similar levels of NUE showed large differences in the relative contribution of uptake and utilization efficiency. For. Sci. 37(2):613-626.
A Bayesian Belief Network Advisory System for Aspen Regeneration
Authors: Haas Timothy C.
Published: April 2024

The probability-based Bayesian Belief Network (BBN) methodology is demonstrated to be an alternative to rule-based methods in forest management expert systems. Unlike a rule-based system, a BBN incorporates uncertainty in the knowledge and input data without sacrificing knowledge modularity. After reviewing the graph and probability theory needed to define a BBN as a joint distribution representable by a directed acyclic graph, an 11-variable network modeling Rocky Mountain aspen sucker density response to different management options is constructed. For a typical aspen site, the model's estimated marginal probabilities of sucker response exhibit values consistent with those expected. Finally, a BBN is shown to be fairly tolerant to small parameter errors, and a new method is given for BBN model validation. For. Sci. 37(2):627-654.