bluuebunny/crossref_metadata_2025 huggingface dataset:
A Strategy for Multiproduct Stand Management with Uncertain Future Prices
Authors: Forboseh Philip F. , Brazee Richard J. , Pickens James B.
Published: April 2024

This paper presents a strategy for stand management with multiple series of stochastic prices. When the only decision is to reject or accept a set of prices for a clearcut, the strategy is to accept and clearcut in the current period if the revealed revenue is at least as large as the current reservation revenue. This strategy is shown to be optimal when the price process is stationary and temporarily independent with the possibility of cross-product price dependence. Simulation involving red pine yields separated into two products, pulp and sawtimber, show the reservation revenue harvest strategy is far more consistent with current management practice than previous analyses involving a single product, sawtimber, have indicated. The probability distribution of optimal rotation ages is similar to a series of exponential (also called "waitingtime") distributions with new peaks at each major ingrowth event in the multiproduct yield function. The financial implications of considering pulp and sawtimber price uncertainty simultaneously are also addressed. For. Sci. 42(1):58-66.
A Coordinate-Free Area Variance Estimator for Forest Stands with a Fuzzy Outline
Authors: Magnussen Steen
Published: April 2024

Digitized forest maps offer the added convenience of automated area calculation of forest stand polygons. However, the "actual" stand areas in a forest management operation may deviate from the map value due to the mapping process and the delineation procedures used to identify stand boundaries for management operations. Three sources of area variances of mapped forest stand polygons are considered: the first due to the uncertainty inherent in coordinates, a second due to the linear interpolation between points, and a third due to the basic fuzziness of the boundary. A simple coordinate-free variance estimator is introduced, and predictions made from it are compared to a standard method requiring input of all polygon coordinates. When the coordinate-free variance estimator was applied to a set of simple polygons and a set of 120 natural forest stand polygons, a generally good agreement was found between the results from the two types of estimators. The coordinate-free method is suited for planning purposes when the error components arising from the uncertainties of forest stand areas are needed. For. Sci. 42(1):76-85.
Spatial and Vertical Leaf Area Index of a Deciduous Forest Resolved Using the LAI-2000 Plant Canopy Analyzer
Authors: Strachan I. B. , McCaughey J. H.
Published: April 2024

The LAI-2000 Plant Canopy Analyzer (LI-COR Inc., Lincoln, Nebraska) was used to determine the spatial and vertical canopy structure of a heterogeneous deciduous forest near Chalk River, Ontario. Overstory vegetation area index (VAI) demonstrated the spatial heterogeneity that exists between points at 10 m spacing and also with direction along transects, emphasizing the need for an appropriate sampling strategy. Average (± standard deviation) VAI for the forest was determined to be 3.00 ± 0.70, which lies within 3% of an estimate made by litterfall analysis in 1989 for the same forest location. The average VAI differs from the plant area index (PAI) determined by hemispherical photography by 9%. Owing to the large standard deviation in the estimate of VAI, it was calculated that 84 samples need to be taken to be within 5% of the mean at the 95% confidence level. This number drops to 21 if the accuracy requirement is relaxed to 10%. The large number of samples can be reconciled by the speed of sampling that is possible with the LAI-2000. One-hundred-thirty-two samples were obtained in this forest during a 7 day period. Vertical measurements of VAI were made from five levels on a 25 m scaffold tower in all four cardinal directions. VAI in the top third of the canopy compared well with hemispherical photography values taken along the vertical profile. The estimates in the middle and bottom levels differ from PAI. Directional heterogeneity was shown to increase with height. VAI measured at the lowest canopy level from the tower (3.11 ± 0.34) was not significantly different from the spatial overstory average of 3.00. For. Sci. 42(2):176-181.
A Method for Integrating Risk and Attitude Toward Risk into Forest Planning
Authors: Pukkala Timo , Kangas Jyrki
Published: April 2024

The risk associated with decision alternatives and the attitude of the decision-maker toward risk are two important factors that should be considered in forest planning. This paper proposes an operational way of integrating both risk and attitude toward risk into tactical forest planning. Two sources of risk are considered in the proposed planning method: timber price and level of tree growth. A scenario approach is used to generate a distribution of possible outcomes for alternative forest plans. Each outcome is described by a priority index, which is computed from a priority function. The priority function is estimated by Saaty's eigenvalue technique on the basis of pairwise comparisons between the decision criteria selected by the decision-maker. Estimation of attitude toward risk is based on comparison of the importance given to the worst, the expected, and the best outcomes. The optimum plan is sought with a heuristic algorithm. In optimization, different outcomes are converted to priority indices and weighted in a manner that reflects the attitude of the decision-maker toward risk. The case study indicated that level of risk affects the choice of forest plan. In a situation involving risk, the optimum plan may be different for a risk-avoiding, a risk-neutral, and a risk-seeking decision-maker. For. Sci. 42(2):198-205.
Simulating Wildfire Containment with Realistic Tactics
Authors: Fried Jeremy S. , Fried Burton D.
Published: April 2024

Existing simulation models for fire protection planning rely on a containment algorithm which fails to account for the interaction between the production of containment line and a fire's capacity to spread. This paper describes a technique for simulating wildland fire containment which explicitly accounts for this interaction by extending, generalizing, and, in some cases, simplifying methods reported earlier (Anderson 1983, Albini et al. 1978, Mees 1985, Anderson 1989). Representing the containment boundary in parametric form [i.e., expressing its Cartesian (x, y) or polar (r, ) coordinates as functions of a dimensionless parameter instead of specifying y as a function of x or r as a function of ], leads to a formalism with two significant advantages: (1) it allows a free choice for the shape of the free burning fire boundary, and (2) it is appropriate for simulations of parallel (indirect) attack as well as direct head and tail attack. In general, the technique requires solution of a first-order, nonlinear, differential equation, a task easily accomplished using numerical methods. The dependence of final fire size and containment time on the line-building rate and eccentricity of the free burning fire boundary are illustrated with the special case of an expanding ellipse and constant line-building rate, for which the containment boundary can be obtained by a simple quadrature.

Our General Formulation algorithm is demonstrated with a series of simulations that span the range of likely parameters for fire spread and fireline production. Comparisons made on representative fires between predictions of the General Formulation and models currently in use indicate that current models almost always overestimate fire size, sometimes by as much as an order of magnitude. For. Sci. 42(3):267-281.
Spruce Budworm Defoliation and Growth Loss in Young Balsam Fir: Spacing Effects on Needlefall in Protected Trees
Authors: Piene Harald , Fleming Richard A.
Published: April 2024

Age-dependent Weibull models were used to describe precise measurements of needlefall from a pair of protected plots of young, unspaced, balsam fir (Abies balsamea [L.] Mill.). These models showed that the age-specific rates of needlefall tended to increase with needle age throughout the observed crown. Where crown level effects were evident, needle lifespans were shorter in the lower crown than in the upper crown. The influence of crown level in the unspaced plots, however, was too inconsistent to be useful as a general predictor of needlefall rates. Comparing the results with previous work on spaced sample plots showed that spacing affected many aspects of needlefall. The mean needle lifespan of 5.3 yr (SE = 0.17) on the spaced sample plots was significantly greater than the 4.7 yr (SE = 0.22) estimated for the unspaced plots. These differences were most extreme in the lower crown. Spacing also influenced the earliest phase of needlefall. For needles under 2 yr, the mean age-specific rates of fall were negligible in the spaced plots, but were about 6%/yr in the unspaced plots. Thereafter, annual increases in the age-specific rates of needlefall were similar in the spaced and unspaced plots. Spacing also affected the pattern of year-to-year variation in needlefall. There was evidence of statistically significant trends in mean needle lifespans over time in the spaced plots, but not in the unspaced plots. For. Sci. 42(3):282-289.
Landowner Objectives and Nonindustrial Private Timber Supply
Authors: Kuuluvainen Jari , Karppinen Heimo , Ovaskainen Ville
Published: April 2024

In this paper, nonindustrial private forest owners' objectives are empirically identified, and the link between ownership objectives and observed harvesting behavior is established by estimating a theoretically derived timber supply function. Survey data on 146 Finnish forest owners and their timber sales in 1987-1991 is used. Prior to estimation, forest owners are classified into four groups according to their ownership objectives by K-means clustering. Dummy variables indicating cluster membership are included in the supply function. According to the results, "multiobjective owners" harvest significantly more (m³/ha/yr) than the other owner groups (self-employed owners, recreationists, and investors), ceteris paribus. The results further indicate that the multiobjective owners' harvesting policy can be described as present-value maximizing while the other (single-objective) groups' harvesting behavior seems to reflect the effect of market imperfections, as assumed by the theoretical model of the study. For. Sci. 42(3):300-309.
Diel and Seasonal Patterns of Leaf Gas Exchange and Xylem Water Potentials of Different-Sized Prunus serotina Ehrh. Trees
Authors: Fredericksen T. S. , Steiner K. C. , Skelly J. M. , Joyce B. J. , Kolb T. E. , Kouterick K. B. , Ferdinand J. A.
Published: April 2024

Leaf gas exchange and xylem water potentials were measured in the field throughout the 1994 growing season on leaves in the upper crown of seedling, sapling, and forest canopy black cherry trees (Prunus serotina Ehrh.) in northcentral Pennsylvania. Rates of gas exchange and xylem water potentials generally decreased with increasing tree size. Rates of dark respiration also decreased with increasing tree size. Differences among tree size classes were consistent throughout the growing season for xylem water potentials, but not for leaf gas exchange measurements. In May and June, seedling net photosynthesis and stomatal conductance were approximately 2 x that of larger trees, but their values tended to be similar to or lower than those of larger trees in July and August. Averaged over the entire season, seedlings had higher leaf gas exchange rates than saplings, which had higher rates than canopy trees. Regardless of tree size, stomatal conductance and net photosynthetic rates reached a maximum near mid to late morning. Stomatal conductance and net photosynthesis decreased steadily during the afternoon for larger trees, but seedling rates remained high until late afternoon. Seedlings consistently had the highest predawn and midday xylem water potentials and leaf-to-air water vapor pressure deficits, while canopy trees had the lowest. The results of this study indicate that tree size is an important factor influencing foliar gas exchange and water relations. For. Sci. 42(3):359-365.
An Empirical Assessment of the Dimensions of Softwood Lumber Quality
Authors: Hansen Eric N. , Bush Robert J. , Fern Edward F.
Published: April 2024

On the basis of previous research (Garvin 1984, Parasuraman et al. 1988), an 80-item, 12-dimension model for measuring total product quality in softwood dimension lumber was developed. This model was tested using confirmatory factor analysis and buyer perception data from three segments of the softwood dimension lumber market. Test results did not support the 12-dimension model. Consequently, exploratory factor analysis was used to develop a model consisting of five dimensions: Supplier/Salesperson Characteristics, Supplier Services, Supplier Facilities, Lumber Performance, and Lumber Characteristics. This model was tested by asking softwood lumber buyers (the same ones used for original model development) to rate their suppliers on the five dimensions. On each dimension, buyers rated most-preferred suppliers higher than least-preferred suppliers, providing evidence of the model's appropriateness. For. Sci. 42(4):407-414.
Multiplication Rates In Vitro and by Stem Cuttings Propagation, and Clonal Development from Eucalyptus globulus Seedlings
Authors: Wilson P. J.
Published: April 2024

In developing new clones of forest trees, the first main goal is to propagate enough plantable plants for clonal field trials and a clonal archive. Models of clonal multiplication rates in Eucalyptus globulus indicate that this takes a similar time (about 56 wk) from the sowing of seed, whether multiplication is by axillary shoot culture in vitro or by stem cuttings propagation. Multiplication of unrooted shoots is relatively rapid in vitro but is largely offset by the greater time required for weaning, pricking out, and growth in the nursery. For. Sci. 42(4):415-418.
Shifts in Aboveground and Forest Floor Carbon and Nitrogen Pools After Felling and Burning in the Southern Appalachians
Authors: Clinton Barton D. , Vose James M. , Swank Wayne T.
Published: April 2024

Changes in aboveground and forest floor mass, carbon (C), and nitrogen (N) pools were quantified on three sites in the southern Appalachians 2 yr after felling and burning. Before felling and burning, stands were characterized by sparse overstories and dense Kalmia latifolia L. understories. Two years after burning, foliar C and N pools had reached 25% and 29% of pretreatment levels, respectively. Foliar N concentrations were not different from pretreatment values. Standing wood C and N pools were 1% and 2%, respectively, of pretreatment values. Wood N concentrations were significantly higher on two sites, likely related to differences in fire intensity. Forest floor N content 2 yr after burning was 90% of pretreatment levels, most contained in unconsumed large woody material. Forest floor mass was significantly lower in the Oi layer and unchanged in the Oe + Oa layers. Forest floor N concentrations were generally lower after treatment. The site with the least intense fire and the lowest mass loss from the forest floor had the highest forest floor, foliage, and wood N concentrations 2 yr after burning. Site recovery after felling and burning was a function of fire severity and the capacity for site-nutrient retention through plant uptake. For. Sci. 42(4):431-441.
Differences in Silvicultural Investment Under Various Types of Forest Tenure in British Columbia
Authors: Zhang Daowei , Pearse Peter H.
Published: April 2024

This paper presents empirical evidence on the relationship between forest tenure and investment in silviculture. Silvicultural activities and expenditures on a large number of recently logged tracts in British Columbia, under four distinct forms of tenure, are assessed using a silvicultural investment model based on the conventional theory of capital. The empirical results indicate that silvicultural investment is correlated with security of tenure, and the level of investment under the most secure form--private land--is more than 67% greater than that under the least secure form--Forest Licences. For. Sci. 42(4):442-449.
Productivity and Research and Development in Two Canadian Forest Product Industries
Authors: Mohnen Pierre , Jacques Romain , Gallant Jean-Sébastien
Published: April 2024

This paper examines the role of research and development (R&D) in two important sectors of the Canadian economy, its pulp and paper and wood industries. A cost of adjustment model with two quasifixed inputs (capital and R&D) and three variable inputs (labor, materials, and wood) is used to estimate the technology, the rate of return on R&D, and its contribution to total factor productivity growth in these two industries. The sample is from 1963 to 1988. R&D is found to earn a net real after-tax annual rate of return of 1.6% in the pulp and paper industry and of 7.8% in the wood industry. The contribution of R&D to total factor productivity growth is minimal. Scale remains the main determinant of total factor productivity growth. For. Sci. 42(4):487-497.
Public Acceptability Thresholds of Clearcutting to Maintain Visual Quality of Boreal Balsam Fir Landscapes
Authors: Pâquet Joséet , Bélanger Louis
Published: April 2024

Clearcutting transforms forest landscapes by creating important visual contrasts between cut areas and adjacent stands. The object of this study was to determine if it is possible to harvest a certain proportion of the visible landscape while maintaining a visually acceptable setting in the social and ecological context of the boreal balsam fir (Abies balsamea L. Mill.) forest of central Québec. Using an adaptation of the Scenic Beauty Estimation (SBE) method, a survey was conducted through slide presentations to 309 persons from 11 groups of forest users. Levels of acceptability for single-patch and dispersed-patch cutting strategies were established for this ecosystem. The results confirmed that an increase in the percentage of clearcut areas in the visible landscape induced a lower level of acceptability and that even a small clearcut created a visual impact. However, despite a generally unfavorable reaction to clearcuts, a certain level of landscape alteration was acceptable to the tested groups. When clearcuts were in the form of a single patch, the acceptability threshold of the user groups was reached at an average percentage of 25% of the visible landscape harvested by clearcutting. The dispersed-patch strategy reduced the negative visual impact; for 6 of the 11 groups, the acceptability threshold increased to a harvesting level of 50%. To remain visually acceptable, clearcuts must be in a subdominant position in the visible landscape. The visual impact of a clearcut is effectively mitigated when the vegetation has reached a minimum height of 4 m. For. Sci. 43(1):46-55.
Trends in Genetic and Environmental Parameters for Height, Diameter, and Volume in a Multilocation Clonal Study with Loblolly Pine
Authors: Paul A. D. , Foster G. S. , Caldwell T. , McRae J.
Published: April 2024

Seedlings from 30 full-sib families (contained in 2, 4 x 4 factorials) of loblolly pine (Pinus taeda L.) were cloned and planted in three test sites in Georgia. Analyses were conducted on total height at ages 1 to 5 yr in the field, dbh at age 5, and individual tree volume at age 5. Four sources of genetic control were tested: male parent, female parent, male x female parent interaction, and clone within family. Differential growth responses due to test sites were present. Significant differences were detected among male parents for only one (age 5 height) of the seven traits in only one factorial. However, variation for height among female parents was found at ages 1 to 5 in only one of the two factorials accounting for 1% to 9% of the total variation. Significant effects of clone within family were found at all ages in one factorial and at ages 1, 3, and 4 in the other factorial for height but not for dbh or individual tree volume. None of the parental sources (male, female, or male x female) were interactive with test sites except one isolated case at age 2 in one factorial. However, the clone within family source of variation interacted significantly with site for height at ages 3 to 5 in factorial 1. Differences due to male or female parent effects were somewhat lower than has been found in other similar studies, possibly due to the relatively low number of parents in both factorials and hence, sampling effects. Future genetic studies should include more parents in the mating design but with approximately the same number of cloned individuals per cross in order to provide a better test of sources of variation. Trends in genetic and environmental variances and heritabilities were examined. Additive genetic variance (VA')for tree height displayed a steady increase from age 1 to 5. Dominance genetic variance (VD') for height also increased steadily over the same age range. The relationship between VA' and VD' differed between the two factorials. In factorial 1, VA' was larger than VD' for ages 1 to 4, then VD' became larger for age 5. The reverse pattern occurred in factorial 2. Epistatic genetic variance was detected only at age 1 for height in factorial 1 and at ages 1 and 3 in factorial 2. Dominance variance equaled or exceeded additive genetic variance for dbh and individual tree volume at age 5. Narrow-sense and broad-sense heritabilities for height were low to intermediate (0.05 to 0.37) from ages 1 to 5 and were more or less stable over ages. The importance of dominance genetic variance, at least to age 5, underscores the likelihood of additional genetic gains through a clonal tree improvement and deployment program beyond the gains achieved in a seed orchard/seedling based program. For. Sci. 42(1):87-98.
New Zealand's Privatization of Forest Lands: Policy Lessons for the United States and Elsewhere?
Authors: Hall O. F.
Published: April 2024

Two forest policy questions are examined: 1. What particular problems in New Zealand's privatization of public forest lands (1985 to 1995) need thorough examination prior to proposing it in the United States or elsewhere? 2. What light does the New Zealand experience throw on the question of whether privatization and subdivision of forest lands is the solution to multiple use conflicts among forest land uses and users? A brief history of the origin and implementation of New Zealand's forest privatization policy is given, including the disestablishment of its national Forest Service. Two unique features of New Zealand made privatization especially appropriate there: the history of many government-operated businesses, and the great area and productivity of a very distinctive and differentiated forest type—radiata pine plantations. Nine objectives of privatization stated in New Zealand, 5 specifically on forestry, are analyzed. Six of the 9 were concluded to be successful in New Zealand. Possibilities of success in the United States are examined. As a solution for multiple-use problems, both positive and negative results of the policy are found. Finally, 6 tentative "lessons" are concluded that should be reviewed in countries where a similar policy is proposed: 1. Privatization should involve either leasing or fee simple sale of forested land primarily suited to rapid tree growth of commercially valuable species suitable for being managed for successive crops of timber at a profit, with covenants for regeneration after harvest. 2. Lands critical for recreational, aesthetic, or habitat values should remain publicly owned. 3. Lands on which re-investment of some of the income in regeneration is of questionable profitability should not be entered into the policy. 4. The policy could be successful in avoiding many but not all multiple-use conflicts for the managers. 5. In public forests retained for exclusively noncommodity uses, questions of the availability of some useful and valuable woods may require arbitration of conflicts. 6. Privatization doesn't solve the struggle to financially support park and wilderness and special wildlife habitat. For. Sci. 43(2):181-193.
Impacts of Timber Harvesting on Soil Organic Matter, Nitrogen, Productivity, and Health of Inland Northwest Forests
Authors: Jurgensen M. F. , Harvey A. E. , Graham R. T. , Page-Dumroese D. S. , Tonn J. R. , Larsen M. J. , Jain T. B.
Published: April 2024

Soil organic components are important factors in the health and productivity of Inland Northwest forests. Timber harvesting and extensive site preparation (piling, windrowing, or scalping) reduces the amount of surface organic material (woody residues and forest floor layers) over large areas. Some wildfires and severe prescribed burns can have similar consequences. Such organic matter reductions can have important implications for soil chemical, biological and physical properties. A number of studies have linked substantial reduction in mycorrhizae development and tree growth to high levels of soil disturbance, or removal of organic horizons. Timber harvesting also removes a large percentage of coarse woody debris, which has unknown ramifications on soil productivity. Current woody residue guidelines in this region recommend leaving <10 to 125 Mg ha-1 on site to replace woody materials lost during harvesting operations. Large amounts of soil nitrogen (>500 kg ha-1) can also be lost from timber harvesting and site preparation, especially when using prescribed fire. The time required to replace this lost nitrogen may range from <10 to >275 yr, and depends on the severity of site treatments, presence or absence of nitrogen-fixing plants, and amounts of atmospheric deposition. Maintaining adequate amounts of organic matter on some forest sites in the Inland Northwest may temporarily increase the risk of wildfire or favor the activity of certain insects or disease fungi. However, carefully planned prescribed burns and mechanical site preparation can be practiced on most sites with relatively low impacts on soil organic levels, while accomplishing the important forest management objectives of fuel reduction, seedbed preparation, and reducing competing vegetation. Organic matter management will be the most difficult on very dry sites, with their historically low soil organic and nitrogen content, and high fire potential. The maintenance of adequate soil organic matter levels is critical for sustaining forest health and productivity under the variable moisture and temperature conditions of this region. Thus, soil organic components will become more important in the future as ecosystem management systems are developed for western forests. For. Sci. 43(2):234-251.
Comparative Plant Water Relations and Soil Water Depletion Patterns of Three Seral Shrub Species on Forest Sites in Southwestern Oregon
Authors: Conard Susan G. , Sparks Steven R. , Regelbrugge Jon C.
Published: April 2024

We compared stomatal conductance, transpiration, plant water potential, and soil moisture depletion patterns for three shrub species common on early seral forest sites in southwestern Oregon following logging or fire. Our goal was to determine which of these species were more likely to be the strongest competitors with regenerating conifers. The three species, Arctostaphylos patula Greene, Ceanothus sanguineus Pursh., and Holodiscus discolor (Pursh.) Maxim., were selected to represent a range in leaf morphology and expected water use patterns. Diurnal patterns of leaf conductance, plant water potential, and environmental parameters were measured throughout the growing season, along with seasonal patterns in soil moisture. As with any data obtained under ambient field conditions, environmental parameters and exact timing of measurements varied among shrubs. To better evaluate the response of individual species to common environmental parameters, we constructed models of leaf conductance based on field data and used these models to estimate responses of conductance and transpiration to averaged environmental conditions. This allowed us to better compare species responses to seasonal and diurnal trends in environmental variables. C. sanguineus typically had the highest transpiration rates per unit leaf area, and H. discolor the lowest; however, due to much higher leaf area indices of H. discolor, the two species depleted soil moisture at about the same rate. C. sanguineus and A. patula both had high predawn water potentials throughout the season, even when soil water potential at 1 m depth was less than -1.2 Mpa, suggesting that these species, but not H. discolor, had roots in deeper soil layers. We predict that the two deciduous species, C. sanguineus and H. discolor, will be stronger competitors for soil moisture than A. patula, at least in the top meter of soil. In contrast, A. patula and C. sanguineus are capable of depleting moisture from deeper in the soil and may therefore strongly compete even with deep-rooted conifers late in the season. Our use of empirical models allowed us to compare species responses to common environmental conditions, which facilitated ecological interpretation of species differences in water use patterns. By early August, soil water potentials under all species were low enough to significantly inhibit conifer transpiration, photosynthesis, and growth. For. Sci. 43(3):336-347.
Growth and Physiological Responses of Young Loblolly Pine Stands to Thinning
Authors: Peterson J. A. , Seiler J. R. , Nowak J. , Ginn S. E. , Kreh R. E.
Published: April 2024

Although yield responses to thinning in loblolly pine have been well documented, short- and long-term morphological and physiological changes are largely unknown. To investigate these responses, three 8-yr-old, 0.2024 ha replicate stands of loblolly pine were thinned by 50% in May 1988, and bole growth and morphological changes in the crown were measured annually for the next 6 yr. In situ gas exchange measurements were monitored in the upper and lower third of the crowns monthly during the third through sixth growing seasons following thinning. First- and second-year physiological responses to thinning have been reported earlier (Ginn et al. 1991). Thinning slowed live crown recession and increased crown diameters resulting in increased photosynthetic surface area per tree. Over the 6 yr study period, the crown diameters of thinned trees increased 82% while the crown diameters of control trees increased only 20%. Larger bole diameters were observed for thinned trees four growing seasons after thinning. Photosynthetic rate and needle conductance did not increase overall, but were increased in the lower crown foliage of thinned trees. Needle dark respiration was higher in thinned stands in both the upper and lower crowns. Increased bole diameter growth is likely the result of the large increases in foliar biomass as well as initially higher physiological activity in the lower crowns of thinned stands. For. Sci. 43(4):529-534.
A Longitudinal Analysis of Height/Diameter Curves
Authors: Lappi Juha
Published: April 2024

The paper describes a simultaneous statistical analysis of height/diameter curves in data consisting of several temporal and permanent plots. Two jack pine data sets, one from planted stands and the other from naturally regenerated stands, were analyzed using the same model structure. Parameters of a logarithmic height/diameter curve at a given age in a given stand were decomposed into a trend (an age-dependent population mean), a random stand effect, and a random time effect. The deviation of an observed height from the stand and age specific height/diameter curve was decomposed into a random tree effect and a random residual error which have nonhomogeneous variances. Trend functions for the parameters of the height/diameter curve were estimated using least squares estimates of parameters as dependent variables (generalized least squares would lead to inconsistent estimates). The trend equations describe most of the variation in the height curve parameters. Other stand variables (in addition to age) can explain the variation further, but development over time cannot then be predicted. A less stable description of the height/diameter curves is obtained in terms of dominant height. In applications, height/diameter curves can be calibrated by predicting the random stand and time effects using any combination of height measurements. A simultaneously estimated set of curves will be logical also when there are so few measurements that ordinary least squares curves show erratic fluctuations. For. Sci. 43(4):555-570.
Modeling the Dynamics and Species Composition of a Tropical Mixed-Species Uneven-Aged Natural Forest: Effects of Alternative Cutting Regimes
Authors: Favrichon Vincent
Published: April 2024

Sustainable tropical rain forest management is currently the subject of strong interest. There are only a few experimental stations available to research the impact of forest management (especially logging practices) on stand growth. This study develops a quantitative model to describe and simulate the dynamics of an undisturbed stand, as well as a logged uneven-aged, multispecies stand in French Guiana. This is a management-oriented matrix model. It takes into account three main characteristics of the forest dynamics in this type of ecosystem. First, we estimated density-dependence by nonlinear regression of the dynamics parameters (growth, mortality, and ingrowth). Second, a site effect is introduced on the assumption that the stand density in a natural stand is an approximate site characteristic and may help define the steady state corresponding to undisturbed conditions. Third, the very high species diversity is reduced by combining species into five groups based on growth behavior with reference to shade tolerance and maximum potential size. The model has been validated with short-term as well as medium-term projections. It was used to assess the stability of such a stand. We also evaluated the biological sustainability of logging practices, that is, the ability to return to the steady state in terms of total density as well as species composition. For. Sci. 44(1):113-124.
Effects of Plant Growth-Promoting Rhizobacteria on Loblolly and Slash Pine Seedlings
Authors: Enebak S. A. , Wei G. , Kloepper J. W.
Published: April 2024

Loblolly and slash pine seed were inoculated at sowing with 1 of 12 different strains of plant growth-promoting rhizobacteria (PGPR) in the greenhouse. Time to germination and seedling densities were determined at 21 days, and seedling biomass was measured at 12 wk after sowing. All bacterial strains significantly increased the speed of seedling emergence over nontreated pine seed. By 12 wk, however, no differences in stand densities were observed between bacteria-treated and nontreated seed for either pine species. Postemergence damping-off was reduced in loblolly pine when seed was treated with 3 of the 12 bacterial strains; however, postemergence damping-off on slash pine seedlings was not affected by rhizobacteria. Treatment with rhizobacteria had a significant positive and negative effect on seedling growth and biomass, which depended on tree species. Loblolly pine shoot and root lengths, as well as the above- and belowground biomass, were significantly reduced when seeds were treated with strains BS1 and BS2. In contrast, loblolly pine seeds treated with strains BS3, PM2, and INR7 significantly increased the below ground biomass of the seedling root systems. Slash pine seedlings had similar interactions with the bacterial strains. Strain BS1 significantly reduced shoot lengths compared with nontreated seeds, while strains 90-166, INR7, and SE49 increased shoot biomass. Slash pine root lengths and biomass were also reduced when treated with strains BS1 and BS2. Unlike loblolly pine, no bacterial strain increased slash pine root length or biomass. This study suggests that the effects of rhizobacteria inoculation on seedling emergence and plant growth are independent and that the effects are species specific. For. Sci. 44(1):139-144.
Measuring Softwood Lumber Value: A Conjoint Analysis Approach
Authors: Reddy Vijay S. , Bush Robert J.
Published: April 2024

Conjoint analysis was used to determine softwood lumber value perceptions among buyers of wood for preservative treatment and to determine trade-offs between lumber attributes and price. Utility functions for each lumber attribute and a model to estimate overall lumber value were developed. Wane was found to be the most important attribute in the evaluation of lumber value, followed by price, accuracy of grading, damage to the lumber package, lumber straightness, and lumber moisture content (in that order). Utility scores of individual respondents and simulation techniques were used to quantify trade-offs between quality and price. Buyers of softwood lumber for preservative treatment were found to be willing to pay a higher price to obtain wane-free lumber. The results of the study provide guidelines for softwood lumber suppliers seeking to differentiate their product while maximizing customer-perceived product value. For. Sci. 44(1):145-157.
Canopy Dynamics, Light Interception, and Radiation Use Efficiency of Selected Loblolly Pine Families
Authors: McCrady R. L. , Jokela E. J.
Published: April 2024

Needlefall, aboveground net primary production (ANPP), canopy light interception and attenuation, and "radiation use efficiency" of five open-pollinated loblolly pine (Pinus taeda L.) families were investigated using 100-tree family block plots near Summerville, SC. Family variation in annual needlefall amounts was significant during the fourth (from 4796 to 6191 kg ha-1) and fifth growing seasons (from 4717 to 5721 kg ha-1); needlefall patterns for the poorest performing family were asynchronous from those of the others, with notably higher needlefall rates from April to July. Estimates of ANPP at age 4 yr varied by 16% (from 32.9 to 38.2 Mg ha-1) among families, and were generally commensurate with progeny test rankings based on height growth. The relationship between ANPP and leaf area index (LAI) was both significant and curvilinear, with an apparent optimum level of production (42.6 Mg ha-1) achieved at a LAI of about 13 (all-sided; February). The least productive families had the lowest mean LAI (e.g., 7.9), while the most productive families generally had higher levels of LAI (e.g., 13.6). Significant family differences in canopy light interception were present in every month sampled except June, when photosynthetically active radiation (PAR) interception exceeded 90% for all families. Light extinction coefficients (k) for February differed significantly among the five families, and ranged from 0.28 to 0.38; families with the largest LAIs generally had the lowest values of k and the highest levels of PAR interception. A strong linear relationship (r² = 0.74) was found between ANPP and intercepted PAR. Estimates of the dry matter:radiation quotient (ε "radiation use efficiency") differed significantly among families, and ranged from 1.33 g MJ-1 to 1.48 g MJ-1. Results of this study suggest that fundamental differences exist in production ecology among loblolly pine families, and that canopy-level characteristics such as LAI, PAR interception, and "radiation use efficiency" are important in conferring differential family performance. For. Sci. 44(1):64-72.
Ensuring the Compatibility of Aquatic Habitat and Commodity Production Goals in Eastern Oregon with a Tabu Search Procedure
Authors: Bettinger Pete , Sessions John , Johnson K. Norman
Published: April 2024

We present a land management scheduling model for ensuring the compatibility of aquatic habitat quality and commodity production goals in forest management. This model uses Tabu search procedures to select feasible land management activities (timber harvesting and road system management) subject to an even-flow constraint and aquatic habitat quality goals, as represented by stream sediment and temperature indices. The methodology for evaluating the effects of land management activities on the realization of aquatic habitat goals utilizes established procedures, yet makes evaluations with each incremental decision choice. We apply the procedures to a 5,926 ha case study watershed in eastern Oregon to evaluate the performance. For comparison, a global optimum solution is estimated using extreme value theory techniques. Results show that all solutions are spatially and temporally feasible with respect to stream sediment and temperature index goals. Eighty percent of solutions had net present values within 10% of an estimated optimal solution. Further, out of 20 independent runs, one was within 2% of an estimated global optimum, and all 20 were within 15% of the estimated global optimum. While improvements to the model can be made, we have demonstrated that moderately complex aquatic habitat quality evaluation techniques, with spatial elements, can be nested inside a land management scheduling model. For. Sci. 44(1):96-112.
Variation in Selected Wood Properties of Vochysia Guatemalensis from Four Sites in Costa Rica
Authors: Gonzalez J. Eugenio , Fisher Richard F.
Published: April 2024

Vochysia guatemalensis D. Smith is distributed naturally from Mexico to Panama. It is a promising species for commercial reforestation on degraded lands, but little is known about the variation in important wood traits. Trees of this species were sampled in four natural stands to estimate the variation and radial gradients in wood specific gravity, fiber length, vessel density and vessel radial diameter. Increment cores were extracted from each tree at breast height and divided into 1 cm segments from pith to bark. Specific gravity was determined for each segment. The same wood cores were macerated for measuring fiber length. Vessel density and vessel radial diameter were measured for each segment from cross sections. Significant differences were found among sites (P < 0.05) for specific gravity and fiber length. Both of these variables also increased from pith to bark at all sites, and these radial gradients were significantly different among sites (P < 0.05). Vessel density was also significantly different among sites, but there was no significant change from pith to bark. No significant differences were detected among sites for mean vessel radial diameter; however, radial change in vessel diameter was significantly different among sites. For. Sci. 44(2):185-191.
The Role of Mycorrhizae, Site Preparation, and Organic Amendment in the Afforestation of a Semi-Arid Mediterranean Site with Pinus halepensis
Authors: Querejeta José I. , Roldán Antonio , Albaladejo Juan , Castillo Victor
Published: April 2024

A factorial field experiment was conducted in a degraded semi-arid site of southeastern Spain to test the effectiveness of mycorrhization and several soil preparation techniques on afforestation with Pinus halepensis. The mycorrhizal treatments were nursery inoculation with Pisolithus arhizus and forest soil addition to the planting holes. The soil preparation treatments were terracing(mechanical and manual) and the addition of an organic amendment (urban solid refuse). One year after planting, the study revealed significant differences in mycorrhization levels, frequency of mycorrhizal species, fine root production and growth between the inoculated seedlings and the noninoculated controls. Inoculation with P. arhizus gave better pine growth and mycorrhization rates than the addition of forest soil. Both mycorrhization treatments were particularly effective in combination with mechanical terracing. The organic amendment had no apparent negative influence on the mycorrhization level of the seedlings and significantly improved pine growth. The beneficial effects of mycorrhization treatments on P. halepensis growth persisted 2 yr after planting. The increase in growth of the seedlings due to the treatments could be attributed to the change in soil conditions (increased fertility and soil aeration) and probably to a mycorrhization effect on water relations, although it has not been clearly demonstrated. FOR. Sci. 43(2):203-211.
Adapting Distance-Independent Forest Growth Models to Represent Spatial Variability: Effects of Sampling Design on Model Coefficients
Authors: Stage Albert R. , Wykoff William R.
Published: April 2024

If sampling variability of competition variables can be accommodated, a distance independent growth model can (1) simulate patchy stands inventoried by a grid of sampling locations; (2) prescribe treatments for each location; and (3) update inventories using plot sizes differing from those used in model calibration. Ignoring sampling properties of competition biases estimates of stand development and management responses. Our solution to reduce this bias has three steps: First, we model the sampling properties of the competition estimates depending on plot sizes and on spatial patterns. Then we use the modeled error variances when estimating parameters of the structural relation of growth to competition. Finally, we join these two products in a Structural Based Prediction (SBP) procedure that dynamically modifies coefficients during simulation. SBP increases sensitivity to spatial variation and permits valid analyses of location-specific prescriptions for varying inventory designs.

In a model of diameter change for individual Pseudostuga menziesii var. glauca (Beissn.) Franco, coefficients of the competition variables estimated under the structural model were three times as large as when estimated under an ordinary least-squares criterion. This increase reduced sensitivity to crown ratio. Two variants of the Prognosis Model for Stand Development were constructed to compare behavioral changes: (1) using SBP, and (2) using the OLS-based coefficient estimates of the same diameter-growth submodel. Projections with the two variants differed in the internal structures of both uniform and irregular stands and using several sampling methods. Stand averages of volume growth were similar for uniform stands-either from uniform regeneration or from uniformity created by thinning patchy stands. However, the thinning response in patchy stands differed between the two variants. Analysis of the variance model showed little sensitivity within the range of half to twice the Poisson-based estimates of competition variance. For. Sci. 44(2):224-238.
Efficiency Implications of Silvicultural Expenditures from Separating Ownership and Management on Forest Lands
Authors: Luckert Martin K.
Published: April 2024

In pursuing silvicultural goals on licensed public lands, governments worldwide have adopted various policy instruments including contractual requirements, the reimbursement of silvicultural costs, and investment incentives in the form of shares in the value of timber crops resulting from voluntary silvicultural activities. Monte Carlo simulations are used to investigate the efficiency implications of alternative silvicultural policy options. Results indicate that current policies, dominated by requirements and reimbursements with uncertain costs, may create significantly less wealth than policies that include some share of future timber crops. Means of granting shares include reimbursing tenure holders according to the present value of the future benefits created by their expenditures or by sharecropping arrangements. Such policies could potentially provide tenure holders with incentives to efficiently invest in silvicultural activities, by alleviating tenure insecurity while correcting for market failures. For. Sci. 44(3):365-378.