bluuebunny/crossref_metadata_2025 huggingface dataset:
FORCAT: A Single Tree Model of Stand Development Following Clearcutting on the Cumberland Plateau
Authors: Waldrop T. A. , Buckner E. R. , Shugart H. H. , McGee C. E.
Published: April 2024

A single tree model, FORCAT, was developed as a forest management tool for the Cumberland Plateau region of East Tennessee. FORET (Shugart and West 1977), a gap model of forest succession in East Tennessee, served as the basic program for the simulation of stand regeneration, competition, tree growth, and mortality. Gap models have been used to simulate successional changes in species composition over periods of up to 1,000 years for many different forest types. Even though the output of gap models has included specific information such as basal area and density, the accuracy of short-term predictions of these variables remains relatively untested for forest management purposes. A test of FORET indicated that the model was not readily adaptable to different sites and management schemes. Therefore, major modifications to the basic program were necessary. Some of the more significant changes included in FORCAT are: (1) beginning the simulation with a mature stand (which was immediately clearcut) rather than bare ground, (2) growth rates based on site quality and local climatic conditions, (3) basing seed availability on species-specific characteristics, and (4) simulation of periodic clearcutting and prescribed burning.

Validation tests showed that FORCAT successfully predicted basal area, numbers of trees, and species composition of 50- to 100-year-old stands. In younger stands, however, the number of seedlings of pioneer species was underestimated. This variance emphasizes the difficulty of projecting regeneration abundance and indicates the need for further model refinement. Nevertheless, FORCAT serves as a bridge from a highly theoretical model of forest succession to a useful forest management tool. Additional inputs controlling seed availability are needed to make FORCAT more broadly applicable to all forest types found on the Cumberland Plateau. Forest Sci. 32: 297-317.
Environmental and Historical Factors Affecting Red and White Fir Regeneration in Ecotonal Forests
Authors: Parker Albert J.
Published: April 2024

Diameter-class distributions of thirty mixed red fir/white fir forests from Yosemite National Park, California, are used to examine patterns of canopy dominance and regeneration modes of these two zonal dominants. Successful regeneration of each species is associated with open canopies and nutrient rich substrates. Red fir regenerates in greater numbers on a wider range of sites, but suffers greater mortality than white fir. Patterns of canopy dominance indicate that white fir tolerates canopy closure and dominates on nutrient-rich sites in montane forests, whereas red fir is less tolerant of shading and dominates on disturbed, nutrient-poor substrates in subalpine forests. These patterns are interpreted as adaptive responses to complex interactions of site factors, disturbance frequency, and biotic constraints along an elevational gradient. Forest Sci. 32:339-347.
Time-Series Analyses of Tree-Ring Chronologies
Authors: Monserud Robert A.
Published: April 2024

The stochastic time-dependent structure of 33 tree-ring series from the dendrochronology literature was analyzed using autoregressive moving average (ARMA) models. Significant autocorrelation was found in every tree-ring series, for not one of the series was white noise. The overall best model was the mixed ARMA(1,1) process. The collection of parameter estimates for this mixed model were tightly clustered, even though the data were collected from the entire length of western North America. High-order autoregressive models (P = 2 to 4) were always a good choice, but usually not as good as the mixed ARMA(1,1) model. Rarely did the first-order autoregressive model provide an adequate description of the data. Standardization (i.e., weighted residuals from the growth trend) of ring-width series into ring-index series was a useful--and often necessary--step for producing a stationary time series. Many of the unstandardized ring-width series demonstrated a strong tendency toward nonstationarity. The practice of removing certain frequencies by passing the data through a running average filter was found to introduce spurious correlations that did not exist in the original data, and thereby obfuscated any statistical analysis in the time domain. The cross correlation function was found to be a useful tool both for examining the association between series and for synchronizing series, especially after prewhitening with appropriate ARMA models. Because significant autocorrelation was found in every series examined, it is recommended that all statistical analyses be performed using the prewhitened residuals from an appropriate ARMA model. Forest Sci. 32:349-372.
A Dynamic Forest Sector Model with a Swedish Case
Authors: Lönnstedt Lars
Published: April 2024

Forest management and new plant investments are long-term decisions. Consequently, strategic planning is vital for the companies involved and has been one of the most important functions of management. In the future this could be even more important. Many forest companies are facing slow market growth along with, cyclical fluctuations in demand, high interest rates and high investment requirements to increase or replace capacity. This paper presents an instrument to aid managers in their strategic planning. A mathematical description of the instrument, a long-term forest sector model, is presented followed by an example of its use in a Swedish case. The model was developed to analyze the impact of cost competitiveness on the structural change of the Swedish forest sector in a 15-25 year perspective. The model is used now by managers in Sweden to produce scenarios for the Swedish forest industry. The output from the model is also used as input for specific enterprise models. The model consists of two symmetric, competing forest sectors--one for the domestic forest sector and one for the competing forest sectors of other countries. Each forest sector covers all activities, ranging from timber growth to the consumption of forest industry products such as paper, sawn wood, and panels. At the end of this paper an application of the model is illustrated by the Swedish forest sector. One conclusion drawn is that since the Swedish forest sector is competing in a world market the development of its profit level compared with competitors is extremely important. Forest Sci. 32:377-397.
Input/Output Models and Forest Resource Supply Constraints Revisited
Authors: Schallau Con H. , Maki Wilbur R.
Published: April 2024

The authors respond to Vincent's (1986) contention that the results of Leontief (demand) and Ghoshian (supply) interindustry models cannot be gainfully compared. His conclusion follows from a misinterpretation of (1) the Dart and Fight I/O analysis of Douglas County, Oregon (1974), and (2) how the supply and demand models differ regarding causal factors and forward/backward linkages. Forest Sci. 32:401-404.
Hiking Values and the Recreation Opportunity Spectrum
Authors: Rosenthal Donald H. , Walsh Richard G.
Published: April 2024

The contingent valuation technique is used to estimate the net economic value of hiking and backpacking in a National Forest in the Front Range of the Colorado Rockies. The study is based on on-site interviews of 202 hikers, conducted during the summer of 1981. The relationship between dollar value and recreation opportunity spectrum (ROS) class reverses when the unit of measure is switched from trips to recreation visitor days. Trips to the more primitive ROS classes have high consumer surplus, but last a long time, thereby, lowering the consumer surplus per recreation visitor day. Forest Sci. 32:405-415.
Water Stress Response After Thinning Pinus contorta Stands in Montana
Authors: Donner Bryan L. , Running Steven W.
Published: April 2024

Seasonal development of leaf water stress in thinned stands of lodgepole pine (Pinus contorta var. latifolia Engelm.) was compared to adjacent controls at three sites in Montana. Each stand was thinned to varying densities in the fall of 1982 or spring of 1983. Pre-dawn leaf water potential measurements were taken monthly in the summers of 1983 and 1984 using the pressure chamber to determine plant water stress differences between thinned and unthinned stands. Late summer leaf water potential was significantly higher (0.17 to 0.35 MPa) in the thinned stands than in the controls. Computer simulation using the DAYTRANS/PSN ecosystem model suggested that 21 percent greater seasonal photosynthesis could occur in these trees as a result of the approximately 0.3 MPa higher plant water potential measured and additional radiation available to remaining trees. Based on estimated carbon budgets, this additional photosynthate could substantially increase the amount of carbon allocated to stem growth in these trees. Forest Sci. 32:614-625.
A MAXMIN Approach to Nondeclining Yield Timber Harvest Scheduling Problems
Authors: Hof John G. , Pickens James B. , Bartlett E. T.
Published: April 2024

This paper investigates an alternative approach to scheduling timber harvests when nondeclining yield is desired. The approach maximizes the minimum harvest during any one time period, across all time periods in the planning horizon. This approach tends to create an even flow harvest pattern, but allows more flexibility than rigid nondeclining yield or even flow constraints. The approach is tested in a case study involving conversion of an unregulated forest into a regulated state. The results suggest that the approach, in combination with other approaches, may have the potential to generate useful solutions to this type of timber harvest scheduling problem. Forest Sci. 32:653-666.
Seasonal Water Relations of Three Gallery Forest Hardwood Species in Northeast Kansas
Authors: Abrams Marc D. , Knapp Alan K.
Published: April 2024

Field and laboratory studies were used to evaluate several water relations characteristics for saplings of three species: hackberry (Celtis occidentalis), a mesic, late successional tree, and bur and chinquapin oak (Quercus macrocarpa and Q. muehlenbergii), more xeric, early successional trees growing in a northeast Kansas gallery forest understory during a dry summer. For all species, maximum stomatal conductance (gwv) (8.9-9.5 mm · s-1) was recorded early in the season when soil moisture was greatest. Seasonally, sunlit leaves generally had significantly higher gwv than shaded leaves. Both gwv and leaf water potential (ψleaf) decreased during the season in each species, with minimum ψleaf values ranging from -2.13 to -2.48 MPa. Seasonally, ψleaf remained consistently higher than the osmotic potential at zero turgor (ψ0π) for each species (minimum values of (ψ0π) ranged from -2.61 to -3.02 MPa). Hackberry, the most mesic species, experienced the largest seasonal decrease in gwv in both shaded and sunlit leaves (69% and 78% reduction, respectively). Moreover, in contrast to the two oaks, a significant seasonal decline in 600 h ψleaf was shown for hackberry. By season's end, hackberry had the lowest gwv and ψleaf values. In contrast, chinquapin oak had the highest late season gwv for sunlit leaves and ψ leaf, suggesting that this species was better able to utilize late season precipitation. Forest Sci. 32:687-696.
Variation in Sapwood Area-Leaf Area Relations Within Two Stands of Lodgepole Pine
Authors: Dean T. J. , Long J. N.
Published: April 2024

Within-stand variation of the ratio between sapwood cross-sectional area and leaf area was investigated for lodgepole pine (Pinus contorta Dougl.) in northern Utah. For both a mature and a sapling stand, we analyzed the changes in sapwood-leaf area ratio with respect to canopy position and location along the bole, both within and below the live crown.

Excluding suppressed trees, sapwood area at the base of the live crown (BLC) was linearly related to leaf area; however, the slope of the regression for the saplings was 40% greater than the slope for the mature trees. This difference was virtually eliminated when sapwood area at BLC was related to a power function of leaf area for all crown classes. Sapwood area increased from the base of the crown to the base of the crown-free bole. For the mature and sapling trees 98% and 91%, respectively, of the variation in sapwood below the live crown was explained using nonlinear regression with the model

SA = β0(L·LA)β¹

where SA = any sapwood cross-sectional area below the live crown, L = distance from the cross section to midway into crown or center of leaf area, LA = total leaf area per tree, and β0 and β1 = regression coefficients. The sapwood-leaf area ratio varied within the crowns of the mature and sapling trees; the maximum ratio occurred toward the base and the top of the crown and the minimum ratio was found at about the center of leaf area. Forest Sci. 32:749-758.
Prediction of Scenic Quality for Southern Pine Stands
Authors: Buhyoff Gregory J. , Hull R. Bruce , Lien John N. , Cordell H. Ken
Published: April 2024

Statistical models which predict scenic beauty from an in-stand viewer perspective were developed for southern pine stands more than 9 years old. These models indicate that stand age, average stand diameter, and stand stocking density are positively related to scenic quality assessments by the general public. However, the models also show that the number of stems in the 1 to 5 inch dbh classes is related to scenic quality in a negative quadratic fashion. The highest scenic quality for stands of differing ages and average tree diameters is when the sapling and pole stocking is between 1,100 and 1,200 per acre, past which scenic quality will decrease. Results also indicate that optimal stand density is dependent upon stand age. Forest Sci. 32:769-778.
Continuing Response of Pinus radiata to Phosphatic Fertilizers Over Two Rotations
Authors: Gentle S. W. , Humphreys F. R. , Lambert Marcia J.
Published: April 2024

Considerable growth responses to two differing phosphatic fertilizers (rock phosphate and superphosphate) applied to Pinus radiata (D. Don) were previously reported by the authors (Forest Science 11, 1965). At that time the experimental site had carried two rotations of trees, the first unfertilized. The same site has now been grown through a similar period of time in the third rotation (to first thinning) with no further fertilizer applications. Growth responses, foliage and soil chemical analyses have been compared with those obtained over the first fertilized rotation. Results showed that tree growth responses have been maintained significantly through two fertilized rotations to the present time by the original 1947 fertilization. The bulk of the phosphorus from both sources is still present in the soil surface horizon, that from rock phosphate mainly as calcium phosphate, and from superphosphate mostly in aluminum- and iron-bound forms. Implications for forest management are that where adequate growth responses can be obtained from a single long-lived fertilizer source, the investment in fertilizer becomes a long-term addition to forest site quality. Cost effectiveness has been compared for both rotations in terms of 1983 dollars. Forest Sci. 32:822-829.
An Econometric Analysis of Residential Demand for Fuelwood in the United States, 1980–1981
Authors: Hardie Ian W. , Hassan Aziz Abu
Published: April 2024

This paper presents an econometric study of residential fuelwood demand in the United States. It is based on a residential energy consumption survey conducted by the U.S. Department of Energy in 1980-81. Estimates are derived of the probability that a particular household will burn wood and of the quantity of wood that will be burned. Aggregate fuelwood demand is predicted for five census regions and for the contiguous United States. The predicted average probability of burning wood is 0.32, and the average predicted quantity burned is 1.57 cords. Residential fuelwood demand is found to be quite responsive to changes in the price of nonwood heating fuel. Forest Sci. 32:1001-1015.
Effects of Interfering Vegetation on Biomass, Fascicle Morphology and Leaf Area of Loblolly Pine Seedlings
Authors: Zutter Bruce R. , Gjerstad Dean H. , Glover Glenn R.
Published: April 2024

Loblolly pine (Pinus taeda L.) seedlings growing with no interfering vegetation were consistently greater in diameter and biomass than those growing with only herbaceous vegetation. Seedling diameter and biomass were more responsive than height to reduction in interfering vegetation. During the first growing season in the field, pine growth appeared to be influenced more by the presence of herbaceous than woody vegetation. For a given seedling age, the proportion of biomass in branches increased as interfering vegetation decreased.

Seedling age and the absence of interfering vegetation each increased the percentage of foliage biomass in four-needled fascicles, fascicle diameter, total length, sheath length, dry weight, and surface area and decreased specific leaf area. Four-needled fascicles from two-year-old seedlings, growing with or without herbaceous vegetation, tended to be greater in diameter, total length, sheath length, dry weight, and surface area and were approximately equal in density to three-needled fascicles.

Leaf area (total needle surface area) was strongly related to groundline basal area and was quite responsive to changes in herbaceous vegetation. The strong relationship between stem diameter and leaf area at several levels of interference suggests that either measure might be used as an indicator of loblolly pine response to interference from other plants. Forest Sci. 32:1016-1031.
The Impact of Chronic Cadmium Exposure on Growth of Pin Oak Seedlings
Authors: Kazimir Janet , Brennan Eileen
Published: April 2024

Two-year-old pin oak (Quercus palustris Muenchh.) seedlings were grown in sand culture and given complete nutrient solution with or without 0.1 μg/ml Cd (as CdCl2) for one or two growing seasons from May to September and the effect on growth determined. Cadmium accumulated primarily in the roots of the seedlings during chronic exposure but was translocated slowly into the shoot over time. Growth of newly planted two-year-old seedlings was stimulated after one year of Cd treatment, but that of established three-year-old seedlings was not affected. The more frequent application of Cd and the larger root system of the older seedlings resulted in a greater Cd accumulation in the root than that associated with growth stimulation. No measurable effect of Cd on tree growth was detected after two successive years of cadmium treatment; however, the percentage of trees exhibiting foliar toxicity symptoms increased. Where Cd treatment was terminated after one year and the trees replanted in uncontaminated sand, leaves continued to show high levels of Cd due to translocation from perennial tissue, but this response was not reflected in any growth change. Forest Sci. 32:1061–1066.
Variation in Flood-Induced Stomatal and Photosynthetic Responses of Three Bottomland Tree Species
Authors: Pezeshki S. R. , Chambers J. L.
Published: April 2024

The effects of flooding on plant water status, stomatal conductance, and net photosynthesis in seedlings of three bottomland species, Fraxinus pennsylvanica Marsh., Quercus michauxii Nutt., and Taxodium distichum (L.) Rich. var. distichum were studied under controlled environmental conditions. Flooding for three weeks induced significant stomatal closure in all species. After 24 hours of flooding, stomatal conductance was reduced to 49% of the preflood level in T. distichum, 56% of the preflood level in Q. michauxii, and 53% of preflood level in F. pennsylvanica. Leaf water potential measurements indicated that water deficits did not develop as a result of flooding; therefore, stomatal closure was apparently not caused by water deficits in any of the study species. Limited photosynthesis data indicated that flooding did not substantially reduce net photosynthesis in T. distichum or F. pennsylvanica, even though partial stomatal closure was induced. Net photosynthesis was, however, substantially reduced in flooded Q. michauxii. Forest Sci. 32:914-923.
Trends in Genetic Parameters with Stand Development and Their Influence on Early Selection for Volume Growth in Loblolly Pine
Authors: Foster G. Sam
Published: April 2024

Analysis was conducted on data from a 15-year-old progeny test of 11 open-pollinated families of loblolly pine. Plots consisted of 49-tree blocks of single families, and measurements were taken annually for the first 8 years and at 10 and 15 years.

Three types of analysis were used to explore early selection for a more mature trait. These analyses included: age-related trends in genetic and environmental variances, juvenile-mature genetic correlations, and indirect selection.

The age-related trends varied by trait. The trends for additive genetic variance ranged from flat (survival) to exponential (total plot volume) or concave (live crown ratio). However, for all traits, additive genetic variance dipped around age 7 or 8, presumably due to intensifying competition at crown closure.

Genetic correlations between early traits (juvenile) and more mature traits (15 years) were generally high. The correlations of height or total plot volume at age 15 with juvenile traits improved rapidly from age 1 to 5. Diameter at breast height, in which there was little or no increase from ages 3 to 5, was the one exception. When correlating earlier height with height or plot volume at age 15, the pattern of correlation coefficients took a noticeable dip at ages 7 or 8.

With total plot volume at age 15 (TVOL15) as the goal of selection, response to indirect selection for height and survival at various ages was predicted. The predicted, indirect response was expressed as a ratio of response to direct selection for TVOL15 and termed relative efficiency. The relative efficiency of selection by ages 3, 4, or 5 was 81, 82, and 85%, respectively. Forest Sci. 32:944-959.
The Declining Even Flow Effect—Non Sequitur of National Forest Planning
Authors: McQuillan Alan G.
Published: April 2024

The traditional concept of sustained yield has evolved into the more rigid notion of even flow for timber harvest regulation on national forests. Combination of an even flow constraint with a wealth-maximizing objective function in current formulations of the forest planning model can lead to an anomaly, dubbed the declining even flow effect (DEFE), when the national forest planning process is repeated periodically as required by law. When the effect occurs, first-decade harvests fall during successive planning cycles. The cause lies in both the redefinition of the even flow constraint that occurs at successive planning cycles and the assumptions associated with a capital efficiency objective function that are violated when an even flow constraint is imposed. Forest Sci. 32:960-972.
The Role of Exchange Rates in Canadian—United States Lumber Trade
Authors: Adams Darius M. , McCarl Bruce A. , Homayounfarrokh Lalehrokh
Published: April 2024

The paper employs graphical analysis, simple statics and an econometric model to examine the impacts of exchange rate on consumption, production, prices, and bilateral trade flows in the Canadian-U.S. lumber market. Based on annual data for the 1950-1983 period, the econometric model is comprised of a U.S. demand relation and supply, capacity, and stumpage price relations for three U.S. regions and Canada. Analysis with the model indicates short-term elasticities with respect to exchange rate (expressed as $C/$US) of less than 0.1 for U.S. consumption, roughly -0.3 for U.S. delivered price and 0.5 for import volume. The elasticity of Canadian market share was found to be approximately 0.4. The greatest Canadian market share expansion (from roughly 20 to 27%) and rise in the U.S. dollar strength occurred during the years 1975-1979. A hypothetical simulation of this period, under the assumption of no increase in the nominal exchange rate, yielded a reduction in Canada's 1979 share to 24%, roughly a 40% reduction in market share gain. Both elasticity and simulation results indicate that exchange rate has been an important, but by no means the sole, factor in recent expansion of Canada's share in U.S. lumber markets. Forest Sci. 32:973-988.
A Logistic Model of Mortality in Thinned and Unthinned Mixed Conifer Stands of Northern Idaho
Authors: Hamilton David A.
Published: April 2024

Published mortality models have not always done an adequate job of predicting the probability of mortality following thinning. This paper describes a mortality model based on a series of thinned and unthinned sample plots located in northern Idaho, some of which have been measured for 70 years. Independent variables are diameter at breast height (dbh), stand basal area, annual diameter growth, relative dbh, and species. Thinning results in changes in three of these variables: the stand basal area, relative dbh, and diameter growth rate. Model performance is evaluated by considering how well the model fits the development data set, how well the model fits an independent data set, and how well the model fits biological reality. In each evaluation the selected model shows a marked improvement over the performance of the mortality model used in previous releases of the Stand Prognosis Model (Wykoff et al. 1982). The model is shown to perform well in both thinned and unthinned stands. Forest Sci. 32:989-1000.
Predicting Regeneration in the Grand Fir-Cedar-Hemlock Ecosystem of the Northern Rocky Mountains
Authors: Ferguson Dennis E. , Stage Albert R. , Boyd Raymond J.
Published: April 2024

Conifer establishment following regeneration treatments can be predicted in the grand fir-cedar-hemlock ecosystem of the northern Rocky Mountains. Alternative treatments can be evaluated by a model that represents regeneration establishment and early development. This model is designed to be used with the Intermountain Forest and Range Experiment Station's Prognosis Model (Stage 1973). Mathematical equations representing most harvest and site preparation methods common in the northern Rocky Mountains predict the probability of stocking, trees per acre, species composition, and tree heights between 3 to 20 years following treatment. These relations were derived from a stratified random sample of areas managed by conventional harvest and site preparation treatments. However, the analysis and modeling methods are structured to permit combinations of treatments within a stand that might differ from past practices.
A Growth and Yield Model for Thinned Stands of Yellow-Poplar
Authors: Knoebel Bruce R. , Burkhart Harold E. , Beck Donald E.
Published: April 2024

Simultaneous growth and yield equations were developed for predicting basal area growth and cubic-foot volume growth and yield in thinned stands of yellow-poplar. A joint loss function involving both volume and basal area was used to estimate the coefficients in the system of equations. The estimates obtained were analytically compatible, invariant for projection length, and numerically equivalent with alternative applications of the equations. Given estimates of basal area and cubic-foot volume from these equations, board-foot volumes can also be calculated.

As an adjunct to the stand-level equations, compatible stand tables were derived by solving for the parameters of the Weibull distribution from attributes predicted with the stand-level equations. This procedure for estimating the parameters of the diameter distributions of the stands before thinning gave reasonable estimates of number of trees, basal area, and cubic-foot volume per acre by diameter class. The thinning algorithm removes a proportion of the basal area from each diameter class and produces stand and stock tables after thinning from below that are consistent with those generated before thinning.
A World Model of the Demand for Paper and Paperboard
Authors: Baudin Anders , Lundberg Lars
Published: April 2024

The objective of this study is to develop and evaluate econometric models describing the long-term development of demand for paper products, which could be used for simulation, policy evaluation, and long-term projections, on a global scale as well as for regions and individual countries. The study is intended to cover a relatively large sample of countries on varying levels of economic development. This means, however, that the availability of data sets rather restrictive limits on the model building. The basic approach in this paper is the same as that by Buongiorno (1978). The final model chosen here for projections and simulations of demand is, however, somewhat different from Buongiorno's model. In addition, a number of alternative model specifications were explored and evaluated. For. Sci. 33(1): 185-196.
Calibration of the Hemispherical Photographic Technique to Measure Leaf Area Index Distributions in Hardwood Forests
Authors: Wang Y. S. , Miller D. R.
Published: April 2024

Measured distributions of leaf inclination angles and leaf azimuth angles from one stand of red maple (Acer rubrum L.) are used to modify hemispherical photograph determinations of leaf area index in two other plots of red maple as well as in the stand where structure measurements were made. LAI determinations by this technique were within 3.5% of leaf weighting measurements and 5.8% of LAI measurements by a point drop technique. This is approximately twice the accuracy of the photograph technique without calibration. For. Sci. 33(1):210-216.
Combustion Losses of Sulfur from Forest Foliage and Litter
Authors: Tiedemann A. R.
Published: April 2024

Sulfur (S) content of samples of ponderosa pine (Pinus ponderosa Dougl. Ex Laws.), Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco), Sitka alder (Alnus sinuata [Regel] Rydb.), snowbrush ceanothus (Ceanothus velutinus [Dougl.]), and forest litter combusted in an aerated muffle furnace at 375°-575°, 575°-775°, 775°-975°, and 975°-1,175°C for 5, 30, and 60 min was compared with S content of unburned samples. Sulfur losses at 375°-575°C for 5 min ranged from 24 to 79% of S contained in unburned material. At 975°-1,175°C for 60 min, losses ranged from 61 to 92%. Results suggest that prescribed burning and wildfire could potentially cause substantial volatilization losses of S from foliage and litter. For. Sci. 33(1): 216-223.
Freeze-Crack-Related Measurements on Platanus × acerifolia Trees
Authors: Neely Dan , Himelick E. B.
Published: April 2024

For four consecutive winters, stem temperature, stem shrinkage, and widths of freeze cracks were measured on London plane trees, Platanus × acerifolia, in Urbana, Illinois. At temperatures below 0°C, trunk shrinkage and widths of freeze cracks were substantial and inversely correlated with temperature. Wood shrinkage was greater in trees with cracks than in trees without cracks. For. Sci. 33(1):239-244.
Long-Term Storage of Douglas-fir Pollens
Authors: Copes Donald L.
Published: April 2024

A test of pollen fertility after 3 years of cold storage is reported. Douglas-fir (Pseudotsuga menziesii) pollen was as fertile after 1, 2, or 3 years of storage in liquid nitrogen as was fresh pollen. Fertility of the same pollen lots decreased significantly after 1 or 2 years of storage at 0°C. For. Sci. 33(1):244-246.
Evaluation of Researchers' Decisions in Short-Rotation Forestry
Authors: Fege Anne S.
Published: April 2024

A survey of short-rotation forestry research from 1966-82 provided insights into the political, socioeconomic, institutional, and personal factors influencing decisions made by forestry researchers. Scientists first entered short rotation forestry research because of personal contacts with other scientists, because they considered this a "productive" research area, because funds were available, and because of the "energy crisis." They attributed their success primarily to cooperation with other scientists and potential users and to adequate financial support. These findings offer insight into the individual decisions and the economic and political factors that will shape other forestry research frontiers. For. Sci. 33(1):30-42.
Genetic Structure of Southern Pine Beetle Populations
Authors: Roberds J. H. , Hain F. P. , Nunnally L. B.
Published: April 2024

The pattern of geographic variation among southern pine beetle (SPB) populations of the enzootic infestations of 1978 was similar to that found among populations in the declining epizootic of 1977. Results for two Texas collections made in 1977 and 1978 indicated that these populations were genetically differentiated from each other. Allele frequencies estimated for the Arkansas and Mississippi populations provided evidence that they belonged to the more genetically uniform group of populations found outside of Texas. Two different types of population structures were found in the infestations studied in Arkansas and North Carolina. Infestations within Arkansas were slightly differentiated genetically but displayed little variation in allele frequencies among single-tree subpopulations within infestations. In the North Carolina populations, allele frequencies did not differ among infestations or among single-tree subpopulations within infestations; however, homozygosity in some single-tree subpopulations was greater than expected for random mating. Evidence for considerable two-locus linkage disequilibria was found in subpopulations of unexpanded infestations studied in North Carolina. Within subpopulations of the expanded infestations however, linkage disequilibria were less extensive. For. Sci. 33(1):52-69.
Drought Tolerance of Southwestern Oregon Douglas-Fir
Authors: White Timothy L.
Published: April 2024

Seedlings from two open-pollinated families of Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) from each of 35 seed sources in southwestern Oregon were tested for their ability to survive simulated drought in growth room, greenhouse, and coldframe test environments. Generally, seedlings from seed sources originating from higher elevations and, to a lesser extent, from drier sites, were more drought tolerant. Seedlings from drought-tolerant sources tended to have earlier bud-set, smaller initial height, and less winter injury. The main selective force leading to earlier bud-set and smaller height growth appeared to be the colder temperature regime associated with higher elevations. Seedlings from high elevations entered dormancy sooner and were better able to survive the imposed drought. Implications for seed transfer and for breeding for drought-tolerant genotypes in southwestern Oregon are discussed. For. Sci. 33(2):283-293.
Reduction of Phellinus weirii Inoculum in Douglas-Fir Stumps by the Fumigants Chloropicrin, Vorlex, or Methylisothiocyanate
Authors: Thies Walter G. , Nelson Earl E.
Published: April 2024

Three dosages of chloropicrin and Vodex, with and without sealing, and one dosage of methylisothiocyanate (MIT) in capsules or open glass tubes were applied to Douglas-fir stumps to reduce Phellinus weirii (Mutt.) Gilb. inoculum. After 2 years, all fumigants had reduced the amount of inoculum, but MIT was less effective than chloropicrin or Vorlex. Neither higher levels of fumigant nor sealing the stump tops resulted in further reduction of inoculum. Inoculum in dead stumps was not further reduced by covering stumps with a plastic tarp. Presence of advanced decay did not seem to be advantageous for movement of the fumigant in stumps and roots. Assessment of inoculum survival by using either aseptic isolation techniques or observations of fungal regrowth on the cut surfaces of incubated root disks were comparable for detecting viable P. weirii in root disks from untreated stumps. As a percentage of prefumigation inoculum volume, isolations from fumigated stumps, indicated more viable P. weirii in roots (22%) than did fungal regrowth (7%). Most root disks contained viable P. weirii where residual fumigant was not detected in bioassays, whereas viable P. weirii was not found in 26 of 27 root disks where fumigant was detected. For. Sci. 33(2):316-329.
Organic Matter and Nutrients Associated with Fine Root Turnover in a White Oak Stand
Authors: Joslin J. D. , Henderson G. S.
Published: April 2024

Organic matter and nutrients cycled by fine root turnover were quantified in a mature white oak (Quercus alba L.) stand and compared to contributions from litterfall. The budget method, a revised version of the traditional repeated sampling method, was used to measure root turnover. The magnitude of the live and dead pools of three size classes of fine (<5 mm diameter) roots were monitored bimonthly for 14 months. Decomposition rates over these intervals were also measured, while production and mortality were calculated. Litterfall was collected simultaneously, and the nutrient concentrations of the various detritus components determined. Root pools fluctuated less, and total root turnover biomass (220 g m -2 yr-1) was also less than previously noted in most other stands studied. Fine root turnover accounted for 30% of the total detritus production and 20-40% of the turnover of the five macron utrients (N, P. K, Ca, Mg) studied. Differences with previous studies suggest that there may be rather large species and/or site-related differences in the amount of energy various stands allocate for fine root maintenance. For. Sci. 33(2):330-346.
Decay Fungi and Wounding in Advance Grand and White Fir Regeneration
Authors: Aho Paul E. , Filip Gregory M. , Lombard Frances F.
Published: April 2024

A total of 464 living white and grand fir tree stems in 24 stands in Oregon and Washington were dissected to detect infections of hymenomycetes (decay fungi) and other microorganisms in woody tissue. Of 21,249 attempted isolations from dissected trunks, 43.2% yielded bacteria or yeasts, 38.6% were sterile, 11.0% were nonhymenomycetes, 3.1% were hymenomycetes, and 4.1% were contaminated or mixed cultures. Hymenomycetes most frequently isolated were Echinodontium tinctorium and Heterobasidion annosum, both of which caused the most discoloration and decay. Nearly 20% of all hymenomycetous isolations, particularly Hericium abietis and E. tinctorium, were from clear tissue not associated with discolored or decayed wood. More than 300 trunk wounds on 248 dissected trees were classified by size, location, age, and hymenomycetous associations. At least 45% of all trees with wounds had hymenomycetes present, of which E. tinctorium and Pholiota limonella were isolated most frequently. Discoloration caused by E. tinctorium was associated with wounds as recent as a year or as small as 56 cm2. All E. tinctorium infections that caused discoloration or decay were within 30 cm of a wound, whereas all infections within clear tissue were beyond 30 cm. These data support a hypothesis that E. tinctorium enters hosts via minute branchlet stubs, becomes dormant after the branchlet stubs occlude, and is activated by wounds in the vicinity of dormant infections. For. Sci. 33(2):347-355.
Generalized Error Structure for Forestry Yield Models
Authors: Gregorie Timothy G.
Published: April 2024

The combined time-series cross-sectional nature of remeasurement data from permanent forest plots is examined with an aim toward improving the precision of yield models fitted with these data. The linear model error term is regarded as an aggregation of plot, time period, and residual random effects with possibly distinct variances and correlations. Four alternative error covariance structures are posited that differ in the manner in which serial correlation, plot variance heterogeneity, and cross-plot correlations are prescribed. Yield models with the presumed error covariance specifications were fitted to a panel of 65 pure, even-aged Douglas-fir plot remeasurements, using two-stage generalized least squares and, in one case, a full maximum likelihood estimation. Ordinary least squares results were used as a basis for comparison. Comparison of the fitted models by prediction error and likelihood criteria indicate ordinary least squares nearly always performs better by the former measure, whereas one or more of the alternate specifications always have higher likelihood. For. Sci. 33(2):423-444.
Landform-Mediated Differences in Successional Pathways Among Upland Forest Ecosystems in Northwestern Lower Michigan
Authors: Host George E. , Pregitzer Kurt S. , Ramm Carl W. , Hart James B. , Cleland David T.
Published: April 2024

Seedling and sapling densities were compared with current overstory composition in 30 upland forest stands in northwestern Lower Michigan to study potential successional pathways. The patterns of compositional change were strongly related to topographic and edaphic differences among glacial landforms. Glaciofluvial landforms, currently dominated by oak, have relatively high densities of oak seedlings (4913 stems/ha) that seldom move into the sapling layer (10 stems/ha). Oak-dominated ecosystems on hilly ice-contact stratified drift exhibited relatively high densities of red maple saplings (48 stems/ha). Oak-dominated ecosystems on extremely well drained outwash plains exhibited sparse sapling regeneration of any species; red maple was typically absent, and oak saplings were usually in an apparent state of decline. Differences in the potential for recruitment of saplings into the overstory among these ecosystems may be attributable to differences in fire history or site-dependent effects on the competitive abilities of species. Morainal landforms, currently supporting relatively diverse northern hardwood overstories, showed little potential recruitment of any species other than sugar maple. Glacial landforms in northwestern Lower Michigan direct compositional change by influencing soil moisture and nutrient availability, and historical patterns of disturbance and species establishment. For. Sci. 33(2):445-457.
Twenty-four Years of Ponderosa Pine Growth in Relation to Canopy Leaf Area and Understory Competition
Authors: Oren R. , Waring R. H. , Stafford S. G. , Barrett J. W.
Published: April 2024

With data from a long-term experiment in which initial stocking of trees and understory vegetation were controlled, we tested the hypothesis that stand growth is directly correlated with the development of the forest canopy; e.g., growth is proportional to canopy leaf area. The hypothesis was generally supported. Stands of ponderosa pine without understory vegetation more rapidly developed canopy leaf area than stands with an understory. At very low leaf area indices, wood production per unit of leaf area was more efficient, particularly in stands where the understory vegetation had been removed. Once the leaf area index exceeded 2.0, however, the efficiency of wood production remained stable and was comparable for stands with and without understory vegetation. For. Sci. 33(2):538-547.
Rates of Free-Living Nitrogen Fixation in Some Piedmont Forest Types
Authors: Grant Deborah , Binkley Dan
Published: April 2024

We examined rates of free-living (nonsymbiotic) nitrogen fixation in a successional sequence of forest types in the Piedmont of North Carolina. Annual nitrogen input through this process did not differ among ecosystems, averaging roughly 0.002 kg/ha annually. The rate in a 20- to 30-year-old stand did not increase with irrigation or additions of nitrogen, phosphorus, or molybdenum. Free-living nitrogen fixation in these forests should not be expected to compensate for nitrogen losses through natural processes or management activities. For. Sci. 33(2):548-551.
Adjusted Inclusion Probabilities with 3P Sampling
Authors: Furnival George M. , Gregoire Timothy G. , Grosenbaugh Lewis R.
Published: April 2024

The mean square error efficiency of Grosenbaugh's (1964) adjusted 3P estimator is examined relative to four alternative estimators which use regression estimates of the conditional inclusion probabilities and true conditional inclusion probabilities. Actual mean square errors were calculated as the result of exhaustive sampling of populations that ranged in size from 9 elements to 144 elements and that exhibited widely different proportionality between the variable of interest and the auxiliary variable used for probability selection. The adjusted 3P estimator is as efficient or more efficient than all four competitors except when the unconditional probability of inclusion neared unity for some population elements. For. Sci. 33(3):617-631.
Height and Diameter Growth Response in Loblolly Pine Stands Following Fertilization
Authors: Bolstad Paul V. , Allen H. Lee
Published: April 2024

Significant mean height and mean diameter responses to nitrogen and phosphorus fertilization were observed 5 years after treatment in 31 loblolly pine stands located in the southeastern United States. Stands were consistently most responsive to the addition of 112N-56P kg/ha. Gains averaged 12% for all sites, and 31% for statistically responsive sites. Responses for other N or P rates were lower, but still positive and significant. Depending on the treatment, between one-fourth to one-half of the experimental installations exhibited a statistically significant positive response to fertilization. Twenty-two of 31 installations had significantly different height growth-diameter growth relationships following fertilization, although treatment effects were not consistent. Fertilizer-induced changes in H-D equation parameters were statistically nonsignificant for 27 of the 31 studies. Changes in H-D curve parameters associated with 1 or 2 year acceleration in stand development were small compared to the errors associated with fitting H-D curves to 15 or more years of cumulative height and diameter. For. Sci. 33(3):644-653.
Predicting Growth and "Success" of Coppice-Regenerated Oak Stems
Authors: Lowell K. E. , Mitchell R. J. , Johnson P. S. , Garrett H. E. , Cox G. S.
Published: April 2024

Logistic regression models were derived from data collected in the Missouri Ozarks to estimate the probabilities that 5-year-old stems of red oaks and white oaks in thinned and unthinned sprout clumps would attain a specified dbh at ages 12 and 30. In deriving each model, several success criteria based on selected future dbh were specified. A stem was considered "successful" for a particular criterion if it attained that dbh or larger, but considered a "failure" if it did not achieve that criterion because of either slow growth or mortality. Consequently, each model accounted for both growth and mortality probabilistically. Growth of survivors was also estimated using linear regression models. These models were developed for two species groups using data for stems that were alive at both the beginning (age 5) and end of a measurement period (ages 12 and 30). The logistic models indicated that height at age 5 was a significant predictor of competitive success of stems in subsequent years in stands with either thinned or unthinned clumps. Diameter of the parent stump was also significantly correlated with success, but only in stands where clumps were thinned. Results indicate that under the conditions of this study, which was conducted on a single site, stems with high success probabilities could be identified early in the life of this coppice-regenerated stand, and that early clump thinning in this stand increased success probabilities and diameter growth. For. Sci. 33(3):740-749.
A Solution Procedure for the Sort Yard Location Problem in Forest Operations
Authors: Sessions John , Paredes Gonzalo
Published: April 2024

Sort yards placed at selected intermediate points between timber cutting sites and mills have potential for increasing the value of logs or trees destined for processing into different products. A two-phase modeling procedure is presented for identifying the efficient placement of sort yards using computations much simpler than those in standard linear mixed-integer programming methods. For. Sci. 33(3):750-762.