bluuebunny/crossref_metadata_2025 huggingface dataset:
Timber Harvesting with Fluctuating Prices
Authors: Brazee Richard , Mendelsohn Robert
Published: April 2024

Because of volatility in demand, timber prices tend to fluctuate from year to year. Timber owners know today's price but are uncertain about tomorrow's prices. Traditional Faustmann harvesting ignores these random annual price fluctuations and prescribes harvests on the basis of expected prices. In this paper, we adapt an asset sale model to forestry and solve for the optimal schedule of reservation prices. When current price is above the reservation price, owners should cut that age class, otherwise they should wait another year. This flexible price harvest policy significantly increases the present value of expected returns over the more rigid Faustmann model. For. Sci. 34(2):359-372.
Multiple Use vs. Organizational Commitment
Authors: Twight Ben W. , Lyden Fremont J.
Published: April 2024

Q factor analysis and cluster analysis data demonstrate a high level of homogeneity among USDA Forest Service district rangers resembling that found by Kaufman in the 1950s, suggesting a current organizational culture committed primarily to one constituency group rather than the multiple constituencies implied by the Multiple Use-Sustained Yield Act. Such strong commitment to a single-constituency perspective may preclude agency sensitivity to other public perspectives obtained through citizen participation. Organization theory and social institutions theory are used to explain the findings. For. Sci. 34(2):474-486.
Leaf Area, Stemwood Growth, and Nutrition Relationships in Loblolly Pine
Authors: Vose James M. , Allen H. Lee
Published: April 2024

The relationships among loblolly pine (Pinus taeda L.) stand leaf area index (LAD, stemwood volume growth (m3/ha/yr), and growth efficiency (m3stemwood/ha/yr/LAI) were examined in three nitrogen (N) by phosphorus (P) fertilization field trials. Prior to fertilization, stockinglevels and nitrogen limitations varied for the three stands. LAI increased significantly (up to 60%) following N fertilization on the two N deficient stands. Phosphorus additions did not affect LAI. Stemwood growth was positively and linearly related to LAI across treatments and stands. Variationsin LAI across stands reflected the differences in stocking and N availability. On average, a unit of LAI produced 7.3 m3stemwood/ha/yr. Growth efficiency was not affected by fertilization on two of the three stands. A decrease in growth efficiency at a projected LAI above 3.5 resultedfrom an asymptotic relationship between stemwood growth and LAI on a stand that was fully stocked and highly responsive to N fertilization. The use of LAI as an index of stocking is proposed because LAI integrates tree size, stand density, and site resource supply. In addition, it is proposedthat the deviation of a stand's current LAI from the maximum supportable LAI based on fixed site factors (e.g., water, temperature) may provide a good measure of a stand's potential responsiveness to fertilization. For. Sci. 34(3):547-563.
The Effect of Eccentricity on the Estimation of Basal Area and Basal Area Increment of Coniferous Trees
Authors: Biging Greg S. , Wensel Lee C.
Published: April 2024

A sample of noncircular tree cross-sections was examined to determine basal area and basal area increment. Basal area estimates were calculated with a circular model from single measurements of diameter and from averages of two diameter measurements. Basal area increment estimates were made with several geometric models from single measurements of radial increment and averages of two measurements of radial increment. Commonly used tree cross-sectional area estimates investigated were biased, usually overestimating basal area. Several generalized geometric models of area increment were investigated, but none tested were uniformly supported by the data with accuracy related to the specific increment measurements selected. However, results indicated that either a single increment measurement taken on the minor axis or the shortest increment from the major axis yielded accurate estimates of basal area increment for several of the models tested. For. Sci. 34(3):621-633.
A Forestry Application of Schnute's Generalized Growth Function
Authors: Bredenkamp Brian V. , Gregoire Timothy G.
Published: April 2024

A case is presented where the Chapman-Richards growth function is suitable to describe growth for a certain period during the life of a stand of Eucalyptus grandis in South Africa. Toward the end of that period, diameter growth exhibited strong asymptotic properties. After marked competition mortality, the stand resumed growth beyond what had appeared to be an asymptotic level and the Chapman-Richards function could no longer be satisfactorily fitted. A generalized growth function developed by Schnute successfully tracked this renewed growth. The parametric relationships between the two models are established. For. Sci. 34(3):790-797.
Stand Structure in Subalpine Forests of Yosemite National Park, California
Authors: Parker Albert J.
Published: April 2024

Variation of seedling densities and diameter-class distributions with site condition is examined for 5 coniferous tree species sampled in 30 stands between 2400 and 3300 m elevation in Yosemite Park, California. There is an apparent tolerance ranking from mountain hemlock and red fir (high tolerance) through lodgepole pine (intermediate) to whitebark and western white pine (low tolerance). Diameter curves for each species vary in form across environmental gradients, from stable, persistent forms (reverse-J and multimodal) on optimal sites to random forms on marginal sites. Multimodal diameter structure is common among populations in Sierran subalpine forests. In this climatically rigorous setting, interannual variability of conditions affecting seedling survival and growth rates may combine with canopy gap dynamics to yield stable diameter curves punctuated by discrete episodes of establishment, release and growth. For. Sci. 34(4):1047-1058.
The Ratio of Shoot Silhouette Area to Total Needle Area in Scots Pine
Authors: Oker-Blom Pauline , Smolander Heikki
Published: April 2024

The dependence of light interception efficiency on shoot structure was studied. The silhouette areas of 258 Scots pine (Pinus sylvestris L.) shoots inclined at different angles were measured, and the corresponding silhouette area to total needle area ratios (STAR) were determined. For each shoot, a mean silhouette to total needle area ratio (STAR) with respect to a spherical shoot orientation was calculated. STAR varied between 0.09 and 0.21 and averaged 0.14. For spherically oriented individual needles or leaves, the corresponding mean projection of unit foliage area is 0.25. Thus, the light interception efficiency of the shoots as indicated by STAR-values was on average reduced by 43% because of mutual shading of needles on the shoots. The silhouette areas and STAR-values were also calculated theoretically using a previous model of shoot geometry, and these values were compared to the empirical measurements. For. Sci. 34(4):894-906.
Minimum Age-To-Age Correlations in Early Selections
Authors: Magnussen Steen
Published: April 2024

The concepts and computational procedures of minimum age-to-age selection efficiency and correlations are introduced to assist the tree breeder in deciding selection age. When observed age-to-age correlations in a field test exceed the required minimum, selection at the current age will yield a higher rate of improvement than selection at an older age. For. Sci. 34(4):928-938.
Model Fitting Under Patterned Heterogeneity of Variance
Authors: Gregoire Timothy G. , Dyer Michael E.
Published: April 2024

Two approaches toward fitting regression models with multiplicative error heteroscedasticity recur in the forestry, ecology, and statistical literature. One includes the estimation of the heterogeneity in the fitting process. The alternative approach entails the use of variance estimators that are robust to the error variance heterogeneity. Under suitable conditions, the former method offers nonnegligible gains in efficiency, whereas the robust alternatives provide accurate assessment of ordinary least squares estimators even in the presence of heteroscedasticity. The performance of both approaches are examined and contrasted, and suggestions for future applications and research are made on the basis of these results. For. Sci. 35(1):105-125.
Application of Growth Models For Simulating Genetic Gain of Loblolly Pine
Authors: Knowe Steven A. , Foster G. Sam
Published: April 2024

A technique for predicting genetic gain in progeny tests using height-age models and stand simulations is presented for loblolly pine (Pinus taeda L.). Periodic remeasurements for a block-plot open-pollinated progeny test are used to examine trends in height growth, selection differential, and percent gain in height and volume. Using the Chapman-Richards model and approximate F tests, significant differences among families were detected in asymptote and rate parameters but not for the shape parameter. Separate base-age invariant height-age equations were developed for each family to account for polymorphism associated with the rate parameter.

Selection differential calculated from either observed or predicted heights exhibited similar trends although estimates from the height-age equations are consistently higher than obtained with observed height after age 5. Family rankings using the height-age models are consistent with those obtained using observed heights. Also, percent gain calculated from predicted heights is within 2% of the estimates obtained with observed heights at ages greater than 3 years.

Differences in survival, height, and diameter were combined to examine trends in volume production associated with families. Predicted volume for each family was simulated using a bivariate distribution of height and diameter accounting for differences in height-growth patterns among families. Family rankings for volume are also closely correlated, resulting in two or three of the same families being selected using observed and predicted data. Selection differential obtained from simulated and observed volume fluctuates in rank producing a satisfactory trend based on predicted volume after age 5. Gain based on simulated volume tends to be slightly greater than gain based on observed volume. Estimates of percent gain obtained by reinitializing the simulations with quadratic mean dbh and residual trees per acre after thinning differed more from the observed trends than the unthinned simulations. For. Sci. 35(1):211-228.
Projections with Ingrowth by Markov Chains
Authors: Valentine Harry T. , Furnival George M.
Published: April 2024

A Markov chain that accounts for ingrowth as well as growth, death, and harvest of trees is formulated for projecting a size-class distribution. Live trees of minimal or greater size reside in size classes 1 through n. A special size class 0 serves as a reservoir of potential ingrowth trees and as a repository for dead or harvested trees. Ingrowth is the movement of a tree out of size class 0 and into a larger size class. Conversely, death or harvest is represented by the movement of a tree out of a larger size class and into size class 0. Application of the Markov chain, including the calculation of a stationary size-class distribution, is demonstrated. For. Sci 35(1):pp. 245-250.
Genetic Variation Among and Within Single-Tree Progenies of Northern Red Oak
Authors: Kolb T. E. , Steiner K. C.
Published: April 2024

Twelve genotypes from each of five open-pollinated families of northern red oak (Quercus rubra L.) were clonally multiplied by splitting embryos from seeds. Height and stem diameter were measured on all clones over two growing seasons in outdoor planters. Families, and clones from the same family, differed significantly in first- and second-year height and diameter adjusted to the same seed weight. Clone-within-family variance was greater than family variance for first-year height (53% versus 35% of total variance), while family variance was greater than clone-within-family variance for second-year height (40% versus 35%). For. Sci. 35(1):pp. 251-256.
Root System Structure in Planted and Seeded Loblolly and Shortleaf Pine
Authors: Harrington Constance A. , Brissette John C. , Carlson William C.
Published: April 2024

Differences in root system structure attributable to stand origin were examined by pairing seeded and planted stands of loblolly (Pinus taeda L.) and shortleaf pine (P. echinata Mill.). The 17 paired stands were 3 to 9 years old and located in Arkansas, Oklahoma, and Texas on similar soil and site conditions. Root systems from 12 trees were excavated from each stand, classified by root system type and measured for number and size of first-order lateral roots and amount of root spiraling and bending. Although root systems of planted trees were commonly deformed, the most consistent difference in root system structure between planted and seeded trees was the increased distance from groundline to the uppermost lateral roots on planted seedlings. A linear discriminant function including this variable correctly classified all loblolly pine plots and 89% of the shortleaf pine plots as to whether the plot had been planted or seeded. Planted trees also had fewer first-order lateral roots less than 10 mm in diameter and exhibited greater spiraling and bending of major first-order laterals than seeded trees. Differences in root system structure between planted and seeded trees were similar for the two species. For. Sci. 35(2):469-480.
A Production Function Analysis of Loblolly Pine Yield Equations
Authors: Liu Chiun-Ming , Leuschner William A. , Burkhart Harold E.
Published: April 2024

A timber production function analysis for unthinned loblolly pine plantations was made using a four-equation system. In the system, the yield equation is the production function. The production function and other equations fit the data well, using biological consistency, significance, goodness of fit, and minimal collinearity as criteria. The system also predicted volume for lightly and heavily thinned stands with a Mean Difference of 2 and 5% of mean volume, respectively. Analysis of the production function coefficients verified the functional form. More specifically, all input factors are complementary, output elasticities indicate a relatively unresponsive production function, the Elasticity of Scale is 2.3, the elasticities of substitution lie between zero and 1.0, and the production function has Variable Elasticity of Substitution (VES). For. Sci. 35(3):775-788.
An Economic Analysis of Harvest Behavior: Integrating Forest and Ownership Characteristics
Authors: Dennis Donald F.
Published: April 2024

This study provides insight into the determinants of timber supply from private forests through development of both theoretical and empirical models of harvest behavior. A microeconomic model encompasses the multiple objective nature of private ownership by examining the harvest decision for landowners who derive utility from forest amenities and from income used for the consumption of other goods. Tobit analysis is used to estimate the relationship between harvest behavior and forest, owner, and economic characteristics from cross-sectional data for individual forest plots in New Hampshire. The empirical results highlight the influence of forest characteristics and landowner affluence on the harvest decision. Decomposition of the Tobit coefficients indicates that changes in timber supply are expected to result primarily from changes in the number of acres from which timber is offered for sale and to a much lesser extent from changes in per-acre harvesting intensity. Marginal supply responses varied considerably depending on the values for the other coefficients and variables, underscoring the need to consider the shape of the distribution as well as the mean values for the explanatory variables when projecting harvest behavior. For. Sci. 35(4): 1088-1104.
Biomass Estimation Methods for Tropical Forests with Applications to Forest Inventory Data
Authors: Brown Sandra , Gillespie Andrew J. R. , Lugo Ariel E.
Published: April 2024

This paper contains a strategy for estimating total aboveground biomass of tropical forests. We developed regression equations to estimate aboveground biomass of individual trees as a function of diameter at breast height, total height, wood density, and Holdridge life zone (sensu Holdridge 1967). The regressions are applied to some 5,300 trees from 43 independent sample plots, and 101 stand tables from large-scale forest inventories in four countries, to estimate commercial and total aboveground biomass per unit area by forest type, and to estimate expansion factors defined as the ratio of aboveground to commercial biomass. The quadratic stand diameter (QSD, i.e., the diameter of a tree of average basal area) in a given forest stand influences the magnitude of the expansion factor. Stands of small trees have large expansion factors (up to 6.4), and as QSD increases, the expansion factor decreases to a constant value (about 1.75). For undisturbed forests in moist, moist transition to dry, and dry life zones respectively, the expansion factors for total aboveground biomass were 1.74, 1.95, and 1.57 respectively. For undisturbed, logged, and nonproductive forest categories used by the FAO to report global commercial wood volume data, we estimated expansion factors of 1.75, 1.90, and 2.00 respectively. Applying these factors to FAO data results in a 28 to 47% increase in previous volume-derived estimates of tropical forest biomass. However, estimates of tropical forest biomass based on small destructive samples continue to be high relative to estimates based on volume data. For. Sci. 35(4):881-902.
Controls over Net Inorganic Nitrogen Transformations in an Age Sequence of Pinus Elliottii Plantations in North Florida
Authors: DiStefano J. F. , Gholz H. L.
Published: April 2024

The controls over net ammonification and net nitrification in recently clearcut, 9-year-old and 29-year-old plantations of Pinus elliottii in north Florida were investigated using a combination of field (in situ) and laboratory soil incubations. Fertilization with PK and NPK and prescribed burning were also used in the field to further determine effects of P and NH+4-N availability on net N transformations. Results revealed complex relationships among N availability and plantation age, incubation method, season and treatment. Ammonification rates were generally lower than those found in other studies. The clearcut, 9-year-old and NPK-fertilized plots had the greatest rates. The single burns and PK-fertilization had little effect on rates, although soil chemistry was significantly altered. Net nitrification rates were negligible except on the NPK-fertilized plots, which had greatly elevated rates of both net ammonification and net nitrification. We conclude that P availability had little apparent affect on net N transformations in the surface soil and that N availability was least in the oldest stand. For. Sci. 35(4):920-934.
Optimizing Any-Aged Management of Mixed-Species Stands: II. Effects of Decision Criteria
Authors: Haight Robert G. , Monserud Robert A.
Published: April 2024

The effects of maximum present value and maximum volume objectives on the efficiencies of alternative silvicultural systems are determined by solving any-aged management problems for mixed-conifer stands in the Northern Rocky Mountains. Any-aged management problems are formulated with periodic planting and harvesting controls and without constraints on the stand age or size structure over time. Optimization is performed with the Stand Prognosis Model, a single-tree simulator that has been calibrated for many forest types in the western United States. With a maximum present value objective, 1987 stumpage prices, and no logging damage, steady-state, uneven-aged management using selection cuts is the target silvicultural system for a range of stand types. Optimal transition regimes for understocked stands include clearcutting and planting western white pine (Pinus monticola Dougl. ex D. Don), a high-value, fast-growing species. With a maximum merchantable volume objective, two types of management emerge as optimal: even-aged plantation management and an uneven-aged shelterwood system are both capable of producing the same high level of yield indefinitely. Both types of management rely on a series of thinnings to grow the most vigorous crop trees into the largest size classes. In addition, the shelterwood system ensures that adequate natural regeneration is established when the crop trees are harvested. Because the uneven-aged shelterwood system produces steady-state yields that are as high or higher than plantation management, these results call into question the widely held view that even-aged plantation management maximizes total merchantable volume production. For. Sci. 36(1):125-144.
König-Faustmannism: A Critique
Authors: Oderwald Richard G. , Duerr William A.
Published: April 2024

The König-Faustmann form of marginal analysis derives a valid estimate of the financially optimal rotation for individual trees and other indivisible forest capital: forests whose age-class structure is not to be changed. For divisible capital, the applicable form of the marginal model derives a shorter rotation because it allows for interactions among forest compartments. For. Sci. 36(1):169-174.
Evaluation of Four Estimators of Herbicide Treatment Efficacy for Woody Competition Control Studies
Authors: Knowe Steven A. , Shiver Barry D. , Borders Bruce E.
Published: April 2024

Four estimators of herbicide treatment efficacy based on hardwood crown measurements were evaluated. Using data from untreated plots, expected post-treatment size of treated hardwood rootstocks was obtained by accounting for growth between pre- and post-treatment evaluations with an unadjusted mean, a ratio-of-means estimator, and a regression estimator. Formulas were developed to compare the estimates of hardwood control based on change in crown size relative to pretreatment size, unadjusted mean post-treatment size, and ratio- and regression-adjusted post-treatment size. Conditions for optimum application of the estimators were also discussed. The effects of all four estimation procedures on the estimated means and treatment contrasts were demonstrated for flowering dogwood (Cornus florida L.) and sweetgum (Liquidambar stryaciflua L.) in a site-preparation study located in the Georgia piedmont. The lowest mean control was obtained using change in crown size, while control based on regression-adjusted crown size resulted in the highest mean control. Treatment contrasts for control based on change in crown size and control based on ratio-adjusted crown size had the same level of significance for both species. For dogwood, all four estimators of efficacy resulted in the same conclusion (acceptance or rejection of the null hypothesis) for 8 of 9 contrasts, although regression-based control tended to be the most conservative. For sweetgum, the null hypothesis of no differences among treatments was rejected more frequently using efficacy based on the unadjusted mean post-treatment crown size or regression-adjusted post-treatment crown size. A regression estimator of post-treatment crown size appears to be more flexible in its application than ratio-adjusted estimates. For. Sci. 36(2):201-211.
Heating-Related Water Transport to Intact Lodgepole Pine Branches
Authors: Cohen Warren B. , Omi Philip N. , Kaufmann Merrill R.
Published: April 2024

Woody plants may have the ability to transport water to heated foliated branches. If so, additional water vaporized could have a significant impact on energy absorbed by heated plant crowns. To investigate this, we compared energy absorbed by similar intact and detached branches of well-watered lodgepole pine trees (Pinus contorta Dougl. ex Loud.) during heating in a specially designed calorimeter.

When heated to 250°C, intact branches absorbed 49% more energy than detached branches; an amount equivalent to 0.62 g more of water per gram of dry branch vaporized from intact than from detached branches. After heating, no water remained in the detached branches, while intact branches had a mean residual water content of 10.8%. These results indicate that significant amounts of water can be transported to, and vaporized from, heated branches of non-drought-stressed lodgepole pine trees. Hence, by accounting only for the initial water contained in heated foliated branches, current fire behavior models improperly calculate energy absorption by heated woody plant crowns. For. Sci. 36(2):246-254.
An Economic Evaluation of Research on Herbaceous Weed Control in Southern Pine Plantations
Authors: Huang Y. Star , Teeter Lawrence
Published: April 2024

Interest in forestry research evaluation has steadily increased in recent years. This paper describes an ex ante model, which uses forecasts of the future benefits of current and proposed research to evaluate a research program that focuses on enhancing pine growth by controlling competition from herbaceous weeds. A principal value of this model is its potential for wide applicability to other forest management research programs. The method requires information describing pine growth impacts, the probability of future research success, the probability and rates of future technology adoption, the management strategies of potential users of the technology (weighted by the area and site quality of lands under their control), the costs of research extension, and technology adoption, and the future value of stumpage. Past and planned herbaceous weed control research will produce substantial net economic benefits through the application of research findings to the management of pine forest types in the southern U.S. for. Sci. 36(2):313-329.
Dating Decline and Mortality of Chamaecyparis nootkatensis in Southeast Alaska
Authors: Hennon P. E. , Shaw III C. G. , Hansen E. M.
Published: April 2024

Alaska yellow-cedar (Chamaecyparis nootkatensis (D. Don) Spach) has been declining and dying for a long, but undetermined, span of time in remote and undisturbed forests of southeast Alaska. Aerial photographs indicate mortality was widespread by 1927. The dates of death for individual snags of Alaska yellow-cedar were determined by counting annual rings on 73 western and mountain hemlock trees growing beneath larger, dead Alaska yellow-cedars, and in live callus strips on 46 Alaska yellow-cedars with partial bole death. Average time since death was 4, 14, 26, 51, and 81 years for snags in class I (foliage retained), class II (twigs retained), class III (secondary branches retained), class IV (primary branches retained), and class V (bole intact but no primary branches retained), respectively. Class V snags, which are common on all sites currenty expressing decline, appear to represent the trees initially affected. Snags in a sixth class with deteriorating boles are uncommon and not associated with sites of decline; their death most likely predated the onset of extensive mortality. Because some class V snags died over 100 years ago, these data suggest that extensive mortality began about 1880, and became obvious about 1900-1910—dates supported by historical records. For. Sci. 36(3):502-515.
Identification of a Network Substructure and Some Algorithmic Considerations for Large-Scale Harvest Scheduling Problems
Authors: Sherali Hanif D. , Liu Chiun-Ming
Published: April 2024

Berck and Bible (1984) have suggested a solution approach for harvest scheduling problems based on the Dantzig-Wolfe (1960) decomposition algorithm. We first expose the fact that the area constraints in their problem possess a network structure, requiring the solution of a single longest path problem, and show that the elegant dosed-form solution derived by Berck and Bible is precisely a readily obtained longest path solution. Moreover, we show that when additional variable bounds are imposed, the network structure remains exploitable. Second, we compare the computational effort and storage requirements of the Dantzig-Wolfe algorithm and the revised simplex method for solving this problem. The slow tail-end convergence of the Dantzig-Wolfe approach is of particular concern. However, we provide operational guidelines showing when this procedure may be preferred. Other viable algorithms suitable for solving this problem are also discussed. For. Sci. 36(3):599-613.
Considerations on Modeling the Market for Softwood Lumber in the United States
Authors: Uri Noel D. , Boyd Roy
Published: April 2024

This paper uses the Granger causality test to determine whether the demand for softwood lumber affects price in the current period or subsequent periods, or whether price is exogenous. This test is run for each of four geographically distinct regions in the United States. Further statistical tests are then used to detect the geographical extent of the softwood lumber market. The results indicate that demand is indeed strongly connected to prices, and that there is a national market for softwood lumber. For. Sci. 36(3):680-692.
Identifying Trees in Riparian Areas That Can Provide Coarse Woody Debris to Streams
Authors: Robison E. George , Beschta Robert L.
Published: April 2024

The natural fall of trees into mountain streams provides coarse woody debris that can improve fish habitat and influence stream morphology. Geometric and empirical equations, based on tree size and distance from the stream, were used to determine the conditional probability of a tree's adding coarse woody debris to a stream. Additional equations were developed to relate this probability to basal area factor. For conditions in the Pacific Northwest, Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) was selected to illustrate how the equations can be used for varying tree sizes and probabilities. After selecting a probability and determining basal area factor by these equations, resource managers can use prisms or wedge devices before timber harvesting in riparian areas to identify specific trees that can potentially add woody debris to the stream. For. Sci. 36(3):790-801.
Relationships Between Site Index and Synoptic Environmental Factors in Immature Coastal Douglas-Fir Stands
Authors: Klinka K. , Carter R. E.
Published: April 2024

Indirect synoptic measures of climate, soil moisture, and soil nutrients are used to characterize site quality in the biogeoclimatic ecosystem classification. To assess relationships of these measures to potential forest productivity, environmental and site index data from 133 sample plots established in immature coastal Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) stands were utilized. The stands were distributed across three climatic regimes (biogeoclimatic units), five soil moisture regimes, and five soil nutrient regimes. These regimes were used as categorical variables in stratification of the data and regression analysis.

Direct measures of these regimes, i.e., components of annual water balance and mineralizable-N in the forest floor and mineral soil, were determined for each stand and used as continuous variables in regression analysis. Douglas-fir site index (m/50 yr) and these direct measures were significantly different between groups of stands stratified according to soil moisture and soil nutrient regimes. Five regression models indicated good relationships between site index and both categorical and continuous variables. The analytical models (based on actual evapotranspiration during May and June, growing season water deficit, and/or mineralizable-N in the forest floor and mineral soil) were slightly inferior (R² = 0.72) to the categorical models (based on soil moisture and nutrient regimen (R² = 0.84). Testing on an independent data set showed similar results, i.e., the categorical models continued to have a better relationship with site index than the analytical models. It is concluded that the indirect synoptic measures of climate, soil moisture and soil nutrients were good predictors of Douglas-fir site index over a large area and provided useful estimates of the direct measures. For. Sci. 36(3):815-830.
Adaptation of Acacia koa Leaves and Phyllodes to Changes in Photosynthetic Photon Flux Density
Authors: Walters Gerald A. , Bartholomew Duane P.
Published: April 2024

Koa (Acacia koa Gray) seedlings were grown under full sunlight (HH treatment) and under 27% of full sunlight (LL treatment). Some of these seedlings were moved to the opposite light intensity to form two additional treatments--HL and LH. Phyllodes developed only on seedlings in the HH treatment. If seedlings with phyllodes were placed under shade, leaves instead of phyllodes developed at the terminal. Leaflets of leaves in the HH treatment were smaller but thicker and had lower specific leaf areas than those in the LL treatment. Koa leaves in the HH and LL treatments had similar photosynthetic characteristics. Leaves in the HH treatment had higher ribulose 1,5-bisphosphate carboxylase levels and lower chlorophyll levels than leaves in the LL treatment. When seedlings were moved to the opposite light intensity, leaves and phyllodes adapted both morphologically and physiologically to the altered photosynthetic photon flux density (PPFD). Leaves and phyllodes that were only partially developed when the PPFD changed showed greater adaptive potential than those that were fully developed. Generally, leaves and phyllodes adapted by developing morphological and physiological characteristics of those grown continuously in the new PPFD. There were no detectable deleterious affects to exposing leaves or phyllodes to increased or decreased PPFDs For. Sci. 36(4):1050-1060
Stumpage Prices in Southwestern Ontario: A Hedonic Function Approach
Authors: Puttock G. D. , Prescott D. M. , Meilke K. D.
Published: April 2024

Timber used in the production of lumber in Southwestern Ontario varies in a number of characteristics, and the lump-sum stumpage price is expected to reflect differences in those characteristics. When heterogeneous inputs are used in production, the hedonic price function approach may be used to estimate marginal implicit values of the various input characteristics. Hedonic price functions were estimated for timber in Southwestern Ontario using pooled time-series cross-section data from a large sample of timber sales. The results indicate that volume, species composition, tree size, timber quality and distance to the purchasing mill all affect lump-sum stumpage prices. Estimates of the contributions that each of these characteristics makes to stumpage prices are presented. The estimated hedonic model was tested by comparing the model's forecasts of stumpage prices with forecasts made by personnel from the Ministry of Natural Resources. For. Sci. 36(4):1119-1132.
Seed Source Variation in Specific Gravity of Loblolly Pine Grown in a Common Environment in Arkansas
Authors: Tauer C. G. , Loo-Dinkins Judy A.
Published: April 2024

Wood specific gravity in a rangewide sample of loblolly pine (Pinus taeda L.) grown in a common environment in southwest Arkansas differed from reported values of trees sampled in situ. Differences were greatest at the extremes of the species range. In the common environment trees from western and northeastern sources produced the highest specific gravities; northeastern trees produced the highest dry weight per hectare yields but they were not significantly greater than yields of trees from east coast and northwest sources. On an individual tree basis, specific gravity was significantly negatively correlated with height, diameter, and volume, although the r values were small; 0.272, 0.090, and 0.129, respectively. Provenance region correlations between specific gravity and growth and stand density parameters were generally weak to negligible. For. Sci. 36(4):1133-1145.
Storage Temperature and Duration Influence Cold Tolerance of Red Spruce Foliage
Authors: DeHayes D. H. , Waite C. E. , Ingle M. A.
Published: April 2024

Laboratory assessments of cold tolerance were conducted to examine the influence of duration and temperature of foliar sample storage on relative and absolute cold tolerance of excised shoots of red spruce (Picea rubens Sarg.) trees during midwinter and early spring. Although differences in cold tolerance associated with temperature and duration of sample storage were statistically significant, the rate of dehardening of red spruce foliar samples was largely a function of the storage temperature/duration combination rather than either temperature or duration alone. Foliar samples stored at 15°C dehardened significantly after 45 hours of storage, whereas samples stored at 24°C dehardened significantly after only 18 hours. Samples stored at 4°C for up to 72 hours were similar in cold tolerance to fresh samples. Foliar samples from different trees responded differentially to foliar sample storage regimes, indicating that both absolute and relative cold tolerance of individual trees may be altered by relatively short periods of sample storage at above-freezing temperatures. For. Sci. 36(4):1153-1158.
Predicting Post-Harvest Performance of Advance Red Oak Reproduction in the Southern Appalachians
Authors: Loftis David L.
Published: April 2024

Models are presented for predicting: (1) height growth of red oak advance reproduction after clearcutting, and (2) the probability of stems becoming dominants or codominants in new stands as a function of preharvest size of advance reproduction and site quality. The second model permits silviculturists to predict, prior to harvest, the contribution to a new stand of an existing population of advance red oak reproduction. For. Sci. 36(4):908-916.
Intensification of Dwarf Mistletoe on Southwestern Douglas-fir
Authors: Geils B. W. , Mathiasen R. L.
Published: April 2024

From a sample of 445 Douglas-fir trees infected with dwarf mistletoe (Arceuthobium douglasii), three models for predicting mistletoe intensification are developed. Two models relate the mean rate of intensification since the tree became infected to initial and current tree conditions; the third one describes the proportion of trees that increased by 0, 1, 2, or more classes of dwarf mistletoe infection (DMR) in the past 10 years. The models suggest that the rate of intensification is most rapid (2 DMR classes per decade) for severely infected trees of small diameter and slowest (0.5 DMR classes per decade) for lightly infected trees of large diameter. Intensification within a tree increases with the abundance of mistletoe in nearby, larger trees and with stand basal area. No other significant relations were found between rates of intensification and site or stand factors such as habitat type, site productivity, or stand composition. A comparison of mistletoe ratings for standing trees and ratings for carefully examined felled trees indicates that trees can be correctly rated by standard procedures about 75% of the time. For. Sci. 36(4):955-969.
Ecophysiological Responses in Mesic versus Xeric Hardwood Species to an Early-Season Drought in Central Pennsylvania
Authors: Abrams Marc D. , Schultz Jack C. , Kleiner Karl W.
Published: April 2024

Field and laboratory studies were used to evaluate net photosynthesis and plant and tissue water relations in saplings of co-occurring xeric (Quercus prinus and Q. ilicifolia) versus mesic (Q. rubra and Castanea dentata) hardwood species during a droughty summer. Mean daily net photosynthesis, leaf conductance, leaf water potential, and water use efficiency were reduced in all four species during the peak drought period. Throughout the study, net photosynthesis and leaf conductance were on average high in Q. ilicifolia and Q. prinus, intermediate in Q. rubra, and low in C. dentata. Leaf water potential was generally highest in C. dentata and not significantly different among the Quercus species. There were few consistent patterns in the tissue water relations data, including a lack of osmotic adjustment during peak drought, a lack of correlation between osmotic potentials and gas exchange rates, decreases in osmotic potentials and tissue elasticity after the peak drought period ended, and bulk leaf water potential values below the osmotic potential at zero turgor, despite relatively high gas exchange in those plants. Thus, the tissue water relations data provided little insight to mechanisms of drought tolerance in these species and suggest some methodology problems using standard pressure-volume procedures. For. Sci. 36(4):970-981.
Effects of Time and Frequency of Cutting on Hardwood Root Reserves and Sprout Growth
Authors: Kays Jonathan S. , Canham Charles D.
Published: April 2024

We examined the effects of time and frequency of cutting during the growing season on fall root starch reserves and sprout production in saplings of four hardwood tree species--red maple, gray birch, white ash, and black cherry. For all species, there was a well-defined window of time during the growing season when cutting resulted in low levels of starch in roots at the end of the growing season, and subsequent low sprout growth rates the following year. Cutting at the very beginning or the very end of the growing season resulted in the highest levels of fall root reserves and sprout production. The duration of the window varied for each species and was closely related to the phenology of aboveground growth. The species with a determinant shoot growth pattern had the shortest window (white ash), while the two species with the most indeterminant shoot growth pattern had the longest windows (red maple, gray birch). For. Sci. 37(2):524-539.
Integration of Geographic Information Systems with a Diagnostic Wind Field Model for Fire Management
Authors: Zack James A. , Minnich Richard A.
Published: April 2024

The past 10 years have seen an increased interest in diagnostic wind modeling efforts in the fields of air pollution research and wind energy engineering. Applications relating wind to forest fire behavior are also beginning to capitalize on computer-generated outputs from wind models. Most wind model outputs have been considered useful only as intermediate data files loaded into specialized software packages for further processing. Output data are used to generate various output products without being passed into sophisticated mathematical models. With the developed technology of geographic information systems (GIS), new map products can be created. If designed properly, these maps can pass information more efficiently to both the decision maker and the GIS for further analysis. The methods used to create and edit topographic and meteorological databases, display the results of the KRISSY diagnostic wind field model, and perform analyses on the topography and estimated wind field are described. For. Sci. 37(2):560-573.
Changing Stand Structure and Regional Growth Reductions in Georgia's Natural Pine Stands
Authors: Bechtold W. A. , Ruark G. A. , Lloyd F. T.
Published: April 2024

Forest Inventory and Analysis (FIA) data indicate reductions in the growth of naturally regenerated pines in Georgia between the two latest measurement periods (1961-72 vs. 1972-82). Analysis of Covariance was used to adjust stand-level basal area growth rates for differences between periods in stand age, stand density, site index, mortality, and hardwood competition. The adjusted mean growth of pines during the later period declined by 19% for natural loblolly, 28% for natural shortleaf, and 28% for natural slash pine stands. The factor(s) causing the reductions remain unidentified, but differences in stand structure are not likely responsible. For. Sci. 37(2):703-717.
Fine Root Carbohydrate Dynamics of Loblolly Pine Seedlings Grown Under Contrasting Levels of Soil Moisture
Authors: Hallgren Stephen W. , Tauer Charles G. , Lock John E.
Published: April 2024

Fine root growth, mortality, and carbohydrate concentration were compared for North Carolina and Oklahoma-Arkansas families of loblolly pine (Pinus taeda L.) seedlings under well-watered and drought conditions. The objective was to determine if moisture stress affected fine root carbohydrate dynamics and fine root longevity. Seedlings under drought produced new roots with the same starch concentration as well-watered seedlings, despite a 50% reduction in whole-plant growth. The starch concentration in fine roots of seedlings grown under periodic drought did not increase with age; in contrast, the starch concentration in fine roots of well-watered seedlings continued to increase for at least 70 days. There was no evidence that moisture stress accelerated fine root starch depletion. Fine root starch concentration was around 20% less and sugar concentration nearly 13% greater under periodic drought than under well-watered conditions. Fine root starch concentration never dropped below 4%. Fine root mortality was negligible and showed no effect of treatment or seed source. The results of this study do not support the hypothesis that drought accelerates carbohydrate depletion and thereby increases fine root mortality. Plants from the Oklahoma-Arkansas families contained higher starch concentrations in roots and shoots than plants from North Carolina families but produced slightly less biomass. For. Sci. 37(3):766-780.
Strategic Positioning in a Turbulent Environment: An Empirical Study of Determinants of Performance in the North American Forest Industry
Authors: Booth Darcie , Vertinsky Ilan
Published: April 2024

This paper investigates the extent to which geographical and product diversification provide firms in the forest products industry of North America with means for coping with a turbulent environment. A turbulent environment is one where there is a high degree of uncertainty and sharp discontinuities; hence it is an unpredictable environment. The relationship between the firm's strategic positioning and performance is investigated. Six models relating various attributes of performance, including measures of risk, returns, and growth, to strategic positioning and other attributes of firms were estimated using regression equations. The results indicate that unrelated-product diversification and geographical diversification reduce risk, but at a significant cost in terms of performance, notably rate of return. Opportunities for related-product diversification that reduce risk are limited. Product differentiation and investment in new technology provide opportunities for increased returns and risk reduction. For. Sci. 37(3):903-923.
Seasonal Cambial Activity in Larix laricina Saplings in Relation to Endogenous Indol-3-ylacetic Acid, Sucrose, and Coniferin
Authors: Savidge Rodney A.
Published: April 2024

Although some quantitative research on the role of endogenous auxin (indol-3-ylacetic acid, IAA) in regulating anatomical aspects of diameter growth in trees has been reported, there have been no attempts to correlate cambial IAA content with biochemical aspects of wood formation. In this study, the cambial region (phloem, cambial zone, and differentiating cambial derivatives when present) at four positions (1, 3, 8, and 17 years) in the main stems of 20-year-old Larix laricina (Du Roi) K. Koch were sampled to determine the endogenous contents of IAA, sucrose and coniferin in relation to seasonal cambial growth. IAA and sucrose were both present throughout the dormant period, and their concentrations increased in late spring and summer in association with leaf and shoot development. Coniferin, the principal molecule supporting lignification in conifers, was not detected throughout the winter period of cambial dormancy, but was detected in spring immediately preceding resumption of cambial cell division, was present throughout the period of cambial growth, but then disappeared after the last-produced latewood tracheids had completed their differentiation. The coniferin content varied independently of IAA and sucrose, suggesting that the cambium's seasonal competence for coniferin biosynthesis is controlled by factors other than IAA or sucrose availability. For. Sci. 37(3):953-958.