bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stem and Foliage Elongation of Young Loblolly Pine as Affected by Ozone
Authors: Mudano J. E. , Allen H. L. , Kress L. W. 
Published: April 2024

Abstract
The rate, timing, and pattern of shoot and foliage elongation on the main stem of 3-year-old loblolly pine exposed to two levels of ozone were examined in the Piedmont of North Carolina. Shoot growth rates were generally greater in plots which received charcoal-filtered air (CF) than in plots which were exposed to ozone at three times ambient levels (3X). The pattern and duration of height growth were unaffected by ozone. Main stem elongation occurred continuously from late March to September and was 90% complete by mid-August in both treatments. Foliage elongated continuously from early April to early November. First and second flush foliage elongation rates were significantly greater in CF plots. Foliage elongation rates for subsequent flushes were similar for the two treatments. Except for the fifth flush, the number of fascicles produced was consistently greater in CF plots. As with shoot growth, the pattern and duration of foliage elongation on the main stem did not appear to be affected by ozone. For. Sci. 38(2):324-335.
Impacts of Pear Thrips Damage on Root Carbohydrate, Sap, and Crown Characteristics of Sugar Maples in a Pennsylvania Sugarbush
Authors: Kolb T. E. , McCormick L. H. , Simons E. E. , Jeffery D. J. 
Published: April 2024

Abstract
Fall root total nonstructural carbohydrate concentration (TNC), spring sap sugar concentration and volume, and summer crown condition were compared for 2 years among sugar maples (Acer saccharum Marsh.) that exhibited different degrees of crown damage following a 1989 attack of pear thrips (Taeniothrips inconsequens Uzel) in a Pennsylvania sugarbush. Trees with heavy damage had lower root TNC the fall following attack and greater crown transparency in both years following attack compared with trees with less damage. In the first year following attack, sap sugar concentration and volume were greater for trees with light damage than trees with moderate or heavy damage. In the second year following attack, sap volume was still greatest for trees with light damage while trees with heavy damage had the highest sugar concentration of all damage classes. Calculated syrup production based on sap sugar concentration and volume was greatest for trees with light damage and lowest for trees with heavy damage in both years. Trees with heavy damage in 1989 had earlier 1991 spring budburst than trees with light damage, and early budburst was associated with greater 1991 thrips infestation. The results indicate that pear thrips damage had a detrimental impact on tree health and syrup production for the next 2 years. For. Sci. 38(2):381-392.
Age-Age Correlations and Early Selection for Wood Density in Young Coastal Douglas-Fir
Authors: Vargas-Hernandez Jesus , Adams W. T. 
Published: April 2024

Abstract
Age-age correlations and age-associated changes in the genetic control of wood density and its components (earlywood density, latewood density, and latewood proportion) were investigated in 15-yr-old trees of 60 open-pollinated families of coastal Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco). The possibility of using wood density components as secondary traits to increase the efficiency of early selection for overall wood density was also explored. Heritability estimates for overall density and its components increased with age, mainly because of a decrease in the error variance as the number of rings in the core sample increased. Overall density and its components at age 15 had strong genetic correlations with their respective traits at all younger ages analyzed. Moreover, with few exceptions, age-age genetic correlations were greater than phenotypic correlations. Early selection to improve overall density at age 15 was quite efficient (relative efficiency above 79%), even when selection was based on core density at the youngest age (age 7). Using wood density components as secondary traits produced a slight increase in the efficiency of early selection only at the youngest ages, presumably because age-age correlations for overall core density were already strong, limiting the possibility of additional improvement. For. Sci. 38(2):467-478.
A Note on the Welfare Gains from Genetic Progress in Forestry: What Can the Market Tell Us?
Authors: Löfgren Karl-Gustaf 
Published: April 2024

Abstract
In this note we pinpoint what the market can tell us ex-post about a previously unanticipated genetic breakthrough in tree breeding. The approach is, however, perfectly general and can be used in ex-post evaluations of new drugs in the pharmaceutical industry. The fundamental idea, which is accredited to Weitzman (1976), is that a flow concept like net income in a dynamic economy contains precise information about a stock concept like wealth. For. Sci. 38(2):479-483.
The Law of One Price in the Trade of Forest Products: Co-Integration Tests for U.S. Exports of Pulp and Paper
Authors: Buongiorno Joseph , Uusivuori Jussi 
Published: April 2024

Abstract
According to the law of one price, the export price of a well-defined commodity should be the same, regardless of destination, and the import price should be independent of the country of origin. This law has been used as a maintained hypothesis in several models of the international trade of forest products. Here, the law was tested with data on United States exports of pulp and paper, which represented 54% of the value of all forest product exports in 1988. The test was done with co-integration methods and with data from January 1978 to December 1988, for six European countries and Japan. The law of one price could not be rejected in 52 of the 56 pairs of price series analyzed. Thus, markets for United States pulp and paper exports were generally competitive, so that prices tended to converge in the long run. Consequently, spatial equilibrium models that do not distinguish between exports to different countries could be used in this context. Furthermore, the 1992 European unification should not affect markedly the prices obtained by United States exporters in different countries. Finally, the incomplete pass-through of exchange rates to export prices found in previous studies is likely to be due to demand and supply shifts induced by exchange rate realignments, and not to monopolistic forces. For. Sci. 38(3):539-553.
Optimizing the Management of Uneven-Aged Forest Stands: A Stochastic Approach
Authors: Gove Jeffrey H. , Fairweather Stephen E. 
Published: April 2024

Abstract
Mathematical programs used for management and policy decisions in natural resources normally contain at least one underlying component which is stochastic. A technique is presented that allows marginal, conditional, and empirical confidence regions to be calculated for a widely known model of optimal uneven-aged stand structure. The technique uses the nonparametric bootstrap to approximate the joint sampling distribution for the decision variables of the nonlinear programming model. Subsequently, multivariate normal theory is used to obtain 95% confidence statements on the decision variables and functions thereof. Results show that the optimal steady-state investment-efficient diameter distribution for uneven-aged northern hardwood stands is an imprecise estimate given the data used for growth model calibration and the assumptions of the mathematical model. However, confidence statements found using this methodology are only approximate as they rely on an estimate of the sampling distribution for the optimal diameter distribution, not on classical statistical theory. These findings suggest a very real need for modelers, managers, and policy makers to begin considering the role of stochastic model components in mathematical programming models in natural resources. For. Sci. 38(3):623-640.
Early Selection in Pinus ponderosa: Compromises Between Growth Potential and Growth Rhythm in Developing Breeding Strategies
Authors: Rehfeldt G. E. 
Published: April 2024

Abstract
Shoot elongation of seedlings from 13 wind-pollinated families in each of 3 natural populations was described in years 2 and 5 by a function that allowed calculation of the start, rate, duration, and cessation of elongation. Additive genetic variances for these variables and for height in year 5 were pronounced, heritabilities were high, and expected responses to selection were large. The age-age genetic correlation for each trait was strong, as were the genetic correlations for 5-year height with all traits except the start of shoot elongation. Expected responses to selection suggested that (1) genetic gains in growth can be pronounced; (2) strong selection for increased growth is accompanied by a change in growth rhythm to that typical of unselected populations from much milder environments; (3) selecting for the rate of shoot elongation tends to control the correlated responses in growth rhythm while providing about 70% of gains expected from direct selection on height; and (4) selecting in the greenhouse in year 2 is nearly as effective as selecting the field in year 5. While breeders might choose among strategies that either control correlated responses or optimize gains in growth potential, developing a program that is capable of realizing the expected gains requires an understanding of the system of genetic variability. For. Sci 38(3):661-677.
The Strategic Management Paradigm and the Wood Building Products Industry: A Model of Strategies and Firm Profitability
Authors: Cohen David H. , Sinclair Steven A. 
Published: April 2024

Abstract
A model of strategies and firm profitability was developed and tested for the North American wood building products industry. Five strategic variables (adoption of process technology, grade sector focus, investment intensity, forward integration, relative market share) were used to predict firm profitability as measured by return on sales for the largest producers of wood building products in North America. Adoption of process technologies, grade sector focus (i.e., product quality), and investment intensity all had significant positive impacts on return on sales. From a managerial perspective, this research shows no advantage in larger market share beyond a minimal efficient scale. However, superior firm profitability was linked to the application of new process technologies, investment intensity, and the production of higher grade products. For. Sci. 38(4):786-805.
Marked Point Processes in Forest Statistics
Authors: Penttinen Antti , Stoyan Dietrich , Henttonen Helena M. 
Published: April 2024

Abstract
Trees in a forest interact and therefore have to be considered as a system of dependent random variates from an unknown stochastic process. One such mathematical model which considers the spatial dependence among trees in a forest and their characteristics is a marked point process. The "points" are the tree positions and the "marks" are tree characteristics such as stem diameters or tree species. Statistical methods for marked point processes can give valuable information on the spatial interaction of trees. They are applied in this paper to describe spatial dependence of stem diameters in a spruce forest, of heights of trees in a stand of pine saplings, and of heights, stem diameters, and crown lengths in a mixed birch-pine forest area. For. Sci. 38(4):806-824.
Spatial Variability of Canopy Foliage in an Oak Forest Estimated with Fisheye Sensors
Authors: Wang Y. S. , Miller D. R. , Welles J. M. , Heisler G. M. 
Published: April 2024

Abstract
The vertical distribution of forest canopy elements is an important factor in canopy-atmosphere exchange processes and knowledge of the shape of the average vertical profile of leaf area density is a critical input to models of these processes. This study was conducted to determine the spatial variability of Leaf Area Index (LAI) in an oak forest when estimated with indirect fisheye techniques. A 35 mm camera with a 180° hemispherical lens and a LI-COR LAI-2000 Plant Canopy Analyzer (wavelengths &lt; 490 nm) were used simultaneously to estimate vertical leaf area profiles and the horizontal variability in an oak forest in central Pennsylvania. Measurements were made at eight different heights in the canopy and repeated at nine different locations. The two sensors were in reasonable agreement. The photographic technique estimated the total leaf area index (LAI) to be 3.58, and the light sensor estimates resulted in an estimate of 3.40. The average precision was 8% for the LAI-2000 and 17% for the photographic technique. The point-to-point spatial variability of the LAI estimates was low when the whole canopy was measured from the ground and quite high when measuring the upper canopy. Ground level estimates of LAI using these fisheye techniques spatially average the canopy to the point where only four replications were necessary to sample the total LAI with 90% confidence. For. Sci 38(4):854-865.
Spatial Reduction Factors for Strata-Based Harvest Schedules
Authors: Daust David K. , Nelson John D. 
Published: April 2024

Abstract
The impact of block size and exclusion period on sustained yield predictions is examined for 27 hypothetical forests; forests are delineated by species, site and rotation age. Long-range harvest schedules are developed for the forests using (1) aspatial, strata-based formulations solved with linear programming, and (2) spatial, block scheduling formulations solved with Monte Carlo Integer Programming. The sustained yields estimated by the spatial formulations are in all cases lower (range: 2% to 29%) than those estimated by the aspatial formulations. The magnitude of the reduction in sustained yield increases as the exclusion period increases and the block size decreases. The magnitude of the reduction does not vary with species or site but is influenced by rotation age. Forests which are managed under longer rotation ages are less affected by exclusion period and block size constraints. Exclusion period reduction factors are developed which allow strata-based sustained yield estimates to be reduced to account for exclusion period constraints. FOR. SCI. 39(1):152-165.
Evaluation of the Size-Density Relationships for Pure Red Alder and Douglas-Fir Stands
Authors: Puettmann Klaus J. , Hann David W. , Hibbs David E. 
Published: April 2024

Abstract
Size-density trajectories were developed for pure red alder (Alnus rubra Bong) and Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) stands with quadratic mean diameter of the stand as the tree-size variable. The resulting self-thinning or maximum size-density line for red alder had a steeper slope (-0.64) than that for Douglas-fir (-0.52). The assumption of a common slope for all species is therefore not supported by our study. For red alder, the shape of the size-density trajectory and the elevation of the maximum line were not influenced by initial density or stand origin. Red alder and Douglas-fir mortality started at a relative density of 44% and 58%, respectively. FOR. SCI. 39(1):7-27.
Starch Content in Douglas-Fir: Diurnal and Seasonal Dynamics
Authors: Webb Warren L. , Kilpatrick Kran J. 
Published: April 2024

Abstract
Diurnal and seasonal starch dynamics in the crowns of young-growth Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco), and seasonal starch dynamics in various tissues of field-grown Douglas-fir seedlings, were determined in coastal mountains and valley sites in Oregon. The accumulation of photoassimilated carbon in the starch pools of seedlings also was investigated with steady-state 14C labeling. The pattern of starch buildup in twigs and attached needles of the young-growth Douglas-fir in spring and subsequent decline to nondetectable levels in fall was found to be correlated with budburst--later budburst at higher elevation signaled later increases in starch content. Starch content in the needles, stems, and roots of the Douglas-fir seedlings also was highest just after budburst and lowest in fall and winter. The daily starch pattern, which fluctuated considerably over 24 hr, was similar at all crown locations, and for needles and twigs. These data, and those from the 14C labeling, indicate that starch buildup in spring is from current photosynthesis. However, total starch content is too small to directly affect growth rates during the growing season--indeed, starch may be a buffer between rapidly fluctuating photosynthesis rates and ensuing translocation or growth processes. FOR. SCI. 39(2):359-367.
Estimation with Different Stratification at Two Occasions
Authors: Schreuder H. T. , Li J. , Scott C. T. 
Published: April 2024

Abstract
Since forest surveys may use different strata over time, permanent plots may be remeasured and new plots may be selected with different probabilities. The inclusion probabilities and joint probabilities of selecting both remeasured and new plots, considering both occasions, are derived. The Horvitz-Thompson estimator using two approximations to actual probabilities of selection and a stratified sampling estimator ignoring initial probabilities of selection are compared for bias and efficiency. The Yates-Grundy, probability proportional to size with replacement, jackknife, and stratified sampling variance estimators are evaluated in terms of bias in estimating the true variance of the estimators. Three populations are constructed with different rates of movement between strata from time 1 to time 2 to evaluate the estimators. The stratified sampling estimator performed poorly. The jackknife variance estimator is recommended. FOR. SCI. 39(2):368-382.
Regulating Competition on Conifer Plantations with Prescribed Cattle Grazing
Authors: Karl Michael G. , Doescher Paul S. 
Published: April 2024

Abstract
On conifer plantations, competitive understory vegetation often retards growth and establishment of tree seedlings. Livestock grazing exemplifies a method of controlling the understory vegetation and increasing the availability of site resources to tree seedlings. We hypothesized that prescribed cattle grazing ameliorates water stress of young tree seedlings by reducing root growth of competing understory species. On a Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) and ponderosa pine (Pinus ponderosa Dougl.) plantation in southwest Oregon planted in 1986, seedling water stress was evaluated with the pressure chamber technique and supplemented with gravimetric soil water determinations in 1986-1989. Root growth of orchardgrass (Dactylis glomerata L.), the major understory competing species, was quantified in 1988 and 1989 with the root periscope/mini-rhizotron technique. Seedling water stress levels during spring and summer were similar in a cattle-grazed vs. ungrazed area in 1986 through 1988, but in summer 1989, water stress was reduced significantly in the grazed area. Soil water content was higher in the grazed area in 1989, especially at the 10-20 cm soil depth. End of season (July) orchardgrass root growth was reduced 18% and 15% with grazing in 1988 and 1989, respectively. We conclude that repeated cattle grazing of orchardgrass reduced transpirational surface area and root growth sufficiently to increase soil water availability to seedlings. Thus, prescribed cattle grazing on conifer plantations can enhance seedling physiological status by acting as a regulator of above- and belowground competition. For. Sci. 39(3):405-418.
Patterns of Occurrence and New Sampling Implications for Instar IV Western Spruce Budworm (Lepidoptera: Tortricidae)
Authors: Torgersen Torolf R. , Colbert J. J. , Hosman Kevin P. 
Published: April 2024

Abstract
This study examines relations of western spruce budworm (Choristoneura occidentalis Free.) larval distribution on terminal tips, whole branches, among crown strata (vertical crown thirds), and within and among whole trees. Study sites were in Washington, Oregon, Idaho, Montana, and New Mexico and represented 63 plot-yr of data. A range of densities from &lt;1.0 to &gt;600 larvae per m² of foliage on midcrown terminal tips were observed. We validated and expanded on earlier published descriptions of intratree and intertree distribution of larvae as they influenced sampling schemes. Larval density on nominal 45 cm terminal tips in the lower crown-third were slightly better predictors of whole-tree density than were midcrown tips. Therefore, we propose the use of a two-tip sample from the middle of the lower crown-third of each sample tree. Equations are given to determine the number of trees to sample for desired precisions and confidence levels. We provide equations describing relations between larval densities on branch tips and whole branches in vertical crown-thirds, and their relation to whole-tree density. For. Sci. 39(3):573-593.
Acid Mist Affects Dehardening, Budburst, and Shoot Growth in Red Spruce
Authors: Sheppard L. J. , Cape J. N. , Leith I. D. 
Published: April 2024

Abstract
Red spruce seedlings growing in open top chambers in a nutrient-poor medium were exposed to mists containing one of five different combinations of H+, SO42-, NO3- and NH4+ ions, three at pH 5.6 and two at pH 2.5. The mists were applied twice weekly from May until November, and the plants overwintered outdoors with no additional mist treatment. Seedlings that received mists containing sulphate (1.6 mol m-3) the previous growing season were more frost-hardy (i.e., their dehardening was delayed) the following April than seedlings that received lower concentrations of sulphate or none. Neither ammonium nor nitrate in the applied mist had any effect on dehardening, but they did advance budburst when applied together. In the presence of sulphate there was no effect of ammonium-N on the time of budburst. Exposure to mists containing nitrogen significantly increased the dry weight and length of the leading shoots that emerged from the buds and extended the following summer. There was no evidence that the stimulatory effects of nitrogen on growth made the seedlings less frost-hardy in spring. For. Sci. 39(4):680-691.
Effects of Light, Nitrogen, and Phosphorus on Red Pine Seedling Growth and Nutrient Use Efficiency
Authors: Elliott Katherine J. , White Alan S. 
Published: April 2024

Abstract
Growth and nutrient use efficiency were determined for red pine (Pinus resinosa Ait.) seedlings grown at various levels of light, nitrogen, and phosphorus. Nutrient use efficiency was estimated for nitrogen (NUE) and phosphorus (PUE) and was calculated as biomass production divided by total nutrient content. Seedlings grown in high light had four to five times more biomass than those in the low light treatment. Nitrogen supply had a significant effect on total biomass as well as other biomass components. Phosphorus supply did not have a significant effect on any of the biomass components. NUE and PUE decreased with increased supply of N and P, respectively. The results of this study suggest that red pine seedlings can adjust their nutrient use efficiency, particularly for N, when light and nutrient availability are varied. NUE was highest with high light and low N-high P supply in nutrient solutions. For. Sci. 40(1):47-58.