bluuebunny/crossref_metadata_2025 huggingface dataset:
Acid Mist Affects Dehardening, Budburst, and Shoot Growth in Red Spruce
Authors: Sheppard L. J. , Cape J. N. , Leith I. D.
Published: April 2024

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

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.
Two-Stage Forest Sampling: A Comparison of Three Procedures to Estimate Aggregate Volume
Authors: Nelson Ross , Gregoire Timothy G.
Published: April 2024

Three two-stage forest sampling procedures are examined in order (1) to quantify the variance penalty (if any) associated with second-stage sample restrictions; and (2) to quantify the variance gains (if any) associated with the incorporation of tree height data at the second stage. The three two-stage procedures share a common first stage, i.e., horizontal point sampling (HPS), which selects trees with probability proportional to tree basal area. The second stage selection approaches vary, as follows:

1. Trees are selected with replacement with probability proportional to tree height from a single list composed of all trees sampled across all first-stage sample points.

2. Trees are selected with replacement with probability proportional to tree height from separate lists compiled on each first-stage sample point.

3. Trees are selected randomly, with replacement, on each first-stage point.

The results indicate that little or no reduction in variance accrues from incorporating height data into the two-stage sample design for the three mapped stands considered. HPS/simple random sampling yielded variances ranging from 7.1% larger to 9.2% smaller than the smallest HPS/list sampling variance, while maintaining an advantage in an even-aged stand. It is hypothesized that the HPS/list sampling procedures may prove more useful in mature, all-aged stands where height may account for a significant portion of volume or biomass variation. No loss of precision is noted when second-stage sampling is restricted by point on these three forest tracts. An investigation into the effects of first-and second-stage sample sizes provide a convincing argument to select only one tree per first-stage sample point when sampling is restricted by point. Considering both precision of estimation and field efficiency, these results suggest that the HPS/simple random sampling procedure is the most useful of the three tested. For. Sci. 40(2):247-266.
Stand and Tree Dynamics of Uneven-aged Ponderosa Pine
Authors: McTague John P. , Stansfield William F.
Published: April 2024

A system of algebraic difference equations is presented for projecting, at the stand level, number of pole trees, survivor number of merchantable trees, and survivor basal area. Ingrowth is indirectly derived from projection equations that estimate the total change in the number of pole trees. The individual tree growth equation and mortality function are consistent with the stand level projection equations. The ingrowth diameter distribution is modeled with a parameter recovery method for the Uniform distribution. The species of ingrowth trees are predicted from equations that are a function of habitat series and cumulative ratios of trees per acre by species. For. Sci. 40(2):289-302.
A Compatible Volume-Taper Model Based On the Schumacher and Hall Generalized Constant Form Factor Volume Equation
Authors: Bailey Robert L.
Published: April 2024

The generalized constant form factor volume equation fitted in logarithmic form by Schumacher and Hall (1933) has a logical basis in solid geometry. By extension of this rationale to a consideration of stem tip volume above a specified top diameter, compatible models for inside- and outside-bark variable-top volume and stem taper are derived and fitted with data from 872 plantation grown slash pine trees. The volume equations predict total volume when upper diameter is zero and always predict nonnegative volumes for any upper diameter. The taper curves have inflection points near dbh and are constrained to diameters of 0, dbh, and stump diameter when merchantable height equals total height, 4.5 ft and stump height, respectively. Statistics of fit on an independent subset of the data suggest that the outside-bark model compares favorably to a recently published compatible taper and volume model based on polynomials. For. Sci. 40(2):303-313.
Genetic Analysis of 16 Clonal Trials of Eucalyptus grandis and Comparisons with Seedling Checks
Authors: Lambeth Clements , Endo Masatoshi , Wright Jeff
Published: April 2024

In sixteen 3-yr-old trials, clones of plus trees of Eucalyptus grandis (Hill ex. Maiden) had better yield, uniformity, survival, straightness, limb diameter, and more vigorous and full crowns for shading of competing grasses than check lots of seed origin. A select group of 65 out of 460 clones were far superior with mean height = 17.3 m, and volume/ha = 219 m³, versus check lot means of height = 15.2 m and volume/ha = 130 m³. Genetic gain calculations indicate that the expected age three performance values for the selected clones would be height = 16.9 m and volume/ha = 200 m³.

Heritability (broad sense) was high for height, dbh, and volume/tree (37% to 41%). Clonal rank correlations among the quality traits (stem straightness, branch diameter, and crown score) were moderately strong (r = 0.57 to 0.81) and their correlations with growth traits were moderate to low but positive. Clonal ranks were consistent across two sites (genetic correlation = 1.00 for volume per tree).

Ranks of clones at ages 1 and 2 yr were positively related to their ranks in volume/ha at age 3. Clones selected at these early ages resulted in substantial gains in volume/ha at age 3. For. Sci. 40(3):397-411.
A Regional-Scale Survey and Analysis of Forest Growth and Mortality as Affected by Site and Stand Factors and Acidic Deposition
Authors: Brooks Robert T.
Published: April 2024

Regression analyses were used to identify factors most closely related to species growth and mortality on continuous forest survey plots in Pennsylvania. In 1985, 200 plots with two prior measurements (in the 1960s and 1970s) were selected and measured for a third time to determine periodic forest growth and mortality rates. Growth and mortality were analyzed for temporal change and for relationship to site, stand, defoliation, and climatic factors and to wet atmospheric deposition. While basal area growth increased over the two intersurvey periods, growth rates declined and mortality rates increased from the first to the second intersurvey period. Growth and mortality patterns were most frequently related to stocking, defoliation by insects, and drought. Neither sulfate nor nitrate deposition for the years 1982-1985 was determined to be a major influence on tree growth or mortality. For. Sci. 40(3):543-557.
Simulations of Buoyancy-Generated Horizontal Roll Vortices over Multiple Heating Lines
Authors: Heilman W. E.
Published: April 2024

A two-dimensional nonhydrostatic atmospheric model is used to simulate the boundary-layer circulations that develop from multiple lines of extremely high surface temperatures. Numerical simulations are carried out to investigate the role of buoyancy and ambient crossflow effects in generating horizontal roll vortices in the vicinity of adjacent wildland fire perimeters. Numerical results suggest that the downdraft segments of buoyancy-generated horizontal roll vortices can be reinforced when multiple heating lines are present, with the degree of reinforcement dependent on the heating-line spacing. Significant low-level horizontal flow directly over the bounding heating lines is observed in some simulations, suggesting a mechanism for low-level flame migration in actual wildland fires. Multiple heating lines also affect the development and behavior of buoyancy-generated horizontal roll vortices when ambient crossflows are present. Simulations indicate that vortices are more likely to persist for multiple heating lines than for a single heating line when light ambient crossflows are introduced. Although simulation results should be viewed qualitatively, they suggest the potential importance of adjacent fire perimeters in actual wildland fire episodes for the development and behavior of buoyancy-generated horizontal roll vortices. For. Sci. 40(4):601-617.
Two Methods for Solving Stand Management Problems Based on a Single Tree Model
Authors: Eriksson Ljusk Ola
Published: April 2024

Two methods are presented for solving the stand management problem where the growth dynamics are depicted with a single tree model. With the nongradient method the problem is recast into a combinatorial problem, which in turn is solved with the method of simulated annealing. The gradient method, of which three versions are given, utilizes a combination of nonlinear and mixed integer techniques for solving the problem. In both cases, a linear programming problem solves the single tree harvest selection problem. In tests with nine sample problems, all methods are within 1% of the best solution found. The computational effort of the nongradient method is about one order of magnitude greater than that of the gradient methods. The results indicate the advantage of being able to divide the problem into a suitable hierarchy, since management problems based on single tree models are often too complex to be solved in one step. At each level an appropriate technique can then be applied. For. Sci. 40(4):732-758.
Provenance Variation in Rooting Ability of Juvenile Stem Cuttings from Racosperma Auriculiforme and R. Mangium
Authors: Khasa Phambu Damase , Vallée Gilles , Bousquet Jean
Published: April 2024

Provenance variation in rooting ability was examined in Racosperma spp. using leafy stem cuttings of 11 provenances of R. auriculiforme and 12 of R. mangium taken from 5-month-old ortets. The cuttings were set in a 1:1 peat moss and vermiculite mixture and were rooted in a "bouturathèque" propagator. The application of 0.8% indole butyric acid (IBA) hormone significantly increased (P < 0.05) number of roots per cutting, root length, root dry weight, and rooting percentage, but marginally decreased number of shoots. However, significant hormone X species interactions were noted for mean root length, root dry weight, and rooting percentage, which were greater in R. mangium than in R. auriculiforme. Hormone X provenance within species interaction was also significant for the number of roots, rooting percentage, and shoot height. The differences among provenances within species were greater when hormone treatment was used. In principal components analysis of plot means, we identified the first factor as a rooting ability index of cuttings (RAIC). We further show how this index can be used, in conjunction with field growth data, for selection of provenances, families, or genotypes that both root and perform well after outplanting. In all cases, selection appeared more efficient following hormone treatment. For. Sci. 41(2):305-320.
Interactive Resolution of Multi-objective Forest Planning Problems with Shadow Price and Parametric Analysis
Authors: Liu Gao , Davis Lawrence S.
Published: April 2024

Forest management planning is a joint process of decision synthesis and tradeoff analysis. We present an interactive method of multi-objective linear programming for supporting the planning process. In the proposed procedure, emphasis is placed on reducing uncertainty that surrounds the resolution of goal conflicts. Parametric analysis is iteratively performed to shed insights into the question of what happens to goal tradeoffs if a particular criterion is achieved at alternative levels. The composite objective function guiding the parametric analysis is updated as decision maker replaces a previous choice with an improved one. Central to this step is the induction of criterion weights implied by a decision instance, through the use of shadow prices. Finally, ordinal goal priority is employed to generate initial solution and decompose a multi-objective planning problem into more tractable subproblems. The interactive procedure is illustrated by a land-use planning model containing five forest-related outputs, including noncommercial grazing, commercial grazing, timber, camping, and profit. For. Sci. 41(3):452-469.
Optimal Timber Rotations with Evolving Prices And Costs Revisited
Authors: Yin Runsheng , Newman David H.
Published: April 2024

In this paper, we extend previous work that modeled the impact of evolving prices and costs to evaluate the full range of rotation length and input changes resulting from changing prices and costs. Our model suggests that if prices and costs change at the same rate, then production derisions are invariant. Any specific proportionate rate of change in prices and costs acts as an adjustment factor on the discount rate which corresponds to a constant rotation length. We also find that in the normal range of changes, namely, rates of any change less than the discount rate, the following results hold: if prices rise faster than costs, then the rotation length becomes shorter and establishment inputs increase; on the other hand, if costs rise faster than prices, then the optimal harvest age becomes longer and stand establishment inputs are reduced. These results not only extend and generalize those derived by McConnell et al. and Newman et al., but also further demonstrate the robustness of the Faustmann model. For. Sci. 41(3):477-490.
Effects of Water Stress on Biomass Partitioning of Ponderosa Pine Seedlings During Primary Root Growth and Shoot Growth Periods
Authors: McMillin Joel D. , Wagner Michael R.
Published: April 2024

Biomass partitioning patterns of ponderosa pine (Pinus ponderosa Dougl. ex Laws.) seedling genotypes were investigated under greenhouse conditions at different levels of water stress applied during either the early season root or shoot growth period. The growth of seedlings varied in response to the season in which water stress occurred and among water stress levels. Water stress applied during the shoot growth period resulted in a significantly higher fine root:current-year foliage biomass ratio than seedlings stressed during the root growth period. Seedlings subjected to the high water stress treatment during shoot growth also had the highest fine root:current-year foliage biomass ratio of all treatment combinations. Differences in biomass partitioning among families of ponderosa pine were also present for all treatments combined, suggesting biomass partitioning to roots and shoots is partially under genetic control. For. Sci. 41(3):594-610.
Photosynthesis and Leaf Water Relations in Four American Sycamore Clones
Authors: Tang Zhenmin , Land Samuel B.
Published: April 2024

Photosynthesis, transpiration, stomatal conductance, and xylem pressure potential were studied to examine clonal variation and clone-by-season interactions in rooted cuttings of four sycamore clones (Platanus occidentalis L.). These physiological parameters were measured during June through November of the second and third growing seasons in the field. Stomatal conductance, xylem pressure potential, and photosynthesis were higher in June-July than in August-November. The four clones did not differ significantly in yearly average photosynthetic rates, but clone 11 tended to have higher rates early in each growing season (June-July) than did the other three clones. Dry periods during August-September of the second season and during October of the third season apparently caused clone 11 to close its stomata more than clone 17, as indicated by significant clone-by-season interactions for reductions in stomatal conductance and transpiration late in the morning. Clone 17 was generally able to maintain high xylem pressure potential, stomatal conductance, and transpiration throughout the growing season, probably because of its large root system. For. Sci. 41(4):729-743.
Compatible and Time-Additive Change Component Estimators for Horizontal-Point-Sampled Data
Authors: Eriksson Marian
Published: April 2024

New definitions for the components of change are proposed and estimators for horizontal-point-sampled data are developed. The new definitions are more closely tied to the progression over time of growth, eligibility, cut, and mortality than the commonly employed definitions. This is made possible through the use of continuous time, rather than only initial and final measurement times. The estimators are based on the notion that the elemental sample unit is the sample point. The associated trees are simply observational units. A tree is considered to be associated with a point when a ring, centered on the tree, with area proportional to the tree basal area, covers the sample point. The estimators are shown to be unbiased, compatible with net change, and additive over time. This is the first time-additive set of change component estimators. Time-additivity may be of particular importance for long-term monitoring, growth and yield model development, and acceptance and understanding by the general public. The theory holds for both fixed-radius-plot and horizontal-point-sampling due to the duality between these procedures. For. Sci. 41(4):796-822.
Different Incidences of Pine Wilt Disease in Pinus densiflora Seedlings Growing with Different Tree Species
Authors: Nakamura Katsunori , Togashi Katsumi , Takahashi Fumiki , Futai Kazuyoshi
Published: April 2024

Field-grown Japanese red pine (Pinus densiflora) seedlings were inoculated with the pine wood nematode (Bursaphelenchus xylophilus) in early July 1991 to clarify the effect of co-occurring tree species on the susceptibility of P. densiflora to pine wilt disease. Sixteen weeks after inoculation, 48, 33, 14, and 18% of pine seedlings were diseased when they grew with Alnus sieboldiana, with Sarothamus scoparius, with the naturally associated species of P. densiflora such as Ilex pedunculosa and Eurya japonica, and in a pure stand of P. densiflora, respectively. When associated with A. sieboldiana or S. scoparius, pine seedlings quickly had visual discoloration of foliage. Twenty percent of P. densiflora seedlings treated with water died within 6 months when growing in the stand with A. sieboldiana, suggesting that the seedlings were stressed. The susceptibility of P. densiflora seedlings to pine wilt disease was enhanced by the different tree species co-occurring with the seedlings. For. Sci. 41(4):841-850.
Documentation and Evaluation of Growth and Other Estimators for the Fully Mapped Design Used by FIA: A Simulation Study
Authors: Williams M.S. , Schreuder H.T.
Published: April 2024

For the proposed mapped design of the USDA Forest Service, Forest Survey and Inventory (FIA) units, in a simulation study for a realistic mapped population, Grosenbaugh's ingrowth estimator Î1 and Van Deusen's survivor growth estimator ΔS2 are best. If additivity of estimates is desired, ΔY1 should be used for total growth estimation. If additivity is not required, a plausible assumption as FIA users become more statistically literate, Roesch's estimator ΔY4, which is 12% more efficient than ΔY1 should be used if survivor ongrowth trees can be cored to determine their first time period diameters. If not, Grosenbaugh's nonadditive estimator ΔY2 should be used which is 8% more efficient than ΔY1. The classical variance estimator yields unbiased estimates of the variance of the parameter estimates as expected. Area estimation, change in area estimation, percentage of plots in more than one condition, means per tree, and changes in means per tree over time can be estimated reliably if sample size is large enough and conditions or changes in conditions are not too infrequent. The length of boundaries between conditions are consistently underestimated. For. Sci. Monogr. 31:26-45.
Techniques and Computations for Mapping Plot Clusters that Straddle Stand Boundaries
Authors: Scott Charles T. , Bechtold William A.
Published: April 2024

Many regional (extensive) forest surveys use clusters of subplots or prism points to reduce survey costs. Two common methods of handling clusters that straddle stand boundaries entail: (1) moving all subplots into a single forest cover type, or (2) "averaging" data across multiple conditions without regard to the boundaries. These methods result in biased estimates of tree attributes (volume/acre, basal area/acre, etc.) and/or misclassification of discrete stand-area attributes (cover type, stand size, etc.). To circumvent the problems encountered with these approaches, a technique is described whereby subplots always are arranged in a fixed pattern, and trees are tallied by the cover type or "condition class" in which they occur. This involves mapping boundaries that bisect a subplot and proportioning subplot area by condition class. Field and calculation procedures leading to unbiased estimates are given. For. Sci. Monogr. 31:46-61.
Some Atmospheric Turbulence and Stability Effects on Aerial Spray Penetration into Hardwood Forest Canopies
Authors: Miller David R. , Wang Yansen , Ducharme Kirk M. , Yang Xiusheng , Mierzejewski Karl , McManus Michael A. , Reardon Richard E.
Published: April 2024

Vertical profiles of wind, turbulence, and stability were measured in and above a partially foliated 16 m tall, oak forest during a series of single-swath, aerial spray trials. The distribution of cross-swath spray deposits was sampled after each application at the top of the canopy and below the canopy. Spray penetration to the canopy top and through the canopy was highly dependent on the relative intensity of mechanically generated turbulence (due to wind across a rough surface) to that of thermally generated turbulence (due to warm air rising) in the unstable roughness sublayer above the canopy. In conditions with mechanical turbulence dominant, termed mixed convection conditions (u* > 1 m s-1 and -0.01 > Ri > -1), the amount and consistency of material reaching the canopy top was higher than during periods with thermal turbulence dominant, termed free convection conditions (u* < 1 m s-1 and Ri < -1). A greater proportion of the material penetrated through the canopy in the free convection conditions. The relationship of the structure of the Reynolds stress in the roughness sublayer to the spray behavior is discussed. For. Sci. 42(1):93-101.
Line Intersect Sampling of Forest Canopy Gaps
Authors: Battles John J. , Dushoff Jonathan G. , Fahey Timothy J.
Published: April 2024

Line intersect sampling (LIS) is commonly used to measure the fraction of forest area under canopy gaps (gap fraction) and the size distribution of gaps. The typical application of this technique makes assumptions about the shape of the gaps. Potential errors associated with these assumptions were quantified. To measure the gap regime in an old-growth, subalpine spruce-fir forest, regression equations were used to describe empirically gap area and perimeter. Most gaps in the spruce-fir forest were shaped like nonconvex polygons. Mapped gap areas were 22% less than estimates based on an elliptical model of gap shape and 22% more than area estimates based on a rhomboidal model of gap shape. An LIS method was developed that works for nonconvex shapes and was used to assess gap fraction in a subalpine, spruce-fir forest. The LIS approach for irregularly shaped gaps provided an estimate of gap fraction that was significantly smaller (35%) than the one based on an elliptical model of gap shape. The modifications in the application of LIS to the study of gap regimes seemed to preserve the efficiency and power of LIS while improving the accuracy of the results. For. Sci. 42(2):131-138.
Germination Responses of Northern Red Maple (Acer rubrum) Populations
Authors: Tremblay M.-F. , Mauffette Y. , Bergeron Y.
Published: April 2024

Samaras of red maple (Acer rubrum L.) were collected at six locations at the northern edge of its distribution. Two populations from southern Québec, in the deciduous forest, and four populations at its northern limit in the boreal forest were selected. Germination responses of these populations were evaluated in growth chambers and in the field. The effects of cold moist stratification, temperature (20/10°C, 10/1°C) and light intensity (750 μmol • m-2 • s-1, 160 μmol • m-2 • s-1) were evaluated in growth chambers. Seeds collected at the two most southern sites had 46% to 90% germination without stratification, while germination without stratification varied between 0% to 41% for the four most northern populations. In the six populations tested, the highest germination percentages were obtained at 10/1°C under low light conditions. Cold moist stratification enhanced germination of the four most northern populations. We observed in the field experiment that germination occurred during the summer months for sites located in the deciduous forest, while germination was delayed until the next spring for the sites located in the boreal forest. The percentages of seedling emergence in the field were similar under shade and nonshade conditions. Overall, our results indicate a marked degree of dormancy in the most northern populations. The heterogeneous germination response of northern red maple populations could be associated with the temperature regime at the collection site. For. Sci. 42(2):154-159.
Analyzing Cliques for Imposing Adjacency Restrictions in Forest Models
Authors: Murray Alan T. , Church Richard L.
Published: April 2024

Adjacency considerations have a significant impact on the acceptability of forest planning alternatives and have forced analysts to look for effective methods for incorporating such concerns. Various attempts have been suggested for representing adjacency restrictions within planning problem formulations. This paper investigates the use of cliques for representing adjacency conditions. Several approaches are presented for generating and incorporating cliques into operational level forest planning formulations. Properties of the various clique sets are detailed, which form a basis for understanding why certain clique sets outperform others. A number of forest planning problems are solved, demonstrating the superior performance of the clique approach presented in this paper. This work has broad implications on the types of planning problems that can be effectively modeled. For. Sci. 42(2):166-175.
Above- and Belowground Dry Matter Accumulation Pattern Derived from Dimensional Biomass Relationships
Authors: Reed David D. , Liechty Hal O. , Jones Elizabeth A. , Zhang Y.
Published: April 2024

A model of dry matter accumulation pattern is derived from above- and belowground dimensional biomass relationships as a function of basal diameter growth and total height increment. Without loss of generality, the model is illustrated utilizing previous results of analyses with eight years of growth records from precompetitive red pine (Pinus resinosa, Alt.) plantations in northern Michigan. Model behavior corresponds with previous knowledge concerning the seasonal patterns of dry matter accumulation in conifers and with the response of plant allocation patterns to temperature and moisture stress. Changes in accumulation fraction as a function of tree size also agree with previous observations. This model can be developed using existing above- and belowground dimensional biomass equations and functions describing the seasonal growth of diameter and height. The range of its applicability depends on the ranges of applicability of the component equations. Unification of this "mensurational" approach to modeling dry matter accumulation with previous functional balance methods can be achieved by placing appropriate constraints on model components. For. Sci. 42(2):236-241.
Sampling with Partial Replacement Extended To Include Growth Projections
Authors: Bokalo Miko , Titus Stephen J. , Wiens Douglas P.
Published: April 2024

The original theory of Sampling with Partial Replacement (SPR) is modified to incorporate growth model projections of the unmatched plot data on the initial measurement. The Modified Sampling with Partial Replacement (MSPR) theory is illustrated by estimating growth and current volume using simulated plot data. In addition to the assumptions required by SPR, MSPR requires that the growth projection errors be random and have a mean of zero. If these assumptions are met, the modified theory improves the precision of the volume and growth estimators over the original SPR estimator. For. Sci. 42(3):328-334.
Predicting the Present Value Distribution of a Forest Plantation Investment
Authors: Reed William J. , Haight Robert G.
Published: April 2024

Forestry investment decisions may be based on the probability distribution of financial return in addition to a point estimate of mean return. This study describes an approach to predicting the present value distribution of a plantation investment using actual data on timber price and yield. Changes in stumpage price are modeled with a lognormal diffusion process called geometric Brownian motion (GBM). Timber yield is modeled with a variant of GBM that includes an age-dependent growth component. Model parameters are estimated with time-series observations of loblolly pine (Pinus taeda L.) price and yield in the southeastern United States. Because GBM models have lognormally distributed errors, present value distributions are skewed with extremely long right-hand tails. The median and quartiles of the distribution provide a better measure of central tendency and spread than do the mean and standard deviation. A median-maximizing feedback cutting rule does not perform any better than a median-maximizing fixed rotation age suggesting that no economic gain can be obtained by monitoring timber price and yield under the assumptions of our models. The forecast error, measured by the distance between quartiles, is about twice the size of the median present value. System error is the primary cause, and error in the price process contributes more to the variability in present value than does error in the yield process. Parameter uncertainty increases forecast error 15 to 35%. The large forecast error raises the question of whether better predictive models can be built or whether the present value of a plantation investment is inherently uncertain. For. Sci. 42(3):378-388.
Valuing the Impacts of Forest Fires on Backcountry Forest Recreation
Authors: Englin Jeffrey , Boxall Peter C. , Chakraborty Kalyan , Watson David O.
Published: April 2024

A discrete choice travel cost model was developed for backcountry forest recreation using 2 yr of backcountry canoe registrations from Nopiming Park, Manitoba. A statistically significant variable explaining choice of route was the amount of forest along the route that was burned in the last 10 yr; virtually all of which occurred in two particularly severe fires during 1983. The current economic welfare loss from these fires was estimated using a discrete choice travel cost model combined with a count model of trip demand. Since the forest grows back following fire, these losses will eventually decrease to zero. A linear intertemporal damage function for one of the fires is estimated, and the present value of damages under alternative discount rate assumptions is presented. For. Sci. 42(4):450-455.
A Comparison of Dynamic Programming and A* in Optimal Forest Stand Management
Authors: Arthaud Greg J. , Pelkki Matthew H.
Published: April 2024

A model that adds a forward value estimator to traditional forward recursion dynamic programming (DP) is developed. State classes are used to store continuous values for stand basal area and stem density. A simple forward heuristic that estimates future value from deviations within a node is used in the model in combination with accumulated value to determine path choice (A*). A loblolly pine growth and yield model with both pulpwood and sawtimber product outputs is used in the model. The model is tested on combinations of initial planting density, site index, and interest rates to compare A* to DP in optimization of thinning age, thinning intensity, and rotation age. Results from tests using single-year stage intervals show increases of 0.0% to 1.2% in net present value for A* compared to DP. An A* approach increases computer program size very little but requires additional time for parameter searching. However, A* always generated solutions at least as high as DP. For. Sci. 42(4):498-503.
Estimating Leaf Area and Leaf Biomass of Open-Grown Deciduous Urban Trees
Authors: Nowak David J.
Published: April 2024

Logarithmic regression equations were developed to predict leaf area and leaf biomass for open-grown deciduous urban trees based on stem diameter and crown parameters. Equations based on crown parameters produced more reliable estimates. The equations can be used to help quantify forest structure and functions, particularly in urbanizing and urban/suburban areas. For. Sci. 42(4):504-507.
Dynamics and Stocking-Level Relationships of Multi-Aged Ponderosa Pine Stands
Authors: O'Hara Kevin L.
Published: April 2024

Ponderosa pine (Pinus ponderosa Dougl. ex Laws.) stands in western Montana and central Oregon were sampled to determine total leaf area index (LAI), leaf area distribution among age classes or cohorts, and stem volume increment. Stands included from one to five cohorts. LAI was assumed to represent occupied three-dimensional growing space. Within multi-aged stands, cohorts varied in their total LAI, with older cohorts generally having more LAI, or growing space, than younger cohorts. Older cohorts also produced stem volume growth more efficiently per unit of leaf area than younger cohorts. Higher individual tree leaf area, or growing space occupancy, was strongly related to increased stem volume growth in all cohorts. A general increasing relationship between growing space efficiency and number of cohorts per stand was also observed.

A model, termed PP-MASAM for Ponderosa Pine-Multi-Aged Stocking Assessment Model, was developed to assess multi-aged stocking relationships. Results indicate that residual age structures with large numbers of young trees reduce stand production from structures with fewer young trees because they grow more slowly than older trees and will die, need to be thinned, and will not become merchantable. Stocking relationships which appeared most productive are characterized by a positive linear relationship between LAI and cohort age, and a negative linear relationship between number of trees per cohort and age. These options produced the most gross and recoverable stem volume increment, produced acceptable tree vigors, and maintained sufficient growth rates in younger cohorts to sustain the structure.

Formal stocking guidelines for uneven-aged silviculture typically define stocking and residual stand structure using diameter distributions. The most common of these procedures, the q-factor, attempts to create and maintain "balanced" sustainable structures with a negative exponential diameter distribution. These size structures designed with the q-factor approach are assumed to be sustainable and to represent equal occupancy of growing space by each diameter or age class. PP-MASAM results indicate residual size structures defined by the q-factor are no more sustainable than other structures that, for example, provide linearly increasing growing space to each older age class. The q-factor approach also perpetuates ponderosa pine size structures which are atypical of structures which developed under a typical presettlement fire regime. For. Sci. Monograph 33:1-34.
Notes: Pollen Tube Growth in Quercus
Authors: Cecich Robert A.
Published: April 2024

Fluorescence and brightfield microscopy were used to evaluate pollen tube growth in the Erythrobalanus and Lepidobalanus subgenera of the genus Quercus. All three species had the same pattern of pollen tube growth behavior, from the time pollen landed on the stigmas to the cessation of pollen tube elongation in mid-May. Pollen tubes grew from the apertures, penetrated the stigmatic epidermis, and produced a series of callose plugs as they advanced basipetally through the transmitting tissue of the styles. Pollen tubes grew through the solid transmitting tissue until they reached the level of the visible portion of the perianth, where the three styles join. In white oak, the arrested pollen tubes resumed growth in early June, and fertilization occurred during the week of June 11. In northern red oak and black oak, resumption of pollen tube growth occurred in the following growing season. Pollen tubes of northern red oak resumed growth in the May 22 collections and fertilization occurred during the week of June 12. In black oak, however, pollen tubes resumed growth in the June 5 collections and fertilization occurred in late June. The control over pollen tube elongation may be environmental or sporophytic. For. Sci. 43(1):140-146.
Output Supply and Input Demand in the Pulp and Paper Industry: A Nonparametric Model for the United States and Canada
Authors: Hseu Jiing-Shyang , Buongiorno Joseph
Published: April 2024

Demand and supply relationships are needed to understand the economics of the pulp and paper industry and to make forecasts of inputs, outputs, and prices. Here, long-run supply and demand elasticities were derived with a nonparametric method exploiting the consequences of the weak axiom of profit maximization (WAPM). No assumption was required regarding the form of the profit function, and all own-price elasticities necessarily had the expected theoretical signs. But, an infinite number of quantity responses being consistent with the theory and data, finding a unique response required a new assumption: that quantities adjusted just enough to satisfy the WAPM. The data pertained to the pulp and paper industries of the United States and Canada from 1959 to 1987. They recognized four outputs and nine inputs. A price shock of 20% led to elasticities that closely satisfied local homogeneity of the supply/demand functions, and symmetry of their price derivatives. Output supplies were all elastic, or nearly so, with respect to their own prices. The own-price elasticities of input demand ranged from -0.4 to -2.2, demand for capital being one of the most elastic. Cross-price elasticities tended to be small. The method was also applied to make out-of-sample forecast of inputs and outputs conditional on observed prices, under nonregressive technical change. Forecasts for 1983 to 1987 were generally unbiased. A synthesis of parametric and nonparametric methods is still needed to improve forecasts. For. Sci. 43(1):35-45.
Radial Growth Response of Douglas-fir and Grand Fir to Larval Densities of the Douglas-fir Tussock Moth and the Western Spruce Budworm
Authors: Mason Richard R. , Wickman Boyd E. , Paul H. Gene
Published: April 2024

Statistical models were developed relating corrected tree-ring chronologies of grand fir (Abies grandis [Dougl. ex D. Don] Lindl.) and Douglas-fir (Pseudotsugata menziesii var. glauca [Beissn.] Franco) to population time series of Douglas-fir tussock moth (Orgyia pseudotsugata [McDunnough]) and western spruce budworm larvae (Choristoneura occidentalis Freeman) in the same stands. The study was conducted in northeastern Oregon and spanned 22 yr including 2 periods of defoliator outbreaks as well as an interval of no outbreaks. Changes in the radial increment of host trees, corrected for tree-ring age and weather, were inversely related to larval densities in the same year of growth and in each of the 4 preceding years. The strongest growth response was a delayed function of larval density with a 3 yr time delay. Regression models giving the best fit to pooled data were second-degree polynomials in which log larval density with a 3 yr delay accounted for 28.7% of the variation in rate of change in corrected tree-ring indices, and 46.4% of the variation in the absolute size of corrected indices. The results imply that reductions in radial growth are directly related to density of feeding larvae and that the cumulative maximum effect on increment in the lower bole lags defoliation by 3 yr. The models are recommended either for directly forecasting mean reductions in radial increment from monitored densities of larvae or for inversely predicting past mean densities of defoliating larvae from dendrochronology data. For. Sci. 43(2):194-205.
How to Calculate Optimum Family Number When Starting a Breeding Program
Authors: Lindgren Dag , Wei Run-Peng , Lee Steve J.
Published: April 2024

Methods were developed to calculate the optimum number of initial unrelated families (equivalent to founders) in a breeding program, which, following selection in a predetermined way, would result in the maximum gain. The required entries were: (1) effective population size (effective family number) after selection, (2) family type (half-sib or full-sib), (3) heritability, (4) number of selections, (5) available resources, and (6) cost per additional family in the initial population. Suggestions of optimum family numbers and other characteristics of the optimum were calculated for particular examples. It seemed important to consider cost components when planning breeding programs. The optimum initial family number was far greater than the intended effective family number when the marginal cost of adding initial families was low. If this cost was high, it was worth investing more than half of any fixed resources in obtaining many families. The value of heritability appeared rather unimportant. For. Sci. 43(2):206-212.
Estimating Foliage Area of Loblolly Pine Shoots
Authors: Murthy Ramesh , Dougherty Phillip M.
Published: April 2024

In this study, foliage surface area of loblolly pine (Pinus taeda L.) shoots from plants grown in a 2 x 2 factorial study of nutrients and water and three levels of CO2 was predicted by flush (growth cycle). Harms (1971) predicted foliage surface area of a flush from the weighted product of foliated flush length and average needle length. In the present study flush foliage surface area was predicted using the product of the natural log of foliated flush length and average fascicle length, and an additional independent variable fascicle density. Equations generated for each of the whole-plot treatment combinations did not differ significantly, therefore one prediction equation was developed for all whole-plot treatment combinations. Flush location significantly affected prediction of flush foliage area, therefore separate equations for predicting flush surface area were developed for the main and lateral shoots. The equations explained 96% of the variation in predicting flush foliage surface area for both main and lateral shoots with fascicle density explaining an extra 12% of the variation. The equations predicted flush foliage surface area with an average absolute percent deviation of predicted values of 16.1% and 12.6% for the main and lateral shoots. For. Sci. 43 (2):299-303.
Applying Objectively Estimated and Spatially Continuous Forest Parameters in Tactical Planning to Obtain Dynamic, Treatment Units
Authors: Holmgren Peter , Thuresson Thomas
Published: April 2024

Forestry planning is usually approached as the problem of combining and scheduling stand treatments. Stands are assumed to be homogeneous and spatially static and are usually delineated and described by subjective surveying methods. Because, in reality, stands vary internally, only subsets of the possible management alternatives will be considered in stand-based planning. As price expectations and other planning parameters change over time, it is likely that optimal locations, extensions, and schedules for forest operations change. This paper proposes a method whereby timber volumes and treatment priorities are estimated on objectively inventoried geo-referenced circular plots. Kriging interpolation and image analysis of scanned aerial photographs are then used to predict the variables in a spatially near-continuous raster. Treatment units are dynamically formed, based on price-expectations, and objectives defined by the forest owner. Given strategic goals, tactical plans are produced for two wood price situations, and compared with a plan based on conventional stands. The results imply that forest management planning should, perhaps, not be based on static stands if economic efficiency and planning flexibility are desirable. For. Sci. 43(3):317-326.
Communication Media and Demand for Printing and Publishing Papers in the United States
Authors: Zhang Yibing , Buongiorno Joseph
Published: April 2024

To predict the demand for printing and publishing papers, a model was first developed of the demand for printed materials—newspapers, books, magazines, and their substitutes--computers, and televisions and radios. A two-stage Almost Ideal Demand System (AIDS) represented the consumer demand for communication media (stage one) and for printed materials, computers, and televisions and radios (stage two). Annual United States data from 1960 to 1991 were used to estimate the expenditure share equations and related elasticities. The results suggest that during that period: (1) printed materials and computers were luxury goods; (2) the demand for printed materials was independent of the price of computers and slightly complementary of the demand for televisions and radios; and (3) the demand for printed materials was most sensitive to its price and to income. Then, the demand for paper by the printing and publishing industry was derived from a two-stage translog cost minimization model. The first stage describes the demand for paper to make printed materials together with labor, capital, and other materials. The second stage decomposes the demand for paper into that for each printing and publishing grade. Results show that during the period of observation, (1) paper demand was inelastic; (2) labor, capital, and other materials were substitutes for paper in making printed materials; and (3) technical change led to a relative decrease in the use of newsprint, and an increase in that of other paper grades. Equating production of printed materials to consumer demand led to the derived demand for each paper grade. The elasticities suggested that paper demand was not influenced much by the price of electronic media. A decomposition analysis of the growth in demand for printing and publishing papers showed that from 1981 to 1991 the positive income effects were most important, followed by the negative effects of changes in the prices of printed materials. For. Sci. 43(3):362-377.