bluuebunny/crossref_metadata_2025 huggingface dataset:
Gains Expected from Clonal Orchards under Alternative Breeding Strategies
Authors: Cotterill Paul P. , Jackson Neville
Published: April 2024

Gain equations were developed under the assumption of an additive genetic model and were used to calculate responses from clonal seed orchards under six strategies for breeding trees. The six strategies involve combinations of phenotypic or combined index selection to establish orchards, and polycross, single-pair, or half-diallel mating for progeny testing to cull orchards and for regenerating the breeding population. Open-pollinated mating was considered for progeny testing only.

Combined index selection with half-diallel mating produced the greatest gains from orchards. Single-pair mating used in conjunction with open-pollinated progeny testing proved to be the next best option under the range of heritabilities studied (heritabilities from 0.05 to 0.6). However, combined index selection with single-pair mating (and no open-pollinated testing) was also very efficient. Combined index selection with poly-cross mating produced substantial gains from culled orchards but was less appealing for unculled orchards. For. Sci. 35(1):183-196.
Microgeographical Patterns of Allozyme Differentiation in Douglas-Fir from Southwest Oregon
Authors: Moran G. F. , Adams W. T.
Published: April 2024

The genetic structure of stands of Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco var. menziesii) from two areas in southwest Oregon was examined. In the Little Butte Creek study area, stands on north- and south-facing slopes at each of three elevations were sampled. In the Applegate area, stands on opposing north- and south- facing aspects in each of three V-shaped canyons were sampled at a single elevation. Although considerable genetic variation was present in all stands, no significant differences among stands were found in single-locus measures of genetic diversity. The expected heterozygosity had a mean of 0.164 and a range of 0.128 to 0.189 among stands. Observed heterozygosities were not significantly different from expected heterozygosities. Associations of allele frequencies with slope aspect or elevation were either very weak or lacked consistency between the two study areas. Indeed, only 1.8% of the total genetic diversity could be apportioned among stands. Of this 1.8%, only 13% of the variation could be attributed to differences between aspects. Thus, in marked constrast to variation in the quantitative characters of seedlings as reported in other studies, there was very little allozyme differentiation between stands of different aspect or elevation within populations of Douglas-fir in southwest Oregon. Possible reasons for these conflicting findings are discussed. For. Sci. 35(1):3-15.
Estimating Site Index of Douglas-Fir (Pseudotsuga menziesii [Mirb.] Franco) from Ecological Variables in Southwestern British Columbia
Authors: Green R. N. , Marshall P. L. , Klinka K.
Published: April 2024

Relationships were examined between Douglas-fir site index (at 50 years breast height age), understory vegetation, and site classification units based on 88 sample plots from south coastal British Columbia. Analysis of variance showed differences in site index (P < 0.01) among the site units. Of the regression models tested, the one based on site units plus indicator species groups was most successful in predicting site index (R² = 0.87, SE = 2.96 m, and 75% of cases classified within 3 m of actual site index). The models using indicator species alone as variables had consistently poorer performance, which we attribute largely to inherent variation in understory vegetation. Further testing of the models over a wider range of sites and in earlier seral stages is suggested. For. Sci. 35(1):50-63.
Perceived Scenic Beauty and Contingent Valuation of Forest Campgrounds
Authors: Daniel Terry C. , Brown Thomas C. , King David A. , Richards Merton T. , Stewart William P.
Published: April 2024

Campers' photo-based scenic beauty judgments of 35 forest areas were compared with other campers' photo-based judgments of their willingness to pay to camp at the same areas. A nearly perfect linear relationship was found between the scenic beauty and willingness to pay judgments, indicating that respondents using either response mode were sensitive to the same variations in forest characteristics in providing their judgments. Forest conditions that produced perceptions of greater scenic beauty also increased the value that recreationists verbally assigned to their campground experience. For. Sci. 35(1):76-90.
New Compatible Estimators for Survivor Growth and Ingrowth from Remeasured Horizontal Point Samples
Authors: Roesch Francis A. , Green Edwin J. , Scott Charles T.
Published: April 2024

Forest volume growth between two measurements is often decomposed into the components of survivor growth (S), ingrowth (I), mortality (M), and cut (C) (for example, Beers 1962 or Van Deusen et al. 1986). Net change between volumes at times 1 and 2 (V2 - V1) is then represented by the equation V2 - V1 = S + I - M - C. Two new compatible pairs of estimators for S and I in this equation are presented for use with the usual estimators of V2 and V1 from permanent horizontal point samples. In addition, a new estimator for V1 (V1**) is presented, which takes advantage of the data from time 2. These estimators are evaluated along with previously existing estimators over a range of sample sizes. In all but the smallest of inventories, one of the new estimators of S (S**) will provide better estimates of survivor growth in more cases than any previously developed estimator of S. S** is shown to be compatible with V1** and the Purdue estimators of ingrowth, while empirical evidence is presented to support earlier contentions that the Purdue estimator is the best possible estimator of ingrowth from point samples. Recommendations are given based upon the presence or absence of a compatibility requirement and willingness to change the estimate of volume at time 1. For. Sci. 35(2):281-293.
Predicting Wood Production by Canopy Trees in Forest Communities in the Western Great Smoky Mountains
Authors: Callaway Ragan M. , Clebsch Edward E. C. , White Peter S.
Published: April 2024

A sequence of multivariate techniques (after Golden 1981) including hierarchial classification, detrended correspondence analysis, and multiple discriminant analysis was used to classify forest types in the Great Smoky Mountains National Park. Multiple regressions were used to develop predictive equations for canopy tree productivity (periodic bole volume increment) from environmental variables and measurements of tree growth. An index of topographic shape was constructed to quantify the effects of landform on forest distribution and productivity.

The topographic index "protection" was the most important variable for predicting forest productivity. Elevation was the most important variable determining vegetation distribution with protection the second. Predictability of forest productivity from environmental factors was lower on older logged and farmed sites than on undisturbed sites. For. Sci. 35(2):338-348.
Effects of Costs, Demand, and Labor Productivity on the Prices of Forest Products in the United States, 1958-1984
Authors: Buongiorno Joseph , Lu Hsien-Chih
Published: April 2024

The objective of this study was to investigate the reasons for changes in the prices of forest products. To do this, a mark-up model of price formation was proposed. It linked yearly price changes to changes in variable costs and changes in demand. This model was estimated with annual data on prices, variable costs, and inventory-output ratios, from 1958 to 1984. Four solidwood industries and three pulp and paper industries of the United States were studied. The results showed that, depending on the industry, the theory explained 83 to 98% of the variation in annual price changes. Rises and declines of variable costs had symmetric effects on prices, except for pulp mills, the most concentrated industry, in which downward-price inflexibility was apparent. Decomposition analysis showed that over the interval 1958-1984, the rise in variable costs explained most of the rise in product prices. Further decomposition indicated that within variable costs, increases in material costs led to increases in prices that were much higher than those due to labor costs. Finally, in no industry did the increase in labor productivity between 1958 and 1984 compensate for the rise in the wage rate, so that increases in wages also contributed to the general inflation in forest product prices. To improve their competitiveness, the forest products industries should strive to control material costs and increase their labor productivity. For. Sci. 35(2):349-363.
Development and Evaluation of an Expert System for Diagnosing Pest Damage of Red Pine in Wisconsin
Authors: Schmoldt Daniel L. , Martin George L.
Published: April 2024

An expert system for diagnosing pest damage of red pine stands in Wisconsin, PREDICT, runs on IBM or compatible microcomputers and is designed to be useful for field foresters with no advanced training in forest pathology or entomology. PREDICT recognizes 28 damaging agents including species of mammals, insects, and pathogens, as well as two types of abiotic damage.

Two separate development tools (EXSYS and INSIGHT2 +) were used. Each employs a role-based method for representing knowledge, which was obtained from the literature and from human experts in the fields of forest pathology and entomology. The pest-inference rule blocks, for each damaging agent, are based on the abduction model of diagnosis and include rules for eliminating a pest from further consideration, diagnosing a pest as certain, and compiling evidence in favor of a pest. Both development tools employ a backward-chaining control strategy; however, it was necessary to modify this approach by designing a special block of rules to approximate the mixed strategy used by the human experts. A logic and completeness rule block was also constructed to deduce facts omitted by the user and to minimize the need for questioning.

Input to PREDICT is obtained from pest damage reports containing specific information about stand/site conditions, tree symptoms, and signs. Diagnoses from PREDICT take the form of a list of one or more possible agents with corresponding confidence values. Actual and hypothetical test cases were used to refine the knowledge base, then a separate set of 20 actual cases was used as a basis for testing and evaluating the completed system. It was necessary to develop special procedures for refining and evaluating the system to accommodate the often vague and uncertain nature of pest damage information.

Two versions of PREDICT (developed with the EXSYS and INSIGHT2 + tools, respectively) were evaluated and compared with three recognized experts and two field foresters. No significant differences were found between the performances of PREDICT and the experts; however, PREDICT performed significantly better than the two foresters, even though they both have training and experience in forest pest diagnosis. It was concluded that PREDICT is able to improve the diagnoses of field foresters to a level comparable with recognized experts. For Sci. 35(2):364-387.
Determinants of Log-To-Lumber Conversion Efficiency: A Washington Case Study
Authors: Cardellichio Peter A.
Published: April 2024

Log-to-lumber conversion efficiency is modeled using pooled cross-section and time-series data for individual sawmills. The analysis incorporates economic variables, technological characteristics of sawmills, and timber characteristics. To exploit optimally the panel structure of the database, fixed effects and error components models are estimated, along with the ordinary least squares model. The elasticity of substitution between sawlogs and other inputs used in manufacturing lumber is small, but statistically significant. However, the data are not adequate to rule out the conclusion that lumber production is a fixed proportions production process because relative prices may be correlated with exogenous technological change. Mill size, mill vintage, headrig type, and log diameter also are key factors that influence log use. However, once a sawmill is in place, there is a large unsystematic component to its recovery performance. For. Sci. 35(2):437-452.
The Generation and Fate of Road-Surface Sediment in Forested Watersheds in Southwestern Washington
Authors: Bilby Robert E. , Sullivan Kathleen , Duncan Stanley H.
Published: April 2024

Studies conducted in southwestern Washington, examining the generation of sediment on gravel road surfaces, its transport to small streams and its fate after entering flowing waters, are reviewed. The amount of sediment produced on an hourly basis from a road segment was related to traffic rate. Accumulated material flushed rapidly from the road surface with precipitation, leading to a decrease in sediment concentration in the ditch with time during a storm. Depth of road ballast and type of surfacing material also influenced sediment generation. The majority of the sediment produced by these roads was finer than 0.004 mm. Steeper roads produced a higher proportion of coarser particles. Approximately 34% of surveyed road drainage points entered streams, mainly first- or second-order channels. Thus, the delivery of road sediment to larger streams often depended on its transport through these smaller channels. Small streams temporarily retained a high proportion of road sediment input to them. Coarser particles were retained at a higher rate than finer material. Due to the fine particle size of road sediment delivered to streams, little effect of this material on the composition of streambed gravel could be discerned. The results of these studies provide guidelines for management of those roads where sediment has the highest potential to impact aquatic resources. For. Sci 35(2):453-468.
Spatial and Temporal Variability of Foliar Nutrient Levels in Fraser Fir Christmas Trees
Authors: Hockman Joseph N. , Burger James A. , Smith David Wm.
Published: April 2024

The variation of Fraser fir (Abies fraseri [Pursh] Poir.) foliar nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) levels within plantations, the tree crown, and season of the year was studied. Extensive variation in nutrient concentrations existed. The data show that use of foliar nutrient levels for diagnosing nutrient sufficiency without regard to this variation could cause erroneous fertilization prescriptions. Recommended foliar sampling technique consists of sampling current-year's tissue from 2- or 3-yr-old south-facing branches in October. For. Sci 35(2): 632-639.
Height-Age Trends from an Arkansas Seed Source Study
Authors: Sprinz Peter T. , Talbert Cheryl B. , Strub Mike R.
Published: April 2024

An analysis of average and dominant height, and height growth indicated the geographic origin of planted loblolly pine significantly affected height development through 29 years in Arkansas. For average and dominant height, sources west of the Mississippi were shorter than eastern sources at all ages; coastal Carolina and Virginia sources were taller than local sources from Arkansas, northern Louisiana, east Texas, and Oklahoma at all ages. The interior sources from northern Mississippi, Alabama, Georgia, and piedmont Carolina were shorter than the coastal sources initially, but became similar by age 25. It was also determined that region rankings for dominant height remained fairly consistent with age, but the relative magnitudes of difference among regions decreased with age. Region rankings for average and dominant heights were similar, but the relative differences in magnitude were greater for average height than for dominant height. A flexible height-age model suggested that while dominant height maximized at a common level, the shape of development varied to that asymptote with seed source. Lastly, it was found that region differences existed in the shape and level of height growth over time. Eastern origin material showed the greatest height growth initially, but the western origin stands had attained the same height growth rate by age 20. For. Sci. 35(3):677-691.
Stockability: A Major Factor in Productivity Differences between Pinus Taeda Plantations in Hawaii and the Southeastern United States
Authors: DeBell Dean S. , Harms William R. , Whitesell Craig D.
Published: April 2024

Basal area and volume production in loblolly pine spacing trials in Hawaii were nearly double the average production in research plantings in the Southeastern United States. The higher productivity in Hawaii was associated, to some extent, with site index and more rapid growth of individual trees. Competition-related mortality, however, was considerably lower in Hawaii, despite the fact that trees were larger. Consequently, limiting density and mortality threshold boundary lines were much higher. Such differences in stockability (or maximum mean tree size-stand density relationships) accounted for most of the differences in productivity. Forest managers and scientists should pay more attention to possible differences in stockability in the quest for productivity improvement. For. Sci. 35(3):708-719.
Design Efficiencies with Planned and Unplanned Unbalance for Estimating Heritability in Forestry
Authors: McCutchan Barbara G. , Namkoong Gene , Giesbrecht Francis G.
Published: April 2024

Design efficiencies are evaluated for the estimation of heritability in unbalanced designs using Modified Maximum Likelihood estimation. Assuming knowledge of the variance components, the variance of the estimate of heritability is calculated. The effects of block size, plot size, family size, variance of family size, and total number of observations on design efficiency are examined across the range of heritability and under 100%, 90%, 80%, and 60% survival. The implications of each of these design factors are discussed. There is no uniformly best design for estimating heritability; the most efficient design is a function of the heritability. For. Sci. 35(3):801-815.
Influence of Disease Management Strategies on the Production of White Spruce in a Forest Tree Nursery
Authors: Enebak S. A. , Palmer M. A. , Blanchette R. A.
Published: April 2024

In a Wisconsin forest tree nursery dazomet, captan, thiram, captan-thiram combination, or silica sand did not reduce populations of three soilborne fungi. Preemergence mortality was greatest in nontreated plots, (56%) and least in plots treated with dazomet (46%). Nontreated plots had the most post-emergence damping off, (15%) and silica sand the least (3%). Rhizoctonia solani (AG-1) was isolated from 52% of damped-off seedlings collected while Pythium spp., Fusarium spp. and Cylindrocladium spp. were recovered from 24%, 23%, and 1% of the seedlings, respectively. Seedling mortality from May 18 to September 23, 1986, ranged from 28% in the dazomet plots to 61% in nontreated plots. At the end of the first growing season, plots treated with dazomet had significantly more seedlings than any other treatment. The incidence of stunted seedlings was greatest in plots treated with dazomet and least when seed was covered with silica sand. Silica sand or thiram treatments produced seedlings with the greatest total dry weights. For. Sci. 35(4):1006-1013.
A Model to Predict the Moisture Content of Reindeer Lichen
Authors: Péch Gy.
Published: April 2024

The Fine Fuel Moisture Code (FFMC) of the Canadian Forest Fire Weather Index System is modified to apply to the top layers of reindeer lichen (Cladina rangiferina [L.] Nyl.). While the basic assumption for FFMC, i.e., exponential drying in constant weather influenced by relative humidity, air temperature, and wind, is retained in the calculation of the reindeer lichen moisture code, actual drying in the model is accelerated by isolation. The equilibrium moisture content (E) of sun-exposed reindeer lichen is 3-4% lower than that for shaded fuels. Rainfall causes a more rapid rise of moisture content in reindeer lichen than in FFMC, and the change is proportional to the initial (Mo) and saturation (Ms) moisture contents of the lichen, and the amount of rain (R). The model postulates that after rain the moisture content of the lichen (Mr) is: Mr = Mo + [a(Ms - Mo)/(a + Mo)][1 - e -b(Ms-Mo)R;] Comparison of experimental measurements with calculated values suggests that the model represents moisture content in the top 3-4 cm layer of reindeer lichen. For. Sci. 35(4): 1014-1028.
Endemic and Epidemic Populations of Southern Pine Beetle: Implications of the Two-Phase Model for Forest Managers
Authors: Mawby W. D. , Hain F. P. , Doggett C. A.
Published: April 2024

Typical of many Dendroctonus species, the southern pine beetle (D. frontalis Zimmerman) exhibits dramatic fluctuations in population levels. Using field observations of beetle damage, this study empirically demonstrates that a two-phase model described for mountain pine beetle (D. ponderosae Hopkins) is appropriate for southern pine beetle at each of five hierarchical levels: the tree, the local infestation, the county, the state, and the region. The model has three points that represent a stable low-level (endemic) phase maintained by host-tree-defensive capabilities, a transient high-level (epidemic) phase determined by the availability of host material, and a threshold between the two phases. The threshold depends on local environmental and biotic factors and is a rarely observed phenomenon. Implications of these results for southern pine beetle management and control are discussed. The necessity for establishing and maintaining control programs during the endemic phase is stressed. For. Sci. 35(4): 1075-1087.
Red Spruce Rhizosphere Dynamics: Spatial Distribution of Aluminum and Zinc in the Near-Root Soil Zone
Authors: Smith William H. , Pooley H.
Published: April 2024

Red spruce roots, associated with mature, healthy trees occupying canopy positions, were located in three 8.5 m² forest floor plots at 250 m elevation in the Hubbard Brook Experimental Forest, White Mountain National Forest, New Hampshire. Roots, 0.25-1.0 cm diam, were severed, and cut ends were placed in soil in plastic bags. In 14 months, new roots developed behind cut ends and were cultured in wooden trays containing screened forest floor material. Forest floor concentrations of aluminum, calcium, chlorine, iron, lead, and zinc were established. Trays containing roots were supplied with a distilled water treatment or with distilled water containing chloride salts of aluminum, lead or zinc sufficient to increase substrate cation concentration by 500 ppm. Eight weeks following treatment, roots (largely ectomycorrhizal, diam 0.4-1.0 mm) with associated rhizosphere soil were harvested by impregnating specimens in agar and freezing in liquid nitrogen. Cross sections of root-rhizosphere soil samples were freeze dried and examined with a scanning electron microscope and energy dispersive x-ray spectrometer. Gradients of element concentrations were established along transects from root interiors (cortex) through the inner and outer rhizosphere zones (2 mm from root) and in bulk soil (devoid of roots). The pH of rhizosphere soil was approximately 0.5 unit less than bulk soil. Aluminum concentrations exhibited a strongly descending gradient from bulk soil through the rhizosphere to the root. Estimated concentrations ranged from 1000 ppm within 200μ of the root to 10 X this amount in soil beyond 2000μ. Calcium distribution, without aluminum amendment, was relatively constant through the rhizosphere, but with aluminum amendment, calcium exhibited a sharply decreasing gradient near the root. In the unamended treatment, the Al:Ca ratio dropped from 7 to 0.2 across the rhizosphere. Chlorine was constant in the rhizosphere but exhibited pronounced accumulation inside the root. Iron counts were variable in the rhizosphere, but on average suggested constant concentrations across the rhizosphere. Zinc concentrations were marginally detectable and exhibited slight accumulation in cortex tissue. Aluminum uptake appeared to be strongly mediated by rhizosphere processes. Solubility, and more importantly exchangeability, of aluminum may be enhanced in the rhizosphere by lowered pH; greater availability of low molecular weight organic ligands, or some other unique chemical characteristic of the rhizosphere. Judgments made concerning potential uptake of aluminum from bulk soil characteristics of forest soils, without consideration of rhizosphere dynamics, could lead to improper conclusions. For. Sci. 35(4):1114-1124.
A Tree-Ring Reconstruction of Western Spruce Budworm History in the Southern Rocky Mountains
Authors: Swetnam Thomas W. , Lynch Ann M.
Published: April 2024

Tree-ring width chronologies from ten mixed-conifer stands in the Colorado Front Range and New Mexico Sangre de Cristo Mountains were used to reconstruct the timing, duration, and radial growth impacts of past outbreaks of western spruce budworm (Choristoneura occidentalis Freeman). At least nine outbreaks were identified in the stands from 1700 to 1983. Severity and timing of outbreaks was highly variable. The average duration of reduced growth periods caused by budworms was 12.9 years and ranged from 5 to 26 years. The average interval between initial years of successive outbreaks was 34.9 years and ranged from 14 to 58 years. The average maximum and periodic radial growth reductions were 50% and 21.7%, respectively. There was a relatively long period of reduced budworm activity in the first few decades of the twentieth century, and since that time outbreaks have been markedly more synchronous among the sampled stands. It is hypothesized that the increased synchroneity of outbreaks in the latter half of the twentieth century is due to changes in age structure and species composition following harvesting and fire suppression in the late nineteenth and early twentieth centuries. For. Sci. 35(4):962-986.
A Variable-Form Taper Function for Pinus Oocarpa Schiede in Central Honduras
Authors: Perez D. N. , Burkhart H. E. , Stiff C. T.
Published: April 2024

A variable-form taper equation was developed for Pinus oocarpa Schiede in central Honduras. The model predicts tree profile as a function of total height, diameter at breast height, and relative height with a continuous function using a changing exponent to compensate for the form of different tree sections. The proposed five parameter model predicts underbark diameters with a standard error of 1.4 cm. The point where the taper curve changes from neiloid to paraboloid form, the inflection point, was assumed to occur at 25% of total height. For the data used, no changes in the predictive ability of the model were observed with different locations of the inflection point. For. Sci. 36(1):186-191.
Classification Model to Predict Fraser Fir Christmas Tree Grade
Authors: Hockman J. N. , Burger J. A. , Smith D. Wm.
Published: April 2024

Objective measures of Christmas tree grade that would better quantify tree responses to cultural treatments were sought. Fraser fir Christmas tree attributes in a 3-year-old plantation were measured and correlated with conventional three-class grade categories, and a discriminate classification model was developed to test the predictability of grade based on tree attributes. Tree attributes best correlated with grade were basal diameter, terminal leader length and total bud and lateral bud frequencies on the terminal leader. Grade prediction based on five easily measured growth attributes produced a discriminate classification success rate of 72%. For. Sci. 36(1):45-53.
A Stochastic Restrictions Regression Model Approach to Volume Equation Estimation
Authors: Meng C. H. , Tang S. Z. , Burk T. E.
Published: April 2024

The stochastic restrictions regression estimator is suggested as a means of combining auxiliary information with standard regression applied to a data set. A derivation of the estimator is given, and the estimator is compared to other estimators that use auxiliary information and other regression approaches that have previously been applied in forestry. A test statistic for determining whether the auxiliary information is unbiased is presented along with a table of critical values. Approximate confidence interval procedures are obtained, and consistent means of estimating nuisance parameters are given. Finally, an example is provided to illustrate calculations. For. Sci. 36(1):54-65.
Growth Response and Drought Susceptibility of Red Spruce Seedlings Exposed to Simulated Acidic Rain and Ozone
Authors: Lee Woong S. , Chevone Boris I. , Seiler John R.
Published: April 2024

One-year-old seedlings of red spruce were exposed to O3 (≤0.025 or 0.10 μl 1-1, 4 h d-1, 3 d wk-1) in combination with simulated rain (pH 5.6 or 3.0, 1 h d-1, 2 d wk-1, 0.75 cm h-1) for 10 weeks. After pollutant treatments, seedlings were subjected to two successive drought cycles. Whole-plant fresh weight increment (FWT) and dry weight were reduced after O3 exposure, whereas FWT and shoot height growth were increased after simulated rain exposure at pH 3.0 compared to pH 5.6. No interaction between O3 and rain treatments was observed for any growth variable measured. Foliar concentrations of K and S were greater in seedlings exposed to simulated rain at pH 3.0 compared with those at pH 5.6. Root hydraulic conductivity was highest in seedlings exposed to 0.10 μl 1-1 O3 + pH 3.0 rain solution compared with all other treatments after the first drought cycle. There were no significant O3 effects on net photosynthesis (Pn), transpiration or water-use efficiency prior to the drought cycles. However, during the second drought cycle, Pn was more sensitive to branch water potential in seedlings exposed to 0.10 μl 1-1 O3 + pH 3.0 solution compared with seedlings exposed to low O3 + pH 5.6 solution. For. Sci. 36(2):265-275.
Growth and Biomass Partitioning Response of Northern Red Oak Genotypes to Shading and Grass Root Competition
Authors: Kolb T. E. , Steiner K. C.
Published: April 2024

First-year biomass, biomass relative growth rate, and biomass partitioning among organs were compared among eight open-pollinated families of northern red oak (Quercus rubra L.) under crossed levels of light intensity (100% and 37% full sun) and grass root competition [presence and absence of grass roots (Poa pratensis L.)]. Ontogenetic patterns of biomass partitioning during the first year of seedling development were characterized by coefficients of the allometric equation Y = aXb. Grass root competition reduced seedling biomass at both levels of light intensity. Shading reduced seedling biomass in the absence of grass but had no effect in its presence. Total biomass and biomass relative growth rate differed among families, and family X environment interaction variance was negligible compared to family variance. Results suggest that families with superior juvenile growth rate under competition-free conditions will also have superior growth rate under at least some conditions of shading and root competition. Biomass partitioning to leaf area, and to shoot weight relative to root weight declined during seedling development. Both shoot-root ratio and leaf area ratio were greater in shaded compared to full sun environments, while the presence of grass root competition had an opposite effect on both ratios. Families differed in shoot-root ratio, and shoot-root ratios of families responded differently to grass root competition. However, family differences in biomass partitioning were not consistently related to family differences in growth rate in any environment. For. Sci. 36(2):293-303.
U.S. Trade in Transition—An Econometric View of South Sea Wood Flows
Authors: Cengel Dennis , McKillop William
Published: April 2024

There were distinct stages of growth and development in the 1960s and 1970s in the flow of South Sea tropical hardwood as it made its way from the forests of Indonesia, East Malaysia, and the Philippines to the transit plywood-manufacturing plants of Japan, South Korea, and Taiwan, and thence to U.S. markets. In the introductory stage, the dominant end-use was flush-doors, the dominant manufacturer was Japan, and the dominant provider of logs was the Philippines. The expansionary phase started in the early 1960s and was characterized by a dramatic rise in South Korean and Taiwanese plywood exports which found distinct niches in the U.S. market. By its end, in the early 1970s, these countries supplied, respectively, 60% and 30% of U.S. demand. A quasi-spatial econometric model was used to investigate plywood and log flows over the 1962-1979 period. The consequences of SEALPA log export restrictions that started around 1980 were analyzed using estimated reduced-form relationships and a gap-type model. Future U.S. imports of South Sea plywood are expected to be around 60% of the peak level reached in the early 1970s, with more than 80% of them coming from Indonesia. For. Sci. 36(2):425-437.
An Analysis of Three Methods for Fitting Site-Index Curves
Authors: Furnival George M. , Gregoire Timothy G. , Valentine Harry T.
Published: April 2024

The analysis of covariance method, the method of algebraic differences with all possible differences, and the method of weighted parameter prediction are shown analytically to be identical for fitting a site-index equation that can be transformed into a simple linear model. Results of the analysis apply to both anamorphic and polymorphic systems, which are linear in the parameters. For. Sci. 36(2):464-469.
Relationships Among Humus Forms, Forest Floor Nutrient Properties, and Understory Vegetation
Authors: Klinka K. , Wang Q. , Carter R. E.
Published: April 2024

Morphologically characterized humus forms and their associated understory vegetation have been used to infer different modes of decomposition of forest floor materials, but few studies have analyzed relationships among humus forms, forest floor nutrient properties, and understory vegetation. Examination of these relationships was accomplished in this study by a numerical analysis of forest floor and vegetation data that were obtained from 151 cool mesothermal forest ecosystems of southern British Columbia and stratified into seven humus form groups. Four forest floor nutrient properties (pH, C/N ratio, total N, and sum of exchangeable Ca, Mg, and K) and nine diagnostic combinations of species differentiated the groups. pH and mineralizable-N consistently increased, and C/N ratio consistently decreased from Lignomors to Hemimors, Humimors, Mormoders, Leptomoders, and to Vermimulls, indicating the presence of a regional decomposition gradient. Multivariate summaries of the nutrient properties and diagnostic species were highly correlated. A consistent correlation was also found between the nutrient properties and indicator plants of nitrogen-rich soils. For. Sci. 36(3):564-581.
Species Substitution and Tropical Log Imports by Japan
Authors: Vincent Jeffrey R. , Gandapur Alamgir K. , Brooks David J.
Published: April 2024

Tropical rainforests contain many "lesser known species" that have not achieved widespread acceptance in international timber markets. This paper provides a quantitative analysis of the effects on tropical log demand of two economic factors: relative prices and technical change. A multi-output cost function framework is developed to analyze tropical log demand as derived from the production of plywood and sawnwood. Data analyzed are Japanese imports of dipterocarp and nondipterocarp logs (proxies for well- and lesser known species, respectively) from the South Seas during 1970-87. The econometric results indicate that the composition (dipterocarp vs. nondipterocarp) of tropical log imports was not significantly influenced by either relative prices or technical change during the period analyzed. For. Sci. 36(3):657-664.
Shifting Southern Softwood Stumpage Supply: Implications for Welfare Estimation from Technical Change
Authors: Newman David H.
Published: April 2024

This paper estimates the economic benefits from increasing timber inventory in the southern softwood forest over the period from 1950 to 1980. The analysis measures the benefits arising to consumers and producers of stumpage from increases in softwood stumpage availability. Over the period of the analysis, average total benefits are roughly equal between the pulpwood and solidwood (combined lumber and plywood) stumpage markets. Average combined benefits range from $1.3 million to $5.3 million per year (1967 $). The size of the total benefits are more greatly affected by the level of shift assumed than they are by the structural characteristics of the market. The distribution of the benefits, however, differs quite markedly depending on the market structure. Pulpwood consumers (pulp and paper mills), for instance, receive greater than 150% of the total benefits from increased productivity effects on stumpage production as producers receive negative benefits. Solidwood producers receive positive benefits from increasing supply, although only 10% of the total benefits that are created. These distributional imbalances in the effects of policies designed to improve forest productivity should be considered in future analyses which assess the impacts and returns of these policies. For. Sci. 36(3):705-718.
Nutrient Leaching of a Loblolly Pine Forest Floor by Simulated Rainfall II. Environmental Factors
Authors: Duffy P. D. , Schreiber J. D.
Published: April 2024

A multiple-intensity simulator was used to apply 25.4 mm of simulated rainfall to forest floor samples (L and F. horizons) collected from a loblolly pine plantation and placed in l-m² pans. Leachate (rainfall that flowed through the forest floor) was sampled at intervals during each application. As simulated rainfall and forest floor materials temperature were increased from 8°C to 35°C, the PO4-P, NH4-N, and TOC concentrations in leachate increased about twofold. In contrast, NO3-N concentrations were independent of rainfall temperature. In a series of five simulated storms over a 27-day period, nutrient concentrations in leachate collected on the 27th day were only 16% to 41% of those sampled in the storm on the first day. Nutrient concentrations in leachate from simulated acid rain (pH 4.2) were similar to those produced by deionized water (pH 5.3). Within individual simulated storms, nutrient concentrations in leachate rapidly increased to a maximum and then decreased to a near constant value as the storm progressed. After maximum concentrations, the function C = aTb best described the relationship of concentration (C) with time (T); the function C = aebQ best described the relationship of concentration (C) with cumulative leachate volume (Q). Quantification of environmental influences on forest floor nutrient leaching, as described in this report, should aid nutrient cycling and water quality modeling. Results demonstrate that the rainfall simulator is a useful tool to study leaching kinetics. For. Sci. 36(3):772-789.
Hybrid Econometric/Input-Output Modeling of the Cumulative Economic Impact of National Forest Harvest Levels
Authors: Sullivan Jay , Gilless J. Keith
Published: April 2024

Econometric and input-output methods are combined to assess the multiforest personal income impacts of timber harvesting activities on regional economies in Northern California. The importance of a combined assessment is demonstrated using data from the El Dorado and Shasta-Trinity national forests. Depending upon the timber harvest levels of other national forests in the area, projected changes in personal income resulting from a change in harvest level on either forest varied by as much as 27%. For. Sci. 36(4):863-877.
An Investigation of the Rule-of-Thumb Method of Estimating After-Tax Rates of Return
Authors: Campbell Gene E. , Colletti Joe P.
Published: April 2024

The effect of income taxes may significantly alter an investment's expected profitability relative to competing alternatives. With one exception, both post-tax cash flows and a post-tax discount rate must be used if the effects of taxation are to be correctly incorporated into an investment analysis. The adjustment of the pre-tax discount rate to a post-tax rate often is accomplished by using an estimate derived by rule-of-thumb. This estimate (effectively reducing the pre-tax rate by the product of itself and 1 minus the marginal income tax rate) is accurate only when the alternative used to determine the opportunity cost of capital involves a nondepreciating asset, returning equal annual payments, whose salvage value is exactly 100% of first cost, or where the alternative investment's life is equal to 1 year. For alternatives with depreciable, depletable, or tax-deferred assets, the rule-of-thumb estimate is not accurate. Its accuracy depends on the alternative's real rate of return, the investor's marginal income tax rate, the level of inflation, and the investment period. In general, the rule-of-thumb method's accuracy decreases as the real rate of return decreases and as the income tax rate, inflation, and investment period increase. In addition, its accuracy is further decreased as depreciation or depletion is accelerated, or if an investment tax credit is included as part of the expected income stream. For. Sci. 36(4):878-893.
Nonlinear Programming Approaches to Multistand Timber Harvest Scheduling
Authors: Hof John G. , Kent Brian M.
Published: April 2024

This paper describes several nonlinear programming formulations of multistand (analysis area) timber harvest scheduling problems and compares these formulations with more traditional approaches. The strengths of the nonlinear programming approaches include the abilities to represent explicit nonlinear timber yield functions and to define continuous harvest timing variables. Optimal control theory has these capabilities but, to date, the technique has not proven applicable to multistand problems or to problems with common exogenous constraints. Linear programming works well with multistand problems but utilizes piecewise approximations of yield functions and discrete time periods. Both nonlinear and linear programming can accommodate common programming constraints such as output targets and limits on inputs. The nonlinear programming formulations were solved using a version of the generalized reduced gradient algorithm. It was discovered that a local optimum exists for each number of harvests on each analysis area. Because nonlinear programming finds local optima, the global optimum was determined with multiple advanced starts. A nonlinear programming formulation that can handle time-period-based constraints is provided, but could not be solved. For. Sci. 36(4):894-907.
Winter Injury Susceptibility and Cold Tolerance of Current and Year-Old Needles of Red Spruce Trees from Several Provenances
Authors: DeHayes D. H. , Waite C. E. , Ingle M. A. , Williams M. W.
Published: April 2024

Winter injury to red spruce (Picea rubens Sarg.) trees from 12 provenances in a plantation near Colebrook, NH, was described and quantified in spring 1986 through 1989. Winter injury was found exclusively on current-year needles (i.e., buds and twigs were virtually uninjured), and 34% to 68% of trees were injured each year. Laboratory assessments of cold tolerance of current and year-old needles of trees representing four red spruce and four balsam fir (Abies balsamea [L.] Mill.) provenances indicated that current-year needles of red spruce, but not balsam fir, were 8° to 12°C less cold tolerant than year-old needles in late autumn and early winter. Also, throughout the winter, current-year needles of red spruce were about 10°C less cold tolerant on average than those of balsam fir, a sympatric species that does not suffer winter injury. Thus it appears that a "window" of freezing injury susceptibility exists naturally for red spruce in early winter. Provenance differences in foliar winter injury and percentage of trees injured were highly significant in 1986, 1987, and 1989, and marginally significant in 1988. Trees from Quebec, New York, and New Brunswick were consistently among the least injured each winter, whereas trees from Massachusetts and New Hampshire were consistently among the most injured. It is likely that repeated winter injury is a major contributor to the reported decline of red spruce in northern forests. For. Sci. 36(4):982-994.
Integrating Short-Term, Area-Based Logging Plans with Long-Term Harvest Schedules
Authors: Nelson John , Brodie J. Douglas , Sessions John
Published: April 2024

Procedures are developed and evaluated for integrating short-term, area-based plans with long-term, strata-based harvest schedules. A combination of these two approaches to forest planning provides a spatially feasible, short-term solution that can also incorporate strategic harvest goals over a long-term period. Three basic steps are used to combine the area and strata-based plans: (1) a 15-decade strata-based plan is solved with linear programming (LP) to establish strategic harvest goals; (2) with these goals as guidelines, 3-decade, area-based plans are generated with a random search technique caned Monte-Carlo integer programming (MCIP); and (3) those area-based plans become the first 3-decade solution within 15-decade integrated plans that are solved with LP. Both the harvest units and the road projects within the area-based plan are specified as strict binary variables.

MCIP is an effective technique for generating feasible solutions to integer problems encountered in area-based planning. Although no guarantee of optimality can be assured, the technique is a major improvement over manual methods, and it is a practical alternative to mixed-integer programming for identifying feasible alternatives.

In comparison to the integrated plans, it was found that the strata-based model consistently overestimated long-term revenues, and consistently underestimated long-term volumes. The integrated plans produced net revenue and volume levels within 10% of the strategic goals established by the strata-based linear program. The case study was conducted in 1987-88 on a forest located in British Columbia. For. Sci. 37(1):101-122.
Availability, Quality, and Selection of Browse by White-Tailed Deer after Clearcutting
Authors: Hughes Jeffrey W. , Fahey Timothy J.
Published: April 2024

We evaluated the effect of large-scale forest harvest on the production, nutritive quality, twig size, and use of four preferred species of browse by white-tailed deer in a spruce-fir forest in New Hampshire. Red maple produced the most new twigs (44-fold increase 3 years after harvest), and 99% of these were sprouts from stumps. Mountain maple and mountain ash twig production increased by factors of 3.5 and 1.9, respectively, and most twigs were borne on stems that survived the clearcutting. Most yellow birch (4-fold increase after 3 years) colonized from newly dispersed seed. For all species of browse except yellow birch, clearcutting resulted in (1) significantly larger, heavier twigs, and (2) significantly higher concentrations of protein and soluble carbohydrates. Deer removed a higher proportion of twigs from the clearcut than from the uncut forest. Mountain ash and mountain maple were the preferred species on both sites. Management implications are discussed. For. Sci. 37(1):261-270.
Transportation Specification in Forest Trade Models
Authors: Krutilla Kerry
Published: April 2024

Computable spatial equilibrium models in the forestry literature are based on an analytic simplification of the transportation sector. This paper evaluates whether the usual transportation specification can cause biased economic estimates of trade policy actions implemented in forestry markets. The analysis reveals that estimates of tariff policy actions in fact can be sensitive to the transportation specification. This leads to some conclusions about the interpretation of economic estimates generated by spatial equilibrium forestry trade models. For. Sci. 37(1):284-295.