bluuebunny/crossref_metadata_2025 huggingface dataset:
Needlefall, Canopy Light Interception, and Productivity of Young Intensively Managed Slash and Loblolly Pine Stands
Authors: Dalla-Tea F. , Jokela E. J.
Published: April 2024

Canopy dynamics, light interception, and productivity of 6-yr-old slash (Pinus elliottii vat. elliottii Engelm.) and loblolly pine (P. taeda L.) were investigated using a 2 x 2 x 2 factorial experiment (species, annual fertilization, sustained weed control) in north central Florida. The strong nutritional gradient imposed by the cultural treatments significantly accelerated canopy development. Needlefall (NF) mass for the weed control + fertilization treatments was increased over the checks by about 400% (0.8 to 4.0 Mg ha-1) for slash pine and 1050% (from 0.4 to 4.6 Mg ha-1) for loblolly pine. Levels of annual NF were strongly correlated (r² > 0.90) with stand basal area, and cumulative NF through time was successfully modeled using a logistic function. Cultural treatments had no significant effect on needle longevity or temporal NF patterns; however, large treatment related responses in leaf area index (LAI; all-sided) were apparent for both species (slash pine = 1.5 to 7.2 m² m-2 loblolly pine = 1.0 to 10.6 m² m-2). Mean annual light interception (photosynthetically active radiation) for the check and combination treatments paralleled LAI responses and ranged from 28 to 74% for slash pine and 22 to 81% for loblolly pine. Significant species differences in aboveground biomass production (loblolly pine = 3.1 to 16.0 Mg ha-1 yr-1; slash pine = 3.5 to 8.0 Mg ha-1 yr-1) were principally due to greater LAI (reflecting differences in specific leaf area and branch structure) and higher light use efficiency (0.81 vs. 0.47 g MJ-1) of loblolly pine. For. Sci. 37(5):1298-1313.
Predicting the Effects of Silvicultural Regime on Branch Size and Crown Wood Core in Douglas-Fir
Authors: Maguire Douglas A. , Kershaw John A. , Hann David W.
Published: April 2024

Three major determinants of wood quality in Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) were estimated from the dynamics of crown structure in ORGANON, an individual-tree, distance-independent growth model. Branch whorl locations were estimated directly from the height growth predictions assuming formation of one whorl per year. Mean maximum branch diameter was predicted as crown base receded past each whorl; branch diameter estimates were based on current depth of the whorl into crown, tree diameter, stand relative density, and site index. Diameter of crown wood core was established as diameter inside bark, likewise at time of crown recession past each branch whorl. This approach facilitated description of harvested log distribution (40-ft butt logs) by various branch size, whorl frequency, and crown wood core indices. Based on projections of a 9-yr-old Douglas-fir stand to final harvest at 65 years, thinning precommercially to 121 trees/ac at age 9 resulted in a BD4 (mean of four largest branch diameters per log) of 2.5 in., vs. 1.5 in. for the unthinned stand (484 trees/ac). When thinned to 121 trees/ac, approximately 55% of the volume/ac in 40-ft butt logs consisted of crown wood as opposed to 30% at 484 trees/ac. Responses to subsequent thinnings were less pronounced, but included larger branches in the largest 80 trees/ac, and larger total crown wood percentages for a given initial stand density. Thinning from below resulted in larger average BD4's and slightly greater crown wood percentages than proportional thinning. Individual-tree growth models that contain a crown recession component can easily be modified to predict crown wood core and indices of branch size. For. Sci. 37(5):1409-1428.
Effects of Southwestern Pine Tip Moth and Vegetation Competition on Ponderosa Pine Growth
Authors: Long David W. , Wagner Michael R.
Published: April 2024

The effects of southwestern pine tip moth Rhyacionia neomexicana (Dyar) and vegetation competition on ponderosa pine Pinus ponderosa (Doug. ex Laws) growth was studied in northern Arizona. Tip moth attack rates varied significantly among three sites. Weeding had little effect on attack rates but increased tree survival by 17%, height growth by 96%, and diameter growth by 83%. Insectidde treatment for tip moth control increased height growth 49% and diameter growth only 12%. High tree mortality rates in insecticide treated plots suggest a possible phytotoxic effect of the insecticide. Tree growth declined as tip moth attacks increased. Height growth was further reduced with each added year of tip moth attack. Diameter growth was less affected by multiple years of attack. For. Sci. 38(1):173-186.
Solving for Habitat Connections as a Steiner Network Problem
Authors: Sessions John
Published: April 2024

The problem of finding habitat connections in forest planning can be modeled as a Steiner network problem. Although exact solutions exist for solving Steiner network problems, no methods that can be solved in polynomial time are known. A network modeling procedure for habitat connections is discussed and a heuristic algorithm is presented which is suitable for solving large scale Steiner networks. For. Sci. 38(1):203-207.
Thinning and Nitrogen Fertilization in a Grand Fir Stand Infested with Western Spruce Budworm. Part III: Tree Wound Dynamics
Authors: Filip Gregory M. , Wickman Boyd E. , Mason Richard R. , Parks Catherine A. , Hosman Kevin P.
Published: April 2024

In a grand fir stand defoliated by western spruce budworm, we tested the effects of thinning and urea fertilization on stem-wound closure and associated wood decay as affected by tree growth and vigor. After 3 years, thinning or fertilizing significantly improved tree diameter growth, and fertilizing significantly improved tree vigor as measured by cambial electrical resistance (CER). Although wound closure and cross-sectional area of decay were not significantly affected by our treatments, the percentage of stem cross-sectional area with decay was significantly less in trees that had been both thinned and fertilized. We found relatively poor correlations between decay area or decay percent and tree vigor, tree diameter growth, or wound diameter, but relatively moderate correlations between wound diameter and tree vigor or tree growth. Heterobasidion annosum was the dominant fungus causing the stem decay. Our results support the use of thinning and fertilization to improve grand fir growth and vigor and reduce losses from wound-associated stem decay. For. Sci. 38(2):265-274.
Thinning and Nitrogen Fertilization in a Grand Fir Stand Infested with Western Spruce Budworm. Part IV: An Ecosystem Management Perspective
Authors: Waring R. H. , Savage T. , Cromack K. , Rose C.
Published: April 2024

A stand of grand fir, Abies grandis (Dougl.) Lindl., was thinned and (or) fertilized with 350 kg/ha of nitrogen during an outbreak of the western spruce budworm, Choristoneura occidentalis Freeman. With thinning, the leaf area index was reduced by >30%. Tree growth efficiency, measured as wood production per unit of leaf area, increased by 60% within 2 years. Thinning combined with fertilization improved growth efficiency by 140%. Fertilization without thinning brought a much delayed response in growth, awaiting some beneficial effects of defoliation.

Fertilization provided tree roots in the upper soil horizons access to nitrogen during the spring, increasing the concentration of nitrogen in emerging foliage from 1 to 1.5% of dry weight and free amino adds levels 4-fold. Foliage enriched in amino acids increased shoot growth 3-fold, more than compensating for any nutritional benefits to insect larvae.

From an ecosystem perspective, managers should recognize that allowing pine forests to be replaced with fir through fire protection and selective logging has increased the nitrogen demand beyond that readily supplied in the ponderosa pine/true fir type. Fertilizing with one application of nitrogen at the time of an insect outbreak may reduce mortality and associated fire hazard through a period of up to 5 years. For. Sci. 38(2):275-286.
Production and Nutrient Cycling in Mixed Plantations of Eucalyptus and Albizia in Hawaii
Authors: Binkley Dan , Dunkin Kristie A. , DeBell Dean , Ryan Michael G.
Published: April 2024

Experimental plantations of pure Eucalyptus saligna (Sm.), pure Albizia falcataria (L.) Fosberg (a nitrogen-fixing species), and five proportions of mixtures of these species were examined at age 6 for biomass, production, nutrient cycling in litterfall, and resource-use efficiencies. Biomass was greatest in the 34% Eucalyptus/66% Albizia treatment, averaging 174 Mg/ha, compared with 148 Mg/ha in the fertilized pure Eucalyptus treatment and 132 Mg/ha for the pure Albizia treatment. The 34% Eucalyptus/66% Albizia treatment also showed the greatest aboveground net primary production (52 Mg ha-1 yr-1) and annual increment (39 Mg ha-1 yr-1). The N and P content of above-ground litterfall ranged from 35 and 3.5 kg ha-1 yr-1 in pure Eucalyptus to 240 and 9.5 kg ha-1 yr-1 in pure Albizia. Nutrient-use efficiency, defined as Mg of ANPP/kg of nutrient in fine litterfall, was greater for Eucalyptus (1.1 for N, 13.4 for P) than for Albizia (0.2 for N, 5.7 for P). Light-use efficiency ranged from about 14 kJ/MJ of intercepted light in the pure Albizia treatment, to 17 kJ/MJ in the pure Eucalyptus treatment, to 18 in the 34% Eucalyptus/66% Albizia treatment. The patterns of productivity across the mixtures resulted from the combination of (1) greater nutrient use efficiency of Eucalyptus, (2) greater nutrient cycling under Albizia, and (3) greater light capture and high use efficiency in mixed stands. For. Sci. 38(2):393-408.
Spatial Optimization for Wildlife and Timber in Managed Forest Ecosystems
Authors: Hof John G. , Joyce Linda A.
Published: April 2024

This paper presents several nonlinear formulations for land allocation that optimize spatial layout for a single time period and that have the property that the number of choice variables increases linearly with the level of spatial resolution. Two nonlinear models are presented: one that accounts for spatial patterns with a cellular grid, and an alternative that uses geometric shapes. The formulations account for four criteria important to wildlife: the amount of edge, the juxtaposition of different habitat types for cover versus feeding needs, the dispersal distance between favorable habitats, and the minimum size of a patch of habitat. Case examples demonstrate the selection of different sizes of cuts as well as different spatial distributions of the cuts over the landscape, in response to different habitat needs for several species of wildlife. Sensitivity analyses were performed on alternative formulations and objective function coefficients. These model formulations are initial exploratory efforts, and extensions to this study are identified. For. Sci. 38(3):489-508.
GCA Variance Components in 36 Pinus sylvestris L. Full-Sib Families Cultivated at Five Nutrient Levels in a Growth Chamber
Authors: Jonsson Alena , Dormling Ingegerd , Eriksson Gösta , Norell Lennart
Published: April 2024

Seedlings belonging to 36 families from a partial diallel mating between 11 parents of Scots pine (Pinus sylvestris L.) were cultivated for three growth periods in growth chambers at five different nutrient levels in the range 5-45 mg N/l. The relation between N:K:P was always 100:65:13. Several growth, growth component, and quality characters were assessed, mainly during the third growth period. ANOVAs were run to estimate GCA and SCA variance components at each treatment level and on pooled data from all five or the four higher nutrient treatments. In the two latter the interaction GCA x nutrient treatment variance component was also estimated. For most growth and growth component characters, the highest values of GCA variance component were found at the intermediate nutrient treatments (25 and 35 mg N/l). This phenomenon was less pronounced for quality characters. The SCA was in most cases of less importance than the GCA. ANOVAs based on pooled data from all treatments resulted in GCA x treatment variance components which were mostly a few times smaller than the GCA variance component. This interaction became negligible when the lowest nutrient treatment was dropped from the analyses. For. Sci. 38(3):575-593.
Predicting Crown-Height Increment for Thinned and Unthinned Loblolly Pine Plantations
Authors: Short III E. Austin , Burkhart Harold E.
Published: April 2024

Several nonlinear, individual tree crown-height increment equations were tested for their ability to predict annual crown-height increment in thinned and unthinned loblolly pine plantations. The selected model contained tree height (HT), tree crown ratio (CR) raised to the one-half power, age (A), and a measure of competition. The distance-dependent and the distance-independent models were the same form; however, the competition index (CI) in the distance-dependent model was replaced by the ratio of quadratic mean diameter to tree dbh (DR) for the distance-independent model.

The individual-tree increment models were used as a basis for a stand-level crown-height increment model. The independent variables were collapsed to stand-level statistics; the model contained average height of dominant and codominant trees (HD), average crown ratio (R), and age (A). Unlike the individual-tree models, raising the average crown ratio to 0.5 did not improve the fit.

Hypothesis tests revealed that thinning, both its intensity and the elapsed time since its occurrence, had a significant effect on crown-height increment. A thinning variable, T, which accounted for thinning intensity and the interval since thinning, was developed and incorporated into the final individual-tree and stand-level increment models. Predictions of crown-height increment were improved using models with the T variable as compared to those with no thinning allowance. For. Sci. 38(3):594-610.
Interaction of Virulent Single-Gall Rust Isolates of Cronartium quercuum f. sp. fusiforme and Resistant Families of Loblolly Pine
Authors: Kuhlman E. George
Published: April 2024

Basidiospores derived from 6 virulent single-gall aeciospore isolates of Cronartium quercuum f. sp. fusiforme produced different frequencies of galls on half-sib progeny of 21 loblolly pine families. One family was immune to infection by 2 of the isolates (0% of seedlings with galls), but only moderately resistant (53% galls) to another isolate. Another family was susceptible to all 6 isolates (70-82% of seedlings with galls). The interactions between individual families and the 6 isolates suggest that there are at least 9 different patterns of relative susceptibility among these 21 pine families to the 6 isolates, based on percentage of seedlings with galls. The patterns suggest that there are a variety of resistance genes among these families providing a broad genetic base for field resistance. Gall length was not always related to relative resistance. Three resistant families, 151-791,152-60, and 11-41, had the shortest average gall lengths of 21, 26, and 27 mm, respectively. However, resistant family 10-5 had the greatest average gall length of 52 mm. For. Sci.: 38(3):641-651.
Competitive Interference Between Selected Herbaceous and Woody Plants and Pinus taeda L. During Two Growing Seasons Following Planting
Authors: Morris L. A. , Moss S. A. , Garbett W. S.
Published: April 2024

Interference between loblolly pine (Pinus taeda) seedlings and selected herbaceous (panicum grass, Panicum dichotomiflorum; coffeeweed, Sesbania exaltata; broomsedge, Andropogon spp.) and woody (sweetgum, Liquidambar styraciflua) competitors was evaluated during the first two growing seasons following planting on a loamy sand Coastal Plain site. Pine seedling growth was reduced by all competitors. During the first growing season, competition for water was the dominant factor affecting pine growth. Panicum grass, which most rapidly depleted available water in the soil surface, was the strongest competitor. Reductions in N, Ca, and K foliar concentrations were associated with reduced surface soil water availability in grass and coffeeweed plots during this period. On plots with less competitive broomsedge and sweetgum, only K and Ca concentrations of pine foliage were reduced. Fertilization with NPK or P alone had no affect on pine growth and had only a minor affect on pine foliage nutrient concentrations. Although differences in growth occurred among families, all families responded to competitor and fertilizer treatments in a similar manner. Competitors had less influence on seedling water use and nutrition during the second growing season. Although absolute differences in seedling size among competitor treatments increased, much of this was due to differences in seedling size at the start of the growing season. FOR. SCI. 39:166-187.
Age Trends in Genetic Parameters for Tree Height in a Nonselected Population of Loblolly Pine
Authors: Balocchi C. E. , Bridgwater F. E. , Zobel B. J. , Jahromi S.
Published: April 2024

Additive variance for height of loblolly pine (Pinus taeda L.) in Georgia was very low at younger ages (1 to 8) but rapidly increased thereafter. Nonadditive variance increased from ages 1 to 10 and then remained constant through age 26. The ratio of nonadditive variance to total genetic variance increased from 17% at age 1 to a maximum of 82% at age 6, and then declined to 20% at age 26.

Heritability values ranged from almost zero to approximately 0.75 with the lowest values occurring at very young ages and for within-family and individual-tree heritabilities. The largest values were associated mainly with family heritabilities and older ages. Almost all estimates of heritability exhibited similar trends; values were very low at early ages and a maximum value between ages 14 and 16. Narrow-sense heritabilities were near zero until approximately age 8, then they increased sharply through age 16 and declined at the final measurement age.

Finally, the coeffident of genetic prediction for tree height between juvenile ages (1 to 16) and the final measurement age for tree height, when based on the total genetic component (CGP_G), showed a nearly linear increase from age 1 to age 16. The maximum values for this parameter were those associated with full-sib family means and ranged from 0.13 at age 1 to 0.67 at age 16. The additive (CGP_A) and nonadditive (CGP_D) components of CGP_G followed the same patterns the additive and nonadditive variances followed. FOR. SCI. 39(2):231-251.
Growth and Nutrition of Hybrid Poplar in Response to Phosphorus, Zinc, and Gibberellic Acid Treatments
Authors: Teng Yuanxin , Timmer Victor R.
Published: April 2024

Phosphorus-induced growth inhibition in poplar hybrid shoots in a greenhouse trial was corrected by treatment with either soil-incorporated Zn fertilizer or leaf spray of gibberellic acid (GA). Increasing P applications depressed plant growth. Zinc added alone failed to stimulate growth, but when combined Zn with P it increased total biomass production by 27-41%. GA spray increased height and dry weight of shoot by 32% and 11%, respectively, at the expense of root growth without increasing total biomass. Foliar P and Zn concentrations were unchanged by GA treatment, but N concentrations were reduced, probably because of dilution. Although GA may be useful for stimulating shoot elongation, it may not be practical for correcting P-induced Zn disorders in hybrid poplar culture. FOR. SCI. 39(2):252-259.
Disaggregating Stand Volume Growth to Individual Trees
Authors: Zhang Lianjun , Moore James A. , Newberry James D.
Published: April 2024

A disaggregation function, relative size-growth (RSG), was proposed and developed for interior Douglas-fir (Pseudotsuga menziesii var. glauca [Beissn] Franco) to distribute stand volume growth to a list of individual trees. The RSG function was formulated as a quadratic equation relating relative tree growth to relative tree size in a stand. The shape of the RSG function was linear, convex, or concave depending on initial stand conditions and structure. A recursive system of equations was developed to predict the three coefficients of the RSG function using initial stand density, mean tree size, and coefficient of variation of tree size distribution as predictor variables. This disaggregation function determines within-stand growth of individual trees and simulates stand development and dynamics. The RSG function provides a biologically based link between whole-stand and individual tree resolution models. FOR. SCI. 39(2):295-309.
Modeling Multiplicative Error Variance: An Example Predicting Tree Diameter from Stump Dimensions in Baldcypress
Authors: Parresol Bernard R.
Published: April 2024

In the context of forest modeling, it is often reasonable to assume a multiplicative heteroscedastic error structure to the data. Under such circumstances ordinary least squares no longer provides minimum variance estimates of the model parameters. Through study of the error structure, a suitable error variance model can be specified and its parameters estimated. This error model is used to construct a covariance matrix which in turn is used to form an estimated generalized least squares estimator of the forest model parameters. The theory is illustrated with data on baldcypress (Taxodium distichum [L.] Rich.). A multiple linear regression equation is developed for predicting diameter at 3 m from solid-wood stump diameter (i.e., diameter inside the fluting) and stump height. By modeling the error structure, standard errors on three of the four coefficients from the tree diameter-stump dimensions regression were reduced by 13 to 50%. The effect on prediction confidence intervals is graphically illustrated. For. Sci. 39(4):670-679.
An Integer Programming Approach for Spatially and Temporally Optimizing Wildlife Populations
Authors: Hof John , Bevers Michael , Joyce Linda , Kent Brian
Published: April 2024

This paper presents mixed integer linear programming formulations that optimize the spatial layout of management actions for providing wildlife habitat, over time. The formulations focus on wildlife growth and dispersal as a dynamic, probabilistic process. Habitat fragmentation/connectivity is thus modeled indirectly. Multiple timber age classes are accounted for as different wildlife habitat types, which define carrying capacity limitations that are tracked spatially. A variety of objective functions are specified, including ones based on piecewise-approximated nonlinear functions that relate wildlife populations to the probability of species viability. All of the formulations and objective functions are demonstrated with a case example. For. Sci. 40(1):177-191.
Measuring Net Investment and Productivity in Timber Production
Authors: Wear David N.
Published: April 2024

An index number approach is developed for measuring changes in inputs, outputs, and total factor productivity in a timber-producing sector. These methods are applied to timber production in the U.S. South for the period 1952 to 1985. Results suggest that development of the sector may be described by an adjustment phase between 1952 and 1962 and a growth phase between 1962 and 1985. Aggregate output grew during the latter period at an annual rate of 2.0% for the forest industry and 1.2% for all other private lands. Input growth was also strong for the industry reflecting expansion in both the area of timberland and the intensity of management. On other private lands, however, timberland and inputs showed steady declines. Output growth net of input growth shows that productivity grew at about 0.5% per year on the industry lands and 2.5% per year on other private lands. However, the strong productivity measure for the other private ownership likely reflects measurement error related to the classification of timberland. These results demonstrate the potential hazards of using either trends in timberland area or gross investment (planting) alone to assess the development of a timber-producing sector. For. Sci. 40(1):192-208.
Seasonal Physiology of Douglas-fir Saplings: Response to Microclimate in Stands of Tanoak or Pacific Madrone
Authors: Harrington Timothy B. , Pabst Robert J. , Tappeiner II J. C.
Published: April 2024

Plant water potential, leaf conductance, and photosynthesis of saplings of Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) were monitored monthly in 1986 through 1988. The objective was to describe influences of microclimate (light, soil water, temperature, and relative humidity) associated with young stands of tanoak (Lithocarpus densiflorus [Hook. & Arn.] Rehd.) or Pacific madrone (Arbutus menziesii Pursh) on Douglas-fir physiology. Hardwood shade reduced photosynthetically active radiation to 20 to 38% of full sunlight; as a result, photosynthesis of Douglas-fir shaded by hardwoods was light-limited throughout the year. Soil water potentials (30-cm depth) in summer (July through September) averaged -0.64 MPa in the presence of hardwoods and - 0.23 MPa in their absence. Reduced soil water availability in the hardwood stand, coupled with elevated air temperatures and lower relative humidities, reduced photosynthesis of associated Douglas-fir. Stomatae neared complete closure at the following plant water potentials: -2.3 (tanoak), -2.5 (Douglas-fir), and -3.4 MPa (madrone). Although seasonal rates of photosynthesis did not vary greatly among the three species, specific water-use patterns were apparent. The abilities of species to minimize water stress were ranked as tanoak > Douglas-fir > madrone. For. Sci. 40(1):59-82.
Growth of Outplanted Lodgepole Pine Seedlings One Year After Inoculation with Plant Growth Promoting Rhizobacteria
Authors: Chanway C. P. , Holl F. B.
Published: April 2024

Four-month-old lodgepole pine seedlings were inoculated with plant growth promoting rhizobacteria (Bacillus polymyxa strain L6-16R) and outplanted at one interior site (Gavin Lake) and two coastal sites (University of British Columbia South Campus and Totem Field) in British Columbia. The percentage of seedlings that incurred overwinter injury and that survived 13 months after outplanting were not influenced by bacterial inoculation. At Totem Field, where growth of control seedlings was greatest, inoculation had an inhibitory effect on seedling performance. At South Campus, where growth of control seedlings was intermediate compared with seedlings at Totem Field and Gavin Lake, inoculation had a slight stimulatory effect on seedling performance, but bacterial effects were not significant. However, at Gavin Lake, where seedlings attained only 14% of the biomass of those grown at Totem Field, inoculated seedlings had significantly increased stem diameter (7%), root dry weight (32%), and shoot dry weight (33%). While the effects of site history and site quality were confounded in this study, these results suggest that inoculation of lodgepole pine with strain L6-16R may be useful for seedlings targeted for outplanting on relatively harsh or poorer quality sites, but less so for seedlings to be planted at higher quality sites. For. Sci. 40(2): 238-246.
Adaptedness of Noble Fir (Abies procera Rehd.) Beyond Its Northern Limit
Authors: Xie Chang Yi , Ying Cheng C.
Published: April 2024

The adaptedness of noble fir (Abies procera Rehd.) beyond its northern limit was examined at 12 locations distributed throughout the Maritime, Submaritime, and Subcontinental climates in south coastal British Columbia. Ten-year testing results demonstrated large site effects. Noble fir planted in the Maritime climate survived better, grew faster, entered the period of accelerated growth earlier, and maintained a higher growth rate. In the Maritime climate, the reforestation range of noble fir can be extended considerably north of its current natural distribution and to lower elevations. Low winter temperature and growing-season soil moisture appear to be the major environmental factors limiting the species' expansion into more continental climates, and these factors must be considered in planting site selection.

Provenance differences in both growth and survival were significant but small compared to site differences. Adaptive variation showed gentle geographic clines indicating that northern provenances were better adapted in the Maritime climate, whereas inland provenances were superior in the Submaritime climate. Lack of strong geographic patterns suggests that local environmental factors may be important to the adaptive variation of the species.

The test results suggest that introduction of noble fir to British Columbia should be limited to the Maritime region, and that northern provenances, such as French Butte, McKinley Lake, and Stevens Pass in Washington are the primary seed sources. For. Sci. 40(3):412-428.
Topographic Variation of Soil Nitrogen Dynamics at Walker Branch Watershed, Tennessee
Authors: Garten Charles T. , Huston Michael A. , Thoms Christopher A.
Published: April 2024

Understanding the spatial and temporal variability of soil nitrogen (N) transformations is central to quantifying the N dynamics and productivity of ecosystems. The objectives of this work were to examine spatial and temporal variation of soil N dynamics and to identify factors correlated with topographic variation in soil N dynamics in a forest watershed. Net N mineralization and net nitrification potential were measured by aerobic laboratory incubations of surface (0-7 cm) mineral soils. Principal components analysis was used to describe sampling sites across the watershed based on 13 site characterization variables. A topographic index used in hydrologic modeling, In (α/tan β), was calculated for each site as the natural logarithm of the ratio of the upslope drainage area per unit contour length (α) to the local slope angle (tan β). Soils from valley floors had greater total N concentrations, lower carbon-to-nitrogen (C:N) ratios, greater potential net nitrification, and greater microbial activity (as indicated by short-term urease assays) than soils from ridges. Mean net nitrification potential was 0.59 μg N g-1 d-1 in surface soils from valley floors and was < 0.01 on ridges and slopes. The first principal component was related to the N and C properties of soils, leaf litter, and leaf fall at a site. The second principal component was related to forest stand composition. The topographic index was significantly correlated with important variables related to soil N dynamics. Once calibration data are derived, this index may be useful as a first approximation to total soil N concentrations and soil C:N ratios in forest watersheds because In (α/tan β) can be calculated from geographic information systems that contain topographic data. For. Sci. 40(3):497-512.
Random-Parameter Height/Age Models when Stand Parameters and Stand Age are Correlated
Authors: Lappi Juha , Malinen Juha
Published: April 2024

Height/age curves of dominant trees in a stand can be predicted using models containing random stand and tree parameters. If the population mean curve is estimated from the data where stand-specific parameters are correlated with stand age (e.g., because old stands are growing on poor sites), this correlation may cause biased estimates. The same bias problem occurs in traditional site index methods. It is shown how ordinary least squares estimates of tree specific parameters can be used for computing unbiased estimates of the population mean parameters and for estimating the relationship between stand parameters and stand age. The application of the estimated model several years after the data collection time is problematic because it should be known how the population changes over time. For. Sci. 40(4):715-731.
Note on the Relation Between Ring Widths and Basal Area Increments
Authors: Visser Hans
Published: April 2024

A primary aim of tree-ring analysis is to reconstruct the annual growth patterns of individual trees or groups of trees, and then derive growth models which allow for prediction of wood production. Tree growth is mostly measured as a series of annual ring widths. In practice, however, one is interested in annual basal area increments (BAIs). The calculation of BAIs is quite involved. One needs extra information in addition to ring widths: diameters measured at the thickest and thinnest sides of the tree and an estimate of bark width. In this note a summary of the relevant formulas is presented. For. Sci. 41(2):297-304.
Field and Laboratory Investigations of Seed Dormancy in Red Maple (Acer Rubrum L.) from the North Carolina Piedmont
Authors: Peroni Patricia A.
Published: April 2024

Field and laboratory investigations were conducted using seeds collected from red maple populations located in the North Carolina piedmont to determine: (1) the percentage of red maple seedling establishment each spring that can be attributed to dormant seeds, (2) the percentage of seeds that display dormancy upon dispersal, (3) the effect of short periods of dry conditions at 20-22°C on dormancy and seed viability. The greenhouse results indicated that red maple from these populations display moderate levels of seed dormancy (14%) when provided with conditions conducive to germination immediately upon dispersal. However, in the field, the majority of red maple seedlings that established in both 1988 (59%) and 1989 (nearly 100%) emerged from dormant seeds. The dry delay treatment led to significant increases in seed dormancy and decreases in seed viability, which suggest that some seed dormancy in red maple may be acquired rather than innate. Maternal families showed significant variation in levels of seed dormancy, and the effects of the dry delay treatment on seed viability also varied among maternal families. For. Sci. 41(2):378-386.
Modeling Stand Level Growth and Yield Response to Silvicultural Treatments
Authors: Pienaar L. V. , Rheney J. W.
Published: April 2024

As plantation growth and yield research lead to new, more intensive, and site-specific silvicultural prescriptions, there is a perpetual need to adjust existing yield prediction models to reflect the response to these practices. A height growth model that includes a treatment response term to accommodate different expected response patterns is presented. This model is shown to provide an accurate description of the observed average dominant height growth response of slash pine plantations to several silvicultural treatments, relative to standard practice. An existing per-acre basal area prediction model for unthinned plantations that includes average dominant height as a predictor variable, in addition to age and trees per acre, also required an adjustment term to adequately reflect treatment effects on stand basal area growth. No such adjustment appeared to be necessary, to account for different silvicultural practices, to an existing stand level volume prediction model that includes both average dominant height and basal area per acre as predictor variables, in addition to age and trees per acre. For. Sci. 41(3):629-638.
Estimating the Cost of Fuels Treatment
Authors: Rideout Douglas B. , Omi Philip N.
Published: April 2024

We develop a potentially generalizable cost estimation procedure for fuels treatment using the National Park Service (NPS) nationwide database. The NPS database includes records on the projected cost of fuel treatment projects. These records are kept separately for traditional hazard fuel reduction projects and for resource management projects. Resource management projects are intended to implement objectives associated with the enhancement or restoration of ecosystems. Hence, we used resource management projects as a proxy for activities which might be pursued by public land managers in the name of ecosystem management. Our cost estimation procedure focuses on a constant elasticity of declining unit cost with increases in scale. Using multiple regression techniques, we test and confirm the hypotheses that the constant elasticity estimate can be applied to treatments intended to reduce fuel hazards or to treatments preferred for ecosystem management objectives. We also tested and confirm the hypothesis that ecosystem management cost estimates are more uncertain and therefore less precise than those made for the more traditional fuels hazard reduction treatments. We infer that the constant elasticity cost expression for fuels treatment is generalizable because it was found independent of treatment scale, management objective, fuel type, or other physical and economic attributes common to fuels treatments. We identify additional attributes of fuels treatment, including location, fuel type and treatment method that significantly affect cost estimates. For. Sci. 41(4):664-674.
Hurricanes and the Economics of Loblolly Pine Plantations
Authors: Haight Robert G. , Smith William D. , Straka Thomas J.
Published: April 2024

Following a damaging storm, managers of small forest tracts often want to know when to harvest and reforest to maximize financial return. The assessment of financial return is complicated by the need to project the product value of damaged trees and to account for the risk of another damaging storm. Methods are demonstrated for handling both these complications. The effects of stem sweep on product value is projected by incorporating a sweep distribution into a simulator for stand growth and computing stumpage value using a residual value approach in which trees are optimally allocated to product classes based on their stem dimensions. A single-rotation formula for a stand's expected present value (EPV) is derived assuming age-dependent damage risk and salvage proportion. Using information about damage following Hurricane Hugo in South Carolina and risks of storm damage in coastal areas of the southeastern United States, the stand-level economic impacts of several variables are estimated. Results show that age-dependent damage risk and stocking reduction caused by tree mortality have the greatest impact on the relationship between EPV and rotation age. The effects of salvage proportion and stand damage in the form of stem sweep are relatively small. These results highlight the variables that need careful specification in any assessment of the financial return of a damaged stand. For. Sci. 41(4):675-688.
Correlated Observer Errors and their Effects on Survey Estimates of Needle-Leaf Loss
Authors: Gertner George , Köhl Michael
Published: April 2024

In Europe, crown transparency is one of the most important variables assessed for monitoring forest conditions. Though there are very strict international guidelines and intensive training programs for the evaluation of needle-leaf loss, there still exists a subjective component in the evaluation. This subjective component in the observation process can lead to a nonsampling error that can greatly reduce the precision of estimates of average needle-leaf loss. In this paper, methods for quantifying the potential loss in precision are presented and applied to data from the Swiss National Forest Health Monitoring Program. For. Sci. 41(4):758-776.
Point Sampling with Disjunct Support Near Population Boundaries
Authors: Moisen Gretchen G. , Stage Albert R. , Born J. David
Published: April 2024

In inventories that guide land management, point sampling is heavily used to estimate land area occupied by a population, area by condition class, population mean density, and totals of population attributes. Often, for reasons of efficiency or interpretation, the attributes of the principal sample point are described by aggregating information over a group of satellite points arrayed in a geometric pattern around the principal point. This group of data sampling points forms what is called the "support" for the principal point. Problems arise when the principal point is close enough to a population (or subpopulation) boundary for some of the support points to fall outside that boundary. Ad hoc solutions to this problem that involve replacing some or all of the points in the group may introduce bias into the inventory estimates. Unfortunately, procedures that do not replace points introduce bias into estimates of attributes that can be defined only with respect to the configuration and volume of the support. Examples of such attributes include distribution of area by classes of tree density, stocking, species composition, stand structure, and the ecological frequency and constancy of a species. A rule has been developed for reshaping the pattern of support points that resolves the dilemma for single, straight boundaries. Simulations to evaluate the rule show that it produces a uniform density of points with respect to distance from the boundary while maintaining a compact region of support for the principal point. For. Sci. Monogr. 31:62-82.
Chance-Constrained Optimization with Spatially Autocorrelated Forest Yields
Authors: Hof John , Bevers Michael , Pickens James
Published: April 2024

This note investigates the implications of spatially autocorrelated yields on forest management optimization procedures and results. The problem is defined and analyzed conceptually, followed by a simple case example demonstration. It is concluded that spatial arrangements may be quite important in managing risk and uncertainty in forest ecosystems. For. Sci. 42(1):118-123.
Statistical Causation and National Forest Policy in Oregon
Authors: Burton Diana M. , Berck Peter
Published: April 2024

Granger causality tests are used to examine the relationships among macroeconomic variables, harvests, forestry sector employment, and national forest policy in Oregon. Statistical causation is found to run generally from macroeconomic variables to forestry employment, to harvests and to national forest policy. These findings raise questions about the validity of using national forest harvest policy to effect employment and community stability objectives. For. Sci. 42(1):86-92.
Testing a Mechanistic Model for Predicting Stand and Tree Growth
Authors: Korol R. L. , Milner K. S. , Running S. W.
Published: April 2024

Given the uncertainty of future climate regimes, it has become necessary to develop growth and yield models that can respond to potential changes in climate. TREE-BGC, a derivative of the physiological process model FOREST-BGC, was used to simulate the growth of 998 trees in unevenaged stands near Kamloops, B.C. Stand variables were derived from a tree list. The model used a disaggregation logic to allocate stand level estimates of carbon gain and respiration costs to individual trees. Increments in height and diameter were estimated so as to maintain their allometric relation, but scaled to produce an estimate of stem volume equivalent to the carbon allocated to the trees. Mortality was simulated when the maintenance respiration of the tree exceeded the carbon allocated to the tree. Plot level estimates of 20 yr basal area increment and volume increment were highly correlated with actual measurements (r² = 0.94 and 0.96, respectively; n = 24). The cumulative modeled diameter and height distributions were compared to measured distributions. The simulated cumulative diameter and height distributions were not significantly different from the actual cumulative diameter and height distributions for 23 of the 24 plots (α = 0.05). The model was found to have an accuracy of about 0.16 m² ha-1 yr-1 for basal area and 1.51 m³ ha-1 yr-1 for volume (α' = α" = 0.05), averaged over the 20 yr period. Long-term model behavior was influenced by stand density, basal area, and volumes. Stand mortality appeared to emulate the so-called self-thinning rule, and a maximum size-density relationship was found. For. Sci. 42(2):139-153.
The Influence of Environmental Conditions on Tree-Ring Series of Norway Spruce for Different Canopy and Vitality Classes
Authors: Van Den Brakel Jan A. , Visser Hans
Published: April 2024

A dendroecological study of Norway spruce trees was undertaken by Eckstein et al. (1989) as part of an interdisciplinary project investigating the influence of air pollution on tree growth in northern Germany. They analyzed individual trees stratified according to three different canopy classes and three different vitality classes, using response function analysis (Fritts 1976). Eckstein et al. conclude that there is a significant positive correlation between precipitation during the growing season and the tree-ring series, and that the observed forest decline is probably caused by a severe unknown stress factor (but clearly not a climate factor) during the mid-1950s. The use of response functions has the limitation of time invariance and the separated adjustment of trend and climate variables for the tree-ring series. In this article a model is applied for simultaneous adjustment of trend and explanatory variables for tree-ring chronologies. Time-dependent or stochastic response functions are obtained by writing these models in the so-called state-space form and analyzing them with the discrete Kalman filter. Consequences for chronology building are discussed. After analyzing the tree-ring chronologies of the Norway spruce by these more sophisticated methods, it is found that: 1. the stochastic response functions for precipitation during the growing season are principally constant over time and positive, 2. the stochastic response functions for the temperature in February and March are not constant and become significant after the mid-1950s for trees from the classes "not dominant-vital," "not dominant-moderately vital," "dominant-not vital," "moderately dominant-not vital," and "not dominant-not vital," 3. the influence of climate factors on tree-ring development is higher if the vitality and dominance of the trees is lower, 4. addition of an SO2 emission curve as explanatory variable, simultaneously with trend and climate variables for tree-ring chronologies, did not reveal a significant air pollution effect on tree-ring development. For. Sci. 42(2):206-219.
The Standing Skyline: A Maximum Log Load Solution Procedure
Authors: Brown Cameron , Sessions John
Published: April 2024

Many harvesting operations use a standing skyline cable system in steep topography or on fragile soils. We present an efficient algorithm for calculating the maximum log load which can be carried with a standing skyline system, suitable for analyzing situations where the logs are either fully suspended above the ground or partially suspended above the ground. For. Sci. 42(2):220-227.
Stand Characteristics Associated with Mountain Pine Beetle Infestations in Ponderosa Pine
Authors: Olsen W. K. , Schmid J. M. , Mata S. A.
Published: April 2024

Stand characteristics associated with mountain pine beetle (Dendroctonus ponderosae Hopkins), infestations within a 2.15 ac (0.87 ha) plot were analyzed to determine characteristics most strongly correlated with the infestations. Trees per acre, basal area, quadratic mean diameter, minimum diameter, and the range of diameters in MPB infested groups were significantly different from those in noninfested groups. Maximum diameter was not different between infested and noninfested groups. The results are discussed in regard to the mountain pine beetle-host relationship and stand management. For. Sci. 42(3):310-327.
A Stochastic Model for Tree Survival in Stands Affected by Annosum Root Disease
Authors: Preisler Haiganoush K. , Slaughter Garey W.
Published: April 2024

Mortality of trees surrounding pine stumps colonized by Heterobasidion annosum for about 35 years was monitored over a period of 20 yr in 53 eastside pine stands in northern California. The data were used to develop a stochastic model that quantifies effects of tree characteristics and spatial proximities on survival of trees within 12 m of a colonized stump. The model accommodates mortality data collected at irregular intervals. Variables with significant effects on tree survival included trees species, size, and distance of roots from the root of a previously dead tree. Results from stochastic models based on actual data are useful for detecting factors affecting tree survival and for evaluating assumptions of numerical (simulation) models, such as root disease computer models. For. Sci. 43(1):78-86.