bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impacts of Timber Harvesting on Soil Organic Matter, Nitrogen, Productivity, and Health of Inland Northwest Forests
Authors: Jurgensen M. F. , Harvey A. E. , Graham R. T. , Page-Dumroese D. S. , Tonn J. R. , Larsen M. J. , Jain T. B. 
Published: April 2024

Abstract
Soil organic components are important factors in the health and productivity of Inland Northwest forests. Timber harvesting and extensive site preparation (piling, windrowing, or scalping) reduces the amount of surface organic material (woody residues and forest floor layers) over large areas. Some wildfires and severe prescribed burns can have similar consequences. Such organic matter reductions can have important implications for soil chemical, biological and physical properties. A number of studies have linked substantial reduction in mycorrhizae development and tree growth to high levels of soil disturbance, or removal of organic horizons. Timber harvesting also removes a large percentage of coarse woody debris, which has unknown ramifications on soil productivity. Current woody residue guidelines in this region recommend leaving &lt;10 to 125 Mg ha-1 on site to replace woody materials lost during harvesting operations. Large amounts of soil nitrogen (&gt;500 kg ha-1) can also be lost from timber harvesting and site preparation, especially when using prescribed fire. The time required to replace this lost nitrogen may range from &lt;10 to &gt;275 yr, and depends on the severity of site treatments, presence or absence of nitrogen-fixing plants, and amounts of atmospheric deposition. Maintaining adequate amounts of organic matter on some forest sites in the Inland Northwest may temporarily increase the risk of wildfire or favor the activity of certain insects or disease fungi. However, carefully planned prescribed burns and mechanical site preparation can be practiced on most sites with relatively low impacts on soil organic levels, while accomplishing the important forest management objectives of fuel reduction, seedbed preparation, and reducing competing vegetation. Organic matter management will be the most difficult on very dry sites, with their historically low soil organic and nitrogen content, and high fire potential. The maintenance of adequate soil organic matter levels is critical for sustaining forest health and productivity under the variable moisture and temperature conditions of this region. Thus, soil organic components will become more important in the future as ecosystem management systems are developed for western forests. For. Sci. 43(2):234-251.
Comparative Plant Water Relations and Soil Water Depletion Patterns of Three Seral Shrub Species on Forest Sites in Southwestern Oregon
Authors: Conard Susan G. , Sparks Steven R. , Regelbrugge Jon C. 
Published: April 2024

Abstract
We compared stomatal conductance, transpiration, plant water potential, and soil moisture depletion patterns for three shrub species common on early seral forest sites in southwestern Oregon following logging or fire. Our goal was to determine which of these species were more likely to be the strongest competitors with regenerating conifers. The three species, Arctostaphylos patula Greene, Ceanothus sanguineus Pursh., and Holodiscus discolor (Pursh.) Maxim., were selected to represent a range in leaf morphology and expected water use patterns. Diurnal patterns of leaf conductance, plant water potential, and environmental parameters were measured throughout the growing season, along with seasonal patterns in soil moisture. As with any data obtained under ambient field conditions, environmental parameters and exact timing of measurements varied among shrubs. To better evaluate the response of individual species to common environmental parameters, we constructed models of leaf conductance based on field data and used these models to estimate responses of conductance and transpiration to averaged environmental conditions. This allowed us to better compare species responses to seasonal and diurnal trends in environmental variables. C. sanguineus typically had the highest transpiration rates per unit leaf area, and H. discolor the lowest; however, due to much higher leaf area indices of H. discolor, the two species depleted soil moisture at about the same rate. C. sanguineus and A. patula both had high predawn water potentials throughout the season, even when soil water potential at 1 m depth was less than -1.2 Mpa, suggesting that these species, but not H. discolor, had roots in deeper soil layers. We predict that the two deciduous species, C. sanguineus and H. discolor, will be stronger competitors for soil moisture than A. patula, at least in the top meter of soil. In contrast, A. patula and C. sanguineus are capable of depleting moisture from deeper in the soil and may therefore strongly compete even with deep-rooted conifers late in the season. Our use of empirical models allowed us to compare species responses to common environmental conditions, which facilitated ecological interpretation of species differences in water use patterns. By early August, soil water potentials under all species were low enough to significantly inhibit conifer transpiration, photosynthesis, and growth. For. Sci. 43(3):336-347.
Growth and Physiological Responses of Young Loblolly Pine Stands to Thinning
Authors: Peterson J. A. , Seiler J. R. , Nowak J. , Ginn S. E. , Kreh R. E. 
Published: April 2024

Abstract
Although yield responses to thinning in loblolly pine have been well documented, short- and long-term morphological and physiological changes are largely unknown. To investigate these responses, three 8-yr-old, 0.2024 ha replicate stands of loblolly pine were thinned by 50% in May 1988, and bole growth and morphological changes in the crown were measured annually for the next 6 yr. In situ gas exchange measurements were monitored in the upper and lower third of the crowns monthly during the third through sixth growing seasons following thinning. First- and second-year physiological responses to thinning have been reported earlier (Ginn et al. 1991). Thinning slowed live crown recession and increased crown diameters resulting in increased photosynthetic surface area per tree. Over the 6 yr study period, the crown diameters of thinned trees increased 82% while the crown diameters of control trees increased only 20%. Larger bole diameters were observed for thinned trees four growing seasons after thinning. Photosynthetic rate and needle conductance did not increase overall, but were increased in the lower crown foliage of thinned trees. Needle dark respiration was higher in thinned stands in both the upper and lower crowns. Increased bole diameter growth is likely the result of the large increases in foliar biomass as well as initially higher physiological activity in the lower crowns of thinned stands. For. Sci. 43(4):529-534.
A Longitudinal Analysis of Height/Diameter Curves
Authors: Lappi Juha 
Published: April 2024

Abstract
The paper describes a simultaneous statistical analysis of height/diameter curves in data consisting of several temporal and permanent plots. Two jack pine data sets, one from planted stands and the other from naturally regenerated stands, were analyzed using the same model structure. Parameters of a logarithmic height/diameter curve at a given age in a given stand were decomposed into a trend (an age-dependent population mean), a random stand effect, and a random time effect. The deviation of an observed height from the stand and age specific height/diameter curve was decomposed into a random tree effect and a random residual error which have nonhomogeneous variances. Trend functions for the parameters of the height/diameter curve were estimated using least squares estimates of parameters as dependent variables (generalized least squares would lead to inconsistent estimates). The trend equations describe most of the variation in the height curve parameters. Other stand variables (in addition to age) can explain the variation further, but development over time cannot then be predicted. A less stable description of the height/diameter curves is obtained in terms of dominant height. In applications, height/diameter curves can be calibrated by predicting the random stand and time effects using any combination of height measurements. A simultaneously estimated set of curves will be logical also when there are so few measurements that ordinary least squares curves show erratic fluctuations. For. Sci. 43(4):555-570.
Modeling the Dynamics and Species Composition of a Tropical Mixed-Species Uneven-Aged Natural Forest: Effects of Alternative Cutting Regimes
Authors: Favrichon Vincent 
Published: April 2024

Abstract
Sustainable tropical rain forest management is currently the subject of strong interest. There are only a few experimental stations available to research the impact of forest management (especially logging practices) on stand growth. This study develops a quantitative model to describe and simulate the dynamics of an undisturbed stand, as well as a logged uneven-aged, multispecies stand in French Guiana. This is a management-oriented matrix model. It takes into account three main characteristics of the forest dynamics in this type of ecosystem. First, we estimated density-dependence by nonlinear regression of the dynamics parameters (growth, mortality, and ingrowth). Second, a site effect is introduced on the assumption that the stand density in a natural stand is an approximate site characteristic and may help define the steady state corresponding to undisturbed conditions. Third, the very high species diversity is reduced by combining species into five groups based on growth behavior with reference to shade tolerance and maximum potential size. The model has been validated with short-term as well as medium-term projections. It was used to assess the stability of such a stand. We also evaluated the biological sustainability of logging practices, that is, the ability to return to the steady state in terms of total density as well as species composition. For. Sci. 44(1):113-124.
Effects of Plant Growth-Promoting Rhizobacteria on Loblolly and Slash Pine Seedlings
Authors: Enebak S. A. , Wei G. , Kloepper J. W. 
Published: April 2024

Abstract
Loblolly and slash pine seed were inoculated at sowing with 1 of 12 different strains of plant growth-promoting rhizobacteria (PGPR) in the greenhouse. Time to germination and seedling densities were determined at 21 days, and seedling biomass was measured at 12 wk after sowing. All bacterial strains significantly increased the speed of seedling emergence over nontreated pine seed. By 12 wk, however, no differences in stand densities were observed between bacteria-treated and nontreated seed for either pine species. Postemergence damping-off was reduced in loblolly pine when seed was treated with 3 of the 12 bacterial strains; however, postemergence damping-off on slash pine seedlings was not affected by rhizobacteria. Treatment with rhizobacteria had a significant positive and negative effect on seedling growth and biomass, which depended on tree species. Loblolly pine shoot and root lengths, as well as the above- and belowground biomass, were significantly reduced when seeds were treated with strains BS1 and BS2. In contrast, loblolly pine seeds treated with strains BS3, PM2, and INR7 significantly increased the below ground biomass of the seedling root systems. Slash pine seedlings had similar interactions with the bacterial strains. Strain BS1 significantly reduced shoot lengths compared with nontreated seeds, while strains 90-166, INR7, and SE49 increased shoot biomass. Slash pine root lengths and biomass were also reduced when treated with strains BS1 and BS2. Unlike loblolly pine, no bacterial strain increased slash pine root length or biomass. This study suggests that the effects of rhizobacteria inoculation on seedling emergence and plant growth are independent and that the effects are species specific. For. Sci. 44(1):139-144.
Measuring Softwood Lumber Value: A Conjoint Analysis Approach
Authors: Reddy Vijay S. , Bush Robert J. 
Published: April 2024

Abstract
Conjoint analysis was used to determine softwood lumber value perceptions among buyers of wood for preservative treatment and to determine trade-offs between lumber attributes and price. Utility functions for each lumber attribute and a model to estimate overall lumber value were developed. Wane was found to be the most important attribute in the evaluation of lumber value, followed by price, accuracy of grading, damage to the lumber package, lumber straightness, and lumber moisture content (in that order). Utility scores of individual respondents and simulation techniques were used to quantify trade-offs between quality and price. Buyers of softwood lumber for preservative treatment were found to be willing to pay a higher price to obtain wane-free lumber. The results of the study provide guidelines for softwood lumber suppliers seeking to differentiate their product while maximizing customer-perceived product value. For. Sci. 44(1):145-157.
Canopy Dynamics, Light Interception, and Radiation Use Efficiency of Selected Loblolly Pine Families
Authors: McCrady R. L. , Jokela E. J. 
Published: April 2024

Abstract
Needlefall, aboveground net primary production (ANPP), canopy light interception and attenuation, and "radiation use efficiency" of five open-pollinated loblolly pine (Pinus taeda L.) families were investigated using 100-tree family block plots near Summerville, SC. Family variation in annual needlefall amounts was significant during the fourth (from 4796 to 6191 kg ha-1) and fifth growing seasons (from 4717 to 5721 kg ha-1); needlefall patterns for the poorest performing family were asynchronous from those of the others, with notably higher needlefall rates from April to July. Estimates of ANPP at age 4 yr varied by 16% (from 32.9 to 38.2 Mg ha-1) among families, and were generally commensurate with progeny test rankings based on height growth. The relationship between ANPP and leaf area index (LAI) was both significant and curvilinear, with an apparent optimum level of production (42.6 Mg ha-1) achieved at a LAI of about 13 (all-sided; February). The least productive families had the lowest mean LAI (e.g., 7.9), while the most productive families generally had higher levels of LAI (e.g., 13.6). Significant family differences in canopy light interception were present in every month sampled except June, when photosynthetically active radiation (PAR) interception exceeded 90% for all families. Light extinction coefficients (k) for February differed significantly among the five families, and ranged from 0.28 to 0.38; families with the largest LAIs generally had the lowest values of k and the highest levels of PAR interception. A strong linear relationship (r² = 0.74) was found between ANPP and intercepted PAR. Estimates of the dry matter:radiation quotient (ε "radiation use efficiency") differed significantly among families, and ranged from 1.33 g MJ-1 to 1.48 g MJ-1. Results of this study suggest that fundamental differences exist in production ecology among loblolly pine families, and that canopy-level characteristics such as LAI, PAR interception, and "radiation use efficiency" are important in conferring differential family performance. For. Sci. 44(1):64-72.
Ensuring the Compatibility of Aquatic Habitat and Commodity Production Goals in Eastern Oregon with a Tabu Search Procedure
Authors: Bettinger Pete , Sessions John , Johnson K. Norman 
Published: April 2024

Abstract
We present a land management scheduling model for ensuring the compatibility of aquatic habitat quality and commodity production goals in forest management. This model uses Tabu search procedures to select feasible land management activities (timber harvesting and road system management) subject to an even-flow constraint and aquatic habitat quality goals, as represented by stream sediment and temperature indices. The methodology for evaluating the effects of land management activities on the realization of aquatic habitat goals utilizes established procedures, yet makes evaluations with each incremental decision choice. We apply the procedures to a 5,926 ha case study watershed in eastern Oregon to evaluate the performance. For comparison, a global optimum solution is estimated using extreme value theory techniques. Results show that all solutions are spatially and temporally feasible with respect to stream sediment and temperature index goals. Eighty percent of solutions had net present values within 10% of an estimated optimal solution. Further, out of 20 independent runs, one was within 2% of an estimated global optimum, and all 20 were within 15% of the estimated global optimum. While improvements to the model can be made, we have demonstrated that moderately complex aquatic habitat quality evaluation techniques, with spatial elements, can be nested inside a land management scheduling model. For. Sci. 44(1):96-112.
Variation in Selected Wood Properties of Vochysia Guatemalensis from Four Sites in Costa Rica
Authors: Gonzalez J. Eugenio , Fisher Richard F. 
Published: April 2024

Abstract
Vochysia guatemalensis D. Smith is distributed naturally from Mexico to Panama. It is a promising species for commercial reforestation on degraded lands, but little is known about the variation in important wood traits. Trees of this species were sampled in four natural stands to estimate the variation and radial gradients in wood specific gravity, fiber length, vessel density and vessel radial diameter. Increment cores were extracted from each tree at breast height and divided into 1 cm segments from pith to bark. Specific gravity was determined for each segment. The same wood cores were macerated for measuring fiber length. Vessel density and vessel radial diameter were measured for each segment from cross sections. Significant differences were found among sites (P &lt; 0.05) for specific gravity and fiber length. Both of these variables also increased from pith to bark at all sites, and these radial gradients were significantly different among sites (P &lt; 0.05). Vessel density was also significantly different among sites, but there was no significant change from pith to bark. No significant differences were detected among sites for mean vessel radial diameter; however, radial change in vessel diameter was significantly different among sites. For. Sci. 44(2):185-191.
The Role of Mycorrhizae, Site Preparation, and Organic Amendment in the Afforestation of a Semi-Arid Mediterranean Site with Pinus halepensis
Authors: Querejeta José I. , Roldán Antonio , Albaladejo Juan , Castillo Victor 
Published: April 2024

Abstract
A factorial field experiment was conducted in a degraded semi-arid site of southeastern Spain to test the effectiveness of mycorrhization and several soil preparation techniques on afforestation with Pinus halepensis. The mycorrhizal treatments were nursery inoculation with Pisolithus arhizus and forest soil addition to the planting holes. The soil preparation treatments were terracing(mechanical and manual) and the addition of an organic amendment (urban solid refuse). One year after planting, the study revealed significant differences in mycorrhization levels, frequency of mycorrhizal species, fine root production and growth between the inoculated seedlings and the noninoculated controls. Inoculation with P. arhizus gave better pine growth and mycorrhization rates than the addition of forest soil. Both mycorrhization treatments were particularly effective in combination with mechanical terracing. The organic amendment had no apparent negative influence on the mycorrhization level of the seedlings and significantly improved pine growth. The beneficial effects of mycorrhization treatments on P. halepensis growth persisted 2 yr after planting. The increase in growth of the seedlings due to the treatments could be attributed to the change in soil conditions (increased fertility and soil aeration) and probably to a mycorrhization effect on water relations, although it has not been clearly demonstrated. FOR. Sci. 43(2):203-211.
Adapting Distance-Independent Forest Growth Models to Represent Spatial Variability: Effects of Sampling Design on Model Coefficients
Authors: Stage Albert R. , Wykoff William R. 
Published: April 2024

Abstract
If sampling variability of competition variables can be accommodated, a distance independent growth model can (1) simulate patchy stands inventoried by a grid of sampling locations; (2) prescribe treatments for each location; and (3) update inventories using plot sizes differing from those used in model calibration. Ignoring sampling properties of competition biases estimates of stand development and management responses. Our solution to reduce this bias has three steps: First, we model the sampling properties of the competition estimates depending on plot sizes and on spatial patterns. Then we use the modeled error variances when estimating parameters of the structural relation of growth to competition. Finally, we join these two products in a Structural Based Prediction (SBP) procedure that dynamically modifies coefficients during simulation. SBP increases sensitivity to spatial variation and permits valid analyses of location-specific prescriptions for varying inventory designs.
In a model of diameter change for individual Pseudostuga menziesii var. glauca (Beissn.) Franco, coefficients of the competition variables estimated under the structural model were three times as large as when estimated under an ordinary least-squares criterion. This increase reduced sensitivity to crown ratio. Two variants of the Prognosis Model for Stand Development were constructed to compare behavioral changes: (1) using SBP, and (2) using the OLS-based coefficient estimates of the same diameter-growth submodel. Projections with the two variants differed in the internal structures of both uniform and irregular stands and using several sampling methods. Stand averages of volume growth were similar for uniform stands-either from uniform regeneration or from uniformity created by thinning patchy stands. However, the thinning response in patchy stands differed between the two variants. Analysis of the variance model showed little sensitivity within the range of half to twice the Poisson-based estimates of competition variance. For. Sci. 44(2):224-238.
Efficiency Implications of Silvicultural Expenditures from Separating Ownership and Management on Forest Lands
Authors: Luckert Martin K. 
Published: April 2024

Abstract
In pursuing silvicultural goals on licensed public lands, governments worldwide have adopted various policy instruments including contractual requirements, the reimbursement of silvicultural costs, and investment incentives in the form of shares in the value of timber crops resulting from voluntary silvicultural activities. Monte Carlo simulations are used to investigate the efficiency implications of alternative silvicultural policy options. Results indicate that current policies, dominated by requirements and reimbursements with uncertain costs, may create significantly less wealth than policies that include some share of future timber crops. Means of granting shares include reimbursing tenure holders according to the present value of the future benefits created by their expenditures or by sharecropping arrangements. Such policies could potentially provide tenure holders with incentives to efficiently invest in silvicultural activities, by alleviating tenure insecurity while correcting for market failures. For. Sci. 44(3):365-378.