bluuebunny/crossref_metadata_2025_split huggingface dataset:
Recovering Tree Heights from Airborne Laser Scanner Data
Authors: Magnussen Steen , Eggermont Paul , LaRiccia Vincent N. 
Published: April 2024

Abstract
Airborne laser scanner data collected over forests provide a canopy height. To obtain tree heights from airborne laser scanner data one needs a recovery model. Two such models, one (A) assuming that observations are sampled with probability proportional to displayed crown area, and the other (B) derived from the probability that a laser beam penetrates to a given canopy depth, were developed and applied to laser scanner data obtained over stands of Douglas-fir. Model estimates of recovered arithmetic mean tree heights and quantiles (75%, 85%, and 95%) were not significantly (P&gt; 0.24) different from ground-based equivalents. An overall mean bias of-3 m in the laser canopy heights was eliminated by both methods. The median absolute difference between observed and predicted plot means and quantiles were reduced by 40 to 60%. Three alternative recovery procedures are presented for model B. For a single plot, the predictions varied significantly among the models and estimation procedures with no consistent pattern. Predictions of arithmetic mean heights were best for plots with no understory, while predictions of upper quantiles were consistent in all plots. For. Sci. 45(3):407-422.
A Comparison of Periodic and Annual Forest Surveys
Authors: Scott Charles T. , Köhl Michael , Schnellbächer Hans Jörg 
Published: April 2024

Abstract
Forest surveys of large areas often are conducted on a periodic basis, every 10 yr, for example. However, periodic assessments can be problematic due to fluctuating budgets and survey results that do not reflect forest dynamics between measurements. As a result, many countries are interested in designing surveys with annual measurements, such as the U.S. Forest Health Monitoring (FHM) Program design. The existing periodic design for Switzerland was compared with four annual designs in which an equal number of plots are observed annually. Data for the comparisons were collected annually on 682 plots over 7 successive yr across Switzerland. Three estimation methods were applied to each design: Continuous Forest Inventory, Sampling with Partial Replacement, and Mixed Estimator. These used simple means, regression updating, and inverse weighting of new and old plots, and regression combined with growth-model projections, respectively. For 12 combinations of 3 attributes, the Regional Survey design was the most cost-effective, followed by the National or Regional Update Survey designs. The Periodic Survey and the National Survey (similar to the FHM design) were the least cost-effective. Sampling with Partial Replacement was the most efficient estimator, though the Mixed Estimator would have been the most efficient had less biased growth projection models been used. For. Sci. 45(3):433-451.
A Timber Extraction Method Based On Pavement Serviceability and Forest Inventory Data
Authors: Martin Audrey , Owende Philip , Ward Shane , O'Mahony Micheal 
Published: April 2024

Abstract
A methodology for integrating pavement classification and forest inventory data to determine the capability of forest access roads with weak subgrades to support timber extraction is described. GPS location data recorded in stand-alone mode was superimposed on forest and Ordnance Survey maps. Within a GIS, the acquired spatial data was manipulated and integrated with pavement attribute information and the current and projected forest inventory data. Potential pavement damage by a typical timber haulage truck with payloads of 22, 27, 30, and 35 tonnes (t) was then assessed. It was found that by overloading the truck by 3 and 8 t (GVW of 43 t and 48 t, respectively), the total volume of timber that could be conveyed without damaging the serviceable pavements reduced by an average of 16 and 44%, respectively. Rerouting of timber to avoid critical and failed sections could significantly increase the transportation costs. Rerouting was found to be impractical where forest compartments were accessible by single routes; hence, necessary repairs to facilitate the extraction are recommended in such cases. The final database could be extended to include specific costing of repair and maintenance requirements, and so determine the economic implications of respective routing strategies. For. Sci. 46(1):76-85.
Neutrality of Forestry Income Taxation and Inheritable Tax Exemptions for Timber Capital
Authors: Uusivuori Jussi 
Published: April 2024

Abstract
This article examines the neutrality of income taxation in the so-called Austrian sector of the economy. By focusing on the forestry sector, it is shown that certain exemption practices of yield taxation can be modified to restore the efficiency of the taxation. Earlier research on the production efficiency relating to different capital income tax systems in the Austrian sector shows that yield taxes based on realized income lead to inefficient allocation of resources between the Austrian and the ordinary sector of the economy when pretax distortions are present. The models used in the earlier tax literature do not, however, differentiate between taxing capital income and taxing the initial capital under an individual occupancy of an asset. In this article, by explicitly separating timber capital taxation from timber capital income taxation, a modified yield taxation scheme is presented, which gradually corrects an initially distorted allocation of resources between forests and other assets in the economy. For. Sci. 46(2):219-228.
Using Numerical Optimization for Specifying Individual-Tree Competition Models
Authors: Miina Jari , Pukkala Timo 
Published: April 2024

Abstract
In this article we present a method that combines maximum likelihood estimation and nonlinear programming in growth modeling. The method of Hooke and Jeeves is used to discover the optimal specification of a particular competition index type, while statistical software is used to fit the regression model with the given competition index type. The log-likelihood computed by the statistical software is fed back to the optimization algorithm, which alters the specification of the competition index type based on the changes in the log-likelihood. This approach was tested for a mixture of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies [L.] Karst.). The characteristics of five different competition index types were optimized. The best model included an index computed from vertical angles formed by a horizontal plane and the tops of competitors. The elevation of the horizontal plane was computed with a species-specific linear regression model using height of the subject tree as the predictor. Pine competitors nearer than 6 m and spruce competitors nearer than 9--10 m were included in the optimal competition index. This study showed that the approach used here is highly efficient. For. Sci. 46(2):277-283.
A Theory of Red Pine (Pinus koraiensis) Management for Both Timber and Commercial Seeds
Authors: Li Chuan-Zhong , Löfgren KarI-Gustaf 
Published: April 2024

Abstract
Red pine (Pinus koraiensis), is a commonly distributed species of tree in northeastern China. The wood is used for manufacturing purposes as usual, and the seeds are used as a source of delicious food and for medical applications. If the top of the tree is removed at a mature age, seed production is much enhanced. In this article, we derive optimal harvesting rules for such multiple use management of red pine trees. We give optimality conditions for cutting off the top of the tree, the intensity of removal, and the optimal date for the final felling. The two harvesting dates will indirectly determine the optimal length of commercial seed production. We also derive comparative static results on how the rotation periods and the intensity of removal changes, as a function of prices and the interest rate. The theory is also applicable to the economic management of seed orchards, where the practice of cutting off the top of the tree is used, all over the world, to induce seed production. For. Sci. 46(2):284-290.
Fostering the Production of Nontimber Services Among Forest Owners with Heterogeneous Objectives
Authors: Kline Jeffrey D. , Alig Ralph J. , Johnson Rebecca L. 
Published: April 2024

Abstract
Programs to enhance nontimber services increasingly focus on nonindustrial private forest (NIPF) owners. These owners are believed to possess multiple objectives, causing them to respond to economic forces and policies in complex and unpredictable ways. We examine NIPF owners in western Oregon and western Washington, using a survey to document their forest ownership objectives and willingness to accept incentive payments to forego harvesting to improve wildlife habitat. An empirical model is developed describing owners' willingness to accept incentive payments to delay harvest, as a function of their forest ownership objectives and socioeconomic characteristics. Mean incentive payments necessary to induce owners to forego harvest are higher for owners possessing primarily timber objectives ($301-314/ha/yr), than for owners possessing both timber and nontimber objectives ($254-257/ha/yr) or primarily recreation objectives ($185-210/ha/yr). An estimated supply curve describing the area of NIPF land on which owners would forego harvesting for 10 yr varies from relatively flat to fairly steep. Although many owners would require little or no incentive to forego harvest, others would require a significant incentive. Nontimber services likely could be enhanced by targeting incentive programs or technical assistance toward NIPF owners possessing nontimber objectives. For. Sci. 46(2):302-311.
Trigonometric Variable-Form Taper Equations for Australian Eucalypts
Authors: Bi Huiquan 
Published: April 2024

Abstract
This article introduces a new variable-form taper model that is stable in specification yet flexible in its ability to fit data for species and trees with different stem forms. The base function is constructed from trigonometric volume-ratio equations following the geometry of a tree stem. The specification for the exponent includes variables for depicting changes in stem form along a stem and variables for taking into account differences in stem form among trees of different sizes. This model is fitted to data from 25 species of Australian eucalypts and is compared with Kozak's taper model to demonstrate its characteristics: stability in specification, flexibility in fitting data for species and trees with varying stem forms and accurate predictions of taper and merchantable height. FOR. SCI. 46(3): 397–409.
Genotypic Stability and Genetic Parameters for Growth and Biomass Traits in a Water × Temperature Factorial Experiment with Pinus sylvestris L. Seedlings
Authors: Sonesson Johan , Eriksson Gösta 
Published: April 2024

Abstract
The objective of this experiment was to study genotypic stability for growth and biomass traits recorded in treatments with optimal and limiting water availability at two different temperatures and to study how the different growth environments affected genetic parameter estimates. Open-pollinated families of Scots pine (Pinus sylvestris L.) were collected in 2 seed orchards with 28 and 35 families respectively and cultivated for 1 growth period in a growth chamber. Heritability estimates were generally moderate–high (h2 = 0.3–0.8) for growth traits in individual treatments. Joint analyses of all treatments revealed significant family × temperature and family × temperature × water regime interactions. Family × water regime interaction and family effects were not significant. The results indicate low adaptation to water availability and a higher adaptation to different temperatures in the two Swedish Pinus sylvestris populations. If we assume that our results hold for a large part of the rotation the G × E interactions imply that climate change can alter the ranking of clones in a breeding program and thus decrease genetic gain. Studies of family ecovalence values showed that a minority of families (4–31%) contributed significantly to the interactions. Selection for stability could be a possible way to reduce the negative effects of G × E interaction. FOR. SCI. 46(4):487–495.
Measuring the Performance Improvement of Taiwan Forests after Reorganization
Authors: Kao Chiang 
Published: April 2024

Abstract
The data envelopment analysis (DEA) approach has been widely applied to measure the relative efficiencies of decision making units (DMUs) for a time period. This article measures the performance improvement of a DMU at two time points by using the DEA approach. Two ideas are proposed. One is to treat one DMU at two time points as two different DMUs, and the ratio of the efficiency scores of a DMU at two time points serves as a measure of the efficiency improvement. The other is to calculate the Malmquist productivity index of a DMU to represent its productivity improvement. Both the efficiency ratio and the productivity index can be decomposed into the technical part and the scale part. From the data of the eight forest districts of Taiwan compiled in 1989 and 1992, the efficiency and productivity improvement in these two periods are measured. The results of the two methods are consistent in that both indicate a slight improvement in performance. FOR. SCI. 46(4):577–584.
The Effects of Ozone on a Lower Slope Forest of the Great Smoky Mountain National Park: Simulations Linking an Individual Tree Model to a Stand Model
Authors: Weinstein D.A. , Gollands B. , Retzlaff W.A. 
Published: April 2024

Abstract
We used an individual tree physiology model, TREGRO, and a stand succession model, ZELIG, to extrapolate from the direct response of leaf photosynthesis to ozone exposure in individual plants to an estimate of the possible future ozone effects on a forest located in the Twin Creeks region in Great Smoky Mountains National Park (GSMNP). This forest is dominated by yellow-poplar (Liriodendron tulipifera L.). With TREGRO, we estimated whether the reduction in the supply of carbon caused by ozone exposure would prevent an individual tree from meeting its demands for carbon for growth. With ZELIG, we analyzed the effect that changes in individual tree growth have in altering the ability of trees to successfully compete during forest succession. Current ambient levels of ozone measured at mid-elevations on the west side of GSMNP were predicted to reduce the abundance of yellow-poplar by 10% over the next 100 yr. This reduction would accelerate declines that are expected because of natural successional change. An increase of ozone of 50% above current ambient conditions was predicted to decrease yellow-poplar abundance by 30%. A reduction of ozone to halfambient levels was insufficient to prevent yellow-poplar abundance decreases. Increases in abundance in two other canopy dominants, red maple (Acer rubrum L.) and black cherry (Prunus serotina Ehrh.) were predicted from the release from competition as yellow-poplar was suppressed by ozone exposure. These increases, however, were predicted to be short-lived, with large decreases of up to 30% eventually occurring for both species. Overall basal area of the forest was predicted to be relatively unchanged by ozone exposure. FOR. Sci. 47(1)29–42.
Estimation of Mean Annual Temperature from Leaf and Wood Physiognomy
Authors: Wiemann Michael C. , Dilcher David L. , Manchester Steven R. 
Published: April 2024

Abstract
There are distinct relationships among the anatomy of wood, the morphology of leaves, and the climate in which woody plants are growing. The relationships between leaf morphological characters and climate have been known for many years, but wood characters as climate indicators are less well studied. In this article, we use measurements of wood anatomy and leaf morphology from woody dicotyledonous plants, growing in Florida and Connecticut, to determine the accuracy to which statistical models can predict climate. The strength of the relationship between climate and physiognomy is important because it allows us to evaluate the phenotypic plasticity that woody plants express under various climates. In this study we use canonical correspondence and regression models to examine how precisely wood anatomical and leaf morphological characters are related to climate. For leaves, canonical correspondence analysis (CCA) using 31 characters gave the closest estimate of mean annual temperature (MAT) in Connecticut, whereas a regression equation using only a single leaf character (leaf margins with no teeth) as predictor gave the closest estimate in Florida. For wood, CCA using 13 wood characters gave the closest estimate in Florida, whereas a regression equation using only a single wood character (the occurrence of vessels smaller than 100 μm) gave the closest estimate in Connecticut. CCA showed that, although MAT has a smooth and continuous relationship with leaf physiognomy, this is not the case for wood. Temperate woods form a different physiognomic population than subtropical and tropical woods, in which the physiognomy of temperate woods is more strongly influenced by MAT than is the physiognomy of subtropical and tropical woods. FOR. SCI. 47(2):141–149.
Designing an Evolution Program for Solving Integer Forest Management Scheduling Models: An Application in Portugal
Authors: Falcão André O. , Borges José G. 
Published: April 2024

Abstract
In this article, basic concepts of both genetic algorithms and evolution program design are presented. An evolution program is presented to solve a Model I harvest scheduling problem with 0-1 decision variables for the management alternatives for each stand, with annual constraints on harvested volume. An appropriate data structure (i.e., chromosome representation) is presented, as well as modified selection, crossover, and mutation strategies specially designed for application to large forest scheduling problems. Emphasis is on designing an efficient evolution program to address the complexity of large integer problem model solving and to provide both strategic and operational guidance to forest managers. A new stopping criterion for this iterative heuristic based on the asymptotic behavior of the evolution process is further presented. The new evolution program is applied to a two-product timber harvest scheduling problem in Portugal with a temporal horizon extending to seventy 1 yr periods. Results from 50 test computer runs are discussed for application to this large problem encompassing approximately 122,000 binary integer variables and 1,000 constraints. Statistic analysis of the convergence process suggests that the evolution program may seek optimal solutions at reasonable computational cost. Results thus suggest that evolutionary techniques may be used to confront the complexity of integer forest management scheduling model solving. FOR. SCI. 47(2):158–168.
Using the Branch and Bound Algorithm to Solve Forest Planning Problems with Adjacency Constraints
Authors: McDill Marc E. , Braze Janis 
Published: April 2024

Abstract
This article describes an assessment of the branch and bound algorithm (BBA) for solving forest management planning problems with adjacency constraints. Four questions are addressed: (1) What are the current limits of off-the-shelf optimization software implementing the BBA in terms of types and sizes of problems that can be solved within a reasonable time? (2) To what degree can larger problems be solved if the solution tolerance gap is increased from the default 0.01%? (3) How much can solution times be reduced by increasing the tolerance gap? and (4) If the algorithm is stopped at a larger tolerance gap, how large is the true gap likely to be? To address these questions, 2,676 hypothetical, spatially explicit forest management problems with three planning periods and between 50 and 2,500 management units were created and then solved with CPLEX® Version 6.5 to tolerance gaps of 0.01%, 0.1%, 1%, or 2%. For forests with immature or regulated age–class distributions, the predicted average solution time to a tolerance gap of 0.01% was 7.6 and 17.4 min, respectively, for problems with 2,500 management units—the largest problems solved in this study. For overmature and old-growth forest problems, predicted average solution times to a 0.01% tolerance gap reached 4 hr at about 640 and 213 management units, respectively. Increasing the tolerance gap to 1% increased these limits to 1,420 and 235 units, respectively. Increasing the tolerance gap to 1% reduced solution times by at least 90% in 49% of the overmature forest cases and in 53% of the old-growth forest cases. In overmature and old-growth forest problems, the true gap averaged 0.28% and 0.41%, respectively, when the reported gap was 1%. For. Sci. 47(3):403–418.
The Effects of Legal Limits and Recommendations on Timber Production: The Case of Finland
Authors: Hyytiäinen Kari , Tahvonen Olli 
Published: April 2024

Abstract
One form of legislative regulation on private forestry does not allow a stand to be clearcut until it exceeds a certain average diameter or age. This study examines whether this type of regulation used in Finland, for example, constrains the optimal timber harvesting of various site types of Norway spruce and Scots pine cultures. Applying a Faustmann type of rotation model, well-established growth and yield data and economic time series, we find that the regulations constrain the optimal solution if the rate of interest exceeds 3% or 5% for Scots pine and Norway spruce stands, respectively. They turn out to be more binding, the lower the growth capacity of the stand. Especially for mature stands, the regulations may cause major economic losses. The regulations increase long-term sawlog production but decrease pulpwood production in comparison to the unconstrained optimum. Moreover, the regulations change the structure and reduce the level of costs, and may then reduce working opportunities in forestry. FOR. SCI. 47(4):443–454.
Combining Forest-Level Analysis with Options Valuation Approach—A New Framework for Assessing Forestry Investment
Authors: Yin Runsheng 
Published: April 2024

Abstract
The conventional forest investment assessment at the stand level has difficulty dealing with multiple decisions and capturing the operational flexibility involved in timber production. By combining forest-level analysis with the options valuation approach, this article suggests a new framework for forestry investment assessment. We first articulate the new framework and discuss a few technical issues encountered in adopting it. Then, we present three empirical examples (entry decision, land acquisition, and harvest timing) to illustrate how forest-level analysis and/or real options valuation can be done and what we may learn from this type of exercise. We believe that while adopting this new framework entails challenges, it represents a great opportunity to expand the field of forest investment assessment. FOR. SCI. 47(4):475–483.