bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Estimator of Prediction Error Variance for Projection Equations
Authors: Ni Chengcai , Zhang Lianjun 
Published: April 2024

Abstract
An estimator of prediction error variance for projection equations was derived using the first-order Taylor expansion in this study. The estimator, a modified estimator of the prediction error variance for a population mean regression model, was adapted for situations in which projection equations are applied to unsampled individuals. The estimator accounted for the errors associated with the response variable on the right side of a projection equation, as well as the errors associated with parameter estimation and serial correlations in data. The application of the estimator was demonstrated using the example of 140 trees with diameters measured annually from age 5 to 19. The results indicated that the estimator represented prediction error variance well and was useful for constructing prediction intervals for a given projection equation and providing information on the contributions of the variance components associated with different error sources. It was evident that the error associated with the prior observation of the response variable of a projection equation had an important impact on model predictions for forward projections. Overlooking this variance component may result in significant misestimation for the prediction errors of the projection equation.
Cogongrass (Imperata cylindrica), an Alien Invasive Grass, Reduces Survival and Productivity of an Establishing Pine Forest
Authors: Daneshgar Pedram , Jose Shibu , Collins Alexandra , Ramsey Craig 
Published: April 2024

Abstract
A 27-month-long study was conducted to compare the impacts of Imperata cylindrica (L.) (Beauv.) and native vegetation competition on the productivity of Pinus taeda (L.) seedlings. In March 2003, 1-year-old pine seedlings were planted in the following treatments: vegetation free (VF), native competition (NC), and I. cylindrica (IC) competition. At the end of the study, only 26% of the IC seedlings survived, half of what was observed in the NC treatment. The IC seedlings had significantly smaller root collar diameter than the NC seedlings (P &lt; 0.0001) after the first growing season and by the end of the third growing season the height and stem volume index were significantly less as well (P &lt; 0.0001). After one full growing season, the NC and IC pine seedlings had 21 and 11.5% of the total biomass of the VF seedlings, respectively. After three growing seasons, the IC pine seedling total biomass was 2.4% of that of the VF seedlings and 18% of that of the NC seedlings (P &lt; 0.0001). The greatest difference was in the pine needle biomass with the IC pine needle biomass being only 11% of that of the NC. During the first growing season, the IC pine seedlings maintained the lowest levels of light-saturated net photosynthesis and stomatal conductance. These results may be explained by reduced amounts of foliar nitrogen and water stress that result from I. cylindrica competition. The pines in the IC treatment had the lowest total foliar surface area and the lowest specific leaf area, which may explain the reduced productivity. Evidence from this study suggests that I. cylindrica competition significantly reduces the productivity and growth of P. taeda seedlings compared with that from native vegetation.
Estimation of Genetic-Gain Multipliers for Modeling Douglas-Fir Height and Diameter Growth
Authors: Gould Peter , Johnson Randy , Marshall David , Johnson Greg 
Published: April 2024

Abstract
Methods were developed to calculate genetic-gain multipliers for use in individual-tree models that predict periodic height and diameter growth of coast Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) in the Pacific Northwest. Genetic-gain multipliers are used in growth models that are typically based on extensive measurements of unimproved or “woods-run” stands, to adjust for the increased growth of stands generated from improved seedlots. First-generation progeny test data from multiple breeding zones in the Northwest Tree Improvement Cooperative were used. Data sets included initial heights and diameters and 5-year growth increments for 10- and 15-year-old trees that were identified by open-pollinated families. Nonlinear mixed-effect models were initially developed to predict the average growth of trees in all families, which, taken together, represented woods-run populations. Phenotypic differences in growth rates were then calculated at the family level. Differences among families in height and diameter growth rates were examined using methods from quantitative genetics and raw phenotypic values. Because gain in total height and diameter at age 10 years is currently the most widely available genetic information for improved Douglas-fir, equations were developed to predict genetic-gain multipliers from family breeding values for these traits. A verification procedure illustrated how incorporating multipliers in growth projections could reduce the mean-square error of predicted growth of selected families.
Regional Applicability of Forest Height and Aboveground Biomass Models for the Geoscience Laser Altimeter System
Authors: Pflugmacher Dirk , Cohen Warren , Kennedy Robert , Lefsky Michael 
Published: April 2024

Abstract
Accurate estimates of forest aboveground biomass are needed to reduce uncertainties in global and regional terrestrial carbon fluxes. In this study we investigated the utility of the Geoscience Laser Altimeter System (GLAS) onboard the Ice, Cloud and land Elevation Satellite for large-scale biomass inventories. GLAS is the first spaceborne lidar sensor that will provide global estimates of forest height. We compared accuracy and regional variability of GLAS height estimates with data from the US Forest Service Inventory and Analysis (FIA) program and found that current GLAS algorithms provided generally accurate estimates of height. GLAS heights were on average 2–3 m lower than FIA estimates. To translate GLAS-estimated heights into forest biomass will require general allometric equations. Analysis of the regional variability of forest height-biomass relationships using FIA field data indicates that general nonspecies specific equations are applicable without a significant loss of prediction accuracy. We developed biomass models from FIA data and applied them to the GLAS-estimated heights. Regional estimates of forest biomass from GLAS differed between 39.7 and 58.2 Mg ha−1 compared with FIA.
A Review of Forest Succession Models and Their Suitability for Forest Management Planning
Authors: Taylor Anthony R. , Chen Han Y. H. , VanDamme Laird 
Published: April 2024

Abstract
Successful implementation of ecosystem management requires strategic forest management planning, including the ability to forecast future forest composition. With advances in ecological modeling, many forms of succession models are available. In this review, we provide a broad synthesis of the methods used to model forest succession and discuss their suitability for strategic forest management planning. Qualitative models underpin theoretical understanding of forest succession but require expression in more formal quantitative forms to be applicable to strategic planning. Quantitative modeling methods can be differentiated as empirical or mechanistic. Empirical models rely on observational data of successional change. Mechanistic models rely on knowledge of underlying ecological processes to simulate succession. Hybrid mechanistic models represent a compromise in ecological modeling between empirical robustness and theoretical understanding. With their increased flexibility for scenario planning and enhanced representation of ecosystem processes, hybrid models are well suited to addressing the multiple environmental and social factors increasingly being considered under ecosystem management. However, empirical models still remain a suitable and practical alternative because hybrid models require increased resources to initialize, operate, and interpret; emphasize understanding rather than prediction; and assume that the modeled processes they represent are adequately understood.
Estimating Current Forest Attributes from Paneled Inventory Data Using Plot-Level Imputation: A Study from the Pacific Northwest
Authors: Eskelson Bianca N.I. , Temesgen Hailemariam , Barrett Tara M. 
Published: April 2024

Abstract
Information on current forest condition is essential to assess and characterize resources and to support resource management and policy decisions. The 1998 Farm Bill mandates the US Forest Service to conduct annual inventories to provide annual updates of each state's forest. In annual inventories, the sample size of 1 year (panel) is only a portion of the full sample and therefore the precision of the estimations for any given year is low. To achieve higher precision, the Forest Inventory and Analysis program uses a moving average (MA), which combines the data of multiple panels, as default estimator. The MA can result in biased estimates of current conditions and alternative methods are sought. Alternatives to MA have not yet been explored in the Pacific Northwest. Data from Oregon and Washington national forests were used to examine a weighted moving average (WMA) and three imputation approaches: most similar neighbor, gradient nearest neighbor, and randomForest (RF). Using the most recent measurements of the variables of interest as ancillary variables, RF provided almost unbiased estimates that were comparable to those of the MA and WMA estimators in terms of root mean square error.
Sources of Variation in the Self-Thinning Boundary Line for Three Species with Varying Levels of Shade Tolerance
Authors: Weiskittel Aaron , Gould Peter , Temesgen Hailemariam 
Published: April 2024

Abstract
The species self-thinning boundary line has been widely analyzed with a variety of statistical techniques. Most previous studies in the forestry literature have reported that the relationship does not differ across a range of stand and site factors, but these studies have primarily used statistical techniques that make model fitting subjective or interpretation of covariate significance difficult. There is growing evidence that the use of stochastic frontier analysis is an effective statistical means for objectively fitting the species self-thinning boundary line, offering the opportunity to test the influence of additional covariates. Using extensive even-aged coastal Douglas-fir (Pseudotsuga menziesii var. menziesii [Mirb.] Franco), western hemlock (Tsuga heterophylla), and red alder (Alnus rubra Bong.) data sets in the Pacific Northwest, we examined the assumption that the intercept and slope of the species self-thinning boundary line are insensitive to stand and site factors. Likelihood ratio tests indicated that site index, stand origin (natural versus planted), and purity (proportion of basal area in the primary species) significantly influenced the species self-thinning boundary line intercept for each of the species examined in this study. In Douglas-fir and western hemlock, the slope of the self-thinning boundary was also dependent on stand origin as well as site index in the case of Douglas-fir. Fertilization did not significantly influence the intercept or slope of the species self-thinning line for Douglas-fir and western hemlock. In addition, the inclusion of site aspect and dryness index marginally improved the red alder model of self-thinning, but neither site soil nor climatic variables improved the models for western hemlock and Douglas-fir. Thus, the species self-thinning boundary line can vary significantly among stands, and its variation is driven by several distinct factors; stochastic frontier analysis is an effective tool for identifying these factors.
Effects of Stand Regeneration Management Regimes and Age on Genetic Structure of Quercus aquifolioides (Sclerophyllous Oak) in Southwestern China
Authors: Wang Zhongsheng , Liu Hong , Wei Na , Xu Weixiang , An Shuqing , Liu Shirong 
Published: April 2024

Abstract
As a representative relict forest type, the sclerophyllous oak (Quercus aquifolioides Rehd. et Wils.) forests in the Himalayas-Hengduanshan Mountains of China have been either nearly completely destroyed or heavily fragmented, mostly due to the long-lasting overexploitation by local human population. To evaluate the effect of current silvicultural treatments on regeneration of sclerophyllous oak, we compared inter simple sequence repeats, measures of genetic variation of this species regenerating in three types of stands: natural old-growth oak forest, clearcut spruce plantation, and clearcut naturally regenerated stands in the Miyaluo area, western Sichuan Province of China. Results showed that populations of Q. aquifolioides in the old-growth stands displayed the highest level of genetic diversity, whereas populations in the clearcut naturally regenerated stands had the lowest. In addition, we found that populations in the older spruce plantations (e.g., stands ≥50 years old) were genetically more diverse than those in the younger sites. These findings had the following immediate implications: forest clearcuts had significantly reduced genetic variability within populations of Q. aquifolioides; artificial reforestation of spruce after clearcut could promote the recovery of genetic diversity in Q. aquifolioides, especially in the older stands; and severe human and livestock disturbances hindered the recovery of genetic diversity of Q. aquifolioides in the naturally regenerated stands. We recommend active thinning in spruce plantations (at approximately age 30-40 years) via selective logging at times of rapid height growth and crown closure to promote multistoried stand structures and canopy gaps suitable for the survival and growth of Q. aquifolioides. Finally, we recommend strict management control in the naturally regenerated stands to limit the utilities of these stands by humans and their livestock to facilitate the recovery of Q. aquifolioides genetic diversity.
Evaluating Approaches for Solving the Area Restriction Model in Harvest Scheduling
Authors: Goycoolea Marcos , Murray Alan , Vielma Juan Pablo , Weintraub Andres 
Published: April 2024

Abstract
We survey three integer-programming approaches for solving the area restriction model for harvest scheduling. We describe and analyze each of these approaches in detail, comparing them both from a modeling and computational point of view. In our analysis of these formulations as modeling tools, we show how each can be extended to incorporate additional harvest scheduling concerns. In our computational analysis we illustrate the strengths and weaknesses of each formulation as a practical optimization tool by studying harvest scheduling in four North American forests.
Adaptive Decision Analysis in Forest Management Planning
Authors: Leskinen Pekka , Hujala Teppo , Tikkanen Jukka , Kainulainen Tuomo , Kangas Annika , Kurttila Mikko , Pykäläinen Jouni , Leskinen Leena 
Published: April 2024

Abstract
Societal responsibilities of forestry have diversified, and criteria other than those related to wood production have been given more weight. Demands for forest management planning methods have changed in line with the changes in the operational environment. Thus, forest planners are facing a growing demand for more versatile and customer-oriented decision aid systems and practices in which the data are cost effectively acquired and used. So far, forest planning research has concentrated mainly on the general development of multiobjective and participatory planning methods in the numerical framework. This focus has unintentionally led to practices for which the decision analysis process is often controlled only by the technical needs of the planning methods in a unified setting, independently of the problem characteristics. However, it is important to adapt the use of planning methodologies to each planning problem and use the available information about important variables efficiently. In this article, we introduce a theoretical and methodological framework for adaptive decision analysis (ADA) for forest management planning. In ADA, different decision-support service options, comprising both qualitative and quantitative components, are maintained and carried out flexibly in each planning case with the aid of an adapting processor and feedback management, resulting in computational, social, and organizational learning.
Early Growth Responses of Lodgepole Pine and Douglas-Fir to Soil Compaction, Organic Matter Removal, and Rehabilitation Treatments in Southeastern British Columbia
Authors: Tan Xiao , Curran Michael , Chang Scott , Maynard Douglas 
Published: April 2024

Abstract
Effects of soil compaction, organic matter removal, and rehabilitation on lodgepole pine (Pinus contorta Dougl. ex. Loud.) and Douglas-fir (Pseudotsuga menziesii var. menziesii) were studied after three growing seasons in a long-term soil productivity study established on three calcareous soils in southeastern British Columbia. Effects of soil compaction and organic matter removal on tree growth were site and species specific. Moderate soil compaction increased the diameter and height increment of both species within the stem-only harvest treatment on all three sites, particularly at the coarser textured site (Emily Creek). Compaction tended to reduce tree mortality. Growth of both species was reduced by forest floor removal in the noncompacted soil at Mud Creek and Emily Creek and by whole-tree harvest in the moderately compacted soil at Mud Creek and Kootenay East, possibly due to treatment-induced water limitation. Whole-tree harvest and forest floor removal stimulated lodgepole pine and Douglas-fir growth in the noncompacted soil at Kootenay East. The rehabilitation treatment (established by tilling a heavily compacted soil) reduced lodgepole pine tree mortality on all sites and increased rootcollar diameter and height increment at Mud Creek and Kootenay East. Our findings may provide early growth indication and help assess long-term tree growth trends at these and other long-term soil productivity or related sites.
Approaches for Modeling Vertical Distribution of Maximum Knot Size in Black Spruce: A Comparison of Fixed- and Mixed-Effects Nonlinear Models
Authors: Kershaw John A. , Benjamin Jeff G. , Weiskittel Aaron R. 
Published: April 2024

Abstract
Both linear and nonlinear hierarchical mixed-effects models have been used in recent years to analyze nested data sets. These types of models are effective for partitioning variance between hierarchical levels and increasing model flexibility. Models of knot size and distribution have been developed for several commercially important conifer species. Modeling knots is particularly amendable to the mixed-models approach as they are inherently nested at multiple levels including the individual whorl, tree, and stand levels. Although mixed models are effective for addressing hierarchical nesting of data, in this study we contend that improvements achieved by inclusion of mixed effects can be effectively negated with the use of an appropriate model form. This contention is presented as a case study on the development of a maximum knot size model for plantation-grown black spruce in Ontario (Picea mariana [Mill.] BSP). With a naive and simple model form, the nonlinear mixed-effects approach was significantly superior to comparable generalized nonlinear models as the root mean square error was 16% lower. In contrast, when a model form that accounted for primary covariates with a robust model form was used, difference in root mean square error between nonlinear mixed-effects and generalized nonlinear models was approximately 6%. In addition, graphic techniques for exploring distributions of random effects are presented and discussed. Mixed models are effective tools, but, as illustrated by this case study, their limitations need to be recognized and use of mixed models should not precede development of sound model forms.
Cavity Size and Copper Root Pruning Affect Production and Establishment of Container-Grown Longleaf Pine Seedlings
Authors: Sword Sayer Mary Anne , Haywood James D. , Sung Shi-Jean Susana 
Published: April 2024

Abstract
With six container types, we tested the effects of cavity size (i.e., 60, 93, and 170 ml) and copper root pruning on the root system development of longleaf pine (Pinus palustris Mill.) seedlings grown in a greenhouse. We then evaluated root egress during a root growth potential test and assessed seedling morphology and root system development 1 year after planting in central Louisiana, USA. Seedling size was increased by copper root pruning in small cavities but was unaffected by this treatment in larger cavities. Before planting, copper root pruning increased taproot and secondary lateral root dry weights at the expense of primary lateral root dry weight and increased root growth potential in the top 5 cm of the root plug. Across treatments, survival was 97%, and all seedlings were in the grass stage. Of the lateral root dry weight that elongated during the first year after planting, 33% more occurred in the upper 5 cm of soil when seedlings were treated with copper. Within each cavity size, copper root pruning did not affect the general morphology of 1-year-old seedlings. However, relationships between root collar diameter and root egress by depth indicated that this treatment has the potential to increase the range of cavity sizes used for seedling production.
Fifty Years of Fertilization Experiments on Pinus pinaster in Southwest France: The Importance of Phosphorus as a Fertilizer
Authors: Trichet Pierre , Bakker Mark R. , Augusto Laurent , Alazard Pierre , Merzeau Dominique , Saur Etienne 
Published: April 2024

Abstract
Data from 50 years of fertilization trials on Maritime pine (Pinus pinaster) were compiled to investigate how growth was affected by fertilization or improved nutrient availability. The results demonstrated that only trees fertilized with phosphorus (P) fertilizers showed an overall improvement in productivity. The effects were significant mainly at wetter sites and were less effective at drier sites. The form of P fertilizer does not seem to be important, and a rate of about 17–35 kg of P ha−1 applied as a single dose at stand establishment was found to be sufficient to obtain a significant improvement in growth. Foresters can expect an increase of 20–40% cumulative volume at rotation age or a reduction of 4–5 years in rotation length due to fertilization with P. The duration of the effect of P fertilization on the annual increment varied (up to 20 years after application in the best cases). The high P-fixing capacity of these soils appears to be the most important factor in explaining differential responsiveness to P fertilizers, but stand developmental stage or the appearance of other limitations such as nitrogen may also explain the decline in the effectiveness of P fertilization with age.