John Paul McTague

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• Ph.D.
• Professor (Adjunct) at University of Georgia

A forma das árvores é influenciada por condições locais, idade e por atividades silviculturais, principalmente em plantios de longa rotação, como no caso de árvores de Tectona grandis. Desta forma, objetivou-se com o presente estudo avaliar a forma das árvores mediante variáveis relacionadas ao povoamento e ao local para verificar a suas influência...

Studies show that homogeneity among trees interferes with stand productivity, however, this information has not been incorporated into stand-level growth and yield models to assist forest managers. This paper presents a new format for basal area growth modeling, that includes the effect of homogeneity on stand productivity and was developed for unt...

Propõe-se neste estudo, verificar a utilização do modelo GAMLSS no ajuste de funções afilamento. Foram cubadas 52 árvores de Tectona grandis para o ajuste do polinômio do 5º grau por regressão linear múltipla e pela teoria dos modelos generalizados aditivos de parâmetros de locação, escala e forma (GAMLSS). A qualidade dos ajustes deu-se pelas esta...

Studies show that heterogeneity among plants interferes with stand productivity, however, this information has not been incorporated in models to assist forest managers. This paper presents a new format for growth modeling, that includes the effect of heterogeneity on final stand productivity and was developed for unthinned and thinned Pinus taeda...

The modeling of the taper and shape of the tree stem is of great interest to forest managers and can be carried out using different approaches. The objective of this study was to improve the accuracy of taper modeling, considering a methodology that combines generalization and calibration with an upper-stem diameter. An experiment was conducted wit...

In contrast to the conventional approach of using measured yields for independent variables in a double sampling estimator, a new estimator is presented for Continuous Forest Inventory (CFI) with partial replacement that is based on projected yields for independent variables. This proposed approach requires a modern growth and yield system for pred...

Taper functions have been widely used for various purposes. Several functions were developed and successfully applied; however, most of these functions fail to account for the influence of stand-level and individual-tree effects of variation on the stem profile. Hence, we aimed in this study to assess how these factors influence the stem profile of...

This article returns to the Hossfeldt and Pressler volume formulas that were developed in the 19th century and uses them as predictor variables for total volume equations of species in North and South America. Both the Hossfeldt and Pressler formulas require an upper-stem measurement and are exact equations for the geometric shapes of a cone or par...

Weibull distributions have been widely used to describe tree stem diameter distributions. However, there is a scarcity of studies that suggest the best Weibull formulation. The parameters of the Weibull distribution are usually predicted by either the parameter prediction method (PPM) or the parameter recovery method (PRM), although other methods h...

Stem taper equations, which predict the change in stem form from ground to tip, have become the primary means for estimating bole volume. Stem taper equations can provide predictions with similar levels of accuracy as volume equations, but with greater flexibility, a wider range of potential uses, and consistency between taper and volume. This revi...

Growth models have been applied to assess the growth potential for areas without previous forest plantation records and to update forest inventory when commercial stands have been planted. However, there is a lack of growth models capable of incorporating environmental variables for updating forest inventories and re-computing site quality througho...

Growth and yield (G &Y) model systems aim at forecasting forest productivity. The lack of environmental variables to account for how water availability constrains eucalyptus production in Brazil, however, is argued to be a major drawback of these model systems. Thus, this study aimed to develop a stand-level G & Y model system that accounts for wat...

Growth and yield (G &Y) model systems aim at forecasting forest productivity. The lack of environmental variables to account for how water availability constrains eucalyptus production in Brazil, however, is argued to be a major drawback of these model systems. Thus, this study aimed to develop a stand-level G & Y model system that accounts for wat...

Several approaches for modeling whole-stand survival or mortality have been reported in the literature, although this component is often times neglected for clonal eucalypt stands in Brazil. In addition, the traditional form for projecting whole-stand survival appears incomplete for clonal eucalypt stands, since this tree species is highly sensitiv...

Linking individual-tree and stand-level growth models is required for estimating future forest stand structure, while maintaining the desired accuracy for forest management decision making. There is a scarcity of studies addressing this issue for clonal Eucalypt stands in Brazil. Thus, this paper aims to develop a compatible individual tree and sta...

The research objective of this paper was to group eleven widely planted eucalypt clones based on their volume yield pattern by assessing how climatic variation impacts their productivity in tropical Brazil. A total of 187 plots evenly distributed across eleven clones and 17 sites (from Paraná to Pará State) were used. Plot measurements were carried...

Lack of generalized equations has prevailed in Brazil, because it is assumed that localized or climate-specific equations are needed. This study aimed to develop generalized stem taper and volume equations applicable to 11 eucalyptus clones and evaluate if climate variation impacts the accuracy of the estimates. A total of 693 trees evenly distribu...

Taper functions have been widely used with an existing array of model forms and methods; however, comparisons of contrasting statistical methods have been more limited. This study aimed to assess contrasting statistical approaches for achieving accurate stem taper and individual-tree volume predictions, with a focus on the novel penalized mixed spl...

Abstract A plethora of forest models were developed by transforming the dependent variable, which introduces bias if appropriate corrections are not applied when back-transformed. Many recognized models are still biased and the original data sets are no longer available, which suggests ad hoc bias corrections. The present research presents a proced...

A very common model for prediction of tree stem volumes to upper-stem height or diameter limits is the use of a merchantable to total volume ratio function multiplied by a total stem volume function. Many users of these prediction systems also desire taper equations that can predict heights to upper-stem diameters. While taper equations compatible...

The Atlantic forest biome in Brazil possesses many suitable tree species for cultivation and restoration purposes. This biome was the most rapidly and extensively exploited forest type in Brazil and it displays areas ill-suited for eucalyptus cultivation. Since tropical tree species usually do not form growth rings and long-term growth data are sti...

Growth and yield models are important tools for forest planning. Due to its geographic location, topology, and history of management, the forests in the Adirondacks Region of New York are unique and complex. However, only a relatively limited number of growth and yield models can be reasonably extended to this region currently. In this analysis, 55...

The goals of this study were to identify and group three eucalyptus clones, each under coppice and clear-cut management regimes, into two or more groups based on similar growth rates; and fit a site index equation as a function of rainfall variables for each group to evaluate how different groups were impacted by climatic variation. The database ca...

This study addresses the use of geostatistics to ensure sampling representativeness in a continuous forest inventory (CFI). A database of 89 permanent plots was used. Dominant height was employed for stratification by ordinary kriging. The correlation between the values estimated by kriging was calculated for all measurement occasions to define the...

This study addresses the use of geostatistics to ensure sampling representativeness in a continuous forest inventory (CFI). A database of 89 permanent plots was used. Dominant height was employed for stratification by ordinary kriging. The correlation between the values estimated by kriging was calculated for all measurement occasions to define the...

Background Growth and yield models are important tools for forest planning. Due to its geographic location, topology, and history of management, the forests of the Adirondacks Region of New York are unique and complex. However, only a relatively limited number of growth and yield models have been developed and/or can be reasonably extended to this...

Dominant height growth equations, which given at some base age is defined as site index, is usually used to assess site quality. A flexible and accurate way to represent the potential productive capacity of forest stands of Eucalyptus spp. was developed. The generalized algebraic difference method was used, in which 15 dynamic equations were tested...

When explaining the dynamics of individual trees, the incorporation of size and distance of neighboring trees into a model can improve the prediction of growth and mortality. Several methods have been proposed to define the number of competing trees based on variable zone radii and the principles of angle count sampling. The task of measuring posit...

Prior to the 1980s, the allowable stresses for lumber in North America were derived from testing of small clear specimens. However, the procedures were changed because these models were found to be inaccurate. Nevertheless, small clear testing continues to be used around the world for allowable stress determinations and in studies that examine fore...

Rayonier, Inc. conducts harvest scheduling using mathematical programming with a Model I structure to create its strategic and tactical harvest plans. A large integer formulation is used to solve the cutting schedule for the entire Rayonier timberlands of the southern United States. The inclusion of terminal values in the objective function coeffic...

The private corporate forest landowners of the United States have long abandoned the practice on relying upon permanent sample plots (PSPs) to measure the components of forest growth. Many of the PSPs were inexpensively established using the Bitterlich angle count method, however they furnished estimates of growth with high variance or with non-add...

Dr. Paul Van Deusen's recent passing concluded a rich 30+-year research career dedicated to development and implementation of quantitative methods for forestry and natural resources. Since the early part of his career as a biometrician with the USDA Forest Service Southern Research Station in the 1980s-1990s and continuing with his later employment...

The first chapter of the book initially addresses the definition of planted forests, industrial forests and industrial forest plantations. It also contextualizes historically the evolution of the term forest plantations, citing the several international organizations involved and different attempts to satisfy many actors and opinions. Facts and fig...

The Johnson system of distributions was used to fit both diameter and height data collected from 226 sample plots located in the ponderosa pine (Pinusponderosa P. Laws, ex C. Laws.) and mixed-conifer forest types in New Mexico and Arizona. To estimate the Johnson system parameters, five methods (namely the four-percentile method, Knoebel–Burkhart m...

Loblolly pine (Pinustaeda L.) is an important source of raw material for the forest products industry of Santa Catarina, Brazil. Data from 159 trees were used to develop a simultaneously estimated total and merchantable volume equation, which treats total volume as a special case of merchantable volume with Dm, the diameter limit, equal to zero. By...

A dominant-height equation for ponderosa pine (Pinusponderosa Laws.) was constructed utilizing a parameter prediction method and a model by J.E. King. The site-index equation was obtained by inverting the dominant-height equation. A method was examined for indirectly obtaining parameter prediction equations. It proved superior to two direct paramet...

Stand-level equations are presented that project future merchantable tree survival, pole-tree basal area, and sawtimber basal area. Total basal area (excluding ingrowth) is the sum of the pole-tree and sawtimber components. Ratio equations are used for eight species (seven softwoods and one hardwood) to compute the change in species abundance and s...

A new estimator for basal area is introduced that is based on the concepts of angle count and angle summation sampling. Using the ratio of the angle count basal area factor and the angle summation (borderline) factor, it is possible to estimate stand volume without measuring the diameters and distances of the trees included in the sample. Employing...

This paper presents a dominant height and basal area response function for juvenile (ages 2-8) loblolly pine stands that have been fertilized with a combination dose of 200 lbs/ac of nitrogen and 50 lbs/ac of phosphorus. The data used to construct the response functions originated from the Region-wide 2 Study of the North Carolina State University...

A system of stand level and individual tree growth-and-yield models are presented for southern hardwoods. These models were developed from numerous permanent growth-and-yield plots established across 13 states in the US South on 9 site types, in even-aged (age classes from 20 to 60 years), fully stocked, naturally regenerated mixed hardwood and mix...

FIA has moved toward multiple attribute annual monitoring designs that addresses forest environmental and sustainability issues in a more timely fashion in addition to the core FIA objectives. FIA now covers all forested lands, public and private and has integrated the Forest Health Monitoring Program field detection plot network into the FIA monit...

New functions are presented for spruce-fir survivor growth, ingrowth,and mortality using a data set of Continuous Forest Inventory plots exclusively from the spruce-fir forest type in east-central Arizona. The individual tree diameter squared growth model is validated at the tree and stand level with an independent data set. Individual tree mortali...

In this study, we report field survival results of an analysis of the USDA Forest Service Reforestation Improvement Program. The field survival of 3 test plantings of ponderosa pine (Pinus ponderosa Laws. var. ponderosa) were modeled with regression analysis using a modified logit transformation. The initial predictor variables tested included nurs...

A system of algebraic difference equations is presented for projecting, at the stand level, number of pole trees, survivor number of merchantable trees, and survivor basal area. Ingrowth is indirectly derived from projection equations that estimate the total change in the number of pole trees. The individual tree growth equation and mortality funct...

Dominant height and site index equations were constructed for Douglas-fir (Pseudotsuga menziesii var. glauca) and Engelmann spruce (Picea engelmannii) on the Fort Apache Indian Reservation, located in east-central Arizona. An indirect parameter prediction method was utilized to develop the equations from stem analysis data. The dominant height equa...

Total volume equations and functions that predict Pressler height, the Hohenadl reference diameter squared, and the Girard form class were constructed from 54 ponderosa pine (Pinus ponderosa Dougl.) trees. The sample trees were sectioned into lengths that correspond to 10% of the total tree height. It was hypothesized that enhanced estimates of tot...

Dominant height and site index equations are presented for white fir (Abies concolor), corkbark fir (Abies lasiocarpa var. arizonica) and aspen (Populus tremuloides) in east-central Arizona. The dominant height equations were fitted using the guide curve approach, but included an independent variable consisting of the difference in ring count betwe...

Dominant height and site index equations are presented for white fir (Abies concolor), corkbark fir (Abies lasiocarpa var. arizonica) and aspen (Populus tremuloides) in east-central Arizona. The dominant height equations were fitted using the guide curve approach, but included an independent variable consisting of the difference in ring count betwe...

Total outside and inside bark cubic foot volume equations are presented for southwestern ponderosa pine (Pinus ponderosa) that are functions of total tree height, diameter breast height, and Girard form class. These equations are appropriate for trees of any size or age, and no distinction is made between "blackjack" and "yellow pine" trees. Equati...

A simultaneous basal area growth and yield model based on diameter percentiles is developed. It is suggested that the diameter distribution percentiles essentially provide a description of the past stand history. The subsequent growth of a thinned or unthinned stand is affected by the shape and position of the diameter distribution percentiles. A n...

Stand-level and diameter distribution models for fast-growing plantations

Critical height sampling as a technique for estimating stand volume without using volume tables is explained. Based on point sampling for tree selection, the stand volume estimator is the product of the point sampling basal area factor and the sum of critical heights of trees in the sample. The critical height of a tree is the height to a point on...

Data from 483 trees were used to construct total volume equations, merchantable volume ratio equations, taper functions, and merchantable height equations. The data are composed of three Eucalyptus species: E. grandis, E. saligna and E. urophylla. The sample trees were not stratified by species, and thus the fitted equations are intended to be used...

Data from 483 trees were used to construct total volume equations, merchantable volume ratio equations, taper functions, and merchantable height equations. The data are composed of three Eucalyptus species: E. grandis, E. saligna and E. urophylla. The sample trees were not stratified by species, and thus the fitted equations are intended to be used...