scholarly journals Variable stocking version of Plonski's yield tables formulated

1996 ◽  
Vol 72 (2) ◽  
pp. 181-184 ◽  
Author(s):  
Bijan Payandeh ◽  
Yonghe Wang
Keyword(s):  
Basal Area ◽  
Site Index ◽  
Stand Age ◽  
Data Set ◽  
Management Planning ◽  
James River ◽  
Area Index ◽  
Major Species ◽  
Stand Attributes ◽  
Sigmoidal Growth

Plonski's yield tables have been used extensively in forest management, economic evaluation, and as a basis for management planning in Ontario. However, because these tables are based on site classes, they are not directly applicable to uneven-aged mixed-wood cover types. A four-parameter nonlinear model was employed to express various stand attributes as a function of stand age and recently developed basal area indices for the major species in Ontario. The resulting variable stocking yield functions will be applicable to even-aged stands as well as the boreal mixedwood. Basal area index proved superior to site index for estimating both merchantable basal area and volume for the James River/Marathon data set representing boreal mixed from Northcentral Ontario. In addition, stand basal area index may be determined easily and inexpensively via horizontal point sampling or prism cruising. Key word: Basal area index, sigmoidal growth curve, variable stocking

scholarly journals Leaf area index estimation of even-aged oak (Quercus petraea) forests using in situ stand dendrometric parameters

2021 ◽  
Author(s):  
Briere Maxime ◽  
Christophe Francois ◽  
Francois Lebourgeois ◽  
Ingrid Seynave ◽  
Francois Ningre ◽  
...  
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Basal Area ◽  
Quercus Petraea ◽  
Forest Stand ◽  
Stand Age ◽  
Estimation Errors ◽  
Data Set ◽  
Area Index ◽  
Net Productivity

The leaf area index (LAI) is a key characteristic of forest stand aboveground net productivity (ANP), and many methods have been developed to estimate the LAI. However, every method has flaws, e.g., methods may be destructive, require means or time and/or show intrinsic bias and estimation errors. A relationship using basal area (G) and stand age to estimate LAI was proposed by Sonohat et al. (2004). We used literature data in addition to data form measurements campaign made in the northern half of France to build a data set with large ranges of pedoclimatic conditions, stand age and measured LAI. We validated the Sonohat et al. (2004) relationship and attempted to improve or modify it using other stand/dendrometric characteristics that could be predictors of the LAI. The result is a series of three models using the G, age and/or quadratic mean diameter (Dg), and the models were able to estimate the LAI of an oak only even-aged forest stand with good confidence (root mean square error, RMSE < 0.75) While G is the main predictor here, age and Dg could be used conjointly or exclusively given the available data, with variable precision in the estimations. Although these models could not, by construction, relate to the interannual variability of the LAI, they may provide the theoretical LAI of an untouched forest (no meteorological, biotic or anthropogenic perturbation) in recent years. additionally, the use of this model may be more interesting than an LAI measurement campaign, depending on the means to be invested in such a campaign.

scholarly journals EVOLUÇÃO DA ÁREA BASAL E DO VOLUME EM BRACATINGAIS NATIVOS SUBMETIDOS À DIFERENTES DENSIDADES INICIAIS E EM DIFERENTES SÍTIOS

FLORESTA ◽  
2002 ◽  
Vol 32 (1) ◽  
Author(s):  
Sebastião Do Amaral Machado ◽  
Ana Elizabete N. Tonon ◽  
Afonso Figueiredo Filho ◽  
Edilson Batista Oliveira
Keyword(s):  
Initial Density ◽  
Basal Area ◽  
Site Index ◽  
Metropolitan Region ◽  
Data Set ◽  
Permanent Sample Plots ◽  
Dominant Height ◽  
Site Classes ◽  
Volume Em ◽  
Area And Volume

Foram analisados os efeitos de quatro densidades iniciais (2, 4, 8 e 25,15 mil plantas por hectare) e de 3 classes de sítio, cujos índices de sítios são 10,2; 13,5 e 16,8 m de altura dominante aos 7 anos de idade, sobre a área basal e volume por hectare em povoamentos nativos de bracatinga (Mimosa scabrella Benth.) na região metropolitana de Curitiba. Os dados provieram de um experimento de densidades em blocos ao acaso medidos nas idades de 4,1; 5,1; 6,3 e 7,6 anos. Os efeitos da densidade inicial e do sítio sobre a área basal (G) e volume (V) por hectare foram verificados através de análise de variância seguida do teste de Tukey, quando pertinente. A densidade inicial de 4 mil plantas por hectare gerou maiores valores de G e V nas últimas idades de medição. A área basal/ha não sofreu efeitos significativos do sítio em nenhuma das medições, enquanto que o volume/ha foi afetado por este fator (sítio) até a idade de 6,3 anos. Evolution of Basal Area and Volume per Hectare in Native "Bracatingais" Submited to Different Initial Densities and Different Sites Abstract The objectives of this research were to study the effects of four initial densities (2000, 4000, 8000 and 25150 plants/ha) and three site classes (site index 10.2, 13.5 and 16.8 m of dominant height at age seven) on basal area (G) and volume per hectare (V) for native stands of bracatinga (Mimosa scabrella Benth.) in the Metropolitan Region of Curitiba, Brazil. The data set came from permanent sample plots of a density trial established in a random blocks design. These plots were measured at ages 4.1, 5.1, 6.3, and 7.6 years of age. The effects of initial density and site on basal area and volume per hectare were verified through graphics and analysis of variance followed by the Tukey test when necessary. The initial density of 4,000 plants/ha generated the highest values of basal area and volume in the last ages of measurement. The basal area/ha did not sufered significative effects of site at any one of the measurement ages, while volume/ha was affected by this factor (site) until the age of 6.3 years.

scholarly journals Plonski's (metric) yield tables formulated

1991 ◽  
Vol 67 (5) ◽  
pp. 545-546 ◽  
Author(s):  
Bijan Payandeh
Keyword(s):  
Growth Model ◽  
Computer Use ◽  
Site Index ◽  
Stand Age ◽  
Sigmoidal Growth

A four-parameter sigmoidal growth model was employed to express various characteristics of interest in Plonski's metric yield tables as functions of stand age and site index. Except in a few cases, excellent fits were obtained. The resulting equations will facilitate direct computer use of Plonski's metric yield tables.

Modelling survival probability of individual trees in Norway spruce stands under different thinning regimes

2005 ◽  
Vol 35 (1) ◽  
pp. 113-121 ◽  
Author(s):  
Kjell Karlsson ◽  
Lennart Norell
Keyword(s):  
Norway Spruce ◽  
Goodness Of Fit ◽  
Basal Area ◽  
Site Index ◽  
Stand Age ◽  
Goodness Of Fit Test ◽  
Individual Tree ◽  
Thinning Intensity ◽  
Diameter At Breast Height ◽  
Breast Height

The probability that an individual tree will remain in even-aged Norway spruce (Picea abies (L.) Karst.) stands subjected to different thinning programmes was modelled, using data from a thinning experiment established in 25 localities in southern Sweden. A logistic regression approach was used to predict the probability and the Hosmer–Lemeshow goodness-of-fit test to evaluate the fit. Diameter at breast height (DBH), quadratic mean DBH, thinning intensity, thinning quotient, basal area, number of stems per hectare, stand age, number of thinnings, and site index were used as explanatory variables. Separate analyses for stands thinned from below, stands thinned from above, and unthinned stands were performed. The modelled probability graphs for trees not being removed, plotted against their diameter at breast height, had clear S-shapes for both unthinned stands and stands thinned from below. The graph for stands thinned from above was bell-shaped.

An assessment of the structural method of deriving a black spruce site equation

1987 ◽  
Vol 17 (10) ◽  
pp. 1181-1189 ◽  
Author(s):  
Victor G. Smith ◽  
Martin Watts
Keyword(s):  
Black Spruce ◽  
Nonlinear Models ◽  
Site Index ◽  
Stand Age ◽  
Structural Method ◽  
Northern Ontario ◽  
Data Set ◽  
Permanent Sample Plots ◽  
Stochastic Error ◽  
Stand Height

To date, methods of deriving site index (S) equations assume that stochastic error is only present in the regressor. This paper develops a method, termed the "structural method," which recognizes that both dominant stand height (H) and S measurements contain stochastic error. To achieve this, the structural method utilizes the structural relationship that exists between H and S to derive an S equation. S equations are derived for black spruce, Piceamariana (Mill.) B.S.P., using the structural method and various other methods, with linear and nonlinear models that are currently in use. Data used in the study consist of 56 black spruce permanent sample plots, containing a total of 382 observations, from north central Ontario and the Clay Belt Region of northern Ontario. This data set is split into 36 plots (260 observations) for deriving S equations and 20 plots (122 observations) for testing the equations for accuracy in predicting H, S, and future H. The equations are also examined for bias over stand age. Results show that height development of black spruce is not asymptotic and is best described by a linear model. Overall, the structural method provides the most accurate S equation within the range of the data. It predicted 90% of the H test observations with an error of 0.4 m or less, 89% of the S test observations with an error of 0.4 m or less, and 90% of the future H test observations with an error of 0.7 m or less. The structural method also has the advantage of producing only one equation for predicting both H and S. This enables estimates of both H and S to be made from one graph of H over age by S classes.

RPGrow$: A Red Pine Analysis Spreadsheet for the Lake States

1994 ◽  
Vol 11 (4) ◽  
pp. 141-145
Author(s):  
Carol A. Hyldahl ◽  
Gerald H. Grossman
Keyword(s):  
Financial Analysis ◽  
Basal Area ◽  
Site Index ◽  
Red Pine ◽  
Growth And Yield ◽  
Stand Age ◽  
Management Scenarios ◽  
Stand Management ◽  
Lake States ◽  
Final Harvest

Abstract RPGrow$ is a spreadsheet that interactively projects standlevel growth and yield with financial analysis of red pine plantations in the Lake States. Three types of commonly found conditions related to red pine management can be analyzed: (1) an entire rotation from initial planting to final harvest; (2) an existing stand from any point in time until final harvest; and (3) conversion of an existing stand to red pine (marginal analysis). Stand growth projections are for 70 yr. User input includes site index, stand age, initial basal area, trees per acre, thinning regime, costs associated with establishment and culture, tax rates, inflation rate, and discount rate. RPGrow$ calculates and values pulpwood and sawtimber volumes from user-defined stumpage prices. The financial analysis uses discounted cash flow methods to calculate results both with and without tax effects. Different stand management scenarios and economic factors can be compared easily through sensitivity analysis. North. J. Appl. For. 11(4):141-145.

Whole Stand Yield and Density Equations for Fourteen Forest Types in Minnesota

1993 ◽  
Vol 10 (2) ◽  
pp. 75-85 ◽  
Author(s):  
David K. Walters ◽  
Alan R. Ek
Keyword(s):  
Goodness Of Fit ◽  
Basal Area ◽  
Nonlinear Least Squares ◽  
Analysis Data ◽  
Site Index ◽  
Stand Age ◽  
Parameter Estimates ◽  
Forest Types ◽  
Fit Statistics ◽  
Number Of Stems

Abstract Models that estimate per acre basal area, number of stems, quadratic mean diameter, volumes to specified top diameters, and biomass per acre by stand age and site index were developed and fitted to data for 14 forest types in Minnesota. The resulting equations were developed from linear and nonlinear least squares analyses using USDA Forest Service Forest Inventory and Analysis data. These equations are intended for projecting future forest characteristics including yield on a statewide basis assuming the continuation of the level of management inherent in the data. Parameter estimates and goodness-of-fit statistics are provided for each model. Also discussed are the implementation procedures, assumptions, consistency of estimates, estimates for mixed species stands, and other considerations in applications. North. J. Appl. For. 10(2): 75-85.

scholarly journals Generalized Nonlinear Mixed-Effects Individual Tree Diameter Increment Models for Beech Forests in Slovakia

Forests ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 451 ◽  
Author(s):  
Ram P. Sharma ◽  
Igor Štefančík ◽  
Zdeněk Vacek ◽  
Stanislav Vacek
Keyword(s):  
Basal Area ◽  
European Beech ◽  
Site Index ◽  
Development Stage ◽  
Mixed Effects ◽  
Site Quality ◽  
Stand Age ◽  
Sample Plot ◽  
Individual Tree ◽  
Diameter Increment

Individual tree growth and yield models precisely describe tree growth irrespective of stand complexity and are capable of simulating various silvicultural alternatives in the stands with diverse structure, species composition, and management history. We developed both age dependent and age independent diameter increment models using long-term research sample plot data collected from both monospecific and mixed stands of European beech (Fagus sylvatica L.) in the Slovak Republic. We used diameter at breast height (DBH) as a main predictor and other characteristics describing site quality (site index), stand development stage (dominant height and stand age), stand density or competition (ratio of individual tree DBH to quadratic mean diameter), species mixture (basal area proportion of a species of interest), and dummy variable describing stand management regimes as covariate predictors to develop the models. We evaluated eight versatile growth functions in the first stage using DBH as a single predictor and selected the most suitable one, i.e., Chapman-Richards function for further analysis through the inclusion of covariate predictors. We introduced the random components describing sample plot-level random effects and stochastic variations on the diameter increment, into the models through the mixed-effects modelling. The autocorrelation caused by hierarchical data-structure, which is assumed to be partially reduced by mixed-effects modelling, was removed through the inclusion of the parameter accounting for the autoregressive error-structures. The models described about two-third parts of a total variation in the diameter increment without significant trends in the residuals. Compared to the age independent mixed-effects model (conditional coefficient of determination, R c 2 = 0.6566; root mean square error, RMSE = 0.1196), the age dependent model described a significantly larger proportion of the variations in diameter increment ( R c 2 = 0.6796, RMSE = 0.1141). Diameter increment was significantly influenced differently by covariate predictors included into the models. Diameter increment decreased with the advancement of stand development stage (increased dominant height and stand age), increasing intraspecific competition (increased basal area proportion of European beech per sample plot), and diameter increment increased with increasing site quality (increased site index) and decreased competition (increased ratio of DBH to quadratic mean diameter). Our mixed-effects models, which can be easily localized with the random effects estimated from prior measurement of diameter increments of four randomly selected trees per sample plot, will provide high prediction accuracies. Our models may be used for simulating growth of European beech irrespective of its stand structural complexity, as these models have included various covariate variables describing both tree-and stand-level characteristics, thinning regimes, except the climate characteristics. Together with other forest models, our models will be used as inputs to the growth simulator to be developed in the future, which is important for decision-making in forestry.

Growth basal area: a field method for appraising forest site potential for stockability

1983 ◽  
Vol 13 (1) ◽  
pp. 70-77 ◽  
Author(s):  
Frederick C. Hall
Keyword(s):  
Growth Rate ◽  
Basal Area ◽  
Site Index ◽  
Field Method ◽  
Stand Age ◽  
Diameter Growth ◽  
Forest Site ◽  
A Site

Growth basal area (GBA) is a field method for determining site potential limitations on stockability. It is defined as the basal area (BA) at which dominant trees grow 1 in. (25 mm) diameter per decade at age 100. Diameter growth is a constant used to compare sites; basal area is a variable used to express different site potentials for stockability. For example, a site with GBA = 220 ft2/acre (50 m2/ha) means dominants will grow 1 in. per decade (25 mm) in diameter at 220 ft2 BA. This is twice the stockability potential of a site with GBA = 110 ft2 (25 m2/ha). GBA is determined by relating current stand diameter growth rate and BA to a curve which permits adjustment of current BA to that for 1 in. per decade diameter growth. GBA is based on two assumptions: (i) rate of diameter growth decreases with increasing basal area and is an index of intertree competition. (ii) Change in GBA with age is related to stand age. GBA can be combined with site index (SI), shown as SI-GBA, to connote different productivities within an SI class. GBA is discussed in regard to concept of GBA curve development, assumptions made, applications, and constraints.

scholarly journals Variable stocking yield functions for the boreal mixedwood in Ontario

1996 ◽  
Vol 72 (4) ◽  
pp. 416-419 ◽  
Author(s):  
Bijan Payandeh ◽  
Yonghe Wang
Keyword(s):  
Basal Area ◽  
Site Index ◽  
Eastern United States ◽  
Site Productivity ◽  
Area Index ◽  
Permanent Sample Plots ◽  
Index Model ◽  
Index Site ◽  
Yield Functions ◽  
Site Index Model

A measure of utilized site productivity, "basal area index" was recently developed and used to construct variable stocking yield functions and tables for the boreal mixedwood of northcentral Ontario. Data from 197 permanent sample plots supplied by the James River/Marathon Paper Company Ltd. were used. The resulting yield equations compare favourably with previous ones and are more appropriate for the boreal mixedwood. In addition, the basal area index employed has several advantages: 1) it serves as a valid measure of utilized site productivity which is better correlated with the main stand attributes than site index; 2) it produces variable stocking yield tables suitable for uneven-aged mixed species cover types; 3) unlike the site index, the basal area index may be estimated quickly, easily and inexpensively. The basic improvement in mixedwood yield estimation via basal area index should have broad applications for other stand types particularly for the disturbed hardwoods of southern Ontario and those in eastern United States. Key words: Basal area index, site index model, numerical method

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