A site model for Pyrenean oak (Quercus pyrenaica) stands using a dynamic algebraic difference equation

2005 ◽  
Vol 35 (1) ◽  
pp. 93-99 ◽  
Author(s):  
João P Carvalho ◽  
Bernard R Parresol
Keyword(s):  
Site Index ◽  
Site Quality ◽  
Parameter Estimates ◽  
Quercus Pyrenaica ◽  
Error Statistics ◽  
Site Model ◽  
Dominant Height ◽  
Richards Function ◽  
Algebraic Difference ◽  
A Site

This paper presents a growth model for dominant-height and site-quality estimations for Pyrenean oak (Quercus pyrenaica Willd.) stands. The Bertalanffy–Richards function is used with the generalized algebraic difference approach to derive a dynamic site equation. This allows dominant-height and site-index estimations in a compatible way, using any desirable base age and allowing estimations to be time independent, which are important properties for site models. The database contains all possible height-growth intervals. The model is fitted considering residual autocorrelation, giving more efficient parameter estimates. Finally, the model behavior is analyzed by calculating error statistics from dominant-height and site-index estimations at different ages.

scholarly journals SITE INDEX IN EUCALYPTUS STANDS APPLYING ORDINARY KRIGING: AN APPROACH WITH DIFFERENT MODELS AND METHODS OF CLASSIFICATION

FLORESTA ◽  
2021 ◽  
Vol 51 (4) ◽  
pp. 1000
Author(s):  
Pedro Vaz da Rocha ◽  
Emanuel José Gomes de Araújo ◽  
Vinícius Augusto Morais ◽  
Marco Antonio Monte ◽  
Danilo Henrique dos Santos Ataíde ◽  
...  
Keyword(s):  
Difference Method ◽  
Spatial Dependence ◽  
Ordinary Kriging ◽  
Gaussian Model ◽  
Site Index ◽  
Site Quality ◽  
Productive Capacity ◽  
Dominant Height ◽  
Algebraic Difference ◽  
Predictive Validation

The objective of this work was to evaluate the efficiency of models and methods to obtain the site index, associated with ordinary kriging, to classify productive capacity in eucalyptus stands. Thus, the site quality was performed considering the traditional modeling in clonal stands (2,119 hectares) located in Minas Gerais state, Brazil. 170 plots of 400m2 were randomly allocated, representing a sampling intensity of 0.32%. The dominant height of trees (Assmann) was measured at 24, 36, 48, 60, 72, and 84 months. The site index (S) was estimated by the guide curve and algebraic difference methods, using the models of Schumacher, Chapman and Richards, and Bailey and Clutter. 136 plots were used in the fit and 34 plots in the predictive validation. The spatial dependence of site index was evaluated by experimental semivariogram and adjustment of exponential, spherical, and gaussian models. After confirming the spatial dependence, ordinary kriging was performed to spatialize the site index. For the predictive validation, the dominant height values at 72 months were used. The algebraic difference method provided excellent estimates of site index, which showed spatial dependence in all adjustments, from moderate to strong. In most cases, the gaussian model was the most accurate. It is concluded that the algebraic difference method was more efficient and the site index showed strong spatial dependence at all ages, regardless of the model used. Thus, regression models for site index estimation can be used in combination with ordinary kriging techniques.

Suitability of two methods of evaluating site quality for sugar maple in central Ontario

2006 ◽  
Vol 82 (5) ◽  
pp. 733-744 ◽  
Author(s):  
Nicholas J Buda ◽  
Jian R Wang
Keyword(s):  
Sugar Maple ◽  
Quality Evaluation ◽  
Growth Models ◽  
Site Index ◽  
Height Growth ◽  
Site Quality ◽  
Dominant Height ◽  
Index Site ◽  
Species Mixture ◽  
Stand Conditions

Stem analyses data collected in central Ontario stands were used to develop site index (height and age) and site form (height and diameter) models and curves for sugar maple. The suitability of both methods for evaluating sugar maple site productivity was examined. Two different equation forms were evaluated for both site index and site form models. A common modification of Richard's (1959) equation was most suitable for predicting dominant height at index age (site index) and reference diameter (site form). Potential effects of species mixture on sugar maple site index were examined. We found no significant effects on sugar maple height growth and site index in mixed stand conditions common in the region when compared to pure stands. The potential of site form as an alternative to site index was investigated through correlation analyses with site index and other site variables known to influence sugar maple height growth. Site form was not related to site index, nor any site variables related to sugar maple height growth. It is therefore inadequate for evaluating sugar maple site quality. We recommend height growth models and site index curves developed in this study be used to replace those from other regions currently used in central Ontario. Key words: site index, site form, sugar maple, site quality evaluation, mixedwood, uneven-aged

AN EVALUATION OF SEVERAL METHODS OF ESTIMATING SITE INDEX OF IMMATURE STANDS

1952 ◽  
Vol 28 (3) ◽  
pp. 63-74 ◽  
Author(s):  
John W. Ker
Keyword(s):  
Basal Area ◽  
Site Index ◽  
Site Quality ◽  
Average Height ◽  
Office Procedure ◽  
Minimum Sample ◽  
A Site ◽  
The University ◽  
Site Classes

The use of dominant heights for the estimation of site index is compared with the use of the average of dominant and codominant heights. Data collected on the University Research Forest are presented to illustrate the variability in tree heights and diameters within the two upper crown classes in well-stocked stands of immature Douglas fir.HeightIt is shown that the use of dominant heights reduces considerably the number of measurements required for a site index determination of given accuracy. Minimum sample sizes are given for three limits of accuracy for use in different site qualities. A general field and office procedure is outlined for the determination of minimum sample size in stands other than those described.DiameterThe use of diameter in site determination is discussed. Site indices based on the height of the tree of mean diameter, the height of the tree of mean basal area, and mean height are compared.ConclusionsQuick estimates of site quality can best be obtained by the measurement of total height of sample dominant trees, selected at random. For this purpose, tables are presented which list the average height of dominant trees by age and site classes for use in stands of Douglas fir, and western hemlock, respectively.

scholarly journals SITE QUALITY ESTIMATIONS BASED ON THE GENERALIZED ALGEBRAIC DIFFERENCE APPROACH: A CASE STUDY IN ÇANKIRI FORESTS

2018 ◽  
Vol 42 (3) ◽  
Author(s):  
Ugur Akbas ◽  
Muammer SENYURT
Keyword(s):  
Site Index ◽  
Site Quality ◽  
Model Parameters ◽  
Successful Model ◽  
Index Model ◽  
Prediction Technique ◽  
Algebraic Difference ◽  
Pine Stands ◽  
Site Index Model ◽  
Generalized Algebraic Difference Approach

ABSTRACT In this study, it is aimed that the dynamic site index models were developed for Crimean Pine stands in Sarikaya-Cankiri forests located in middle northern Turkey. The data for this study are 153 sample trees obtained from the Crimean Pine stands. In modeling relationships between height and age of dominant or co-dominant trees, some dynamic site index equations such as Chapman-Richards (M1, M2, M3), Lundqvist (M4 and M6), Hossfeld (M5), Weibull (M7) and Schumacher (M8) based on the Generalized Algebraic Difference Approach (GADA) were used. The estimations for these eight-dynamic site index model parameters with well as various statistical values were obtained using the nonlinear regression technique. Among these equations, the Chapman-Richards’s equation, M3, was determined to be the most successful model, with accounted for 89.03 % of the total variance in height-age relationships with MSE: 1.7633, RMSE: 1.3279, SSE: 1165.6, Bias: -0.0380. After determination of the best predictive model, ARMA (1, 1) autoregressive prediction technique was used to account autocorrelation problems for time-series height measurements. When ARMA autoregressive prediction technique was applied to the Chapman-Richards function for solving autocorrelation problem, these success statistics were improved as SSE: 868.7, MSE: 1.3183, RMSE: 1.1482, Bias: -0.06369, R2: 0.918. Also, Durbin-Watson statistics displayed that autocorrelation problem was solved by the use of ARMA autoregressive prediction technique; DW test value=1.99, DW<P=0.5622, DW>P=0.4378. The dynamic site index model that was developed has provided results compatible with the growth characteristics expected in the modeling of height-age relations, such as polymorphism, multiple asymptote, and base-age invariance.

Dominant-height and site-index equations for ponderosa pine in east-central Arizona

1991 ◽  
Vol 21 (5) ◽  
pp. 606-611 ◽  
Author(s):  
W. F. Stansfield ◽  
J. P. McTague ◽  
R. Lacapa
Keyword(s):  
Ponderosa Pine ◽  
Habitat Type ◽  
Prediction Method ◽  
Site Index ◽  
Site Quality ◽  
Predictive Capability ◽  
East Central ◽  
Dominant Height ◽  
Central Arizona ◽  
Parameter Prediction

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 parameter prediction approaches. Other site-quality variables, such as habitat type groups and elevation, were included in the dominant-height and site-index equations and were successful in refining predictive capability.

scholarly journals Modeling dominant height growth using permanent plot data for Pinus brutia stands in the Eastern Mediterranean region

2021 ◽  
Vol 30 (1) ◽  
pp. eSC03
Author(s):  
Tammam Suliman ◽  
Uta Berger ◽  
Marieke Van der Maaten-Theunissen ◽  
Ernst Van der Maaten ◽  
Wael Ali
Keyword(s):  
Mediterranean Region ◽  
Eastern Mediterranean ◽  
Eastern Mediterranean Region ◽  
Site Index ◽  
Permanent Plots ◽  
Stand Age ◽  
Pinus Brutia ◽  
Dominant Height ◽  
Algebraic Difference ◽  
Generalized Algebraic Difference Approach

Aim of the study: At current, forest management in the Eastern Mediterranean region is largely based on experience rather than on management plans. To support the development of such plans, this study develops and compares site index equations for pure even-aged Pinus brutia stands in Syria using base-age invariant techniques that realistically describe dominant height growth.Materials and methods: Data on top height and stand age were obtained in 2008 and 2016 from 80 permanent plots capturing the whole range of variation in site conditions, stand age and stand density. Both the Algebraic Difference Approach (ADA) and the Generalized Algebraic Difference Approach (GADA) were used to fit eight generalized algebraic difference equations in order to identify the one which describes the data best. For this, 61 permanent plots were used for model calibration and 19 plots for validation.Main results: According to both biological plausibility and model accuracy, the so-called Sloboda equation based on the GADA approach showed the best performance.Research highlights: The study provides a solid classification and comparison of Pinus brutia stands growing in the Eastern Mediterranean region and can thus be used to support sustainable forest management planning.Keywords: site index; Generalized Algebraic Difference Approach (GADA); Sloboda equation.

Site Classification From Air Photos in a Forest Inventory

1981 ◽  
Vol 57 (6) ◽  
pp. 265-266 ◽  
Author(s):  
G. M. Bonnor ◽  
K. C. Morrier
Keyword(s):  
Classification System ◽  
Forest Inventory ◽  
Site Index ◽  
Site Quality ◽  
Site Classification ◽  
Subsequent Test ◽  
Forest Inventories ◽  
Numerical Assessment ◽  
Eastern Ontario ◽  
A Site

A site classification system using 5-metre site index classes was applied in an inventory in eastern Ontario. ir photos and data on site index obtained from fiels work were used by photo interpreters to assign site index classes to individual stands. In a subsequent test of the procedures, the accuracy of the classification was found to be 76 percent. This accuracy, while acceptable, can be increased.The method is intended for use in extensive (regional, provincial) forest inventories and provides an objective (numerical) assessment of site quality.

scholarly journals Modeling Dominant Height Growth in PlantedPinus pineaStands in Northwest of Tunisia

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Sghaier Tahar ◽  
Palahi Marc ◽  
Garchi Salah ◽  
Bonet José Antonio ◽  
Ammari Youssef ◽  
...  
Keyword(s):  
Site Index ◽  
Height Growth ◽  
Pinus Pinea ◽  
Parameter Estimates ◽  
Site Classification ◽  
North West ◽  
Index Model ◽  
Variable Approach ◽  
Algebraic Difference ◽  
Site Index Model

Six generalized algebraic difference equations (GADAs) derived from the base models of log-logistic, Bertalanffy-Richards, and Lundqvist-Korf were used to develop site index model forPinus pineaplantations in north-west of Tunisia. To assure the base-age invariance of the model parameter estimates, a dummy variable approach was used. Data from stem analysis, corrected with Carmean's method, were used for modelling. To take into account the inherent autocorrelation of the longitudinal data, a second-order continuous-time autoregressive error structure was used, which allows the models to be applied to irregularly spaced, unbalanced data. Both a qualitative analysis based on the biological realism of the models and numerical and graphical analyses based on the accuracy of the models as well were used to evaluate the performance of candidate models. The relative error in site index predictions was used to select 30 years as the best reference age. Based on the analysis, a generalized algebraic difference equation (GADA) derived from the base model of Lundqvist-Korf realized the best compromise between biological and statistical constraints, producing the most adequate site index curves. It is a polymorphic model with site-dependent asymptotes. This model is therefore recommended for height growth prediction and site classification ofPinus pineaplantations in north-west of Tunisia.

scholarly journals Assessing site form as an indicator of site quality in even-aged Pinus radiata D. Don stands in north-western Spain

2019 ◽  
Vol 76 (4) ◽  
Author(s):  
Juan Alberto Molina-Valero ◽  
Ulises Diéguez-Aranda ◽  
Juan Gabriel Álvarez-González ◽  
Fernando Castedo-Dorado ◽  
César Pérez-Cruzado
Keyword(s):  
Pinus Radiata ◽  
Goodness Of Fit ◽  
Model Fitting ◽  
Site Index ◽  
Site Quality ◽  
Stand Age ◽  
Fit Statistics ◽  
Dominant Height ◽  
Western Spain ◽  
North Western

Abstract Key message Site form and site index have shown similar precision for estimating site quality in even-agedPinus radiataD. Don stands in north-western Spain. Additionally, SF presents the advantage that it does not require stand age information and can therefore be used in a wider set of situations in the forestry practice. Context Estimation of site quality is essential for characterizing, monitoring and predicting forest resources. Site index (i.e. the dominant height of the stand at a reference age) is ordinarily used to estimate site quality; however, this index is only useful for even-aged stands of known age. By contrast, SF is age-independent as it uses the dominant height of the stand at a reference dominant diameter. Aims The aim of this study was to compare the performance of SF and SI for site quality estimation in even-aged P. radiata stands. Methods Dynamic equations derived with the Generalized Algebraic Difference Approach (GADA) from the Hossfeld IV base model were fitted to predict site quality with both SI and SF. SF predictions were compared with SI regarding variability within the same plot and consistency in site quality predictions, using the observed maximum mean annual volume increment (MAI) as a direct measure of site quality. Results Both approaches showed good performance in model fitting and provided similar goodness-of-fit statistics and variability in the predictions. However, SI performed slightly stronger when related to MAI. Conclusion SF performed adequately in estimating site quality for even-aged P. radiata stands, with results comparable to those obtained using traditional SI.

A site-index model remodified

1994 ◽  
Vol 24 (1) ◽  
pp. 197-198 ◽  
Author(s):  
Bijan Payandeh ◽  
Yonghe Wang
Keyword(s):  
White Spruce ◽  
Site Index ◽  
Parameter Estimates ◽  
Data Sets ◽  
Index Model ◽  
Site Index Model ◽  
A Site

A previously reported site index model with unconstrained parameter estimates may not be amenable to extrapolation. A modification is presented that is more robust and has no apparent shortcomings. Results of fitting both models to white spruce (Piceaglauca (Moench) Voss) and aspen (Populustremuloides Michx.) data sets are presented and discussed.

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