Dominant height growth and dynamic site index models for Crimean pine in the Kastamonu–Taşköprü region of Turkey

2017 ◽  
Vol 47 (11) ◽  
pp. 1441-1449 ◽  
Author(s):  
Mehmet Seki ◽  
Oytun Emre Sakici

Some dynamic site index models based on the generalized algebraic difference approach (GADA) were fitted for Crimean pine (Pinus nigra J.F. Arnold subsp. pallasiana (Lamb.) Holmboe) stands in Taşköprü, Turkey. Data were obtained from 132 dominant trees representing the wide range of site quality in the region. Nonlinear regression analysis and a second-order continuous-time autoregressive error structure were applied. After autoregressive modeling, the fitted models were evaluated both statistically and graphically. The best results were obtained with the dynamic site index model derived from the Bertalanffy–Richards base equation, accounting for about the 99% of the total variance in height–age relationships in dominant trees, with an Akaike information criterion (AIC) value of 119.55 and root mean square error (RMSE) of 0.5446. The selected base-age invariant dynamic site index curves provided the polymorphism with multiple asymptotes and other realistic height growth patterns.

2010 ◽  
Vol 40 (6) ◽  
pp. 1175-1183 ◽  
Author(s):  
Zhengjun Hu ◽  
Oscar García

Height growth was modelled for spruce-dominated, even-aged stands in the Sub-Boreal Spruce biogeoclimatic zone of British Columbia, Canada, using both stem analysis (SA) and permanent sample plot (PSP) data. The model is based on a stochastic differential equation (SDE) formulation of the Bertalanffy–Richards growth equation. The SDE approach accounts for serial correlation and heterogeneous variance and makes hypothesis testing possible. Statistically significant differences in height–age trends between SA and PSP data were found that may be attributed to bias caused by dominance changes in SA trees. Error structure in SA and PSPs was also significantly different. Combining both data sources in a way that respects these different error structures reduced bias and increased precision. Four parametrizations were tested; the best was a polymorphic version. The final model fit the data well with no appreciable bias over the full range of ages and site qualities. The currently used spruce site-index model was found to underestimate growth and overestimate site index in young stands. The new model can be recommended for height prediction and site-quality assessment in interior spruce.


2018 ◽  
Vol 42 (3) ◽  
Author(s):  
Ugur Akbas ◽  
Muammer SENYURT

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.


2001 ◽  
Vol 77 (1) ◽  
pp. 141-150 ◽  
Author(s):  
Willard H. Carmean ◽  
G. Hazenberg ◽  
G. P. Niznowski

Stem-analysis data from dominant and codominant trees were collected from 383 plots located in fully stocked, even-aged, undisturbed mature jack pine stands. Separate site index curves were independently formulated for four regions of northern Ontario using the Newnham constrained nonlinear regression model; these formulations were used for comparing regional site index curves at three levels of site index (10 m, 15 m and 20 m).Comparisons showed that no significant differences existed between the four regional curves as well as with previously published site index curves for the North Central Region. Each of the four regions had similar polymorphic height-growth patterns; therefore, data for the four regions were combined and a single formulation was used to develop a polymorphic set of site index curves for all of northern Ontario. We found that poor sites in each region had almost linear height growth up to 100 years breast-height age, but for each region height growth became more curvilinear with increasing site index. The recommended site index curves for northern Ontario are based on a formulation using only data from plots 100 years and less but this formulation was not significantly different from a formulation using only data from plots 80 years and less, or a formulation that included all data from plots older than 100 years breast-height age.Comparisons were made between our northern Ontario curves and other jack pine site index curves for Ontario as well as curves for other areas of Canada and the United States. These comparisons generally showed considerable older age differences. Reasons for these differences are uncertain but could be due to differences in the amount and kind of data used for these other curves, could be due to differences in analytical methods, or could be due to regional differences in climate, soil and topography. Key words: site quality evaluation, polymorphic height growth, regional site index curves, site index prediction equations, comparisons among site index curves.


2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Sghaier Tahar ◽  
Palahi Marc ◽  
Garchi Salah ◽  
Bonet José Antonio ◽  
Ammari Youssef ◽  
...  

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.


Author(s):  
Gerónimo Quiñonez-Barraza ◽  
◽  
Dehai Zhao ◽  
Héctor M. de los Santos-Posadas ◽  
José J. Corral-Rivas ◽  
...  

1996 ◽  
Vol 72 (6) ◽  
pp. 647-650 ◽  
Author(s):  
Yonghe Wang ◽  
Bijan Payandeh

McDill and Amateis (1992) developed a dimensionally compatible height growth model which may be applied as either a base-age specific or a base-age invariant site index model. Its relative performance was compared with four published site index models on three stem analysis data sets from Ontario and the Northwest Territories of Canada. Results indicated that the modified McDill and Amateis (1992) model performed as well as, if not better than, the other models. Key words: base-age specific and base-age invariant site index models, nonlinear regression models, sum of squared errors


1993 ◽  
Vol 23 (12) ◽  
pp. 2487-2489 ◽  
Author(s):  
Yonghe Wang ◽  
Bijan Payandeh

A numerical solution was derived for previously published site index equations for trembling aspen (Populustremuloides Michx.). Data from aspen stands in north central Ontario were used to verify the validity and accuracy of the numerical method. With the numerical solution, only the height-growth equation is employed to estimate (i) height from site index and age and (ii) site index from height and age. The numerical method simplified site index estimation and improved its accuracy for aspen stands in north central Ontario.


2006 ◽  
Vol 82 (5) ◽  
pp. 733-744 ◽  
Author(s):  
Nicholas J Buda ◽  
Jian R Wang

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


1990 ◽  
Vol 7 (1) ◽  
pp. 27-30 ◽  
Author(s):  
James H. Brown ◽  
Charles A. Duncan

Abstract Growth intercept (GI) techniques were evaluated for estimating site quality in red pine stands planted on old-field sites in the unglaciated Western and Central Allegheny Plateau regions of Ohio. Correlations between height growth of trees below breast height (BH) and height growth above BH were not statistically significant. Site index estimates were made using age at BH and height from BH to the growing tip. Three-year and 5-year growth beginning three internodes above the BH annual increment and 10-year growth beginning one internode above BH were more significantly correlated with height than were intercepts beginning at BH. In equations developed for predicting site index, 3-, 5-, and 10-year intercepts in combination with age accounted for 64 to 80% of the variation in tree heights. Combining thickness of the A soil horizon with GI and age statistically increased the variation accounted for in the 3- and 5-year GI equations; however, for field use, the improvement in accuracy was not sufficient to justify making the additional soil measurement. North. J. Appl. For. 7(1):27-30, March 1990.


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