Diameter growth prediction for individual Pinus occidentalis Sw. trees
Predictive equations calibrated with remeasurement data from 25 permanent plots having individually identified trees were used to project stem diameter of Pinus occidentalis Sw. in Dominican Republic. The general form of the models used to fit the growth and yield functions included fixed effect cov...
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| Format: | Article |
| Language: | English |
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Italian Society of Silviculture and Forest Ecology (SISEF)
2013-08-01
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| Series: | iForest - Biogeosciences and Forestry |
| Subjects: | |
| Online Access: | https://iforest.sisef.org/contents/?id=ifor0843-006 |
| _version_ | 1818154314654285824 |
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| author | Bueno-López S Bevilacqua E |
| author_facet | Bueno-López S Bevilacqua E |
| author_sort | Bueno-López S |
| collection | DOAJ |
| description | Predictive equations calibrated with remeasurement data from 25 permanent plots having individually identified trees were used to project stem diameter of Pinus occidentalis Sw. in Dominican Republic. The general form of the models used to fit the growth and yield functions included fixed effect covariates related to three subsets of explanatory variables: initial tree size, stand attributes, and competition indexes. The subsets were incrementally added in a stepwise fashion for each of the three response variables and the intercept of the model was allowed to vary randomly between plots. The models evaluated included a yield function that predicted future diameter at year t (dt), a periodic annual increment model using five-year diameter increment (id5) and its natural log transformation [ln(id5+0.01)]. For trees that were not remeasured exactly 5 years after the first measurement, id5 was computed by averaging the mean annual increment nearest the 5 year point and multiplying by five. Each approach was evaluated using an independent validation data set based on seven goodness-of-fit statistics, graphical display of residuals and the variance components of each model combination. LMM, including fixed and random parameters, provided a better fit among the models tested. For estimating future diameter, accuracy of predictions is within one centimeter for a five-year projection interval, and bias is negligible. All the models had moderately improved fit statistics when random effects were included in the evaluation. The degree of improvement behaved in a similar manner for most fit statistics, with differences in the range of values for MSE, RMSE and RMSE% of 0.53, 0.23 and 1.05, respectively. The absolute difference between the extreme values for Bias and relative Bias (%) in all the models was 0.20 and 0.92. The differences in values for MAD were only 0.15 and R2 values were practically equivalent. |
| first_indexed | 2024-12-11T14:24:33Z |
| format | Article |
| id | doaj.art-b7fcb7896715481da7f49b58385bcc3f |
| institution | Directory Open Access Journal |
| issn | 1971-7458 1971-7458 |
| language | English |
| last_indexed | 2024-12-11T14:24:33Z |
| publishDate | 2013-08-01 |
| publisher | Italian Society of Silviculture and Forest Ecology (SISEF) |
| record_format | Article |
| series | iForest - Biogeosciences and Forestry |
| spelling | doaj.art-b7fcb7896715481da7f49b58385bcc3f2022-12-22T01:02:45ZengItalian Society of Silviculture and Forest Ecology (SISEF)iForest - Biogeosciences and Forestry1971-74581971-74582013-08-016120921610.3832/ifor0843-006843Diameter growth prediction for individual Pinus occidentalis Sw. treesBueno-López S0Bevilacqua E1Vicerrectoria de Investigaciones e Innovación, Pontificia Universidad Catolica Madre y Maestra, Santiago de los Caballeros (Dominican Republic)College of Environmental Science and Forestry, State University of New York, 1 Forestry Drive, 13210 Syracuse, NY (USA)Predictive equations calibrated with remeasurement data from 25 permanent plots having individually identified trees were used to project stem diameter of Pinus occidentalis Sw. in Dominican Republic. The general form of the models used to fit the growth and yield functions included fixed effect covariates related to three subsets of explanatory variables: initial tree size, stand attributes, and competition indexes. The subsets were incrementally added in a stepwise fashion for each of the three response variables and the intercept of the model was allowed to vary randomly between plots. The models evaluated included a yield function that predicted future diameter at year t (dt), a periodic annual increment model using five-year diameter increment (id5) and its natural log transformation [ln(id5+0.01)]. For trees that were not remeasured exactly 5 years after the first measurement, id5 was computed by averaging the mean annual increment nearest the 5 year point and multiplying by five. Each approach was evaluated using an independent validation data set based on seven goodness-of-fit statistics, graphical display of residuals and the variance components of each model combination. LMM, including fixed and random parameters, provided a better fit among the models tested. For estimating future diameter, accuracy of predictions is within one centimeter for a five-year projection interval, and bias is negligible. All the models had moderately improved fit statistics when random effects were included in the evaluation. The degree of improvement behaved in a similar manner for most fit statistics, with differences in the range of values for MSE, RMSE and RMSE% of 0.53, 0.23 and 1.05, respectively. The absolute difference between the extreme values for Bias and relative Bias (%) in all the models was 0.20 and 0.92. The differences in values for MAD were only 0.15 and R2 values were practically equivalent.https://iforest.sisef.org/contents/?id=ifor0843-006Repeated MeasurementsMixed ModelsStepwise RegressionSite QualityIndividual Tree Competition Indexes |
| spellingShingle | Bueno-López S Bevilacqua E Diameter growth prediction for individual Pinus occidentalis Sw. trees iForest - Biogeosciences and Forestry Repeated Measurements Mixed Models Stepwise Regression Site Quality Individual Tree Competition Indexes |
| title | Diameter growth prediction for individual Pinus occidentalis Sw. trees |
| title_full | Diameter growth prediction for individual Pinus occidentalis Sw. trees |
| title_fullStr | Diameter growth prediction for individual Pinus occidentalis Sw. trees |
| title_full_unstemmed | Diameter growth prediction for individual Pinus occidentalis Sw. trees |
| title_short | Diameter growth prediction for individual Pinus occidentalis Sw. trees |
| title_sort | diameter growth prediction for individual pinus occidentalis sw trees |
| topic | Repeated Measurements Mixed Models Stepwise Regression Site Quality Individual Tree Competition Indexes |
| url | https://iforest.sisef.org/contents/?id=ifor0843-006 |
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