Diameter growth prediction for individual Pinus occidentalis Sw. trees

Abstract

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

Evaluation of Different Modeling Approaches to Estimating Total Bole Volume for <em>Pinus occidentalis, </em>Swartz in Different Ecological Zones

“…Even-aged natural stands of P. occidentalis are located within three ecological zones (EZs) according to the Holdridge [10] classification: Subtropical Dry Forest (DEZ), Subtropical Humid Forest (IEZ), and Subtropical Very Humid Forest (HEZ). Average elevations above sea level are 500, 650, and 800 m, respectively [11]. The climate varies depending on the altitude and precipitation.…”

Evaluation of Different Modeling Approaches for Estimating Total Bole Volume of Hispaniolan Pine (Pinus occidentalis Swartz) in Different Ecological Zones

“…Even-aged natural stands of P. occidentalis are located within three ecological zones according to the Holdridge [10] classification: Subtropical Dry Forest (Dry Zone), Subtropical Humid Forest (Intermediate Zone), and Subtropical Very Humid Forest (Humid Zone). Average elevations above sea level are 500, 650, and 800 m, respectively [11]. The climate varies depending on the altitude and precipitation.…”

“…The average annual temperature is between 12 • C and 24 • C. These forests usually develop in shallow, carbonate, lateritic, low-producing soils with rugged topography. respectively [11]. The climate varies depending on the altitude and precipitation.…”

Predicting Diameter at Breast Height from Stump Measurements of Removed Trees to Estimate Cuttings, Illegal Loggings and Natural Disturbances

“…Diameter at breast height (DBH) is one of the most important tree variables measured in forestry (Corral-Rivas et al 2007, Bueno-López andBevilacqua 2013). Its frequency distribution is used to describe stand structure (Pond and Froese 2015), but above all, it allows the computing of basal area, a variable highly correlated with tree volume, biomass and increment; it is also an attribute easy to measure with sufficient accuracy.…”