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Seven models for predicting crown diameter using diameter at
breast height were tested for Picea orientalis L.
(Link.) in Artvin. Data were obtained from 4208 trees
measured on 117 temporary sample plots. Sample plots were
grouped into categories with 20 year mean age class
intervals. Similarly, sample plots were grouped into
categories based on mean tree diameter at breast height (2
cm diameter class interval). Mean diameter at breast height
and mean crown diameter of sample plots in age class were
analyzed statistically. One linear and six non-linear
diameters at breast height-crown diameter functions were
selected as candidate functions to model diameters at breast
height -crown diameter relationship. Regression analysis
showed that there were statistically significant (P > 0.05)
and strong (R2 > 0.80) relationship between
diameter at breast height and crown diameter variables in P.
orientalis. The results of the study indicated that the
diameter at breast height-crown diameter relationship can be
described by cubic, compound, growth or exponential model
because of the same R2 values. But the cubic
model gave the best result for relationship between diameter
at breast height and crown diameter.
Key words:
Crown diameter, diameter-crown diameter model, oriental
spruce, regression analysis. |
