Modeling of Frequency Distribution of Tree's Height in Uneven- aged Stands (Case study: Gorazbon district of Khyroud forest)

Document Type : Research Paper

Authors

1 Post Doc Researcher, Faculty of Natural Resources, University of Tehran, Karaj, I.R. Iran

2 Professor, Faculty of Natural Resources, University of Tehran, Karaj, I.R. Iran

3 Professor, Faculty of Agricultural Engineering and Technology, University of Tehran, Karaj, I.R. Iran

Abstract

To study the frequency distribution of the data for the height of trees in uneven-aged stands
in Gorazbon forest and its modeling, some statistical distribution were used. The utilized data
belong to 196 trees (Fagus orientalis, Betulus carpinus, Quercus castaneifolia, Alnus subcordata,
Acer velutinum etc.) that were extracted from the data related to the forest management plan
of Gorazbon district located at Khyroud forest. The range of the trees’ height measured was
between 5 and 51 meters which is an indication of height variable in the northern forests. After
initial calculations, four distributions Weibull, Gamma, Normal and Lognormal for frequency
distribution modeling of height variable were selected and related pertinent calculation were
done. The results of Anderson-Darling test and P-P plot showed that lognormal distribution is
not an appropriate model for frequency distribution modeling of trees’ height. Among the other
three distributions, Weibull, Gamma and Normal are respectively more suitable.

Keywords

References

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