A Gamma-Poisson model for vertical location and frequency of buds on lodgepole pine (Pinus contorta) leaders
2010
Nemec, Amanda F Linnell | Goudie, James W. | Parish, Roberta
The aim of this work was to model the vertical location and number of branch primordia (buds) on the leader of lodgepole pine (Pinus contorta Doug. ex Loud.) trees in central British Columbia. For species such as lodgepole pine, where branches occur in clusters rather than individually, the Gamma-Poisson model provides a natural framework for describing and simulating the distribution of buds on the annual shoot. Parameters in the model are identifiable with measurable attributes, that is, the average number of clusters per unit length of the annual shoot and the average number of buds per cluster, and can be related to explanatory variables via a log link. Applicability of the Gamma-Poisson model was demonstrated for a sample of 58 lodgepole pine trees ranging in age from 29 to 103 years old. The agreement between observed and expected cluster counts and spacing, cluster sizes, and total number of branches was good. Height to crown base and length of the annual shoot were selected as the best predictors of the number of clusters and number of buds per cluster, respectively, although other single variables were also identified as having significant predictive value.
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