|dc.description.abstract||The development of the crown structure of Pinus
resinosa Ait. was analysed in terms of three component
processes of tree growth: the number of first order
branches per whorl within the crown, the annual extension
increments of the main stem and first order branches, and
first order branch length - foliage dry weight
relationships. Factors regulating these components were
analysed and stochastic models to describe them were
Thirty-two trees from five different planted stands
located in the Quetico Section (L.ll) of the Great Lakes -
St. Lawrence Forest Region (Rowe 1972) were examined.
These stands represented various site conditions, stand
ages, and spacing categories.
The number of branches per whorl was weakly
correlated with two attributes of the parent structure:
the length of the terminal leader at the time of whorl bud
inception, and the length of the terminal leader on which
the branches occurred as whorl buds. The number of
branches per whorl was not related to the age of the tree
at the time of whorl bud inception. The binomial probability density function was a suitable model to describe the number of branches per whorl,
Extension growth of first order branches varied greatly from year to year. Differences in the extension growth of individual branches were associated with: differences in the annual height increment of the tree,
factors governing apical control, and the relative position of a branch within the crown.
There appeared to be a potential length which
one-year-old branches could attain that was dependent upon
the concurrent height increment of the tree. There also
seemed to be a potential extension increment for branches
after their first growing season that was dependent upon
initial branch length and branch age. The observed
extension increments of branches were related in a
stochastic manner to the potential for branch extension
growth to simulate naturally occurring variation.
Total branch length was a useful estimator of the
total foliage dry weight for branches of the same age.||