Figure 7: Can an Old Tree Learn New Tricks? Trees will
often grow up in companionship with other trees, in both
natural settings and in our urban landscapes. When a
neighboring mature tree is lost, an experienced arborist
can quite easily tell, as there is not only the gap where a
tree once was, but the adjacent tree has not developed
branches or foliage into that now vacated space. This relates
to an effect sometimes called "crown shyness," where many
canopy trees avoid impinging on the crown spread of any
adjacent canopy trees as it's biologically inefficient to do so.
Pictured is a mature oak tree (Quercus x rosacea) that is
growing in a public park in Lancashire, England and which was
a subdominant partner to a massive beech (Fagus sylvatica).
The beech tree was felled due to basal decay, and this then
made very prominent the one-sidedness of this oak tree's
crown, which is why I initially took a picture of this specimen.
Can a mature oak like this make use of such a late-in-
life opportunity, now that it is not suppressed under the
crown of a larger tree? The image says it all; this old oak
is more than willing to sprout into the space provided
and thus rebalance its crown. I hope to make a triptych of
this tree by making a third visit to this park in a decade's
time, to illustrate how an old tree can learn new tricks.
"The image says it all; this old oak is more
than willing to sprout into the space
provided and thus rebalance its crown."
36 CityTREES
