What is a tree?

What is a tree but a throw away term
a northern hemisphere assumption
that we all grow straight and tall
and adopt a standard upward function
 
But when the descriptions were written
no great southern land existed
and the bizarre and the unorthodox persisted
for what is normal can also be beyond description
 
A tree is typically a single trunk or stem found
growing to a considerable height and bearing
with lateral branches some distance from the ground
then what of sprawling shrubs with a form of their own?
 
Those that lie along coastal cliffs and bays of the southern shores
resting limbs along granite tors and spreading in swarms  
gnarled and multi-stemmed marching across deserts sand
conspicuous pink flowers in winter, unburnt on stony lands
or disappearing in fiery hell on the slopes of arid mountains
only to return again, a phoenix of soft green uplifted stems
 
These things that were too unusual to be called a tree
Now take the Aboriginal word of mallee