Gene Royer schreef
That is neither pretty nor simple, and I appreciate your indulgence.
However, Iris's direct explanation melds with my limited knowledge and
answers my question.

My understanding of botany is limited to my burpless cucumber crop each
year--urged on by the steer manure I use to encourage its success.

+ + +
Indeed there is a general correlation between growth speed versus density
and durability of the wood (also, somewhat less, with color). However this
is not necessarily all that is at play he a tree or shrub also has to
stand up to the stresses it is subjected to. As a general rule branchwood is
denser and meaner than the wood of a trunk. This goes for small diameter
trunks as well.

So for a species like Osage-Orange with a reputation for being suitable for
hedges "horse-high, bull-strong and pig-tight" it stands to reason the wood
is not especially tractable.

PvR