I want to create a long, hollow down 2/3 the length of a
deciduous tree's trunk. BRBR
FWIW, it is a sweetgum, Liquidambar styraciflua.

Please note correct spelling
You are in a relatively warm climate, more conducive to infections in plants. I
would suggest first of all that you consult a local arborist on the
advisability of doing this to that species. Or else find a local bonsai grower
who has done something similar.
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)