Green’s Dictionary of Slang

tall timber n.

also tall pines, tall timbers

1. [mid-19C+] (US, also timber) the rural areas, the backwoods, lit. and fig.

2. [1920s] (US) the gallows.

In phrases

take to the tall timber(s) (v.) (also beat it for the tall timber(s), break for tall timber, hit for the tall pines, … the tall timber, make for the tall timber, put for..., pull for..., strike (out) for tall timber, take for the tall timbers, take to the timber, tear to the tall timbers)

[mid-19C+] to run off.