Date 1908, but yes, it is 'stacked tree.'

The verse:
With his grazin' bits and sand stacked tree,
His chaps and taps to boot,
His old maguey tied hard and fast,
Went out to tackle the brute.

See my post of 20 Jan 04 for the complete N. Howard Thorp "Windy Bill," Songs of the Cowboys, News Print Shop, Estancia, New Mexico; Copyright 1908 N. Howard Thorp.

A common variant of the name of the saddle maker, Sam Stagg.

See illus. 13 and links, http://www.schradersaddles.com/ld%20Style%20Saddles.htm