trees, and rocks (not stumps) were expedient, given their time and the fact that in those days folks were not buying and selling 7,000 S.F. lots they were homesteading entire Sections or more of land. The transition to smaller more portable monumentation for parcels was gradual, and related mostly to the shrinking of the parcels in question not so much to do with the permanence or lack thereoff of the monument, and the advent of the Public Land System
in those days folks knew that Big Oak tree, or giant rock was there property corner, so they left it alone, and concentrated on removing only the trees and stumps from the fields or pastures they wished to clear they had enough work to do already than chop down and or blast out their property markers....
try pulling an 50 year old oak tree out of the ground 'by accident', or moving a 10 ton granite boulder.... go ahead, just try it