Eloise Butler wrote in 1915: One of my white birches on a hillside has eight bolls, while opposite opposite in the meadow a yellow birch rejoices with seven. Between them “Monarch,” the largest white oak in Minneapolis, lifts his aged head and rules the landscape"
It is reported that Eloise measured the circumference at 8.5 feet and always stated that the tree was over 700 years old. The age is probably wildly overestimated. Tree age calculation tables for a white oak of that size would indicate an age of at least 160 years for trees growing in perfect environment but up to 260 years for a typical forest tree of the White Oak species. [see note below] But there is no doubt that Monarch was old and decaying.
On April 4, 1912, tree surgeons were brought it. Eloise noted in her log “Monarch treated surgically today.” Dead limbs were removed and concrete was used to reinforce the rotting trunk. The rotting trunk may be the reason that the base of tree usually produced a mushroom, Polyporus frondosus [Hen of the Woods], often of large size - 25 pounds in 1935.
In an essay she wrote in 1926 [Trees in the Wild Garden], Eloise gave some details about that surgical operations and subsequent events.
“ ‘Monarch’,” as we call him, was slowly dying atop. So, in obedience to the scriptural injunction, his dead limbs were cut off and cast away, and decayed portions of his “heart” - not essential as with humans for circulation -- were taken out and replaced with concrete. Thus, lopped and reinforced, he bade fair for many more years to hold sway. Alack and alas! In the tornado of June , large chunks of concrete were belched out and all the limbs torn off. How long will he yet stand without his crown?”
Her question would be answered by her successor, Martha Crone, in 1940. On Oct. 28th 1940 she went back to the Garden (the Garden closed Sept. 30 in those days) to direct some workers on which trees to cut. She met Mr. Lucking there. One of the trees removed was the old giant white oak. [Greg Lucking, Parks horticulturist from 1940 to 1966]. In her annual report to the Board of Park Commissioners (Dec. 11, 1940) Martha wrote:
“It is with deep regret that I record the passing of the oldest inhabitant of the Reserve, the Giant White Oak, estimated age 700 years. It had become a hazard to passers-by, therefore it was removed in October.”
NOTE: An example of a White Oak that can attain an age of 240 years is an old White Oak recently taken down in the forest at St. John's Abbey in Stearns County Minnesota. Tree ring count indicated it started as a acorn around 1776.