General Squier's "floraphone" was a short-lived idea that trees were useful as radio receiving antennas. Because the moisture in a tree allows it to conduct electrical currents, this worked to a limited degree, but it turned out to be much easier and more efficient to just toss a wire into the upper branches of a tree and use that as the receiving antenna.
 
Washington Post, August 24, 1919, page 15:

MARSHALL  AT  FORUM
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Wireless  Telegraph  and  Telephone  to  Report  Address.
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"GREAT  VOICE"  TO  AID,  TOO
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Vi

ews  on  "Problems  America  Must  Face  and  Solve"  to  Be  Given  Wider  Publicity  Tonight  Than  Ever  Before  Attempted--Daniels,  With  Fleet,  to  "Listen."
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    Vice President Marshall will address the Trinity Civic Forum tonight at 8 o'clock. His subject Will be "Problems America Must Face and Solve." The Rev. David Ransom Covell, provost, and Fairfax Naulty, secretary of the civic forum, have arranged to report the address of the Vice President in what is characterized as the "most complete manner ever attempted for a public address."
    The speech will be sent over telephone and telegraph wires, by wireless telephony and wireless telegraphy, through the earth, air and water. Stenographers will take the address in relays, and dictate their notes to typists as soon as the notes are transcribed carriers in motor cars will rush the "copy" to the wireless station at Arlington, Va , where the speech will be wirelessed to the limit of the range of the apparatus.

New  Invention  to  Be  Used.

    The "great voice," which has been installed in the twin spires of Trinity Church by direction of Gen. George E Squier, chief signal officer, U. S. A., will also be used to transmit the speech. Lieut. Col. Paddock, a nephew of Gen Pershing, and a radio expert, supervised the installation of the apparatus, which, it is said, will enable Vice President Marshall's speech to be heard in all parts of Washington.
    Auditors will be stationed at the west plaza of the Capitol, at the Washington monument, at the naval observatory and at Bolling Field and the War College to take the "address from the air."
    Radio operators aboard the President's yacht, "Mayflower," will be at their stations from 8:30 o'clock until the wireless report of the address completed.
    The Arlington wireless station will send the address out under "general call," so that Secretary Daniels, now with the Pacific fleet, will receive a copy of the speech.

Plan  "Floraphones"  on  Trees.

    In Virginia several large trees have been equipped with Gen. Squier's "florophone" by means of which the trees will act as wireless through the earth.
    Preceding the address, there will be the usual evening services, including singing, a cello solo, cornet solo, and an organ recital of Gounod's "Sanctus"
    An airplane from Bolling Field, equipped with radio apparatus and geared for night flying, will take its position over the Trinity Church, at a height of 6,000 to 9,000 feet, and the aviator will endeavor to receive the president's speech by wireless and the "great voice."