L. 1888, Chap. 196—An act to encourage arboriculture.

Arbor day established.
SECTION 1. The Friday following the first day of May in each year shall hereafter be known throughout this state as Arbor day.
School exercises on Arbor day. § 2. It shall be the duty of the authorities of every public school in this state, to assemble the scholars in their charge on that day in the school building, or elsewhere, as they may deem proper, and to provide for and conduct, under the general supervision of the city superintendent or the school commissioner, or other chief officers having the general oversight of the public schools in each city or district, such exercises as shall tend to encourage the planting, protection and preservation of trees and shrubs, and an acquaintance with the best methods to be adopted to accomplish such results.
Course to be prescribed by superintendent. § 3. The state superintendent of public instruction shall have power to prescribe from time to time, in writing, a course of exercises and instruction in the subjects hereinbefore mentioned, which shall be adopted and observed by the public school authorities on Arbor day, and upon receipt of copies of such course, sufficient in number to supply all the schools under their supervision, the school commissioner or city superintendent aforesaid shall promptly provide each of the schools under his or their charge with a copy, and cause it to be adopted and observed.
Throop, Montgomery H., ed. The Revised Statutes of the State of New York, as Altered by Subsequent Legislation. Vol. 2. 8th Ed. Albany, NY: Banks & Brothers, 1889. 1333.

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NOTES ABOUT TOWN.
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—The Arbor day exercises at the public schools yesterday was [sic] very interesting.
—Most of the business houses of this village, did not observed [sic] the legal holiday.
Lansingburgh Courier. May 4, 1889: 3 col 2.

Skinner, Charles R., ed. Arbor Day Manual: An Aid in Preparing Programs for Arbor Day Exercises. Albany, NY: Weed, Parsons & Co., 1890. https://books.google.com/books?id=gJ4CAAAAYAAJ

—Preparations are in progress for exercises to be held Arbor Day in the schools of Upper Troy.
“Upper Troy.” Troy Daily Times. April 18, 1901: 4 col 2.

Burgh Bicentennial Group Names Advisory Body
By ROGER SUTLIFF

An advisory committee to the Lansingburgh Bicentennial Committee and a parade chairman were named at a meeting Monday night at Lansingburgh Elementary School. […]
Lansingburgh schools will plant shrubs and flowers in Powers Park on Conservation Day to be observed by the students in lieu of Arbor Day.
Times Record. December 15, 1970: 28 col 4-5.

See also Shade Trees