Maple Sweet is included in the book, Folk Songs of Old New England, collected and edited by Eloise Hubbard Linscott, 1939. The book has two pieces of factual information about the song, but they seem to conflict slightly.

From p. 238:
Maple Sweet
In the Jackson family of Vermont this song of the early nineteenth century has been sung for five generations. It was contributed by Mrs. Addie Jackson Morse of Underhill, Vermont.

From p. 334, the "References" section:
Maple Sweet
Ref. P. B. Fish, The Palm (published in Keene, N. H., by G. U. Tilden Company).
[note: The surname "Fisk" has been misspelled as "Fish"]
[second note: Published in Keene!]

Linscott identifies Maple Sweet as a "song of the early nineteenth century," but Perrin Batchelder Fisk was not born until 1837, and his poems seem to date from the 1860s and later. As I said, a slight conflict.

If you do an Internet search on "pb fisk," you will be able to view some of his poetry at Google Books - the book available is a collection entitled Green Mountain Poets, by Albert J Sanborn, 1872.

This history site has a short biography of Fisk, mentioning his poetry. Note that the source referenced is dated 1894, and P.B. Fisk was still alive.
http://vermontcivilwar.org/museum/people/bio.php?input=39256

Here is the text of that article (in case the link dies some day!):
Source: Jacob G. Ullery, compiler, Men of Vermont: An Illustrated Biographical History of Vermonters and Sons of Vermont, (Transcript Publishing Company, Brattleboro, VT, 1894), Part II, pp. 138.

Fisk, Perrin Batchelder,
of Lyndon, son of Deacon Lyman and Mary (Spofford) Fisk, was born in Waitsfield, July 30, 1837, and from the age of thirteen to twenty-one labored at his father's trade of coopering. Strongly determined to obtain an education, at his majority he entered Barre Academy. Having chosen the ministry as his profession, he took a course in Bangor (Me.) Theological Seminary, where he graduated in the class of 1863. In the early part of the war of the rebellion he served as delegate of the Christian Commission in the Army of the Potomac. The coffee wagon had been sent to the Christian Commission at City Point, Va., and not being appreciated by those in authority, it had been left to rust by the wayside. Mr. Fisk finding it, saw it was a good idea and got permission to try it. It proved a great success and is remembered with gratitude by many a veteran.

Leaving Dracut in 1865, the subsequent pastorates of Mr. Fisk were in Massachusetts, Vermont, and Minnesota, and for two years he acted as the field agent of Carleton College of the last named state. Ill-health in his family demanded removal to a warmer climate, therefore he served in the home missionary field in Illinois and Florida for about five years. Returning to Vermont, he supplied at Morrisville and afterwards removed to Lyndon, where he now resides and has under his charge the parishes of Lyndon and St. Johnsbury Centre.

August 25, 1863, Mr. Fisk was united in marriage to Miss Harriet L., daughter of Charles E. and Luana (Carpenter) Bigelow. They have four children: Flora F. (Mrs. G. L. Zimmerman), George Shephard, Fidelia, and Grace Harriet.

Mr. Fisk was chaplain of the Vermont Senate in 1869 and 1870, and inaugurated the custom of daily legislative prayer meetings. He is a poet of more than local reputation and a few of his compositions have been published in the "Poets and Poetry of Vermont."