John George Jack

Meet the Explorers

John George Jack (1861–1949)

Dendrologist, Educator, Plant Explorer

John George Jack

John George Jack, March 1898. This photograph showing Jack at age 37 was taken by the Hardy photograph studio during his tenure as Lecturer in Arboriculture for Harvard College (Archives of the Arnold Arboretum).

John George Jack was a notable figure in the early history of the Arnold Arboretum. His story is perhaps less well known than some of his colleagues, but his 40 year dedication to visitor education, and especially his instruction of a generation of Chinese botanists, is unmatched.

In 1905, John George Jack embarked on a year-long trip to the Far East that focused principally on Korea and Japan, and may have also been planned in order to include spending time with his younger brother, the Reverend Milton Jack of the Presbyterian Foreign Ministry, who had long been stationed in Taiwan.

In addition to collecting seeds and herbarium specimens, Jack returned with images, many in a format especially useful for teaching purposes—lantern slides. Covering some of the ground that Arboretum plant explorer Ernest Henry Wilson would later visit, Jack photographed the forest preserves in Japan, as well as the forests of Taiwan and Korea.

Search the VIA image database for Jack’s photography.

Pearson, Lisa. “John George Jack: Dendrologist, Educator, Plant Explorer.” Arnoldia, 71:4, 2014 [pdf].

John George Jack (1861-1949) papers, 1887-1990 [pdf].

The works of John George Jack [HOLLIS].

Early Life
John G. Jack circa 1904

John George Jack, ca. 1904. This photograph was taken just before Jack’s year-long trip to Asia in 1905 (Archives of the Arnold Arboretum).

John George Jack was born in Chateauguay, Quebec, Canada, on April 15, 1861. His father was a farmer and fruit grower, and his mother a poet, author and noted horticulturist. As a boy Jack was interested in natural history with a special attraction to insects. Primarily self-taught with a minimum of private instruction, his formal education ended with only about six months of high school.

Through his natural history observations and collections, he was introduced to a variety of correspondents including Sir John William Dawson (1820-1899), Principal of McGill University, who became his friend and mentor. From 1882-1885, Jack wintered in Boston, attending lectures by Harvard professors, including Dr. Hermann August Hagen (1817-1893), Professor of Entomology, and author of Bibliotheca Entomologia. He studied zoology with Alpheus Hyatt (1838–1902), and attended lectures on botany given by George Goodale, Fisher Professor of Natural History. In 1883, Jack spent the summer working at the River Edge, New Jersey farm of Elbert S. Carman (1836-1900), editor of The Rural New Yorker, who had been conducting experiments on economic and woody plants at his farm since 1877.

John G. Jack 1935

John George Jack, 1935. Detail of a larger photograph taken on the occasion of his retirement from full time employment at the Arnold Arboretum (Archives of the Arnold Arboretum).


In April 1886, Jack visited the director of the Arnold Arboretum, Charles Sprague Sargent at his Brookline, Massachusetts estate, Holm Lea. Promised only manual labor at small compensation, he began work, but within a short time his botanical knowledge became apparent, earning Sargent’s confidence and an increase in his pay to a dollar a day. Jack continued his education by taking the Harvard Summer Course in Botany and continuing to attending lectures.

John George Jack, Educator

By the terms of the Arboretum’s original indenture, the director, as the Arnold Professor of Botany, was to teach the knowledge of trees at the College. Sargent delegated this function, with the approval of the trustees, to Jack who became Lecturer in Arboriculture in 1890. He taught at both Harvard, often with Richard T. Fisher (1876-1934), the first director of the Harvard Forest, and at the Massachusetts Institute of Technology, where he held a lectureship from 1899 to 1908. In 1908, he was made an Assistant Professor of Dendrology at the Arnold Arboretum.

Jack taught throughout his career. He conducted courses in dendrology, using the Arboretum’s living collections as his classroom. His courses were geared toward the layperson and his amicable disposition made them popular. According to the annual report for 1890/91, he “gave twice a week during the months of May and June, instruction … which treated of the plants, in their botanical, economic, and ornamental aspects, were practical and interesting.”

Jack took an active interest in educating and mentoring Chinese students who had come to the United States to study botany. The most notable perhaps was H.H. Hu, who would later identify living specimens of Metasequoia glyptostroboides, the Dawn Redwood, a tree previously thought to be extinct.


John George Jack retired from full time employment at the Arnold Arboretum in 1935 at age 74. He spent his retirement at his home “Folly Farm,” in East Walpole, Massachusetts with his daughter and her husband. In 1948, while tending his orchard Jack fell and broke his hip and was confined to bed. The following year, John George Jack, Arnold Arboretum Assistant Professor of Dendrology, Emeritus, died at age 88.

Plant Explorer
John George Jack Leading Field Studies

John G. Jack with a class of Forestry students in the hickory collection of the Arnold Arboretum, ca. 1900 (Archives of the Arnold Arboretum).

John George Jack, Plant Explorer

Soon after Jack joined the Arboretum he began collecting and documenting plants in the United States and abroad. During the summers of 1898 and 1900, he was an agent for the U.S. Geological Survey and the U.S. Department of Agriculture. He explored the forests of central Colorado and the Big Horn Mountains of Wyoming and produced detailed documentation and photographs of the forest and soil conditions of the Pikes Peak, Plum Creek and South Platte Forest Reserves. In 1891, he visited botanic gardens in France, Germany, Italy, Denmark, and England, and in 1904, he and Arboretum taxonomist Alfred Rehder (1863-1949) collected plant specimens and took photographs in the western United States and in Canada.

John George Jack in Asia

Already an experienced plant explorer when he embarked on a year-long trip to Asia in 1905, Jack became the first staff member after Sargent to visit the region. He focused his travels on Japan and Korea as political unrest at the time made travel in mainland China dangerous. Although Sargent’s annual report for 1904/05, states that “Mr. J. G. Jack has started on a journey to the East to obtain material for the Arboretum in Japan, Korea, and northern China,” his journey was self-financed. He may have planned his trip to spend time with his brother, Presbyterian missionary Milton Jack, who was stationed in Taiwan. Jack’s introduction to an undated, unpublished manuscript entitled Notes on Some Recently Introduced Trees and Shrubs outlined his goals and itinerary for the trip:

“The object of my trip was primarily rest and recreation for three or four months, combined with a desire to observe some of the interesting arborescent flora of central and northeastern Japan.”


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In addition to collecting seeds and herbarium specimens, Jack photographed trees, forestry practices, and landscape views, returning with 172 images, some as lantern slides, a format especially useful for his teaching. Covering some of the ground that E.H. Wilson (1876-1930) later visited, Jack photographed the forest preserves and activities of the lumbering industry in Japan, as well as the forests of Taiwan and Korea.