Andrew Ellicott Douglass

Andrew Ellicott Douglass (1867-1962) is commonly hailed as the father of dendrochronology. He was a husband, a scientist, an astronomer, a teacher, an inventor, a mountain climber, and many other things. There are some contradictory reports about his life but all of the reports appeared to me to be unanimous in their opinion that Douglass was a remarkably kind and hard-working individual.

“…after his fame was established by bridging the gap in dating prehistoric ruins in the Southwest, he became known as the father of dendrochronology.”[1, pp.310-311]
Robert E. Hastings, Jr. (1998)

Aside from the comment by Hastings, the earliest instance I could locate that called Douglass the father of dendrochronology in print dates to 1962, the year of his death.[8]

“Douglass was also an honorary life member of the National Geographic Society, a Rotarian, and a 33° Scottish Rite Mason.”[8, p.5]
Anonymous (1962)

Click here to see my list of his works.


1867, July 5th: In Windsor, Vermont, the fifth child of Reverand Malcolm Douglass and Sarah E. (Hale) Douglass was born. He was named Andrew Ellicott after Reverand Malcolm’s father.[2, p.170], [8, p.3]

Childhood: He grew up in New England.[2, p.170]

Pre-1884: His scientific prowess was developing and people took notice to the degree that his high school teachers allowed him in his senior year to teach his own astronomy class.[2, p.170]

1884: He failed the entrance exam for Trinity College in Hartford, Connecticut. The issue here was a lack of familiarity with the classics (history).[2, p.170]

1885, June: After a year of diligent studying, he passed the entrance exam for Trinity College in Hartford.[2, p.170]

“By the end of his first semester, he had impressed the director of Trinity’s small observatory so deeply that he gave the young scholar a key to the building and made him his chief assistant, a position the boy kept through his Trinity years.”[2, p.170]
George Ernest Webb (1978)

1889: Some say that Douglass graduated from Hartford Connecticut’s Trinity College with honors in astronomy, physics, and mathematics and then went to work for the Harvard College Observatory until 1894.[2, p.171], [5], [8, p.3] However, a different report claimed that Douglass obtained his degree with honors in astronomy, physics, and geology.[3, p.440]

1892: Douglass was a part of Harvard’s trip to Peru to study Mars. He spent his free time climbing the Peruvian mountains and exploring the local ancient ruins.[2, p.171] The trip to Peru was also to help establish Harvard College Observatory’s Peruvian Station.[7], [8, p.3]

1893: He returned to Massachusetts. Douglass was recruited by Percival Lowell, a wealthy man from Boston, to establish an observatory in Arizona.[2, p.171], [6]

1894, Spring: To find a spot for the observatory, he travelled throughout the Territory of Arizona and eventually chose Mars Hill as the final location, which is about a mile west of Flagstaff. Douglass was an important figure in the establishment of this observatory not only because he helped choose the location in which it would be built but because he drafted the plans for the telescope and the observatory and he oversaw the construction project.[1, p.315], [5]

Lowell sought to establish the observatory for the purpose of studying Mars, but more specifically for the purpose of determining if intelligent life on Mars was a possibility.[6] Lowell became increasingly captivated by the belief that there had once been a civilization on Mars because he claimed to have seen canals on the surface of Mars.[1, p.315], [5]

1901, August: Douglass did not support Lowell’s belief in a Martian civilization and this inevitably resulted with Douglass being dismissed from the observatory.[5] Although, there never was an official reason given for his release.[1, p.315]

1901, August & December: He traveled all over the Colorado Plateau.[4, p.293]

1902/1903-1906: He was Probate Judge of Coconino County. Hasting reported that Douglass held this position starting in 1903[1, p.315] but Webb reported that Douglass held the position for a total of 4 years starting in 1902.[2, p.172] The three year term seems to me to be the most popular report.[8, p.3]

1905: He taught Spanish and Geography at Northern Arizona Normal College.[1, p.315], [2, p.172] It was also in this year (on August 3rd[9]) that he married Ida E. Whittington.[8, p.3] Although, Webb reports that they didn’t marry until 1908.[2, p.172]

1906: He moved from Flagstaff to Tuscon in order to teach astronomy and physics as an assistant professor at the University of Arizona.[2, p.172], [5] A different report says that he started there as an Assistant Professor of Physics and Geography, then he moved up to Professor of Physics and Astronomy in 1907. He maintained this later position until 1922.[8, p.3]

In those years between 1894 and 1906, Douglass became increasingly interested in the connection between solar variability and the climate of Earth. Weather records were in short supply and so his study into how the two aforementioned topics were connected was difficult to study. This is what lead Douglass to investigate trees. He had the idea that the growth layers found in trees could potentially give insight into centuries of wet and dry periods.[5] He believed that tree rings showed variations in rainfall and that those variations in rainfall were likely a result of variations in the sun’s activity.[4, p.293] Just as a reminder, these studies were being conducted not for historical dating but to be used as a tool in astrophysics.[4, p.294]

1908: Trinity College awarded Douglass the honorary degree of Doctor of Science.[8, p.5]

1909: The Monthly Weather Review published his first paper on dendrochronology.[1, p.315]

1910, December 10th-1911, March 10th: According to Arizona State University, it was during these 3 months that Douglass was the University of Arizona’s acting president.[7] Although, Webb claimed that Douglass held this position until the May of 1911.[2, p.172]

1911: Upon examining trees from both Prescott and Flagstaff, he discovered that cross-dating could be applied to much greater areas of land than previously thought.[1, p.316], [3, p.442]

1912: He travelled to Scandinavia and Germany.[3, p.442]

1914: His paper from 1909 was updated to be added to The Climatic Factor (Washington: Carnegie Institution).[11] This is the publication that gained Douglass a higher reputation in the scientific community. [1, p.316]

1915-1919: He studied Giant Sequoias in California.[3, p.442], [8, p.4]

1915-1916: At the Four Corners (Arizona, Utah, Colorado, and New Mexico), Douglass applied dendrochronology to archeology in an attempt to obtain dates for the ancient Anasazi Indians’ ruins.[3, p.445] He did so by trying to compare the results from the Four Corners to those from California. This cross-dating did not prove useful and so he had to resort to working solely with local chronologies.[3, p.446]

1915-1917: He was the Dean of the College of Letters, Arts, and Sciences.[8, p.3]

1916: He founded the Steward Observatory, named after its generous benefactor.[5]

1917: He became the first director of the Steward Observatory.[8, p.3]

By 1919: He had established a 500 year chronology for pines (mostly Northern Arizonian Ponderosas) and another 500 year chronology for Californian Sequoias.[1, p.316]

1919-1936: He published his Climate Cycles and Tree Ring Growth, Vols. 1-3. There were 4 volumes planned originally but volume four was never completed. This collection is commonly known as The Carnegie Series.[1, p.311]

1925-1938: He was a Research Associate at the Carnegie Institute of Washington.[8, p.5]

1929: His activities during this year are what earned him the title “Father of Dendrochronology”. In this year, he is believed to have established an absolute age for a number of Southwestern prehistoric ruins.[1, p.317] This was believed to help solve a concern among the academic archeologists about when people had built their prehistoric buildings.[1, p.318]

“When Douglass succeeded in establishing the dates of those structures, this really was a revolutionary accomplishment. An intellectual revolution and it changed not only the thinking of the professional pre-historians, archeologists, and anthropologists, it changed the world view of us all, scientist and layman alike.”[1, p.318]
Robert E. Hastings, Jr. (1998)

“The discovery of the famous beam HH-39 on June 22, 1929 in Showlow, Arizona established the dating and forever changed American archeology.”[3, p.446]
Donald J. McGraw (2000)

1930s: He finished creating the machine known as the Cycloscope.[1, p.311] It was in 1913 that he started designing it. By 1935 he had finished the design and in 1936, Stanford University constructed it. Originally, it was called the Merriam Cycloscope. This naming was done to honor the president of Carnegie Institution of Washington because they were the ones who funded the creation of this machine.[10]

“That machine was essentially an early analog computer. And it was so far ahead of anything of its time that it was understood by few.”[1, p.312]
Robert E. Hastings, Jr. (1998)

1931: He received an award from the Research Corporation of New York.[8, p.5]

1937: He founded the Laboratory of Tree Ring Research (LTRR) at the University of Arizona.[3, p.442, p.447], [5]

1938: He retired from his position as director of the University of Arizona’s Steward Observatory[2, p.186] and became Director Emeritus of that observatory. In the same year, he also became the director of the Laboratory of Tree Ring Research.[8, p.3]

1942-1946: He was Acting Director of the Steward Observatory.[8, p.3]

1946-1958: He was the Steward Observatory’s Director Emeritus, the LTRR’s Director, and a part-time Professor of Astronomy and Dendrochronology.[8, p.3]

1947-1957: He created the Planetary Interpolator (PLINT). This was a “complex, high-precision instrument … used to determine heliocentric longitude, the position of the planets in their rotation around the sun.”[1, p.312]

1956: The Society for American Archaeology and the American Anthropological Association both awarded Douglass with honorary resolutions for his scientific contributions.[8, p.5]

1958: He either retired from the lab[7] or he continued on as the part-time Director Emeritus.[8, p.3]

1962, March 20: He died at the age of 94 in Tucson, Arizona.[7], [8, p.3] Although 94 is the most common age of death that I’ve seen, McGraw reported that Douglass died at the age of 95.[3, p.447]

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[1] – Bannister, Bryant, et al. “Remembering A. E. Douglass.” Journal of the Southwest, vol. 40, no. 3, 1998, pp. 307–318. JSTOR, Accessed 4 Jan. 2021.

[2] – Webb, George Ernest. “The Indefatigable Astronomer: A. E. Douglass and the Founding of the Steward Observatory.” The Journal of Arizona History, vol. 19, no. 2, 1978, pp. 169–188. JSTOR, Accessed 4 Jan. 2021.

[3] – McGraw, Donald J. “Andrew Ellicott Douglass and the Big Trees: The Giant Sequoia Was Fundamental to the Development of the Science of Dendrochronology—Tree-Ring Dating.” American Scientist, vol. 88, no. 5, 2000, pp. 440–447. JSTOR, Accessed 4 Jan. 2021.

[4] – Webb, George E. “Solar Physics and the Origins of Dendrochronology.” Isis, vol. 77, no. 2, 1986, pp. 291–301. JSTOR, Accessed 9 Dec. 2020.

[5] – Accessed 9 Dec. 2020.

[6] – Accessed 9 Dec. 2020.

[7] – Accessed 4 Jan. 2021.

[8] – Anonymous. 1962. Andrew Ellicott Douglass: 1867-1962 (Obituary). Tree-Ring Bulletin 24(3-4):2-10. Accessed 8 Jan. 2021.

[9] – Accessed 8 Jan. 2021.

[10] – Accessed 8 Jan 2021.

[11] – Accessed 8 Jan. 2021.

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