Andrew Ellicott Douglass, the American astronomer and pioneer of dendrochronology, was not born on November 12, 1799. Instead, Andrew Ellicott Douglass was born on July 5, 1867. It seems there is a confusion with the date or identity. Below is a brief account of Douglass’s contributions to science.

Andrew Ellicott Douglass

Born: July 5, 1867
Died: March 20, 1962

Contributions

Andrew Ellicott Douglass was an influential American astronomer known primarily for founding the field of dendrochronology—the scientific method of dating based on the analysis of patterns of tree rings, also known as growth rings. His work in this field has had wide-ranging implications for both archaeology and climatology.

Dendrochronology

• Initiation: Douglass’s interest in tree rings began as he sought to understand the sunspot cycle’s impact on climate. He hypothesized that changes in tree ring growth could be correlated with sunspot activity.
• Development: In the early 1900s, Douglass began collecting and comparing tree ring samples. By 1929, he had developed a continuous tree-ring sequence extending over 1,000 years.
• Impact: His work allowed for precise dating of wooden archaeological artifacts and structures, revolutionizing the understanding of historical chronologies and climatic variations.

Astronomical Work

Before pioneering dendrochronology, Douglass worked at several observatories:

• Lowell Observatory: Douglass worked with Percival Lowell, assisting in the study of Mars and advocating for Mars canals’ theory.
• Southern Astrophysical Research: He collected instrumental in constructing telescopes in Arizona, contributing greatly to observational astronomy during his tenure.

Legacy

Douglass’s pioneering work laid the foundation for dendrochronology being a key tool for archaeologists and climate scientists. The Laboratory of Tree-Ring Research, established by Douglass in 1937 at the University of Arizona, remains a leading institution for dendrochronological studies.