Inyo National Forest

Recreational Activities - Ancient Bristlecone Pine Forest

Your Visit to the Bristlecone Pine Forest

Immature Cones

Pioneers of Modern Dendrochronology

Dendrochronology is simply defined as the study of tree rings. Weather patterns, fire history, volcanic events and even flood cycles can be determined through a detailed analysis of the pattern of tree rings. Leonardo da Vinci is credited with first noticing and documenting tree ring patterns. It was the pioneering work of two research scientists during the twentieth century that opened up this exciting field of discovery: Dr. Andrew Ellicott Douglass and Dr. Edmund P. Schulman.

A.E. Douglass is considered by many to be the founder of modern dendrochronology. Born in Vermont in 1867 and trained as a mathematician and astronomer, Dr. Douglass theorized that periodic sunspot cycles could cause slight weather changes that would be recorded in tree-ring width variances: wider rings representing more rainfall, narrower rings indicating drier periods. It was this pursuit of data to validate an astronomical theory that led Dr. Douglass to collect thousands of tree-ring samples. Through his persistent research, A.E. Douglass became an expert at tree-ring dating and analysis. Ironically, his greatest contribution however, was a crucial archeological discovery. (Photo Inset: Dr. Andrew Ellicott Douglass)

For many years, historians and archeologists struggled to attach a date to early Native American structures that were scattered throughout the desert southwest. By comparing the tree-ring patterns of a timber used in a dwelling against the know, dated pattern of tree rings from living and cross-dated dead trees, Dr. Douglass was able to attach an exact date to the Show Low archeological site in Arizona. That discovery opened the door for dating of other archeological sites throughout the desert southwest using tree-ring dating methods developed and refined by Andrew Ellicott Douglass.

Dr. Douglass' astronomy and tree-ring research led to the establishment of both the Steward Observatory and the Laboratory of Tree-Ring Research on the University of Arizona campus in Tucson, Arizona. He remained active at the Tree Ring Lab well into his 90s and spent over 50 years at the university as an instructor, researcher, Tree-Ring Lab Director, and even University President.

Edmund P. Schulman began his career as an assistant to Dr. Douglass at the Laboratory of Tree-Ring Research. He continued Douglass' work on tree-dating with his own emphasis on climate research. Schulman knew that long periods of tree rings could provide an unparalleled look into past weather and climate conditions.

His search for long tree-ring records led him to the White Mountains of California to examine what were reported to be very old trees. Very old indeed! (Photo Inset: Dr. Edmund P. Schulman)

Dr. Schulman was searching for trees that would break the 3,000 year-old barrier when he took samples from old, weather-beaten, twisted trees along what we now call the Discovery Trail.

Schulman began dating his samples when he soon realized that in addition to breaking the 3,000 year-old barrier he would surpass the 4,000 year-old mark with hundreds of years to spare! Schulman suspected that even older bristlecone pines might be nearby and returned in subsequent years to continue his research. In 1957, he discovered a bristlecone pine with growth rings extending back over 4,600 years. He named this tree Methusela - a reference to the oldest man in the Bible; it is still recognized as the oldest living tree in the world. Schulman went on to discover over twenty 4,000 year-old trees in the White Mountains.

A landmark article written by Edmund Schulman in 1958 and published in National Geographic magazine introduced the world to the majestic bristlecone pines. In 1959, the US Forest Service established the Ancient Bristlecone Pine Botanical Area and dedicated Schulman Grove to the memory of a pioneer of modern dendrochronology: Dr. Edmund P. Schulman.