Latest Dendrochronology Stories

April Flowers for redOrbit.com - Your Universe Online A new tree-ring study, led by the University of Arizona, reveals that long-term droughts in Southwestern North America often mean a failure of both summer and winter rains. This contradicts a long held belief that a dry winter rainy season is usually followed by a wet monsoon season, or vice versa. According to the new data, both summer and winter rains were sparse year after year during the severe, multi-decadal droughts occurring...

The National Science Foundation has funded a study to determine past climates by studying tree rings. Environmental students from Arizona studied bristlecone pine trees to determine aspects about the Earth’s climates during the Paleo age. The study of tree growth rings to understand Earth’s past climate is called dendrochronology. As each year passes, trees add growth rings around their trunks. These dendrochronologists study these rings to gain all sorts of information not only about...

Some climate cooling caused by past volcanic eruptions may not be evident in tree-ring reconstructions of temperature change because large enough temperature drops lead to greatly shortened or even absent growing seasons, according to climate researchers, who compared tree-ring temperature reconstructions with model simulations of past temperature changes. "We know these tree rings capture most temperature changes quite well," said Michael Mann, professor of meteorology and geosciences and...

Researchers with the University of Arizona (UA's) have discovered evidence of a formerly unknown, decades-long drought that occurred in the southwestern United States in the second century, the school announced in a November 3 press release. The study, which was the work of geoscientists Cody Routson, Connie Woodhouse and Jonathan Overpeck of the university's Laboratory of Tree-Ring Research, involved a study of the southern San Juan Mountains in Colorado. The region is said to be a...

Nibbling by herbivores can have a greater impact on the width of tree rings than climate, new research has found. The study, published this week in the British Ecological Society's journal Functional Ecology, could help increase the accuracy of the tree ring record as a way of estimating past climatic conditions.Many factors in addition to climate are known to affect the tree ring record, including attack from parasites and herbivores, but determining how important these other factors have...

Trees are outstanding historians. In fact, scientists dating back to Leonardo da Vinci recognized the value of trees. While others had figured out that you could determine the age of a tree by counting its growth rings, da Vinci went beyond that basic knowledge. "He was a genius and realized also that the width of those growth rings carried information about the environmental conditions during each year the rings were formed," says David Stahle, director of the Tree Ring Laboratory at the...

A group of researchers have studied the history of drought in the Pacific Northwest during the last 6,000 years, a time that spans the mid-Holocene geological epoch to the present. The goal of the research was to improve the understanding of drought history because the instrumental record of drought only goes back a few hundred years and at relatively few locations.Their work extended the drought history of the Pacific Northwest back much longer than the tree ring record, which provides...

A new, detailed record of rainfall fluctuations in ancient Mexico that spans more than twelve centuries promises to improve our understanding of the role drought played in the rise and fall of pre-Hispanic civilizations.Prior evidence has indicated that droughts could have been key factors in the fates of major cultures in ancient Mexico and Central America (Mesoamerica). But there have been many gaps in the paleoclimate record, such as the exact timing and geographic extension of some...

A team of researchers conducting an extensive study of growth rings in trees say there could be a link between the rise and fall of ancient civilizations and sudden shifts in Europe's climate. They based their findings on data from more than 9,000 wooden artifacts that have come from civilizations from over the past 2,500 years, BBC News reports. In the study, published online in the journal Science, the researchers found that periods of warm, wet summers coincided with prosperity,...

An unprecedented, decades-long combination of heat and drought could be headed to the Southwest United States sometime this century, according to a new study by researchers at the University of Arizona.The scientists reviewed previous studies of temperature changes and droughts in the region over the past 1,200 years, and concluded that a 60-year drought similar to the one that occurred during the 12th Century could be in our future. "Major 20th century droughts pale in comparison to...