The tree ring
data create a comprehensive history of drought conditions in the Southwest and Central Plains from about 1,000 years ago to 2005 and show a severely dry period in the 1100s, which may have contributed to the decline of ancient Pueblo peoples of the Colorado Plateau in the late 13th century.
Each tree ring
was exactly dated by using standard dendrochronologic methods described by Douglass (17), and earlywood and latewood growth increments were measured by using a stage micrometer.
The society's Joy Parry, who is retired and lives in Cardiff, said: "He's an authority on tree ring
dating and he's done a lot of diving in various places so we're all looking forward to hearing his lecture.
See Rocky Mountain Tree Ring
Research reference for detailed information on use and care of increment borers.
There is now an archive of tree ring
samples dating back to more than 12,000 years ago.
It has evolved from a tree ring
dating project which established probable building dates for more than 90 properties in the region.
We map their crown structure, we collect leaf and branch samples and tree ring
cores, we install weather stations .
A clear boundary can exist between earlywood and latewood, representing a false tree ring
Figure 2 shows three Northern Hemisphere summer temperature reconstructions based entirely on tree ring
data, using different standardization techniques.
Experts at Stockholm University studied data from tree ring
sediments to investigate temperature changes over the last 2000 years.
Scientists combined tree ring
data and sediment records to investigate long-term changes in northern hemisphere temperature.
Covering subjects like tools and techniques, tree ring
dating, identifying Stone, Bronze and Iron Age objects and using a map to find archaeological sites, it also looks at the origins of place names.