We have made isotopic and dendrochronologic measurements on material collected from the Two Creeks site. Radiocarbon dating of outside wood of four logs yielded an average age of 11,760 +/- 100 BP, in good agreement with results of Broecker and Farrand (1963) over 25 years ago. The range of 11,640 +/- 160 to 11,900 +/- 160 BP suggests a period of forest growth of 200-300 years, consistent with a ring-width chronology established by Kaiser (1987). Ring counting of five specimens gave a range of individual tree ages from 110 to 182 years, and width measurements indicate very low year-to-year variation in ring size. However, preliminary cross-dating of five samples produced a 202-year floating chronology. Stable-carbon isotope chronologies on cellulose from five-year ring groups show deltaC-13 scatter among trees typical of that found within modem sites, with some matches of isotopic maxima and minima. Some downward deltaC-13 trends may result from physiological response to rising lake levels (and/or cooling temperatures) at the site, which also produced very narrow rings in the outer ca. 50 +/- 20 years.
|Number of pages||5|
|Publication status||Published - 1992|
- tree rings