Dendroclimatology of Eastern White Cedar 12th North American Dendroecological Fieldweek Rapide Danseur, Québec, Canada August 14-21, 2002 Dendroclimatology of Eastern White Cedar Ania Cedro, Julie Friddell, Kenjiro Sho, Yassine Messaoud Antoine Nicault, Group Leader
Questions: 1. Is White Cedar responsive to climate? 2. Do different environments modulate the climate-growth relationships in White Cedar ?
Introduction Ecology of white cedar (Thuja occidentalis) Northeast U.S. and Southeast Canada Long-living White cedar and climate Cool and wet No less than -12°C (Jan.) and 710 mm annual Grows well near lakes and rivers Lake Hébécourt!
B C A D E Lake Hébécourt N
Sampling strategy Lake Hébécourt – 5 islands Lake Shore Within 1 m of water Roots usually in water or thin soil Cliff ~2 m above water level Roots in rock Trees are twisted, short, many dead branches Interior of Island >2 m above water Roots in soil, moss
Methods Sample 41 trees from 5 islands in Lake Hébécourt Count and measure rings
Methods Statistical analysis Identify datable cores Create master chronology Make Response Functions Identify pointer years Comparison with other studies
Chronology Statistics Results Chronology Statistics N Mean Ring Width (mm) Mean Sensitivity Autocorrelation Cliff 16 0.48 0.23 0.72 Shore 9 0.57 0.22 0.74 Inside 7 0.79 0.19 0.68 Total 32 0.58 Comparison* 0.36 0.14 0.61 Cliff Chronologie *Archambault and Bergeron, 1992
Results Master chronologies
Results Pointer years Years Rings Climate 1992/93 Wide Warm August 1981/3 Narrow 1981 warm June, dry August 1982 dry June 1968 warm September (+5°C) 1920/24 1920 driest May 1921 driest June
Response Functions – All Cores Results Response Functions – All Cores Precipitation Temperature
Results Temperature Precipitation Inside Cliff Shore
Conclusions White Cedar appears to be not very sensitive to climate Climate explains ~20% of variance 2. White Cedar prefers cool, wet summers 3. Different sites do appear to have different responses to climate implication on dendroclimatological studies