1. 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

2. Questions: 1. Is White Cedar responsive to climate?
2. Do different environments modulate the climate-growth relationships in White Cedar ?

3. 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!

5. B C A D E
Lake Hébécourt N

6. 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

7. Methods
Sample 41 trees from 5 islands in Lake Hébécourt
Count and measure rings

8. Methods
Statistical analysis
Identify datable cores
Create master chronology
Make Response Functions
Identify pointer years
Comparison with other studies

9. 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*
Cliff Chronologie
*Archambault and Bergeron, 1992

10. Results
Master chronologies

11. 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

12. Response Functions – All Cores
Results
Response Functions – All Cores
Precipitation Temperature

13. Results
Temperature Precipitation
Inside Cliff Shore

14. 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