Recent Dendrochronological studies in the Yukon Territory
B. H. Luckman1, M. Kenigsberg1, D. Morimoto1, S. Earles1,
E. Watson 2 and D. Youngblut3
1Department
of Geography, UWO, London, Ontario
2 Environment Canada, Downsview
3 Department of Geography, Carleton University, Ottawa
MTN CLIM 2006
Yukon tree-ring network , Initial UWO sampling
South west Yukon, June- July Maximum temperatures, 1684-1995
(Luckman and Youngblut, submitted )
Anomalies (w.r.t. 1961-90 mean)
3
2
1
0
-1
-2
-3
1650
1700
1750
1800
1850
1900
1950
2000
Year
Revised and extended. adj r2= 46.6% ( 1945-2000)
Composite of seven chronologies : Gray Mountain, Telluride, Canyon Lake,
Eagle 12, Burwash, Big Salmon and Monarch
Whitehorse temperatures
June-July, 1942-2002
1950
MAXIMUM
1960
1970
1980
1990
2000
Calendar Year
18
June Max
July
17Max
Mean Temperature (°C)
Maximum Temperature (°C)
24
23
22
21
20
19
18
17
16
15
14
1940
MEAN
Jun/July Avg. Max.
16
15
14
13
12
11
10
9
8
1940
1950
1960
1970
1980
1990
2000
Calendar Year
June Mean
July Mean
Jun/Jul Average Mean
Comparison of the June-July Maximum
Temperature Reconstruction with Instrumental Data
1940
4
1950
1960
1970
1980
1990
2000
r = 0. 69
Regional Series
(1946-1995)
calibration period
Stations
60° 17" -61° 37“ N
2
0
-2
CALIBRATION
VERIFICATION
r
r2
adjr2 SE
r
RE
CE
1946-1970 0.70 0.49
0.45 June/July
0.98
1971-1995 Temperature
0.63 0.41 0.38
Regional
Maximum
1971-1995 0.71 0.51
0.46 0.82June/July
1946-1970
0.65Temperature
0.42 0.40
Reconstructed
Maximum
-4
r = 0. 54
3
2
1
0
-1
Gridded June/July Mean Temperature (60-65N X 135-140W)
Reconstructed June/July Maximum Temperature
-2
-3
1900
1910
1920
1930
1940
1950
Year
1960
1970
1980
1990
2000
Temperature Anomalies (wrt 1961-1990 mean)
Temperature Anomalies (wrt 1961-1990 mean)
Year
Grid Square
60-65°N, 135-140°W,
1901-1995
Only Dawson
(64° 04’N) prior to
1945
Comparison of Yukon reconstruction with ringwidth PC
from sites in the Wrangell Mountains (Alaska)
4.00
S.W.Wrangells
YUKON
(JUNE-JULY) MAXIMUM TEMP.
RW RCS
Normalised IndexINDICES
NORMALISED
SW Yukon June/July maximum temperature reconstruction
3.00
RINGWIDTH WRANGELL MOUNTAINS CRNS
2.00
1.00
0.00
-1.00
-2.00
-3.00
1700
1750
1800
1850
1900
1950
2000
Calendar Years
CALENDAR
YEAR
Alaska data courtesy of Rosanne D’Arrigo
Number of Yukon chronologies
Number of chronologies
RW Indices
TT HH Chronology
SW Yukon composite
Twisted Tree-Heartrot Hill (TTHH) ca. 65˚N (Jacoby and Cook 1981, updated)
classic temperature sensitive series has 10 cores from 1672 onwards
SW Yukon composite has 8 chronologies
Gray Mountain, Telluride, Canyon Lake, Eagle 12, Burwash, MacDonald Lake, Big Salmon and Monarch
DIVERGENCE
In updating the records from the TTHH site D’Arrigo et al noted a strong decline in
ring-width indices (solid line below) compared with predicted RW indices based on the
previously determined RW temperature relationships at this site (dashed line) .
The “Principle of Limiting Factors” states that rates of plant processes are constrained by
the primary environmental variable that is most limiting.
This divergence attributed to a change from temperature-limited growth to moisturelimited growth in recent decades
Only 1//8 of SW Yukon sites show this effect.
Earles ( in progress) sampled 22 Picea
glauca sites along the Dempster Highway
between 64º 44”and 66º 56” N
Preliminary results from the last 25 years
(17 chronologies) indicate that
• 5 show a declining trend
• 6 show an increasing trend
• 6 show no trend
Trend is not universal and may be site
sensitive
SAMPLING 2002-2006
Faro
Nansen Creek
Dempster Highway
Silver City
Yukon and Northern BC : Sites collected by 2006
Yukon and B.C. > 54˚N details
Species
ITRDB TOTAL
Abies lasiocarpa
1
27
Picea glauca
9
115*
other picea
3
14
other species
1
11
TOTAL
14
167
Yukon
14
123*
BC N of 54
10
44
* 6 in NWT, 1 in Alaska
10 densitometric picea chronologies
Worm Lake 64.29N 136.00 W
Sites
(°N)
66.7
1783
1816-17
63
58.3
61
1780
1790
1800
1810
1820
1830
1840
1850
1860
1870
1880
Summary growth patterns for Yukon Picea glauca sites arranged from north to south
69 sites are shown. The upper block is 58 UWO sites and 11 others.
The bottom 4 sites are around the southern end of Kluane Lake.
Sites
(°N)
66.7
1900 1904 1912
1919-21 1924-6
1948-9 1952
1970 1973 1984 1987-8
63
58.3
61
1890
1900
1910
1920
1930
1940
1950
1960
1970
1980
1990 2000
Summary growth patterns for Yukon Picea glauca sites arranged from north to south
69 sites are shown. The upper block is 58 UWO sites and 11 others.
The bottom 4 sites are around the southern end of Kluane Lake.
Yukon White Spruce high frequency (COFECHA) Master
(excluding Kluane and other poorly correlated sites)
2.5
1982
2
1808
1.5
1832
1918 1923
1905
1936
1844 1848
1946
Indices
1
0.5
0
-0.5
-1
-1.5
1814 -15
-2
-2.5
1780
1872
1973
1850
1817
1949
1887 1904
1800
1820
1840
1860
1880
1900
Calendar Year
1920
1984
1940
1960
1980
2000
Chronologies at the south end of Kluane Lake
1700
Ring-width
Indices
Ring width
Indices
2.5
2.0
Year
1750
1800
1850
1900
1950
2000
Burwash
Burwash
1.5
1.0
0.5
2.5
0.0
Jackson Point
Jackson Point
2.0
1.5
1.0
0.5
Burwash
2.5
2.0
0.0
Landslide
Landslide
1.5
1.0
0.5
0.0
2.5
Telluride
Telluride
2.0
Telluride
1.5
1.0
0.5
1700
1750
1800
1850
Year
1900
1950
0.0
2000
Ring-width Indices
Jackson Point
.
Landslide
Marker Rings in the Kluane Lake and Treeline Residual Chronologies
Year
1750
1800
1850
1900
1950
2000
1750
1800
1850
1900
1950
2000
A
B
Year
A – Marker Rings > 1.5 SD below the mean (narrow )
B – Marker Rings > 1.5 SD above the mean (wide)
P. glauca snag. mean ringwidth
ca. 0.21mm. Tree scarred in 1561.
Snag sampling at Landslide
YLL10 E
KLX11A
KLX0 4 A
L0 0 0 7 W
L9 9 3 9 N
L9 9 3 4 N
C a le n d a r Y e a r
Landslide Ring width
Chronology
Bbbbbbb
bbbbbbbb
bbbbbbbb
b
YLL0 4 W
YLL14 N
YLL16 N
L9 9 17 W
YLL15 S
YLL6 2 A
YLL5 8 C
YLL7 2 A
YLL6 4 A
YLL6 1E
YLL6 9 A
YLL7 1B
YLL6 3 B
YLL5 1A
900
900
2.0
1000
1100
1200
1300
1400
1500
1600
Calendar`years
Samples
1700
1800
1900
2000
2000
300
250
200
1.0
150
100
0.5
50
0.0
0
900
1000
1100
1200
1300
1400
1500
1600
Calendar Year
1700
1800
1900
2000
Number of series
Indexed Ring width
1.5
Landslide RW
Yukon Regional RW
(temperature sensitive)
Wilson, D’Arrigo,
Jacoby, pers. comm.
Landslide and
Yukon Regional
(25 year filter)
November- December GPCC gridded (0.5 degree) precipitation data
vs Landslide RW chronology 1950-2000
R. J. Wilson, pers comm 2006
Other species: the subalpine fir network
2.5
2
RWI
1.5
1
0.5
Subalpine fir
chronologies
Kenigsberg 2005
0
1496 1533 1570 1607 1644 1681 1718 1755 1792 1829 1866 1903 1940 1977
Year
Average absolute chronology length 261 years
(maximum 507= oldest of species?)
Average length with EPS > .85 199 years,
median= 203 years but only 7 > 220 years
The mean sensitivity of these cores is 0.18, similar to spruce
Alpine fir mean chronology
Year
Alpine fir vs SW Yukon spruce
•Strong common signal easily crossdated
•Most chronologies show similar, complex relationships between tree-ring
widths and temperature.
•Ring-width is positively correlated with summer temperatures in the growth
year and the regional pattern is very similar to spruce.
•Therefore can use fir chronologies in treeline networks for regions where
spruce chronologies are not available
•Sites in Northern British Columbia show a negative relationship between
ringwidth and winter precipitation suggesting the potential to reconstruct
winter snowfall
2000
1975
1950
1925
1900
1875
1850
1825
1800
1775
1750
1725
1700
1675
1650
1625
1600
1575
0.5
1550
2000
1975
1950
1
1525
Year
1925
1900
1875
1850
1825
1800
1775
1750
1725
1700
1675
1650
1625
1600
1575
1550
0.5
1525
1
1500
Ring Width Index
1.5
1500
Ring Width Index
1.5
Potential of other species
Pinus contorta (lodgepole pine)
Sweeney B.C. (53˚ 28’N, 127˚ 10’W) oldest tree 1508 to 2002 (495yr.)
Correlates R= 0.60 with June-August PDSI At Smithers, B.C. (1952-2001)
(Watson and Luckman, 2006; IAI presentation).
Carcross ‘desert’ Southern Yukon (60º 11’ 30”N, 134º 42’ 25” W} 1546-2003
Don Youngblut at Carleton University has developed a network of 25 lodgepole
pine chronologies for precipitation reconstruction and fire frequency studies
across the Southern Yukon
Logan Ice Core
Accumulation Data
Moore, Holdsworth, and
Alverson. 2002
Landslide
Spruce
R crit = ca. 0.35
Comparison of tree-ring series and snow accumulation data
on Mount Logan 1700-2000
Dendroclimate Conclusions
These are very preliminary analyses and other
data are likely forthcoming for both tree rings and
ice core parameters ( 3 new ice cores post 2000)
Although accumulation records show some
similarities, the results are often out of phase.
Perhaps this reflects the predominant influence of
summer conditions in the tree-ring record and
winter conditions in the ice core records
Therefore there is a need to perhaps find tree-ring
records that are more winter-precipitation
sensitive than those used here.
Ongoing studies using the ring-width and maximum density
series from spruce and alpine fir tree-ring chronologies should
presently yield a comprehensive picture of summer
temperature variability and possibly other proxy records of
climate over this region for the past 3 or 4 centuries.
Dendrogeomorphic Applications
The network of tree-ring chronology sites developed
during the last 6 years should enable dating of local
wood samples from the last 2-300 years and possibly
much older material , providing this subfossil material
has adequate sample depth ( ca. 100 years+).
This material could be recovered from a variety of
geomorphic settings (glaciers, lake shorelines) and
archeological sites throughout the southern and central
Yukon .
This network will be an invaluable resource for exploring
the environmental and human history of the region.
Landslide site 915-1252 A.D
Dendroglaciology
Kaskawulsh Glacier
Slims River
To Kluane
Tilted Trees
Kaskawulsh Glacier
Drainage via Kaskawulsh
and Alsek to Pacific
Terminal area
Kaskawulsh
Glacier
N
View from east
Tree tilted and
killed 1757
Reyes et al.,
Arctic, 2006
To YUKON
RIVER &
BERING
SEA
Former shorelines
at Extra Point
,Kluane Lake
“Trashline” at the
Landslide site
To ALSEK
RIVER AND
PACIFIC
OCEAN
Dating of sub-fossil
logs at Kluane Lake
Dated logs from beaches
Dated logs from lake level
Elevation Above Sea Level (m)
795
1651
793
1693*
791
789
M inim um height of
Duk e fan
787
785
1210
783
1753*
E stim ated W ater
Levels
? 3-4 m beach
1398
Lak e below present 1650
781
1792*
779
730
777
Lak e 50 m below
present ca. 2200 B P
775
c a. 250
1000B C 1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
Cale ndar Ye ar (AD)
Suggested Lake Level History
•
•
•
•
•
Lake > 50m below present at 2200 yr BP
Below present level ca. 143 A.D. ( based on Duke fan )
Below present 1398-1650 A.D. (in situ trees killed by rising lake )
Rose 10-12m from ca 1650- late 1600s, overflow to north
Dropped to 4-5m by ca. 1750, to ? near present levels by 1800
Slims River
?
?
Future?
Spurr Lake
Abyss Lake
Brady Glacier, Glacier Bay, Alaska
Dundas River
In these highly glacierized environments,
climate change can lead to rapid,
catastrophic changes in the areas adjacent
to or downstream of glaciers.
These have significant geomorphic and
ecological effects and are major natural
hazards.
Brady Glacier and ice- marginal Spurr Lake, Glacier Bay, Alaska
With thanks for
support to ……..
Telluride, NWT 60˚ 35” N 138˚ 08” W
Northern Training
Grant Programme
Thank You for your attention!
Old growth Picea glauca at Tagish, Northern B.C