Through the trees: The story of Prairie drought told by tree rings

TREES THR O U G H T H E THE STORY OF PRAIRIE DROUGHT TOLD BY TREE RINGS

Past dynamics ! Future behavior PRESENT PAST FUTURE Precipitation Drought risks Discharge Sustainable yield Lake level Flood hazards Soil moisture

resource allocation

worst-case scenarios

Photograph: Manitoba Hydro

Photograph: Greg Brooks

Past dynamics ! Future behavior PRESENT PAST FUTURE Precipitation Drought risks Discharge Sustainable yield Lake level Flood hazards Soil moisture

stationarity A stationary time series is free of trends, shifts or periodicity, and has statistical parameters that remain constant through time.

Christopher Milly, Julio Betancourt, Malin Falkenmark, Robert Hirsch, Zbigniew Kundzewicz, Dennis Lettenmaier, Ronald Stouffer Stationarity is dead: whither water management? Science 319, 573-574, 2008

South Saskatchewan River at Saskatoon relative change in summer ﬂow Schindler and Donahue, 2006, PNAS

Annual discharge since 1924 + 58% NO TREND + 52% + 46% NO TREND NO TREND NO TREND NO TREND St. George, Journal of Hydrology, 2007

100 years of stream and lake gauging

CLIMATE HISTORY OF CANADA Younger Demise of Laurentide Dryas Ice Sheet 20 16 12 8 4 0 THOUSANDS OF YEARS AGO Final Drainage of Lake Agassiz LAST GLACIAL MODERN MAXIMUM OBSERVATIONS

paleoclimatology the study of the Earth’s climate prior to the period of instrumental measurements

TREES AS BIOLOGICAL ARCHIVES How can records from the annual growth rings of trees be 1 interpreted as indicators of past environmental change?

TREES AS BIOLOGICAL ARCHIVES How can records from the annual growth rings of trees be 1 interpreted as indicators of past environmental change? PRAIRIE DROUGHTS SINCE AD 1500 What tree rings tell us about severity, persistance and 2 dynamics of past droughts on the Prairies.

R ECO R D S F RO M ANCIEN T TR EES

Tree-ring display at elementary school Photograph: Tom Swetnam

ARIZ ONA

A. E. Douglass University of Arizona

The trees composing the forest rejoice and lament with its successes and failures and carry year by year something of its story in their annual rings. A.E. DOUGLASS

Same environmental forcings Similar growth patterns

Photograph: Howard Arnott

North American Tree-Ring Chronologies Western species Ponderosa pine Douglas-ﬁr Big cone douglas-ﬁr High elevation conifer Mountain Hemlock Other conifer Eastern species White oak group Hemlock Baldcypress Tulip poplar Overcup oak Northern red oak Courtesy David Stahle

MEXICO UNITED STATES Sonora Arizona Baja California California Colorado New Mexico Nevada Utah Wyoming

~15 years of river gauge measurements

Colorado River Basin Water Management National Academy of Sciences, 2007 “... studies of past climate...[reveal] many periods when streamﬂow was lower than at any time in the past 100 years of recorded ﬂows. ”

“rethink old assumptions” CHARLIE ESTER SALT RIVER PROJECT

Photograph: Tom Harlan

Photograph: Peter Kelly

Photograph: Kurt Kipfmueller

Photograph: Greg Pederson

Photograph: Erik Nielsen

53 Photograph: Erik Nielsen

Martin-Philippe Girardin Canadian Forest Service Greg Pederson United States Geological Survey David Sauchyn Glen MacDonald Emma Watson University of Regina UCLA Environment Canada Erik Nielsen Jacques Tardif Manitoba Geological Survey University of Winnipeg

Prairie tree-ring network

T R E E S A ND PRAI RI E DR OUGHT

Photograph: Dave Sauchyn

earlywood latewood cessation of growth Photograph: Kevin Anchukaitis

“ The growth of trees is undoubtably controlled more by the movement of water than by the movement of any other single substance.” HAL FRITTS TREE RINGS AND CLIMATE

water stress narrow ring reduced photosynthesis less cell expansion reduced cell division

never trust one tree

2,860 trees

889,862 tree rings

Palmer Drought Severity Index

69

755 m3/s 847 m3/s 809 m3/s 770 m3/s 823 m3/s 787 m3/s 901 m3/s 3

“This must be ” voodoo. Anonymous water manager

good How are drought records from tree rings?

geography matters

southern Alberta 10 3 2 5 1 Ringwidth PDSI 0 0 -1 -5 -2 -3 -10 1900 1920 1940 1960 1980 2000 Year (A.D.) St. George et al., (2009), Journal of Climate

southern Alberta 10 3 2 5 1 Ringwidth PDSI 0 0 -1 -5 r = 0.62 -2 -3 -10 1900 1920 1940 1960 1980 2000 Year (A.D.) St. George et al., (2009), Journal of Climate

755 m3/s 847 m3/s 809 m3/s 770 m3/s 823 m3/s 787 m3/s 901 m3/s 3

DROUGHT HISTORY OF ALBERTA PDSI 6 4 2 0 -2 -4 -6 1500 1600 1700 1800 1900 2000 Year (AD)

bad How can drought get?

more persistent more severe

1720s

58 oN 1718 - 1722 56 oN 54 oN 52 oN 50 oN 48 oN oW 90 114 oW oW 96 o o 108 W 102 W Ringwidth anomaly (deviations) !2 !1 0 1 2 -2 0 +2

more persistent more severe

1860s

1842 to 1876 Below average Above average

CAPT. JOHN PALLISER 88

“ The grass in this arid soil, always so scanty, was now actually swept away by the buffalo, who, assisted by the locusts had left the country as bare as if it had been overrun by fire; even at the edge of Sage Creek we could obtain but very ” little water for our horses. JOHN PALLISER, 1859 89

Low reservoir Photograph: Glen MacDonald

NUMBER of tree ring records that track seasonal precipitation Autumn Winter Spring Summer 3 7 24 82 138 total

Medicine Hat, Alberta Source: Environment Canada, Adjusted Historical Canadian Climate Data, 1895 – 2006

96

Past droughts and remote forcings

Janice Lough and Hal Fritts The Southern Oscillation and tree rings: 1600 - 1961 Journal of Applied Meteorology 24, 1985 Roseanne D’Arrigo and Gordon Jacoby A thousand year record of northwestern New Mexico winter precipitation reconstructed from tree rings and its relation to El Niño and the Southern Oscillation The Holocene 1, 1991 David Stahle and collaborators Experimental dendroclimatic reconstruction of the Southern Oscillation Bulletin of the American Meteorological Society 79, 1998

ENSO and Prairie tree rings correlation with CTI St. George et al., (2009), Journal of Climate

INSTRUMENTAL PDSI ENSO +0.5 0 correlation coefﬁcient -0.5

St. George et al., (in preparation), Geophysical Research Letters

LE SS ONS L E A RNED

WORLD DATA CENTER for PALEOCLIMATOLOGY

past does the really matter?

climate change YOU CAN TOUCH

100 years of stream and lake gauging

Common sense holds that what has really happened CAN HAPPEN AGAIN VIC BAKER UNIVERSITY OF ARIZONA

Through the trees: The story of Prairie drought told by tree rings

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