Spring IndicesSpring IndicesContinental-scale phenological modelsContinental-scale phenological models

Lilac First LeafLilac First Leaf

Lilac First BloomLilac First Bloom

Lilac Phenological Observation SitesLilac Phenological Observation Sites Years of Observation, 1956-2003Years of Observation, 1956-2003

Cloned lilac first leaf and first bloom datesCloned lilac first leaf and first bloom datesat a single station in Vermontat a single station in Vermont

Model RationaleModel Rationale

Estimating Chilling RequirementsEstimating Chilling Requirements

Lilac Chill Unit DeterminationLilac Chill Unit Determination

Lilac Chill Unit Requirement DeterminationGDH Base 31F, 2322 cases, approx. 450,000 values

200 250 300 350 400 450 500 550 600 650 700 750 800 850 900 950 1000Chill Accum ulation (25 unit ranges)

2 5

3 0

3 5

4 0

4 5

5 0

5 5

6 0

6 5

7 0

SE o

f GD

H A

ccum

. Val

ues

Model ConstructionModel ConstructionDSH = days since start of heat unit accumulationDSH = days since start of heat unit accumulation

(1000/DSH) = Regression Constant + (1000/DSH) = Regression Constant + (A(A11*X*X11/DSH) + (A/DSH) + (A22*X*X22/DSH) + . . . /DSH) + . . . (A(Ann*X*Xnn/DSH) /DSH)

Multiply through by DSH to transform intoMultiply through by DSH to transform into 1000 = (Regression Constant*DSH) + 1000 = (Regression Constant*DSH) +

(A(A11*X*X11) + (A) + (A22*X*X22) + . . . (A) + . . . (Ann*X*Xnn))

Structure of Spring Indices ModelsStructure of Spring Indices Models

Sub-modelsChill Accumulation

Sub-models

First LeafHeat Accumulation

EstimatesFirst Leaf

Sub-models

First BloomHeat Accumulation

EstimatesFirst Bloom

Spring Indices Spring Indices Suite of MeasuresSuite of Measures

First -2.2First -2.2ooC freeze date in AutumnC freeze date in Autumn Composite chill date (SI models)Composite chill date (SI models) First leaf date (SI models)First leaf date (SI models) First bloom date (SI models)First bloom date (SI models) Last -2.2Last -2.2ooC freeze date in Spring C freeze date in Spring -2.2-2.2ooC Freeze periodC Freeze period Damage index value (first leaf – last frost)Damage index value (first leaf – last frost) Average annual, average seasonal, and twelve Average annual, average seasonal, and twelve

average monthly temperaturesaverage monthly temperatures

SI First Leaf Date 1961-2000 SlopeSI First Leaf Date 1961-2000 Slope

Source: Schwartz et al. 2006, Global Change Biology, Figure 1

North America SI First Leaf Date DeparturesNorth America SI First Leaf Date Departures

Source: Schwartz and Reiter 2000, Int. J. Climatology, Plate 4 (updated)

North Amer. Last –2.2North Amer. Last –2.2ooC Freeze Date DeparturesC Freeze Date Departures

Source: Schwartz (unpublished)

Spring Indices First Bloom DateSpring Indices First Bloom Date

SI Damage Index Value 1961-2000 SlopeSI Damage Index Value 1961-2000 Slope(SI First Leaf Date – Last Freeze Date)(SI First Leaf Date – Last Freeze Date)

Source: Schwartz et al. 2006, Global Change Biology, Figure 5

SI First Bloom – First Leaf DifferenceSI First Bloom – First Leaf Difference

Source: Hanes and Schwartz (unpublished)

Integrated ApproachIntegrated ApproachExample: WisconsinExample: Wisconsin

Zhao and Schwartz (2003)Zhao and Schwartz (2003)

Satellite phenology (DMA SOS)Satellite phenology (DMA SOS) Simulated phenology Simulated phenology

(SI first bloom dates) (SI first bloom dates) ““Native” species phenology Native” species phenology

(WPS records of first bloom date (WPS records of first bloom date for 21 introduced and 32 native for 21 introduced and 32 native species)species)

Integrated Species Indices (ISI)Integrated Species Indices (ISI)southwestern Wisconsinsouthwestern Wisconsin

Source: Zhao & Schwartz 2003, Climate Research, Figure 4a (in color)