The role of climate in sugar maple health: Historical

relationships and future projections

1,2Jennifer Pontius, 3Evan Oswald, 4Sandy Wilmot, 3Lesley-Ann Dupigney-Giroux and

3Shelly Rayback

1 UVM, Rubenstein School of Environment and Natural Resources2USFS Northern Research Station3UVM Department of Geography

4 VT Forests Parks and Recreation

The Sugar Maple Decline Complex

Primary Decline Drivers: Soil nutrient status, calcium, aluminum acid deposition, defoliation, herbivory

The Sugar Maple Decline Complex

Field Studies Exploring Sugar Maple Climate relationships:Likely limited by coarse resolution (spatial, temporal and metric detail)

Sugar maple growth (Basal Area Increment)• Nutrition driven with weaker relationship to climate than

expected

Sugar maple mortality • Primarily driven by interaction between base cation status and defoliation• Drought and cold winter temperatures associated with higher mortality

Sugar maple canopy condition• No relationships with climate indices

Sugar Maple Seedling Survival• Mortality driven by herbivory, fungal infection and winter

injury symptoms (nutrient status held constant)

US Forest Service Climate Change Tree AtlasGIS Approach: relative importance of species ….

linked to soil, site and climate characteristics ……to model regional habitat suitability under current and future climate scenarios.

US Forest Service Climate Change Tree AtlasGIS Approach: relative importance of species ….

linked to soil, site and climate characteristics ……to model regional habitat suitability under current and future climate scenarios.

800m Downscaled Climate Indices

Temperature Temperature Extremes Monthly Min T Monthly # days w Max T > 1 stdev Monthly Max T Monthly # days w Max T > 2 stdev Monthly Mean T Monthly # days w Min T < 2 stdev Annual Min T Monthly # days w Min T < 2 stdev Annual Max T Annual Mean T Growing Season Summaries Seasonal Freeze/Thaw Events Growing Degree Days (4C threshold) Monthly # days Min T > 0 Modified Growing Degree Days (4C-30C window) Monthly # consecutive days Min T > 0 Growing Season Length Monthly # of days with > 5C increase and T mean > -5C # of days Min T above 0 Monthly # of days with > 5C decrease and T mean < 5C # of days T mean above 5 # days T mean > 0 in JAN, FEB Cooling Degree Days (18 C threshold) MAY-OCT # days Max T > 10 in JAN, FEB Heating Degree Days (18 C threshold) #V-APRIL # days Min T < -5 in OCT, Nov # days after the first frost is first Max T <= 0

Precipitation Monthly total snowfall Monthly total precipitation Monthly amount rain on the wettest day the longest period of no rain ratio of: T Max to 10-day preceding precipitation

Isolating the Relationship between Climate and Sugar Maple DeclineProject Objective:Develop a set of downscaled, ecologically relevant climate indices

Develop downscaled climate maps for historical and projected climate scenarios for the state of Vermont

Evan Oswald, Ph.D. PACE Fellow(Postdoc Applying Climate Expertise)

Professor Lesley-Ann Dupigny-Giroux, Ph.D. UVM Department of Geography, Char and

Isolating the Relationship between Climate and Sugar Maple DeclineProject Objective:Link climate indices to long-term sugar maple health assessmentsSandy Wilmot, Forest Health SpecialistVermont Department of Forest Parks and Recreation

• 30 plots across a range of elevation and bioregions

• measured annually between 1988 and 2012 • including a suite of canopy condition metrics

Isolating the Relationship between Climate and Sugar Maple DeclineProject Objective:Summarize the various canopy condition metrics into one summary value

Mean of all Normalized Metrics

Forest Stress Index (FSI)

Mean Canopy Dieback

Mean Canopy Transparency

Plot-Level % of trees with High Dieback and

Transparency

Normalize to Historical Plot Distribution

Pontius, J., & Hallett, R. (2014). Comprehensive methods for earlier detection and monitoring of forest decline. Forest Science, 60(2).

Remove the influence of common disturbance agents to isolate relationships with climate indices

Isolating the Relationship between Climate and Sugar Maple DeclineProject Objective:Identify key climate indices linked to sugar maple condition and model FSI under various climate scenariosClimate Only5-termsr2 = 0.185p < 0.001 RMSE = 0.541 PRESS RMSE = 0.546

Table 2. Climate indices that showed a significant association with sugar maple crown health based on plot-wide regression models at the 99.9% confidence level.

Climate Indices Coefficienta Hypothesized Implication

April minimum temperature

+0.15 Warmer minimums could foster earlier spring budbreak and increase the risk of frost injury

October minimum temperature

+0.13

Warmer minimums could increase foliar respiration relative to waning photosynthesis. Also, lower anthocyanin production results in less sugar and nitrogen resorption from sensing leaves.

April minimum temperature

+0.15 Warmer minimums could foster earlier spring budbreak and increase the risk of frost injury

August minimum temperature

-0.10

Warmer minimums could delay foliar senescence, which could increase carbohydrate production and transport, providing more resources for later growth and protection

No. of January days w/ Tmax > 2 SD

+0.08

Warm winter thaws result in lower snowpacks, soil freezing and associated root damage. Thaws may also lead to tissue dehardening – increasing the risk of later freezing injury

No. of January days w/ Tmax > 2 SD

+0.08

Warm winter thaws result in lower snowpacks, soil freezing and associated root damage. Thaws may also lead to tissue dehardening – increasing the risk of later freezing injury

No. of August days w/ Tmax > 2 SD

+0.19

High August temperatures increase foliar respiration rates and cause reductions in net photosynthesis. Imbalances in leaf internal CO2 concentrations can then lead to stomatal closures that further reduce C gains.

Actual FSI

Pred

icte

d FS

I

Climate Plus Disturbance5-termsr2 = 0.309p < 0.001 RMSE = 0.541 PRESS RMSE = 0.546

Isolating the Relationship between Climate and Sugar Maple DeclineProject Objective:Examine region wide historical variability in climate impacts on sugar maple health

Higher Decline

Typical Condition

Healthier than Average

Isolating the Relationship between Climate and Sugar Maple DeclineProject Objective:Project potential impacts to FSI under future climate scenarios

2021 – 2050Low Emissions (B1) High Emissions (A2)

Change in stress condition 0.162 0.201

2041 – 2070Low Emissions (B1) High Emissions (A2)

Change in stress condition 0.344 0.675

Higher Decline

Typical Condition

Healthier than Norm

Isolating the Relationship between Climate and Sugar Maple DeclineProject Objective:Project potential impacts to FSI under future climate scenarios

Higher Decline

Typical Condition

2070 – 2099Low Emissions (B1) High Emissions (A2) Change in stress condition

Low Emissions FSI 0.678

High Emissions Scenario FSI 1.557

Isolating the Relationship between Climate and Sugar Maple DeclineImplications

FSI DistributionBased on Historical “Norms”

Very Healthy

Healthy

Average

Moderate Decline

Severe Decline

2021-20502041-2070

2070-2099

Low Emissions Scenario

Under the Low Emissions Scenario by 2070-2099 Sugar Maple will be in Moderate to Severe Decline 50% of the time.

Isolating the Relationship between Climate and Sugar Maple DeclineImplications

FSI DistributionBased on Historical “Norms”

Very Healthy

Healthy

Average

Moderate Decline

Severe Decline

2021-20502041-2070

2070-2099

High Emissions Scenario

Under the High Emissions Scenario by 2070-2099 Sugar Maple will be in Moderate to Severe Decline 80% of the time.

Isolating the Relationship between Climate and Sugar Maple DeclineImplications

• Target management where sugar maple is most likely to tolerate changing climate

• Minimize secondary stress agents

• Adaptive Management to prepare for the loss of sugar maple in high risk locations

Isolating the Relationship between Climate and Sugar Maple DeclineUtilizing this InformationClimate Change Forest Health Research Group RSENR McIntire Stennis Program

Online Decision Support Tool

To incorporate sugar maple niche mapping as well as many other stress drivers, ecosystem responses and management objectives in a spatial mapping interface.

Isolating the Relationship between Climate and Sugar Maple Decline