Potential Change in Lodgepole Pine Site Index and Distribution under Climate Change in Alberta Robert A. Monserud Pacific Northwest Research Station, Portland, Oregon, USA Yuqing Yang & Shongming Huang Ministry of Sustainable Resource Development, Edmonton, Alberta, Canada Nadja Tchebakova Sukachev Forest Institute, Krasnoyarsk, Russia Western Mensurationists 2007

Objectives Examine variation in both LPP site productivity and species range under future climate change scenarios across Alberta

Lodgepole pine (Pinus contorta) Alberta’s most important & common forest tree 20% of mature stems, 40% of annual harvest Wide ecological amplitude –Best on moist rich sites with long warm growing season –Also grows on dry, nutrient poor sites with short growing season –Can tolerate frost pockets and cold air drainage

Steps 1.Map LPP site productivity (SI) across Alberta 2.Map climate across Alberta 3.Connect SI and climate (GDD 5 ) 4.Connect species range and climate (DI) 5.Interpolate climate change scenarios onto Alberta Climate Map 6.Calculate potential SI and species range under climate change scenarios

Productivity Data: 1145 Stem analysis plots Mean SI = 14.4 m Range = 4.3 to 26.5 m Step 1

ANUSPLIN map of site index across the natural distribution of lodgepole pine Residual Mean = 0 Residual S.Dev.=1.24 m Step 1b: Map SI

Step 2: Alberta Climate Model Basis: network of weather stations Period: (30-yr climate normals) Buffer: 2 o around Alberta Mapping tools: ANUSPLIN & ArcInfo –Thin-plate 4-D smoothing splines –Uses Latitude, Longitude, Elevation to predict 4 th variable –(Hutchinson, Australian Nat’l Univ)

Growing degree days >5 o C (GDD 5 ) Step 2: Map Climate

Step 3 Connect Alberta Climate Model to the network of 1145 Site Index plots for LPP across Alberta Variables in common: Latitude, Longitude, Elevation

Step 3 Results: SI=f(GDD 5 ) Strongest correlations with Site Index: Measures of Heat –Julian date when GDD5 reaches 100 (D 100 ) –Growing degree days >5 o C (GDD 5 ) –Mean temperature of July, the warmest month Explains 26% of variation All 3 are highly intercorrelated (r=0.98)

Step 4: Connect species range and climate Connect species range and climate using Dryness Index (DI) DI is the ratio of GDD 5 to annual precipitation 99% DI limits on natural range of LPP are o C mm -1

Step 5: Climate Change Scenarios Used 3 General Circulation Models (GCMs) from IPCC –Hamburg –Hadley –Canadian Used new SRES A2 emissions scenarios –(“Business-as-usual”) Used all three 30-yr time periods: –2020s ( ) –2050s ( ) –2080s ( ) Scenarios are monthly anomalies (differences) in temperature and precipitation from current climate Anomalies must be added to Alberta current climate map

Step 5: Interpolate Anomalies Interpolate climate change scenarios onto Alberta Climate Map (2 km x 2 km) GCMs are very coarse resolution: 2.5 o to 3.75 o Weighted average of 5 closest anomalies for each of 166,000 pixels (weight = inverse distance squared) Add weighted anomalies to current climate map

Current climate vs GDD 5

Step 6: Potential SI Calculate potential SI and species range under climate change scenarios SI = GDD 5 Species range: Dryness Index 0.9 to 2.6 o C mm -1

CCM Predicted SI: Current & 2020

CCM Predicted SI: 2050 & 2080

Current Climate SI

Hadley: 2020, 2050, 2080 SI

Current Climate SI

Hamburg: 2020, 2050, 2080 SI

Results Similar results across all 3 GCM scenarios: Increasing warming but no increase in precipitation (hotter and drier) Potential productivity (SI) increasing steadily 1 m/decade Potential range expands in 2020s (40-70%), but shrinks greatly in 2050s & 2080s (40-70% reduction in potential area)

Discussion Increased risk of forest fire Increased risk of mountain pine beetle outbreaks (warmer winters) –Potential for MPB to bridge east to the Atlantic Reforestation (planting) should consider populations adapted to future climates Northern populations might already be adapted to future warm climates (Rehfeldt’s BC work on LPP)

That’s all, folks Thanks