Tracking climate-related changes in the productivity and health of western Canadian aspen forests

Transcription

1 Tracking climate-related changes in the productivity and health of western Canadian aspen forests Ted Hogg Research Scientist, Climate Change Natural Resources Canada, Canadian Forest Service (CFS) Northern Forestry Centre Street, Edmonton, Alberta Les midis de la foresterie L Université du Québec en Abitibi-Témiscamingue (UQAT) Rouyn-Noranda (Québec) 20 March 2012 UQAT 20 March

2 Team members & collaborators CIPHA team Ted Hogg (NoFC) Ron Hall (NoFC) Mike Undershultz (ASRD) Michael Michaelian (NoFC) Trisha Hook (NoFC) Eric Arsenault (NoFC) James Brandt (CFS-HQ) Tony Hopkin (GLFC) Al Keizer (GLFC) Collaborators Craig Allen (USGS) Alan Barr (EC) Pierre Bernier (LFC) Andy Black (UBC) Werner Kurz (PFC) Vic Lieffers (U of A) Dan McKenney (GLFC) Juha Metsaranta (NoFC) David Price (NoFC) Dan Rowlinson (OMNR) Taylor Scarr (OMNR) Jim Worrall (US For Serv) and others Forest health crew leaders Mike Michaelian Trisha Hook Mike Undershultz (ASRD) Al Keizer (GLFC) and others Tree-ring analyses Trisha Hook and others Aerial surveys & remote sensing Mike Michaelian Eric Arsenault Rob Skakun Graduate students Sophan Chhin Miranda Hart and others Field & laboratory assistance Jim Hammond Rick Hurdle Roger Nesdoly (MM) Brad Tomm Jim Weber Marc Berube Natacha Bissonnette Sarah Breen Lindsay Bunn Laura Chittick Brian Christensen Owen Cook Andrea Durand Ray Fidler (PC) Michelle Filiatrault Cathryn Hale Bonny Hood Tom Hutchinson Funding (CIPHA study) Climate Change Action Fund Program of Energy Research and Development Mistik Management Ltd., Meadow Lake, Sask. Forest 2020 AAFC PFRA Administration Canadian Space Agency CFS-NRCan A-base funding UQAT 20 March Amy Irvine Oksana Izio Angela Johnson Devin Letourneau Chelsea Martin Sarah Martin Lindsay McCoubrey Pam Melnick Ryan Raypold Erin Van Overloop Mark Schweitzer Dominic Senechal Jessica Snedden Joey Tanney Bill van Egteren Bryan Vroom Cedar Welsh Dave Wieder (PC) and many others

3 Peuplier faux-tremble Trembling aspen (Populus tremuloides) Most widespread tree in North America ~2000 MT of aspen biomass in Canadian boreal forest Important ecologically and commercially Aspen forests have high rate of CO 2 uptake Distribution of Populus tremuloides UQAT 20 March Aspen forests form a Ribbon of green connecting east and west

4 Peuplier faux-tremble Trembling aspen (Populus tremuloides) Dominant native tree in the aspen parkland zone of western Canada (prairie-boreal ecotone) Aspen parkland near Saskatoon Aspen parkland in Alberta, 1970s UQAT 20 March

5 Aspen dieback in western Canada Local dieback events prompted concerns in the early 1990s Early studies showed that drought was a major causal factor Hogg & Schwarz 1999: study funded by Mistik Management, Meadow Lake, SK Hogg et al. 2002: study funded by Weyerhaeuser Canada, Grande Prairie, AB Raised questions about potential impacts of climate change Significant warming trend (up to 2 C during the 20 th century) 1998 was a record-warm year with widespread drought 1998 Aspen dieback & decline in Alberta & Saskatchewan, 1990s UQAT 20 March

6 Potential climate change impacts on the region s aspen forests? Boreal aspen forest (moist climate) Aspen parkland (dry climate) UQAT 20 March

7 CIPHA study Climate Impacts on Productivity & Health of Aspen Initiated by CFS in 1999 (Hogg & Brandt) funding from CCAF, PERD & forest industry (Mistik Management) Includes tree-level monitoring in pure aspen stands (50-90 years old) Multi-scale study with a hierarchical design (30 study sites, total of 180 plots) Collaboration with tower-based monitoring of carbon, water & energy fluxes at the Old Aspen site (Barr, Black et al., BERMS & Fluxnet Canada) BERMS Aspen tree-rings trees per plot 20 m 2 plots per stand 3 stands per site CIPHA study region UQAT 20 March

8 CIPHA study Climate Impacts on Productivity & Health of Aspen Objectives: 1. Early detection of climate-related changes 2. Understanding causes of past changes (tree-ring analysis) 3. Provide field-based knowledge for model forecasting of future changes 4. Provide framework for promoting inter-agency collaboration BERMS Aspen tree-rings trees per plot 20 m 2 plots per stand 3 stands per site CIPHA study region UQAT 20 March

9 Methods: long-term CIPHA plots Annual forest health assessments (2000-present): -defoliation, dieback, mortality, insects & diseases Every 4 years (2000, 2004, 2008, proposed for 2012): -tree measurements (height, dbh etc.) -sampling for tree-ring analysis -regeneration Other: leaf area index (litter traps), soil analysis Annual growth & mortality of stand biomass (T ha -1 ) - calculated from plot-based measurements, tree-rings, & national biomass equations (Lambert et al. 2005) Portable device & system for field data acquisition UQAT 20 March

10 CIPHA plot network in CIPHA west network CFS-NoFC (Hogg et al.) 150 plots assessed annually, CIPHA east network: CFS-GLFC & OMNR (Keizer, Scarr et al.) 30 plots assessed annually, to 2011 UQAT 20 March

11 CIPHA plot network in CIPHA west network CFS-NoFC (Hogg et al.) Alberta SRD (Undershultz et al.) CIPHA east network: CFS-GLFC & OMNR (Keizer, Scarr et al.) 30 plots assessed annually, to 2011 Note: 60 plots (10 sites) not assessed since 2008 Proposal to re-measure all plots in 2012 (funding & resources permitting) UQAT 20 March

12 Methods: tree-ring analysis of aspen White tree rings formed during defoliation by forest tent caterpillar Hogg et al. 2002, CJFR Tree-ring sampling Livrée des forêts (Malacosoma disstria) UQAT 20 March Aspen defoliation by forest tent caterpillar

13 Method for tracking changes in moisture: Climate Moisture Index (CMI) Hogg (1997) Agric. For. Meteorol. 84: CMI = P PET (units in cm/year) P is mean annual precipitation includes water input as both rain and snow PET is annual potential evapotranspiration potential loss of water vapour from a well-vegetated landscape when soil moisture is not limiting, as estimated from mean daily maximum and minimum temperature for each month P PET runoff Note: The CMI provides a simple index for assessing moisture variation & drought severity in remote forested regions where long-term climate data are typically limited to temperature and precipitation UQAT 20 March

14 Results: Tracking past changes in growth Tree-ring analysis showed dramatic changes in regional aspen growth since 1951 Major factors affecting growth: Drought (CMI) Insect defoliation (D) Aspen growth index (A ) Severe drought years Severe defoliation years CIPHA sites included in analysis Regression equation: A = CMI CMI CMI CMI CMI D, r 2 =0.697 From Hogg et al CJFR UQAT 20 March

15 The exceptional drought of Worst drought in >80 years across a large area of AB & SK Led to massive mortality of aspen forests Conifers and urban forests also affected Drought-damaged aspen leaves (2002) Aerial view of mortality in the parkland (2004) Drought-caused dieback resembling fire effects Drought-affected area showing severe dieback of aspen forests UQAT 20 March

16 The exceptional drought of Mapping & analysis of the CMI showed the severity & extent of the drought where dieback & mortality was recorded long-term mean CMI Climate Moisture Index (CMI) in drought survey area for 12-month periods ending 31 July of each given year Dry CMI Moist Drought ( ) Drought survey area DRY CMI MOIST Climate Moisture Index (CMI) UQAT 20 March ANUSPLIN interpolation of CMI by Price, Siltanen & McKenney

17 Results: Tracking changes in CIPHA plots The drought led to a 30% decrease in aspen productivity and was the main cause of aspen mortality (Hogg, Brandt & Michaelian 2005, 2008; CJFR) Regional aspen mortality tripled & has since remained higher than normal Average % mortality of aspen biomass 15 CIPHA sites (90 plots) % Mortality of stem biomass Drought ( ) Year UQAT 20 March

18 Results: Tracking changes in aspen biomass From CIPHA plot measurements ( ) & tree-ring analysis Change in live biomass (T ha -1 y -1 ) Drought Growth Mortality UQAT 20 March CIPHA sites included Hogg et al. 2008, CJFR

19 Results: Tracking changes in aspen biomass The drought led to a multi-year collapse in biomass increment Change in live biomass (T ha -1 y -1 ) Drought Growth Mortality Net change UQAT 20 March CIPHA sites included Hogg et al. 2008, CJFR

20 Results: Contributing factors Increased damage by wood-boring insects Insect defoliation (localized outbreaks) Role of fungal pathogens & decay fungi These agents may have amplified & prolonged the drought s impact Damage by Saperda (wood-boring insect) 30 Stem damage in CIPHA plots % aspen stems affected Drought Borers Phellinus Peniophora Repeat photography of CIPHA plot showing stand breakup UQAT 20 March

21 Scaling up dead aspen biomass in the severely drought-affected area Aspen mortality in the parklands of Saskatchewan, August 2004 (photo by Mike Michaelian) UQAT 20 March

22 Scaling up dead aspen biomass in severely drought-affected area Michaelian, Hogg, Hall & Arsenault (2011), Global Change Biology Aerial survey mapping (2004) Ground measurements in 400 random temporary plots ( ) Spatial interpolation of plot data across the drought survey area (LandSat-based land cover classification) Drought survey area (11.5 Mha) UQAT 20 March

23 Results: Estimation of dead aspen biomass in severely drought-affected area Michaelian et al. (2011), GCB Spatial interpolation of dead aspen biomass Estimated 45 Mt of dead aspen biomass based on spatial interpolation = 20% of total aspen biomass in survey area Ground plot measurements UQAT 20 March

24 Results: Estimation of dead aspen biomass in severely drought-affected area Michaelian et al. (2011), GCB Estimated 45 Mt of dead aspen biomass based on spatial interpolation Equivalent to Canada s total harvest of hardwood tree biomass over 2 years* It would require a train 18,000 km long to carry 45 Mt of dead aspen The estimated C content (21 Mt) is equivalent to ~10% of Canada s annual CO 2 emissions** *hardwood harvest estimated at 40 Mt during based on data from CFS NFCMARS **National Inventory Report, Environment Canada (2007) Aspen snags UQAT 20 March Unlike telephone poles, aspen snags fall down & decay relatively rapidly (but research is needed to measure rate of carbon loss)

25 Related CIPHA initiatives Field-validated remote sensing methods for mapping aspen dieback (with Ron Hall and others) Inclusion of drought impacts in forest carbon accounting (with Kurz, Mesaranta and others) Timely mapping of drought indicators across western Canada Mortality level: Light Moderate Severe Mapping aspen mortality from Landsat imagery (Canopy Reflectance Model, Arsenault et al. 2009) Collectively, this work provides many of the ingredients for building an integrated, multi-scale system for tracking climate-related changes UQAT 20 March

26 Recent developments ( ) CIPHA collaboration with Alberta Sustainable Resource Development Initiated in April 2010 (with Dan Lux & Mike Undershultz) Includes joint monitoring of CIPHA plots in Alberta Providing advice on including climate damage in Alberta s PSP network Proposed expansion of research to include climate impacts on conifers CIPHA field training with CFS & ASRD staff UQAT 20 March

27 Recent developments ( ) Western Canada Forest Health & Climate Change workshop co-hosted by CFS & Alberta SRD, held in Canmore, Alberta, April 2011 Included >60 participants (federal, provincial, universities, industry) The presentations & discussions revealed many examples of climate-related forest decline across western Canada Workshop presentations & summary at UQAT 20 March

28 Recent multi-species decline in Alberta Waterton National Park, 2010 (multi-species forest decline) White spruce mortality Red Deer river valley 2010 Balsam fir mortality (widespread) Urban forest decline, Edmonton, 2011 UQAT 20 March Birch mortality (widespread)

29 Climate-related browning of aspen & poplar across >400 km in NE Alberta, July 2011 Photo by Mike Vassal, Wood Buffalo National Park Aerial view S of Fort McMurray AB, July 2011 Photo by Tom Hutchinson, Alberta SRD UQAT 20 March

30 Douglas-fir decline in southern BC Douglas-fir decline near Merritt, BC Photo by Janice Hodge, July 2011 (BC forest health surveys & acting NFPS Technical Coordinator) UQAT 20 March

31 Recent aspen decline in NW Ontario Aspen decline mapped in 2010 From Taylor Scarr, Ontario Ministry of Natural Resources Note: High mortality rates were recorded at CIPHA East sites during UQAT 20 March

32 Areas with exceptional, recent droughts where the CMI was the lowest on record during Maps based on climate interpolations using the BioSim program UQAT 20 March

33 Areas showing signs of significant drying since 1998 Based on preliminary, interpolated CMI values using BioSIM dcmi dcmi = mean CMI in minus mean CMI in UQAT 20 March

34 Is the recent drying an early sign of climate change? For forests in northern Alberta: Warming since 1900 is consistent with the global trend Annual temperature Temperature trends in northern Alberta Moisture trends in northern Alberta 30 CMI indicates dry climate conditions in 1910s 1940s but early records are less reliable, especially for precipitation Climate Moisture Index Estimated the areas of Alberta north of 54 o N using BioSim UQAT 20 March

35 Is the recent drying an early sign of climate change? Personal reflections: It s consistent with the changes predicted by GCMs, but still too early to answer the question unequivocally for our region. Regardless of the cause, the climate record shows that was generally a period of plentiful moisture in northern Alberta (and elsewhere) 30 Moisture trends in northern Alberta The recent drying trend poses forestry challenges for the future Climate Moisture Index UQAT 20 March

36 Recent papers from analysis of provincial PSPs Peng, C., Ma, Z. et al A drought-induced pervasive increase in tree mortality across Canada s boreal forests. Nature Climate Change 1: 467 Ma, Z., Peng, C. et al Regional drought-induced reduction in the biomass carbon sink of Canada s boreal forests. PNAS 109: UQAT 20 March

37 Drought-induced forest decline: An emerging global change issue Some recent publications: 2002 drought? Worrall et al Effects and etiology of sudden aspen decline in southwestern Colorado, USA. For. Ecol. Manage. 260: 638 Williams et al Forest responses to increasing aridity and warmth in the southwestern United States. PNAS 107: Phillips et al Drought sensitivity of the Amazon rainforest. Science 323: Estimated changes in growth (NPP) for the North American boreal forest from remote sensing (Bunn et al. 2007) Van Mantgem et al Widespread increase of tree mortality rates in the western United States. Science 323: Bunn et al Northern high-latitude ecosystems respond to climate change. EOS 88: 333 Ciais et al Europe-wide reduction in primary productivity caused by the heat and drought in Nature 437: 529 Breshears et al Regional vegetation die-off in response to global-change-type drought. PNAS 102:15144 UQAT 20 March Sudden aspen decline following drought across the intermountain west of the US, see

38 Drought-induced forest decline: An emerging global change issue 2010 paper led by Craig Allen (US Geological Survey) A global overview of drought and heat-induced tree mortality reveals emerging climate change risks for forests Allen, C.D., A.K. Macalady, H. Chenchouni, D. Bachelet, N. McDowell, M. Vennetier, T. Kitzberger, A. Rigling, D.D. Breshears, E.H. Hogg, P. Gonzalez, R. Fensham, Z. Zhang, J.- H. Lim, J. Castro, N. Demidova, G. Allard, S.W. Running, A. Semerci, & N. Cobb (2010) A global overview of drought and heat-induced tree mortality reveals emerging climate change risks for forests. Forest Ecology and Management 259: UQAT 20 March

39 Drought-induced forest decline: An emerging global change issue Allen et al. (2010) documented an increase in global reporting of drought-related forest mortality episodes since the 1980s Raised concerns about the earth s future forests under climate change Cited 88 recent examples from all of the world s forested continents but many episodes not included in this preliminary global overview UQAT 20 March

40 Examples of drought-induced forest decline UQAT 20 March

41 Drought-induced forest decline: An emerging global change issue Updated Oct 2011 Increase in % of papers on forests reporting on drought & mortality (Allen et al. 2010): A very preliminary indicator in the absence of a global monitoring system for forests! UQAT 20 March

42 Technical Session A-07: Is climate change leading to global increases in drought-induced forest die-off? Session coordinators: Ted Hogg and Craig Allen 13 presenters from the USA (Van Mantgem, Shaw, Allen), UK (Jump), France (Vennetier), Switzerland (Rigling), Germany (Bolte), Algeria (Chenchouni), Ghana (Amissah), China (Zhang), South Korea (Lim), Brouwers (Australia) and Canada (Hogg) UQAT 20 March

43 Some ideas on what is needed for tracking climate-related changes in Canada s forests Multi-scale observation systems to assess climate-related forest changes across large areas Standardized, user-friendly methods to enable interagency partnerships for tracking change Timely reporting and communication of results provides early warning knowledge from long-term monitoring Value of moving from the old way to the new way when it comes to data-sharing policies & practices UQAT 20 March

44 Data-sharing policy & practices The Old Way Data viewed as proprietary Data access restricted Fosters exclusivity Builds suspicion Errors remain hidden Delayed or biased reporting Single approach to analysis Focus on narrow discipline Limited impact & relevance The New Way Data seen as a shared resource Data access is encouraged Fosters collaboration Builds trust Errors are flagged early Rapid reporting encouraged Multiple approaches to analysis Multi-disciplinary High impact & relevance UQAT 20 March

45 Existing programs offer complementary advantages for tracking climate-related changes Earliest Measurement Forest measurement frequency coverage PSPs: ~1960s every 5-10 yrs merchantable stands CIPHA: year 2000 annual aspen only NFI plots: early 2000s every 5-10 yrs all forest types UQAT 20 March

46 Canada s National Forest Inventory (NFI) Inventaire forestier national du Canada (IFN) Collaborative project involving federal, provincial & territorial agencies Includes ~1000 ground plots representing Canada s major forest types Multi-scale measurements including air photo plots & remote sensing Wide suite of consistent measurements using jointly-developed standards A valuable investment for tracking climate-related changes in future! Gillis et al. (2005), Monitoring Canada s forests: The National Forest Inventory. For. Chron. 81: 214 Web site at: UQAT 20 March

47 Summary and conclusions Drought-induced forest dieback has emerged as a climate change issue of global concern for the 21 st century Research from CIPHA provides an example of how drought impacts can be estimated across large areas Recent droughts are having widespread impacts on many forest types but the impacts on species other than aspen are not well-documented Climatic drying poses new challenges for forestry in some regions Collaborative monitoring programs (e.g., PSPs, CIPHA & NFI) provide valuable knowledge on climate-related changes in our forests Such knowledge is a key investment for adapting to future climatic changes UQAT 20 March

48 UQAT 20 March