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Sustainable forest management in a changing climate Jay R. Malcolm Faculty of Forestry University of Toronto April 2003.

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Presentation on theme: "Sustainable forest management in a changing climate Jay R. Malcolm Faculty of Forestry University of Toronto April 2003."— Presentation transcript:

1 Sustainable forest management in a changing climate Jay R. Malcolm Faculty of Forestry University of Toronto April 2003

2 Background: causal connection between increasing greenhouse gas concentrations and recent warming magnitude of potential warming in the coming century is enormous from an ecological viewpoint hundreds of species are showing responses already “very high confidence” that anthropogenic climate change is already affecting living systems

3 Using coupled GCMs and GVMs to investigate potential ecological changes:

4 Current Climate (GVM: MAPSS) Doubled-CO 2 Climate (Hadley Centre, with sulphate aerosol cooling) (GVM: MAPSS)

5 Biome change for 14 combinations of GCMs and GVMs: Percent of Models Percent land area Iceland (1 st ): 81.6% Finland (4 th ): 67.9% Canada (14 th ): 46.3%

6 Ecosystem change, but also the outright loss of certain ecosystem types:

7 Current area (a+b) vs. future area (b+c) S A Implications of habitat loss for species diversity:

8 Area Percent area under 2xCO 2 Percent species loss Tundra ****-9.9 Taiga/Tundra ****-11.6 Boreal Conifer Forest * Temperate Evergreen Forest * Temperate Mixed Forest **** Tropical Broadleaf Forest * Savanna/Woodland Shrub/Woodland **-3.6 Grassland ** Arid Lands ***-3.2 Global estimate of species loss based on 14 CGMs/GVMs:

9 Implications for forested ecosystems: Regional disappearances of certain forest types/working groups (e.g., Spruce-fir forests disappeared and maple-beech-birch forests showed near extirpation in eastern U.S. under doubled CO 2 [Iverson & Prasad 1998, 2001, 2002]) Shifts of species ranges by km, including commercially important species (e.g., Sugar maple, balsam fir, trembling aspen, and red pine reduced by more than 90% in eastern U.S. under doubled CO2 [Iverson & Prasad 1998, 2001, 2002]) Increasing stress as climate conditions change, with increased vulnerability to diseases and pests Increased probability of fire Potential for increased growth provided that enough water is available (if insufficient water is available, potential to exacerbate drought conditions) Increased emphasis on forests as carbon sinks (increase sequestration and decrease losses from soil)

10 Economic implications: little or net positive impacts on timber markets in the United States (e.g., between ‑ 1 and +11% [Perez-Garcia et al. 1997, Sohngen & Mendelsohn 1998]). however, assumed appropriate adaptive responses -e.g., Sohngen & Mendelsohn (1998): practices on intensive lands would rapidly establishing appropriate species; lags on low-intensity lands only years. -understanding of likely tree responses is key because changes in forest growth and productivity will constrain the choices of adaptation strategies -promotion of appropriate regeneration through planting (shortens period of stand establishment when C accumulation is low and soil C losses are relatively high) -planting of genetically modified species or specific ecotypes -development of silvicultural systems that maintain forest vigour -important among these strategies are those that facilitate species migration, either through artificial or natural means

11 Potential importance of migration: if migration fails to make up for warming ‑ induced local losses of species, a net decline in forest biomass and local diversity can be expected (e.g., 7 ‑ 11% increase in global forest carbon under perfect migration; 3 ‑ 4% decline under zero migration [Solomon & Kirilenko 1997]) natural migration is especially important in situations where natural regeneration is used as a management tool artificial migration (e.g., planting) not useful for great majority of forest species (In this sense, the conservation of biological diversity as a goal in sustainable forest management could be threatened by climate change) planting has not been successful in many cases even in the absence of climate change

12 Current area (a+b) vs. future area (b only) S A Implications of habitat loss for species diversity: no migration scenario

13 Area Percent area under 2xCO 2 Percent species loss Tundra Taiga/Tundra Boreal Conifer Forest Temperate Evergreen Forest Temperate Mixed Forest Tropical Broadleaf Forest Savanna/Woodland Shrub/Woodland Grassland Arid Lands Implications of habitat loss for species diversity: no migration scenario

14 Migration rate= distance time period How do future rates compare with past rates?

15 Rarely observed How do future rates compare with past rates?

16 Finland (1 st place): 59.9% Canada (8 th ): 33.1% U.K. (13 th ): 29.8% Percent of 14 models showing “high” rates (>1,000 m/yr):

17 Future rates compared with Spruce post-glacial rates:

18 Making future rates agree with post-glacial rates:

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20 Shortest distance (crowfly) Shortest terrestrial path (Dijstra's algorithm) Shortest terrestrial path (plus development) Barriers to migration

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23 Current range (black line) and potential future range (CCC) Colonized future range assuming post-glacial capabilities Iverson, Schwartz, and Prasad (in prep.) Southern Red Oak

24 Climate Scenario Prob. Coloniz.S. Red OakSourwoodSweetgumPersimmonLoblolly CCC>2% CCC>20% CCC>50% HAD>2% HAD>20% HAD>50% Percentage of new suitable habitat colonized in 100 yrs assuming postglacial migration rates

25 Conclusions: Potential migration rates appear to be unprecedented by historical standards Less vigorous, lower biomass “weedy” forests, with lower diversity Most important strategy is to reduce emissions: not clear that “adaptation” per se is viable (clearly not in the arctic) Potentially greater economic impacts where reliance on natural regeneration is higher and adaptive responses are more limited (e.g., Canada vs. United States) Focus on facilitating migration (which is intrinsically limited) by maintaining and restoring functional connectivity in landscapes

26 Central Labrador

27 Current ( ) and future ( ) Potential migration contribution of current populations to new distribution (average distance to new distribution) Sugar Maple: facilitating natural migration

28 i j ΣΣ p ij

29 Conclusions: Potential migration rates appear to be unprecedented by historical standards Less vigorous, lower biomass “weedy” forests, with lower diversity Most important strategy is to reduce emissions: not clear that “adaptation” per se is viable (clearly not in the arctic) Potentially greater economic impacts where reliance on natural regeneration is higher and adaptive responses are more limited (e.g., Canada vs. United States) Focus on facilitating migration (which is intrinsically limited) by maintaining and restoring functional connectivity in landscapes Research focus on more than just carbon (regional climate models, comprehensive information on tree and other species distributions, correlative and process-based approaches) Wake-up call for the forest industry, which is geared towards harvesting of primary forests


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