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Tundra to forest transitions in ALFRESCO. ALFRESCO 1.0. ALFRESCO 2.0. Tundra to Forest Transition. Tundra to Forest Transition. Colonization of tundra by spruce is a two- step process consisting of: seed dispersal
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Tundra to Forest Transition Colonization of tundra by spruce is a two-step process consisting of: • seed dispersal • seedling establishment
Photo: T. Jorgenson Tundra to Forest Transition Once established, infilling of tundra by spruce is also a two-step process consisting of: • tree growth • colonization from within a pixel and/or from neighboring white spruce pixels
Tundra to Forest Transition • If a fire occurred in the past3years, modify seed:seedling ratio by severity: • Low, moderate & high canopy, low surface set to 1:50 • High canopy, high surface set to 1:10(Johnstone & Chapin 2006) • All else in undisturbed tundra set to 1:10 (Hobbie & Chapin 1998)