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:
1) seed dispersal2) seedling establishment
Tundra to Forest Transition
Once established, infilling of tundra by spruce is also a two-step process consisting of:
1) tree growth2) colonization from within
a pixel and/or from neighboring white spruce pixels
Photo: T. Jorgenson
Tundra to Forest Transition
Tundra to Forest Transition
Tundra to Forest Transition
If a fire occurred in the past 3 years, 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)
Tundra to Forest Transition
Tundra to Forest Transition
Tundra to Forest Transition