The Ecology of Maine’s Oldest Forests

NEW ENGLAND FORESTRY FOUNDATION • July 29, 2026

Late-successional and old-growth (LSOG) forests are the oldest natural forests left in New England’s forested landscapes, both managed and unmanaged. These are areas dominated by trees greater than 150 years in age, but they contain the mixture of tree generations — from new seedlings to maturing timber through to huge old veteran trees — that foresters call “uneven aged.” If all the LSOG forests of Maine were harvested and transformed into younger forests, the bird and mammal species would be greatly dimmed. Thus, maintaining some unaltered LSOG forests in the landscape is a crucial element of biodiversity conservation.