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  1. Northern Tree Habitats - Geophysical Institute

    Jan 22, 2026 · Interior Alaskan forests have only six native tree species: white spruce, black spruce, quaking aspen, balsam poplar, larch (tamarack) and paper birch. Northern Canadian forests have all …

  2. More on Why Tree Trunks Spiral | Geophysical Institute

    Jan 22, 2026 · I eventually found a tree with a spiral lightning mark and it followed the spiral grain exactly. One tree, of course, proves nothing. "But why should the tree spiral? More speculation here: …

  3. Cottonwood and Balsam Poplar | Geophysical Institute

    Dec 18, 2025 · The Klukwan giant holds the national record for black cottonwood diameter. Its nearest rival, a tree near Salem, Oregon, does hold the national height record. The Klukwan giant belies the …

  4. Tree Rings and History | Geophysical Institute

    Jan 22, 2026 · A tree's age can be easily determined by counting its growth rings, as any Boy or Girl Scout knows. Annually, the tree adds new layers of wood which thicken during the growing season …

  5. Feltleaf willows: Alaska’s most abundant tree | Geophysical Institute

    May 25, 2023 · The most plentiful moose food in the state — and probably Alaska’s most numerous tree — is the feltleaf willow, which was once called the Alaska willow. As its name implies, the feltleaf …

  6. Skinny Trees and Paleoforests - Geophysical Institute

    Jun 20, 1990 · However, a tree growing in the long-gone warm Arctic wouldn't look like a tree growing in the ancient temperate zone. Even then, a high-latitude tree would probably be skinny, like the …

  7. Boreal owls perform by daylight | Geophysical Institute

    Mar 20, 2024 · The late biologist Dave Klein attached the nest box to a black spruce tree north of the University of Alaska Fairbanks ski trails many years ago. In search of a mate, the owl sings his …

  8. Trees as Earthquake Fault Indicators | Geophysical Institute

    Dec 18, 2025 · Then using tree ring dating methods, it may be possible to date earthquakes occurring before historical records were kept. The ability to identify and date very large earthquakes occurring …

  9. Tree line changes on the Kenai Peninsula | Geophysical Institute

    Feb 6, 2008 · The gradual change in tree line is one of many that people have noticed on the Kenai Peninsula in recent years. The most obvious is the 1980s-to-1990s Spruce bark beetle invasion, …

  10. The largest black spruce in Alaska | Geophysical Institute

    Aug 16, 2010 · The tree leans uphill, and its trunk is 45 inches around. When I hugged it, I could barely clasp my hands together. The largest black spruce in Alaska is a lucky tree, because its neighbors to …